Note: Descriptions are shown in the official language in which they were submitted.
CA Application
Blakes Ref.: 23211/00001
- 1 -
Device and method for selectively carrying out nuclide activations and
measurements in
a nuclear reactor by means of nuclide activation targets and measuring bodies
The present invention relates to a device for selectively transferring nuclide
activation targets and
measuring bodies into and out of an instrumentation finger of a nuclear
reactor. The invention
further relates to a method for activating nuclide activation targets and
optionally for energetically
exciting measuring bodies in an instrumentation finger of a nuclear reactor
using such a device.
Radionuclides are used in many fields of technology and medicine, especially
in nuclear medicine.
To generate radionuclides, typically correspondingly suitable stable nuclides
are irradiated with
neutrons. As a result, by virtue of neutron capture, unstable nuclides are
formed which are
converted into stable nuclides again via radioactive decay chains, with
emission of alpha, beta,
gamma or proton radiation. The irradiation with neutrons, also referred to as
nuclide activation,
generally takes place in research reactors which, however, are in most cases
limited in respect
of their capacity for mass production of radionuclides. Alternatively it has
been proposed that
commercial nuclear reactors used for generating energy be employed as a source
of neutrons for
radionuclide production. One approach being considered for that purpose is to
introduce what are
known as nuclide activation targets into one or more instrumentation fingers
of a commercial
nuclear reactor in order for them to be activated therein by the radiation
emitted by the nuclear
fuel rods. EP 2 093 773 A2 and US 2013/0170927 Al disclose corresponding
devices and
methods for introducing nuclide activation targets into a nuclear reactor and
removing them
therefrom.
The instrumentation fingers used for receiving the targets are usually
existing tubes which run
parallel to the nuclear fuel rods inside the reactor core and are in most
cases part of what is known
as an "aeroball" measuring system for determining the power density
distribution in the reactor
core. In such a system, measuring balls containing activatable matter, for
example of vanadium,
are introduced into the instrumentation fingers of the reactor core for the
purpose of irradiating
measuring bodies. Because their diameter is only very slightly smaller than
that of the
instrumentation finger, the balls lie chain-like immediately one next to the
other or one on top of
the other in the fingers. The balls are activated by the radiation emitted by
the nuclear fuel rods
23892585i
Date Recue/Date Received 2020-04-23
CA Application
Blakes Ref.: 23211/00001
- 2 -
and, after a predetermined dwell time, are transported via a line system out
of the reactor core
region into a measuring device, what is known as the measuring table, for the
purpose of
determining their activity. The line system, including the instrumentation
fingers, is self-contained
and has a diameter in the region of the ball diameter, so that the sequence of
the chain of balls
in the instrumentation finger is retained on transfer to the measuring table.
In that way the balls
in the chain may be assigned a respective longitudinal position of the nuclear
fuel rods, this in
turn allowing conclusions to be drawn as to the axial power density
distribution of the neutron flux
in the reactor core. Such a measuring system, also known as an aeroball
measuring system,
having a measuring device and a corresponding line system is known, for
example, from
US 3 711 714. The findings obtained by means of the ball measurement serve for
reactor safety
and are therefore usually mandatory at regular time intervals. In principle,
other measuring
systems using instrumentation fingers and corresponding measuring bodies are
also known and
are used for measurement of other properties of the measuring bodies that are
variable by
energetic excitation in the nuclear reactor, which properties characterise the
properties of the fuel
rods and the conditions in the interior of the reactor core.
While the measuring bodies for energetic excitation for the purpose of
determining a specific
property of the fuel rods or the conditions in the interior of the reactor
core, for example for
determining the power density distribution, remain in the instrumentation
finger for only a few
minutes, it requires several days or weeks for sufficient nuclide activation
of the targets. During
that time, in the case of the nuclide activation systems proposed hitherto the
instrumentation
fingers used for radionuclide production are not available for a measurement.
In addition, the
nuclide activation systems proposed hitherto require the respective
instrumentation finger to be
uncoupled from the measuring system and recoupled to the nuclide activation
system and back
again. Changing between nuclide activation and measurement is therefore
possible only with an
increased level of technical complexity and, in addition, harbours the risk of
additional
contamination being brought about by the uncoupling and recoupling. Both are
contributing
factors to why the implementation of a nuclide activation system in a
commercial nuclear reactor
has met with little acceptance hitherto.
23892585i
Date Recue/Date Received 2020-04-23
CA Application
Blakes Ref.: 23211/00001
- 3 -
The problem of the present invention is therefore to provide a device and a
method which, on the
one hand, enable the instrumentation fingers of a nuclear reactor to be
utilised for target activation
in a technically acceptable way but, on the other hand, allow a measurement,
for example an
aeroball measurement for determining the power density distribution or the
neutron flux in the
reactor core, to be carried out at any time.
That problem is solved by a device for selectively transferring nuclide
activation targets and
measuring bodies into and out of an instrumentation finger of a nuclear
reactor and by a method
for activating nuclide activation targets and optionally for energetically
exciting measuring bodies
in an instrumentation finger of a nuclear reactor using such a device.
Advantageous embodiments
of the invention are subject-matter of the dependent claims.
According to the invention the device comprises a line system for receiving
and transporting the
measuring balls and targets, which line system comprises a plurality of line
branches which
connect into a multi-way valve and which may be brought selectively into
fluidic connection with
one another via the switchable multi-way valve. According to the invention the
line system
comprises at least one reactor branch having a terminal coupling for coupling
the line system to
the instrumentation finger, a storage branch for intermediate storage of the
measuring bodies or
targets, and a measuring branch having a terminal coupling for coupling the
line system to a
measuring device for determining a property of the measuring bodies that is
variable by energetic
excitation in the nuclear reactor. At least the reactor branch, the storage
branch and the
measuring branch connect node-like into the multi-way valve of the device. The
switchable multi-
way valve is configured, in a first switch position, to fluidically connect
the reactor branch to the
storage branch and, in a second switch position, to fluidically connect the
reactor branch to the
measuring branch. The device further comprises a pneumatic or mechanical
transport device for
transporting the measuring bodies and targets through the device. The line
system and the multi-
way valve are especially fluid- and solid-conducting.
According to the invention it has been found that by the provision of a
storage branch in the line
system it is possible for the first time to interrupt an ongoing target
activation process at any time
23892585i
Date recue/ date received 2022-02-18
CA Application
Blakes Ref.: 23211/00001
- 4 -
for the purpose of a prioritised measurement and to temporarily park, that is
to say intermediately
store, the partly irradiated nuclide activation targets in the storage branch
in order that the
instrumentation finger used for the activation is thus made available for a
short time for a
prioritised measurement, for example an aeroball measurement for determining
the power
density, and the instrumentation finger subsequently filled with the
intermediately stored targets
again to continue the activation process. Accordingly it is therefore
advantageously possible for
the instrumentation finger to be capable of flexible, that is to say multiple,
use and especially to
be available at any time for a measurement when such a measurement is
necessary in
accordance with the operational regulations of the nuclear reactor. As a
result it is therefore
possible, on the one hand, to ensure operational safety and, on the other
hand, additionally to
employ the otherwise unutilised instrumentation finger commercially for the
production of radio-
nuclides. The resulting potential for additionally exploiting the nuclear
reactor is obvious when
one considers that most prescribed measurements, for example aeroball
measurements for
determining the power density, do not have to be carried out every day and
corresponding
measuring bodies for that purpose are typically present in the instrumentation
finger for only a
few minutes. For the remainder of the time, the instrumentation finger is
freely available for nuclide
activation.
Preferably the length of the storage branch corresponds at least to the length
of the
instrumentation finger, so that the maximum possible amount of targets,
corresponding to the
length of the instrumentation finger, may be intermediately parked in the
storage branch.
According to an advantageous embodiment, the length of the storage branch is
at least 5 m,
especially at least 10 m, preferably at least 30 m. Furthermore, the storage
branch preferably
comprises a substantially rectilinear, especially substantially horizontally
aligned section.
Alternatively the storage branch may, at least in some sections, be of spiral
construction, which
results in an especially space-saving embodiment.
In addition, the possibility, provided by the invention, of being able to
interrupt a nuclide activation
process at any time and briefly carry out a measurement, has the advantageous
result that a
plurality, especially in principle all, of the instrumentation fingers present
in a nuclear reactor may
be used for radionuclide production, while respecting the operational safety
regulations. For that
23892585i
Date Recue/Date Received 2020-04-23
CA Application
Blakes Ref.: 23211/00001
- 5 -
purpose, it is possible for some or all of the instrumentation fingers of a
nuclear reactor to be
equipped with a device according to the invention or for the device according
to the invention to
be configured to serve a plurality of instrumentation fingers, that is to say
to selectively transfer
nuclide activation targets and measuring bodies into and out of a plurality of
instrumentation
fingers of a nuclear reactor.
Once the device according to the invention has been implemented, the
switchable multi-way valve
makes it possible ¨ in a technically very simple way, during ongoing operation
of the reactor ¨ to
switch over between the production of radionuclides and a measurement by means
of measuring
bodies, without further modification of the system, especially without opening
of the closed line
system. As a result, the risk of contamination is advantageously reduced to a
minimum. In that
respect the switchable multi-way valve serves as a diverter for clearing or
blocking the various
transport paths between the different branches.
To interrupt the target activation and make the instrumentation finger
available, the targets
previously introduced into the instrumentation finger via the line system are
removed from the
instrumentation finger via the reactor branch and transferred to the storage
branch. For that
purpose the multi-way valve is in the first switch position, so that the
reactor branch is in fluidic
connection with the storage branch. The multi-way valve is then switched into
the second switch
position in order to fluidically connect the reactor branch to the measuring
branch and accordingly
the instrumentation finger to the measuring device in which the measuring
bodies are typically
located in preparation for a measurement. The measuring balls are then
transferred from the
measuring device via the measuring branch, the multi-way valve and the reactor
branch to the
instrumentation finger of the nuclear reactor. After a dwell time of a few
minutes, the measuring
bodies are transferred from the instrumentation finger to the measuring device
again via the same
route, that is to say via the reactor branch, the multi-way valve and the
measuring branch. In the
measuring device it is possible to determine the property of the measuring
bodies that is variable
by energetic excitation, for example the activity of the irradiated measuring
bodies for the purpose
of determining the power density distribution of the neutron flux in the
reactor core. As soon as
the measuring bodies have been transferred into the measuring device, the
instrumentation finger
is available for nuclide activation again. The multi-way valve is switched
into the first switch
23892585i
Date Recue/Date Received 2020-04-23
CA Application
Blakes Ref.: 23211/00001
- 6 -
position again and the partly irradiated targets are transferred from the
storage branch via the
multi-way valve and the reactor branch back into the instrumentation finger in
order thus to
continue or conclude the target activation process. Advantageously the
activation process may in
principle be repeatedly interrupted for a measurement, that is to say as often
as desired.
Once the activation process is complete, the irradiated targets
(radionuclides) may be removed
from the instrumentation finger via the line system for their intended use.
For that purpose, for
example, the storage branch may comprise a terminal coupling for coupling the
line system to a
removal vessel for irradiated targets. Preferably, however, the line system
comprises a separate
removal branch having a terminal coupling for coupling the line system to a
removal vessel for
irradiated targets. The removal branch may, for example, be connected
terminally to the storage
branch, that is to say at the end of the storage branch opposite to the end
that connects into the
multi-way valve. In such a configuration the device may comprise a stop, for
example a magnetic
stop, which is movable into and out of the transport path between the storage
branch and the
removal branch to block the transport path between the storage branch and the
removal branch.
It can thus be ensured that targets or measuring bodies are held back in the
storage branch during
intermediate parking and do not pass further into the removal branch. In both
variants (removal
via the storage branch or via the removal branch terminally connected to the
storage branch) the
multi-way valve is of technically simple construction, for example in the form
of a 3/2-way valve,
especially having only one switchable through-channel.
Alternatively the removal branch may connect directly into the switchable
multi-way valve. In such
a configuration the multi-way valve is further configured, in a third switch
position, to fluidically
connect the removal branch to the reactor branch or the removal branch to the
storage branch.
In the first variant (removal branch is connected to the reactor branch in the
third switch position)
the irradiated targets may advantageously be transferred by a direct route
from the
instrumentation finger via the reactor branch, the multi-way valve and the
removal branch directly
into a removal vessel for irradiated targets. This provides a very quick and,
in procedural terms,
very simple removal process. The second variant (removal branch is connected
to the storage
branch in the third switch position) allows the realisation of a technically
simple multi-way valve,
for example in the form of a 4/3-way valve, especially having only one
switchable through-
23892585.1
Date Recue/Date Received 2020-04-23
CA Application
Blakes Ref.: 23211/00001
- 7 -
channel.
The measuring device is configured for measuring at least one property of the
measuring bodies
that is variable by energetic excitation in the nuclear reactor, that is to
say a property of the
measuring bodies that can be influenced, for example, by excitation by means
of, or by the effect
of, radiation energy or thermal energy in the instrumentation finger of the
nuclear reactor. The
variable property of the measuring bodies may especially be a radiation-
dependent or
temperature-dependent property. Furthermore, the measuring device may be
configured to
determine, on the basis of the measurement of the variable property of the
measuring bodies,
one or more parameters which characterise the properties of the fuel rods
and/or the conditions
in the interior of the reactor core. For example, the measuring device may be
configured especially
for measuring the activity of the measuring bodies brought about by
irradiation. Furthermore, the
measuring device may be configured for determining the power density
distribution or the neutron
flux in the reactor core on the basis of the measured activity of the
measuring bodies. Alternatively
or in addition, the measuring device may be configured for determining a
temperature-dependent
colour change, i.e. a colour change brought about by thermal energy. The
determination of the
colour change may be used, for example, to determine the temperature in the
nuclear reactor.
The measuring bodies and/or nuclide activation targets are preferably balls or
ball-shaped.
Another possibility, however, is for the measuring bodies and/or nuclide
activation targets to have
other shapes, for example cylindrical or ellipsoidal. The shape is chosen so
that the measuring
bodies and/or nuclide activation targets may be transported unimpeded through
the line system
and the instrumentation finger. The diameter of the measuring bodies and/or
nuclide activation
targets is preferably only very slightly smaller than the diameter of the line
system and the
instrumentation finger. According to an advantageous embodiment of the
invention, the diameter
of the measuring bodies and/or nuclide activation targets is in the range of
from 50% to 99%,
especially in the range of from 70% to 95%, preferably in the range of from
80% to 95%, of the
diameter of the line system and/or the instrumentation finger. According to an
advantageous
embodiment of the invention, the diameter of the measuring bodies and/or
nuclide activation
targets is between 1 mm and 3 mm, especially between 1.2 mm and 2 mm,
preferably 1.5 mm
and 1.7 mm.
23892585i
Date Recue/Date Received 2020-04-23
CA Application
Blakes Ref.: 23211/00001
- 8 -
To operate the device, the measuring branch and the reactor branch are coupled
via their
respective terminal couplings to a measuring device and to an instrumentation
finger of the
nuclear reactor, respectively. The coupling of the reactor branch to the
instrumentation finger of
the reactor may especially be effected in the region of what is known as a
cable bridge above the
reactor vessel. In the end region in front of the coupling, the reactor branch
may further comprise
a blocking device, for example a magnetically operable stop, for example a
pin, peg or bolt, which
is especially movable into and out of the reactor branch to block the
transport path through the
reactor branch. The couplings are preferably configured for gas-tight coupling
to the measuring
device and the instrumentation finger in order, in the case of a pneumatic
transport device, to
ensure reliable transport of the targets and measuring bodies by means of
transport gas.
Another possibility is for the reactor branch to be ramified, especially
ramified cascade-like, in
order thus to connect some or all of the instrumentation fingers of a nuclear
reactor to the device
according to the invention via a respective limbs of the reactor branch. This
especially allows
some or all of the instrumentation fingers of a nuclear reactor to be operated
or used with only
one device according to the invention. Each limb of the reactor branch may
comprise a terminal
coupling for coupling the respective limb to an instrumentation finger of the
reactor. On the
ramifications of the reactor branch the device may comprise distributor valves
by which the limbs
of the reactor branch that lead out from a ramification in the direction of
the instrumentation finger
are selectively connected to the multi-way valve or to a multi-way-valve-side
section of the reactor
branch.
The terminal couplings of the reactor branch, of the measuring branch and ¨ as
described
hereinbelow ¨ optionally of a removal branch and an introduction branch are
preferably arranged
at the free ends of the respective branches, that is to say at the ends of the
branches opposite to
the ends that connect into the multi-way valve.
Like the reactor branch and the measuring branch, the removal branch may also
comprise a
terminal coupling for coupling, especially gas-tight coupling, to a removal
vessel for irradiated
targets. For the removal of the irradiated targets, the removal branch may be
correspondingly
coupled via its terminal coupling to a removal vessel. Alternatively, the
removal of the targets may
23892585i
Date Recue/Date Received 2020-04-23
CA Application
Blakes Ref.: 23211/00001
- 9 -
also be effected without direct coupling of the removal branch to a removal
vessel. In particular,
the transfer of the targets from the removal branch to a removal vessel may be
effected
exclusively under the force of gravity, especially without transport gas.
Preferably the device
comprises a shut-off valve in the removal branch, especially in the region of
the free end of the
removal branch, for gas-tight shutting-off of the removal branch with respect
to the environment.
This advantageously minimises the risk of contamination.
In addition, according to an advantageous embodiment of the invention the
device may comprise
an introduction branch with a terminal coupling for coupling, especially gas-
tight coupling, to an
introduction device which is configured for introducing unirradiated targets
into the line system.
The introduction device may be, for example, a container, for example a
cartridge, or a funnel in
which unirradiated targets are located. The introduction device preferably
comprises an outlet for
introducing the targets into the introduction branch, to which outlet the
terminal coupling of the
introduction branch is couplable. The introduction of the targets into the
introduction branch may
be effected (exclusively) under the force of gravity, by means of transport
gas or by means of
mechanical transport means.
The introduction branch may connect into the line system at any desired
location, especially into
a node of the line system. Preferably the introduction branch connects into
the multi-way valve.
In such a configuration the multi-way valve is preferably additionally
configured, in a fifth switch
position, to fluidically connect the introduction branch to the reactor branch
or to the storage
branch. If the multi-way valve connects the introduction branch to the reactor
branch, the
unirradiated targets may be introduced directly from the introduction device
via the introduction
branch, the multi-way valve and the reactor branch into the instrumentation
finger. The filling
operation thus becomes especially effective. Conversely, the multi-way valve
may be realised in
a technically simpler way if it is configured to fluidically connect the
introduction branch to the
storage branch. As in the removal branch, the device also comprises a shut-off
valve in the
introduction branch, especially in the region of the free end of the
introduction branch, for gas-
tight shutting-off of the introduction branch with respect to the environment.
This advantageously
minimises the risk of contamination.
23892585i
Date Recue/Date Received 2020-04-23
CA Application
Blakes Ref.: 23211/00001
- 10 -
According to an especially advantageous embodiment of the invention, the
removal branch may
also serve as introduction branch. In such a configuration the removal branch
may be configured
for coupling selectively to an introduction device or to a removal vessel in
order either to introduce
unirradiated targets into the line system or to transfer irradiated targets
from the line system to a
removal vessel. This is possible both when the removal branch is connected
terminally to the
storage branch and when the removal branch, as a separate branch, connects
directly into the
multi-way valve or into some other node of the line system.
According to a further advantageous embodiment, the storage branch may also
serve as
introduction branch and/or removal branch. In particular, the storage branch
may be configured
for coupling to an introduction device or selectively to an introduction
device and to a removal
vessel in order either to introduce unirradiated targets into the line system
or to transfer irradiated
targets from the line system to a removal vessel. For that purpose the storage
branch may
comprise a correspondingly constructed coupling at one end. For example, for
introducing
unirradiated targets or removing irradiated targets the storage branch may
comprise, at its end
remote from the multi-way valve, a terminal coupling for coupling, especially
selective coupling,
to an introduction device and/or to a removal device. The introduction device
and the removal
device may especially be realised together by a combined introduction/removal
device. The
introduction device and/or the removal device or the combined
introduction/removal device may
comprise a transfer vessel, especially a shielding transfer vessel. In the end
region in front of the
coupling the storage branch may further comprise a blocking device, for
example a magnetically
operable stop, for example a pin, peg or bolt, which is especially movable
into and out of the
storage branch to block the transport path through the storage branch.
According to an advantageous embodiment of the invention, the device comprises
a shield
against ionising radiation, at least along a section of the storage branch.
This increases radiation
safety. Preferably the shield is a lead shield. Especially preferably the
length of the shield along
the storage branch, i.e. the shielded section of the storage branch,
corresponds at least to the
length of the instrumentation finger, so that the maximum possible length of
the target chain,
corresponding to the length of the instrumentation finger, may be
intermediately parked in the
storage branch under shielded conditions. According to an advantageous
embodiment, the length
23892585i
Date Recue/Date Received 2020-04-23
CA Application
Blakes Ref.: 23211/00001
- 11 -
of the shielded section of the storage branch is at least 2 m, especially at
least 4 m, preferably at
least 5 m. Preferably the shielded section of the storage branch is
substantially rectilinear,
especially substantially horizontally aligned. Alternatively the shielded
section may be of spiral
construction, which results in an especially space-saving embodiment.
According to a further advantageous embodiment of the invention, the multi-way
valve may further
be configured, in a fourth switch position, to fluidically connect the storage
branch to the
measuring table branch. As a result, during those periods in which no
measurement is being
carried out the measuring bodies may advantageously be intermediately parked
in the storage
branch, preferably under shielded conditions. In this way, the radiation
safety of the entire device
is likewise increased, especially if the shielding of the storage branch is
more effective than any
shielding of the measuring device. In addition, as a result of the
intermediate storage of the
measuring body, the detectors in the measuring device, which are in most cases
radiation-
sensitive, are protected from excessive or unnecessary action of radiation and
accordingly, for
example, from undesirable ageing.
Another possibility is for the device to have a parking section in the
measuring branch for
intermediate parking of the measuring bodies or targets. Preferably the device
comprises a shield
against ionising radiation, at least along a section of the measuring branch,
especially along the
parking section. This provides inter alia an alternative way of intermediately
parking the measuring
bodies in the parking section of the measuring branch, preferably under
shielded conditions,
during those periods in which no measurement is being carried out. In an end
region of the parking
section remote from the multi-way valve and/or in an end region of the parking
section facing
towards the multi-way valve, the measuring branch may (in each case) further
comprise a
blocking device, for example a magnetically operable stop, for example a pin,
peg or bolt, which
is especially movable into and out of the measuring branch to block the
transport path through
the measuring branch. As an alternative to the blocking device, the measuring
branch may
comprise at least one holding magnet in at least one of the mentioned end
regions of the parking
section, for example at least one electromagnet or at least one switchable or
slidably arranged
permanent magnet. The measuring bodies, which are preferably magnetic, can
thereby be held
in place in the parking branch.
23892585i
Date Recue/Date Received 2020-04-23
CA Application
Blakes Ref.: 23211/00001
- 12 -
The fluidic connections established between the various branches of the line
system by the multi-
way valve are preferably formed by one or more through-channels in the multi-
way valve. For that
purpose, the multi-way valve may comprise at least one movable, especially
displaceable or
rotatable, control element through which the one or more through-channels
extend. In the different
switch positions, the one or more through-channels connect corresponding ports
of the multi-way
valve at which the branches of the line system connect into the multi-way
valve. The multi-way
valve may especially comprise a valve body which comprises the ports and in
which the at least
one movable, especially displaceable or rotatable, control element is
accommodated, especially
mounted. Furthermore, the multi-way valve may comprise an actuator, for
example a servomotor,
by means of which the movable, especially displaceable or rotatable, control
element may be
moved into the various switch positions.
According to an advantageous embodiment of the invention, the multi-way valve
is especially in
the form of a (multi-way) rotary valve or (multi-way) rotary control valve or
(multi-way) slide valve.
For example, the multi-way valve may be in the form of a (multi-way) ball
valve or (multi-way) plug
valve.
As a rotary valve, the multi-way valve may, for example, comprise a control
element which is
sealingly rotatably mounted in a valve body. The valve body comprises at least
three, especially
at least four, preferably at least five, especially preferably six or more,
ports. The at least three,
especially at least four, preferably at least five, especially preferably six
or more, ports are
preferably arranged uniformly distributed around the circumference in respect
of the valve body.
The number of ports is dependent upon the diameter of the multi-way valve and
may be increased
with increasing diameter. Via the at least three, especially at least four,
preferably at least five,
especially preferably six or more, ports, at least the reactor branch, the
measuring branch and
the storage branch and optionally the removal branch, the introduction branch
and/or an exhaust
gas line (as described hereinbelow) connect into the multi-way valve. The
rotatable control
element comprises at least one, especially at least two, preferably three or
even more than three
through-channels in order, in at least the first and second switch positions
of the control element,
to fluidically connect the reactor branch to the measuring branch or the
reactor branch to the
storage branch. In order additionally to realise one or more of the further
switch positions
23892585i
Date Recue/Date Received 2020-04-23
CA Application
Blakes Ref.: 23211/00001
- 13 -
described herein (third, fourth, fifth, sixth and/or seventh switch
position(s)), the rotatable control
element preferably comprises at least two, preferably three or more, through-
channels. In a
technically especially simple realisation, the multi-way valve is in the form
of a 3/2-way valve,
especially in the form of a 3/2-way rotary valve. Alternatively the multi-way
valve may be in the
form of a 3/3-way, 4/3-way, 4/4-way, 5/4-way, 5/5-way, 6/5-way, 6/6-way or 6/7-
way valve.
For example, the multi-way valve may be in the form of a rotary valve having a
rotatable control
element, the rotatable control element having at least a first, a second and a
third through-
channel, which channels run through the control element perpendicularly to a
rotational axis of
the rotatable control element. The first through-channel may run in a straight
line through the
rotational axis of the control element, especially in order to connect two
ports that are located 1800
opposite one another. The second through-channel may run through the control
element in a 120
arc offset symmetrically with respect to the first through-channel, especially
to connect two ports
that are arranged offset with respect to one another on the circumference by
120 . The third
through-channel may be constructed in the same way as the second through-
channel and may
run through the control element, in respect of the first through-channel,
mirror-symmetrically with
respect to the second through-channel. Alternatively the third through-channel
may run secant-
like through the control channel, especially in a straight line or curved,
especially offset
asymmetrically with respect to the first through-channel opposite to the
second through-channel,
in order to connect two ports that are arranged offset with respect to one
another on the
circumference by 60 . Preferably such a through-channel serves solely for
fluidic connection of
two ports, especially for connection of the reactor branch to an exhaust gas
line (as described
hereinbelow). Another possibility is for the rotary valve described above by
way of example to
have no third through-channel but instead only the rectilinear first through-
channel and the second
through-channel running in a 120 arc. According to another example, the multi-
way valve in the
form of a rotary valve may comprise a control element having at least one,
especially just one,
through-channel which runs through the control element in a 90 or 120 arc,
especially to connect
two ports that are arranged offset with respect to one another on the
circumference by 90 or 120 .
Another possibility is for the multi-way valve to be constructed in the form
of a rotary valve having
a valve body and a rotatable control element, the valve body having at least
six, especially just
six, ports and the rotatable control element having at least a first and a
second through-channel
23892585i
Date Recue/Date Received 2020-04-23
CA Application
Blakes Ref.: 23211/00001
- 14 -
which each run in a 1200 arc and are arranged mirror-symmetrically with
respect to one another.
Such an embodiment may especially be used to serve two instrumentation fingers
with one multi-
way valve. For that purpose, two reactor branches, two storage branches and
two measuring
branches may connect into the multi-way valve, preferably at respective
oppositely located ports,
with one reactor branch, one storage branch and one measuring branch being
associated with
each of the instrumentation fingers. In different switch positions, the multi-
way valve connects a
reactor branch to an associated storage branch or to an associated measuring
branch. In that
respect the reactor branch, measuring branch and storage branch associated
with each of the
instrumentation fingers form a sub-line system.
According to an advantageous embodiment of the invention, the multi-way valve
comprises at
least one actuator, especially a pneumatic or electric actuator, for example a
servomotor, for
operating the at least one movable control element. Especially preferably, the
actuator may be
configured for simultaneously operating a plurality of multi-way valves, for
example if a plurality
.. of instrumentation fingers of a nuclear reactor are each equipped or
operated with a device
according to the invention. For example, a plurality of multi-way valves, for
example three multi-
way valves in the form of rotary valves, may be in operative connection with a
common shaft
which is driven by a common actuator. In particular, the rotatable control
elements of a plurality
of multi-way valves that are in the form of rotary valves may be arranged on a
common shaft.
According to the invention, the transport device may be in the form of a
pneumatic transport device
or in the form of a mechanical transport device. In the case of a pneumatic
transport device,
transport gas, for example compressed air or nitrogen, serves as transport
means for conveying
the targets through the line system, into and out of the instrumentation
finger and preferably into
and out of a measuring device and/or an introduction device and optionally
into a removal vessel.
In the case of a mechanical transport device, a mechanical conveyor means, for
example one or
more flexible pressure-transmitting elements, for example cables, wires,
chains or the like, serves
to mechanically push the targets and measuring bodies through the line system,
into and out of
the instrumentation finger and preferably into and out of a measuring device
and/or an introduction
device and optionally into a removal vessel. A mechanical conveyor device as
known from
EP 2 093 773 A2 is also a possibility.
23892585i
Date Recue/Date Received 2020-04-23
CA Application
Blakes Ref.: 23211/00001
- 15 -
Preferably the transport device is in the form of a pneumatic transport
device. According to an
advantageous embodiment of the invention, the pneumatic transport device
comprises a first
transport gas line which, for pneumatic transportation of the measuring bodies
and targets out of
the storage branch in the direction of the multi-way valve, is terminally
coupled to the storage
branch. Furthermore, the pneumatic transport device may comprise a second
transport gas line
which, for pneumatic transportation of the measuring bodies and targets out of
the instrumentation
finger via the reactor branch in the direction of the multi-way valve, is
couplable to the
instrumentation finger. In addition, the pneumatic transport device may
comprise a third transport
gas line which, for pneumatic transportation of the measuring bodies and
targets out of the
measuring device via the measuring branch in the direction of the multi-way
valve, is couplable
to the measuring device. For pneumatic transportation of the targets from the
introduction device
into the line system, especially into an introduction branch, the pneumatic
transport device may
additionally comprise a fourth transport gas line which for that purpose is
couplable to the
introduction device.
The various transport gas lines may all be connected to a common transport gas
source.
Compressed air or nitrogen especially come into consideration as transport
gas. Preferably the
pneumatic transport device is configured for providing the transport gas at a
pressure in the region
of at least 5 bar, especially at least 8 bar, preferably at least 10 bar,
and/or for conveying the
transport gas through the transport gas lines and the line system.
To reduce pressure in the line system, especially for discharging transport
gas from the storage
branch, from the reactor branch and/or from the measuring branch, according to
a further
advantageous embodiment of the invention the device comprises an exhaust gas
device.
Preferably the exhaust gas device may comprise at least one respective exhaust
gas line which
connects terminally into the storage branch, into the measuring branch and/or
into the reactor
branch. Alternatively or additionally, the exhaust gas device may comprise at
least one respective
exhaust gas line which is couplable to the instrumentation finger and/or to
the measuring device
in order to discharge transport gas during the transfer of targets or
measuring bodies into the
instrumentation finger or into the measuring device. For opening and closing,
one or more of the
gas lines may each be provided with at least one shut-off valve.
23892585i
Date Recue/Date Received 2020-04-23
CA Application
Blakes Ref.: 23211/00001
- 16 -
The respective exhaust gas lines may connect into the first, second, third or
fourth transport gas
lines so that some of the respective transport gas lines are used
bidirectionally both for supplying
and for discharging transport gas.
Furthermore, the exhaust gas device may comprise an exhaust gas line that
connects into the
multi-way valve. In that embodiment of the invention, the multi-way valve may
further be
configured, in a sixth switch position, to fluidically connect the reactor
branch to the exhaust gas
line that connects into the multi-way valve. The exhaust gas line that
connects into the multi-way
valve advantageously serves to discharge transport gas from the reactor branch
when the latter
is not in fluidic connection with any other branch of the line system.
Another possibility is for at least two exhaust gas lines to be combined,
preferably via a multi-way
valve, to form a common exhaust gas line, resulting in an exhaust gas device
having a compact
structure. For example, a plurality of exhaust gas lines that connect into the
second and third
transport lines may be combined via a 3/2- or 3/3-way valve to form a common
exhaust gas line.
In the same way, an exhaust gas line coupled into the first transport gas line
via a 3/2-way valve
for discharging transport gas from the storage branch and an exhaust gas line
that connects into
the multi-way valve may be combined to form a common exhaust gas line.
Downstream the one or more exhaust gas lines or common exhaust gas lines
preferably end in
an exhaust gas filter in order to filter any contaminants out of the transport
gas conducted through
the reactor core.
Preferably the transport gas lines and exhaust gas lines have a smaller
diameter than the
branches of the line system and than the targets and measuring bodies. It is
thereby possible, in
a technically simple way, to prevent targets and/or measuring bodies from
inadvertently passing
into the transport gas lines and/or exhaust gas lines. Preferably the
transport gas lines and
exhaust gas lines have a diameter of at most 1.5 mm. Alternatively the
transport gas lines and
exhaust gas lines may comprise a local tapered portion which has a smaller
diameter than the
branches of the line system and than the targets and measuring bodies. Another
possibility is for
23892585i
Date Recue/Date Received 2020-04-23
CA Application
Blakes Ref.: 23211/00001
- 17 -
fluid-permeable retaining elements, for example screens, grids or nets, to be
arranged in the
transport gas lines and exhaust gas lines to hold back targets and measuring
bodies.
According to a further advantageous embodiment of the invention, the multi-way
valve may further
be configured, in a seventh switch position, to fluidically decouple all
branches of the line system
from one another, that is to say to block all branches for the transport of
targets and/or measuring
bodies. That switch position likewise advantageously increases the operational
safety of the
device.
According to a further advantageous embodiment of the invention, the device is
configured for
pressureless removal of the targets from the line system into a removal vessel
(without pneumatic
conveyance by means of transport gas). For that purpose, the removal branch
may be arranged
in the vertical direction below the multi-way valve and preferably has a
monotonically falling
structure, so that the targets may be transferred exclusively under the force
of gravity via the
multi-way valve through the removal branch to a removal vessel. For the
pressureless, exclusively
gravitation-driven removal of targets, the reactor branch ¨ as described
hereinbelow ¨ preferably
comprises a monotonically falling delivery section which connects directly
into the multi-way valve.
In addition, by virtue of the pressureless removal it is possible to dispense
with transfer gas
discharge in the region of the removal branch or removal vessel, which on the
one hand reduces
technical outlay and on the other hand reduces the risk of contamination.
According to a further advantageous embodiment of the invention, the reactor
branch comprises
a delivery section, especially a monotonically falling delivery section.
Preferably the delivery
section connects directly into the multi-way valve. The delivery section may
be used to separate
nuclide activation targets from what are known as dummy targets or to separate
different target
types in an activation charge from one another. Dummy targets are target
bodies which are
introduced into the instrumentation finger as place-holders together with the
nuclide activation
targets to be irradiated so that, in accordance with the power density
distribution in the reactor,
the targets to be irradiated may be positioned along the instrumentation
finger in the correct
position for the purpose of optimum activation. To remove the irradiated
targets, a chain consisting
of targets and dummy targets conducted out via the reactor branch or a chain
comprising at least
23892585i
Date Recue/Date Received 2020-04-23
CA Application
Blakes Ref.: 23211/00001
- 18 -
two target types may be held intermediately in the delivery section for the
purpose of separation.
Preferably the device comprises a blocking device, for example a switchable
magnetic stop, at
the end of the delivery section that faces towards the multi-way valve in
order to hold back targets,
measuring bodies and/or dummy targets in the direction of the multi-way valve.
The blocking
device may also be realised by the multi-way valve itself.
According to an especially advantageous embodiment of the invention, the
separation of the
dummy targets from the actual targets or the separation of different target
types may be effected
magnetically. For that purpose, the targets or dummies or at least one target
type comprise a
magnetic material. Accordingly the device may comprise, along the delivery
section, at least one
holding magnet, for example at least one electromagnet or at least one
switchable or slidably
arranged permanent magnet. In this way, the activation of the at least one
electromagnet enables
the magnetic target bodies of a target chain intermediately parked in the
delivery section to be
held back, while the non-magnetic target bodies of the target chain may be
transferred to another
region of the line system or out of the line system.
Especially for removing a (sub-)quantity of dummy targets, targets or
measuring bodies that has
been isolated or is to be isolated, according to a further advantageous
embodiment of the
invention the device may comprise an intermediate removal device in the
reactor branch. Such
an intermediate removal device preferably comprises, in the reactor branch, an
intermediate
removal valve into which connect a reactor-side section of the reactor branch,
an intermediate
removal section of the reactor branch extending in the direction of the multi-
way valve, an exhaust
gas line and an intermediate removal branch which forms an additional branch
of the line system.
The intermediate removal valve is configured, in a first switch position, to
fluidically connect the
reactor-side section to the intermediate removal section of the reactor
branch, in a second switch
position the intermediate removal section of the reactor branch to the
intermediate removal
branch, and in a third switch position, for the purpose of reducing pressure,
the intermediate
removal section to the exhaust gas line. Preferably the intermediate removal
valve is further
configured, in a fourth switch position, to close off at least the
intermediate removal section,
preferably also the intermediate removal branch and/or the reactor-side
section.
23892585i
Date Recue/Date Received 2020-04-23
CA Application
Blakes Ref.: 23211/00001
- 19 -
For separating a (sub-)quantity of dummy targets, targets or measuring bodies,
the intermediate
removal section may comprise an apex in the transition between a first and a
second
monotonically falling sub-section of the intermediate removal section, the
first sub-section
connecting into the intermediate removal valve. Preferably the length of the
first sub-section
corresponds to the chain length of the (sub-)quantity of dummy targets,
targets or measuring
bodies to be separated. By transferring the entire target chain into the
intermediate removal
section until it strikes against the (closing-off) intermediate removal valve,
the (sub-)quantity of
dummy targets, targets or measuring bodies to be separated or removed in that
way collect in the
first sub-section, while the (sub-)quantity that is not to be removed is
located on the other side of
the apex in the second sub-section. By switching the intermediate removal
valve into the second
switch position, the (sub-)quantity of dummy targets, targets or measuring
bodies to be isolated
or removed may then be transferred exclusively under the force of gravity into
the intermediate
removal branch, while the (sub-)quantity that is not to be removed remains in
the second sub-
section of the intermediate removal section. For that purpose the intermediate
removal branch is
preferably arranged in the vertical direction below the intermediate removal
valve and preferably,
in addition, comprises a monotonically falling structure at least along a
section leading out of the
intermediate removal valve.
The intermediate removal device described above advantageously makes it
possible to dispense
with dummy targets for the purpose of target positioning in the
instrumentation finger. By means
of the device according to the invention, the instrumentation finger may
instead be filled with
nuclide activation targets over its entire length. Targets which have been
insufficiently activated
on account, especially, of their terminal position in the instrumentation
finger, may be separated
from sufficiently activated targets and separately removed by means of the
intermediate removal
device described above and then introduced into the instrumentation finger
again (preferably at a
different position in the instrumentation finger having a higher power
density) for the purpose of
complete activation. For that purpose the partly activated targets may, for
example, be transferred
via the intermediate removal branch into a receiving vessel which in turn may
be coupled to an
introduction branch of the line system for fresh introduction into the
instrumentation finger.
Alternatively the intermediate removal branch may also be connected to the
introduction branch
by a line.
23892585i
Date Recue/Date Received 2020-04-23
CA Application
Blakes Ref.: 23211/00001
- 20 -
If ¨ as described above ¨ the removal of the targets is effected via the
storage branch serving as
removal branch and optionally also as introduction branch, the device may
comprise in one
section of the storage branch, especially in the shielded section of the
storage branch, at least
one holding magnet, for example at least one electromagnet or at least one
switchable or slidably
arranged permanent magnet. In that way, separation of any dummy targets used
from the actual
targets or separation of different target types may be effected magnetically.
According to a further advantageous embodiment of the invention, the device
comprises a shut-
off valve, especially an emergency closure valve, in the reactor branch for
gas-tight shutting-off
of the reactor branch. In the event of a reactor-side leakage into the line
system, the shut-off valve
advantageously serves for immediately closing off the other parts of the line
system that are
associated with the regions of the device remote from the reactor and situated
on the other side
of the shut-off valve. In particular, regions outside the reactor may thereby
be reliably separated
from the region in the interior of the reactor, so that contamination of the
region outside the reactor
by boiling water, steam or the like from the reactor can be avoided. In that
respect the shut-off
valve provides a physical boundary between different operational safety
classes, so that the parts
of the device situated on the other side of the shut-off valve can be
classified in a lower safety
class. The shut-off valve therefore not only increases operational safety but
also significantly
reduces the outlay for safety measures for a large part of the device.
For detection of any leakages, the device may further comprise at least one
humidity sensor
and/or at least one pressure sensor. Preferably the at least one humidity
sensor and/or the at
least one pressure sensor is arranged in an exhaust gas line of the device.
According to a further advantageous embodiment of the invention, the device is
configured for
selective transfer of nuclide activation targets and measuring bodies into and
out of a plurality of
instrumentation fingers. For that purpose, the line system of the device may
comprise for each
instrumentation finger at least a reactor branch, a storage branch and a
measuring branch and
optionally a removal branch and/or optionally an introduction branch. The
branches associated
with each instrumentation finger preferably form a sub-line system.
23892585i
Date Recue/Date Received 2020-04-23
CA Application
Blakes Ref.: 23211/00001
- 21 -
All the advantages, features and special embodiments of the line system
described above in
respect of the use of an instrumentation finger are transferrable
correspondingly to the branches
associated with a respective instrumentation finger.
In one of the variants described above, the branches associated with each
instrumentation finger
may connect into a multi-way valve. In particular, just one multi-way valve of
the kind described
above may be provided for each sub-line system.
Another possibility, however, is for the device to have at least one multi-way
valve into which the
branches of at least two, especially just two, sub-line systems connect and
which connects the
branches of each of the sub-line systems to one another in the way described
above. This
advantageously saves space for the transport device. For example, the multi-
way valve may be
in the form of a rotary valve having a valve body and a rotatable control
element, the valve body
having at least six, especially just six, ports and the rotatable control
element having at least a
first and a second through-channel, especially exclusively one first and one
second through-
channel, which each run in a 1200 arc and are arranged mirror-symmetrically
with respect to one
another. Two reactor branches, two storage branches and two measuring branches
may connect
into such a multi-way valve, with one reactor branch, one storage branch and
one measuring
branch being associated with each of the instrumentation fingers and forming a
sub-line system.
In different switch positions, the multi-way valve connects a reactor branch
selectively to an
associated storage branch or to an associated measuring branch.
Another possibility is for the device to have a multi-way valve block for
serving a plurality of
instrumentation fingers, which multi-way valve block comprises a plurality,
especially at least two
or three, preferably just two or just three, multi-way valves according to the
present invention
which are each configured for realising different switch positions. The multi-
way valve block may
especially comprise a plurality of valve bodies and a plurality of movable,
especially displaceable
or rotatable, control elements which are each accommodated, especially
mounted, in one of the
valve bodies and comprise one or more through-channels. A valve body and a
control element
accommodated therein realise a respective multi-way valve. Alternatively the
multi-way valve
block may also comprise a common valve body and a plurality of movable,
especially displaceable
23892585i
Date Recue/Date Received 2020-04-23
CA Application
Blakes Ref.: 23211/00001
- 22 -
or rotatable, control elements which are each accommodated, especially
mounted, in the common
valve body and each comprise one or more through-channels, with each of the
plurality of control
elements realising a multi-way valve.
Preferably in both configurations at least two, especially all, of the control
elements are connected
to one another in such a way that they are movable, especially displaceable or
rotatable, in
common into different switch positions, for example by a common actuator.
Each of the plurality of valve bodies or the common valve body of the multi-
way valve block may
comprise, for each realised multi-way valve, a plurality of ports at which the
branches of a
respective sub-line system connect into the multi-way valve block. In the
different switch positions,
the one or more through-channels of the associated control element connect the
corresponding
ports of the respective multi-way valve and accordingly different branches of
a sub-line system.
For each of one or more of the reactor branches associated with an
instrumentation finger, the
device may further comprise an intermediate removal valve into which
correspondingly connect
a reactor-side section of the reactor branch, an intermediate removal section
of the reactor branch
extending in the direction of the multi-way valve, and an intermediate removal
branch.
For transporting the measuring bodies and targets, the device may comprise a
separate
pneumatic or mechanical transport device for each of the sub-line systems or
preferably a
common pneumatic or mechanical transport device for all sub-line systems. In
both variants the
transportation of the measuring bodies and targets in the respective sub-line
systems is preferably
effected independently of one another.
Furthermore, the device may comprise a separate exhaust gas system for each of
the sub-line
systems or a common exhaust gas system for all sub-line systems which is
connected to the sub-
line systems via corresponding exhaust gas lines. In both variants the exhaust
gas discharge for
the respective sub-line systems is preferably effected independently of one
another. For that
purpose the exhaust gas device may comprise one or more gas valves for each
sub-line system.
23892585i
Date Recue/Date Received 2020-04-23
CA Application
Blakes Ref.: 23211/00001
- 23 -
The device may comprise a shield along a respective section of the storage
branches and/or a
respective section of the measuring branches, especially along respective
parking branches. The
shield may be configured separately for each section of the storage branches
and/or measuring
branches. Preferably a common shield is provided along all sections of the
storage branches to
be shielded. In the same way, preferably a common shield is provided along all
sections of the
measuring branches to be shielded, especially along all parking sections.
A further aspect of the invention relates to a system for selectively carrying
out nuclide activations
and measurements by means of measuring bodies in an instrumentation finger of
a nuclear
reactor. The system comprises a device for transferring nuclide activation
targets and measuring
bodies in accordance with the present invention and as described above. The
system further
comprises a measuring device for determining a property of the measuring
bodies that is variable
by energetic excitation in the nuclear reactor, the measuring device being
terminally coupled to
the measuring branch of the device.
A further aspect of the invention relates to a method for activating nuclide
activation targets and
optionally for energetically exciting measuring bodies in an instrumentation
finger of a nuclear
reactor using a device for transferring the nuclide activation targets and
measuring bodies in
accordance with the present invention and as described above. The method
comprises the
following steps:
- introducing unirradiated nuclide activation targets into the line system
of the device coupled to
the instrumentation finger;
- transferring the unirradiated targets via the reactor branch to the
instrumentation finger;
- holding the targets in the instrumentation finger for nuclide activation
by irradiation.
The introduction of unirradiated targets may be effected, for example, via an
introduction branch
which at one end connects into the multi-way valve and at the other end is
coupled to an
introduction device. The targets may be transferred from the introduction
branch directly to the
reactor branch or alternatively indirectly via the storage branch, the targets
first being transferred
via the multi-way valve in the third switch position to the storage branch and
then ¨ after switching-
23892585.1
Date Recue/Date Received 2020-04-23
CA Application
Blakes Ref.: 23211/00001
- 24 -
over of the multi-way valve into the first switch position - from the storage
branch via the multi-
way valve to the reactor branch and further to the instrumentation finger.
Another possibility is for the introduction of unirradiated targets to take
place via the storage
branch. For that purpose, the storage branch may preferably ¨ as described
hereinabove ¨ be
coupled at its end remote from the multi-way valve to an introduction device
from which the
unirradiated targets are further transferred via the storage branch, the multi-
way valve and the
reactor branch to the instrumentation finger.
The transfer of the targets to the instrumentation finger is preferably
effected pneumatically by
means of transport gas.
If, optionally, a measurement, for example a ball measurement for determining
the neutron flux in
the reactor, is to be carried out, the method may further comprise the
following steps:
- interrupting holding the targets in the instrumentation finger;
- transferring the targets from the instrumentation finger via the reactor
branch and the multi-
way valve to the storage branch for intermediate storage therein;
- transferring measuring bodies from a measuring device coupled to the
measuring branch or
from a parking section in the measuring branch to the instrumentation finger
via the measuring
branch, the multi-way valve and the reactor branch;
- holding he measuring bodies in the instrumentation finger for energetic
excitation;
- transferring the measuring bodies from the instrumentation finger via the
reactor branch, the
multi-way valve and the measuring branch to the measuring device for
determination of a
property of the measuring bodies that is variable by the energetic excitation
in the nuclear
reactor;
- transferring the targets from the storage branch via the multi-way valve
and the reactor branch
to the instrumentation finger;
- continuing holding the targets in the instrumentation finger.
Before the transfer of the targets from the instrumentation finger to the
storage branch, the multi-
way valve is moved into the first switch position. After that transfer and
before the transfer of the
23892585i
Date Recue/Date Received 2020-04-23
CA Application
Blakes Ref.: 23211/00001
- 25 -
measuring bodies from the measuring device to the instrumentation finger, the
multi-way valve is
moved into the second switch position. After the return transfer of the
measuring bodies to the
measuring device and before the return transfer of the targets from the
storage branch to the
instrumentation finger, the multi-way valve is moved into the first switch
position again.
Before and/or after the transfer of the measuring bodies to the measuring
device, the measuring
bodies may be intermediately parked in the measuring branch, especially in a
parking section of
the measuring branch. Preferably the device ¨ as described above ¨ comprises a
shield against
ionising radiation along the parking section.
For removal of the irradiated or activated targets, the method may further
comprise the following
steps:
- transferring the targets from the instrumentation finger to the reactor
branch;
- transferring the irradiated targets from the reactor branch via the multi-
way valve and the
removal branch to a removal vessel coupled to the removal branch.
For the transfer from the reactor branch to the removal branch, the multi-way
valve is moved into
the third switch position.
As an alternative to direct transfer from the reactor branch to the removal
branch, it is possible to
transfer the irradiated targets from the reactor branch via the multi-way
valve to the storage branch
and subsequent transfer of the irradiated targets from the storage branch via
the multi-way valve
and the removal branch to a removal vessel coupled to the removal branch. For
the transfer from
the reactor branch to the storage branch, the multi-way valve is moved into
the first switch position
and, for the transfer from the storage branch to the removal branch, into the
(alternative) third
switch position.
Instead of removal via the separate removal branch, the irradiated or
activated targets may also
be removed via the storage branch. In that context the method may comprise the
following steps:
- transferring the targets from the instrumentation finger to the reactor
branch;
- transferring the irradiated targets from the reactor branch via the multi-
way valve and the
storage branch to a removal vessel coupled to the storage branch.
23892585i
Date Recue/Date Received 2020-04-23
CA Application
Blakes Ref.: 23211/00001
- 26 -
The two afore-mentioned steps may also take place in one step.
The nuclide activation targets may comprise as activatable matter, for
example, 98-Mo
(molybdenum), 176-Yb (ytterbium) and/or 51-V (vanadium).
Further details, features and advantages of the present invention will be
found in the following
description and the associated drawings which illustrate exemplary embodiments
of the invention.
In the drawings:
Fig. 1 shows a first exemplary embodiment of a device according to
the invention for
selectively transferring nuclide activation targets and measuring bodies into
and
out of an instrumentation finger of a nuclear reactor;
Fig. 2a-2g shows various switch positions of the multi-way valve used in
the device according
to Fig. 1;
Fig. 3 shows a second exemplary embodiment of a device according to
the invention for
selectively transferring nuclide activation targets and measuring bodies into
and
out of an instrumentation finger of a nuclear reactor; and
Fig. 4 shows a second exemplary embodiment of a device according to
the invention for
selectively transferring nuclide activation targets and measuring bodies into
and
out of a plurality of instrumentation fingers of a nuclear reactor; and
Fig. 5 is a detail view of the multi-way valve used in the device
according to Fig. 4.
Fig. 1 shows a diagrammatic view of a first exemplary embodiment of a device 1
according to the
invention for selectively transferring nuclide activation targets and
measuring bodies into and out
of an instrumentation finger 110 of a commercial nuclear reactor 100. The
device 1 on the one
hand allows the operational regulations for carrying out what are known as
aeroball
23892585i
Date Recue/Date Received 2020-04-23
CA Application
Blakes Ref.: 23211/00001
- 27 -
measurements, which serve for determining the power density distribution or
the neutron flux in
the reactor core, to be met and, on the other hand, allows the radiation
emitted by the nuclear fuel
rods 101 to be utilised for irradiating nuclide activation targets during the
intermediate
measurement-free periods.
According to the invention, the device 1 comprises a line system 2 for
receiving and transporting
the measuring bodies and targets, which line system comprises a plurality of
line
branches 10, 20, 30, 40, 50 which connect into a multi-way valve 60 and which,
via the switchable
multi-way valve 60, may be selectively brought into fluidic connection with
one another. In the
present exemplary embodiment, the line system 2 comprises a reactor branch 10,
which is
coupled to the instrumentation finger 110 via a terminal coupling 11 in the
region of what is known
as a cable bridge 130 of the nuclear reactor 100. The line system 2 further
comprises a storage
branch 20 for intermediate storage of the measuring bodies or targets and a
measuring branch 30
which is coupled via a terminal coupling 31 to a measuring device 300,
especially what is known
as a measuring table, for example known from US 3 711 714, for determining the
activity of the
measuring bodies. Furthermore, the line system 2 comprises an introduction
branch 50 which is
couplable by means of a terminal coupling 51 to an introduction device 500,
for example a
transport vessel, in order to introduce fresh, unirradiated targets into the
line system 2. For
removal of irradiated targets, the line system 2 further comprises a removal
branch 40 via which
the irradiated targets may be transferred to a removal vessel 400.
All the branches 10, 20, 30, 40, 50 of the line system connect node-like into
the multi-way
valve 60. In addition, an exhaust gas line 88 for discharging transport gas
connects into the multi-
way valve 60. Fig. 2a-2g show details of the multi-way valve 60 according to
the present
exemplary embodiment. The switchable multi-way valve 60 is configured, in a
first switch position,
to fluidically connect the reactor branch 10 to the storage branch 20 (Fig.
2a), in a second switch
position the reactor branch 10 to the measuring branch 30 (Fig. 2b), in a
third switch position the
reactor branch 10 to the removal branch 40 (Fig. 2c), in a fourth switch
position the storage
branch 20 to the measuring branch 30 (Fig. 2d), in a fifth switch position the
introduction
branch 50 to the storage branch 20 (Fig. 2e) and in a sixth switch position
the reactor branch 10
to the exhaust gas line 88 (Fig. 2f). Furthermore, the multi-way valve 60 is
configured, in a
23892585i
Date Recue/Date Received 2020-04-23
CA Application
Blakes Ref.: 23211/00001
- 28 -
seventh switch position (Fig. 2g), to fluidically decouple all the branches
10, 20, 30, 40, 50 that
connect into the multi-way valve 60 and the exhaust gas line 88 from one
another.
As can be seen from Fig. 2a-2g, the multi-way valve 60 according to the
present exemplary
embodiment is configured as a multi-way rotary valve, especially as a 6/7-way
rotary valve, which
comprises a control element 66 mounted rotatably and sealingly in a valve body
67. The reactor
branch 10, the storage branch 20, the measuring branch 30, the removal branch
40, the
introduction branch 50 and the exhaust gas line 88 connect into the valve body
67 via ports
uniformly distributed around the circumference. In the present exemplary
embodiment, the fluidic
connections established between the different branches 10, 20, 30, 40, 50 and
the exhaust gas
line 88 are formed by three through-channels 63, 64, 65 in the control element
66, which through-
channels run perpendicular to the rotational axis of the control element 66,
that is to say parallel
to the rotational plane of the control element 66. A first through-channel 63
runs in a straight line
approximately centrally through the rotational axis of the control element 66.
A second through-
channel 64 runs in a 120 degree arc offset laterally symmetrically with
respect to the first through-
channel 63. A third through-channel 65 runs secant-like through the control
element 66,
especially offset asymmetrically with respect to the first through-channel 63,
opposite the second
through-channel 64. In the first switch position, the second through-channel
64 connects the
reactor branch 10 to the storage branch 20 (Fig. 2a). In the second switch
position, the second
through-channel 64 likewise connects the reactor branch 10 to the measuring
branch 30 (Fig. 2b).
In the third switch position, the first through-channel 63 connects the
reactor branch 10 to the
removal branch 40 (Fig. 2c). In the fourth switch position, the second through-
channel 64
connects the storage branch 20 to the measuring branch 30 (Fig. 2d). In the
fifth switch position,
the first through-channel 63 connects the introduction branch 50 to the
storage branch 20
(Fig. 2e). In the sixth switch position, the third through-channel 65 connects
the reactor branch 10
to the exhaust gas line 88 (Fig. 2f). In the seventh switch position, none of
the three through-
channels 63, 64, 65 is in fluidic connection with any of the branches 10, 20,
30, 40, 50 or the
exhaust gas line 88. For rotating the control element, that is to say for
switching between the
different switch positions, the multi-way valve 60 may comprise an actuator,
especially a servo
motor (not shown herein).
23892585i
Date Recue/Date Received 2020-04-23
CA Application
Blakes Ref.: 23211/00001
- 29 -
While the first and second through-channels 63, 64 are configured for the
passage of targets and
measuring bodies, the third through-channel 65 is configured exclusively for
the passage of
transport gas. Accordingly, the diameter of the first and second through-
channels 63, 64
corresponds substantially to the diameter of the branches 10, 20, 30, 40, 50
and is slightly larger
than the diameter of the targets and measuring bodies. In comparison, the
diameter of the third
through-channel 65 is smaller than the diameter of the branches 10, 20, 30,
40, 50 and smaller
than the diameter of the targets and measuring bodies. In that way, undesired
passage of the
targets and measuring bodies through the third through-channel 65 is
prevented.
For pneumatically transporting the measuring bodies and targets, the device 1
comprises a
pneumatic transport device 90. As transport gas there is preferably used
nitrogen which is
provided by a transport gas source 99. Leading out of the transport gas source
99 there is a first
transport gas line 92 which, for pneumatic transportation of the measuring
bodies and targets out
of the storage branch 20 in the direction of the multi-way valve 60, is
terminally coupled to the
storage branch 20. Also leading out of the transport gas source 99 there is a
second transport
gas line 91 which, for pneumatic transportation of the measuring bodies and
targets out of the
instrumentation finger 110 via the reactor branch 10 in the direction of the
multi-way valve 60, is
coupled to the instrumentation finger 110 via a reactor-side finger gas line
120. The coupling to
the finger gas line 110 is likewise effected at the cable bridge 130 of the
nuclear reactor 100.
Furthermore, leading out of the transport gas source 99 via the second
transport gas line 91 and
a 3/2-way gas valve 96 there is a third transport gas line 93 which, for
pneumatic transportation
of the measuring bodies out of the measuring device 300 via the measuring
branch 30 in the
direction of the multi-way valve 60, is terminally coupled to the measuring
device 300. For
pneumatic transportation of the targets from the introduction device 500 to
the introduction
branch 50 there is provided a fourth transport gas line 95 which is terminally
coupled to the
introduction device 50. In the present exemplary embodiment the fourth
transport gas line 95
branches off from the first transport gas line 92 and may be closed off with
respect thereto by
means of a gas valve 94.
For reducing pressure or discharging transport gas, the device 1 comprises an
exhaust gas
device 80 which, in addition to the exhaust gas line 88, comprises further
exhaust gas lines. A
23892585i
Date Recue/Date Received 2020-04-23
CA Application
Blakes Ref.: 23211/00001
- 30 -
first (further) exhaust gas line 82 branches off from the first transport gas
line 92 via a 3/2-way
gas valve 97 in the terminal region and serves for discharging transport gas
from the storage
branch 10. Two further exhaust gas lines 81, 83 branch off from the second and
third transport
gas lines 91, 93, respectively, and serve for discharging transport gas from
the instrumentation
finger 110 and the measuring device 300, respectively. The two exhaust gas
lines 81, 83 are each
guided into the exhaust gas line 88 via a 3/2-way gas valve 87. The exhaust
gas line 88 and
accordingly also the two exhaust gas lines 81, 83 and the exhaust gas line 82
end in an exhaust
gas filter 89 in which the discharged transport gas is freed of any possible
contamination.
For activation of targets in the instrumentation finger, the device 1
according to the present
exemplary embodiment may be operated as follows. By opening the valve 94,
unirradiated targets
held in the introduction vessel 500 are transferred via the introduction
branch by means of
transport gas from the vessel 500 via the introduction branch 50 and the multi-
way valve 60 to
the storage branch 20. For that purpose the multi-way valve 60 is in the fifth
switch position. For
reducing the transport gas pressure in the storage branch 20, the storage
branch 20 is connected
to the exhaust gas filter 89 via the valve 97 and the exhaust gas line 82.
Measuring bodies already
present in the system are at this point in time preferably located in the
measuring device 300.
Once the transfer of the targets to the storage branch 20 is complete, the
valve 94 is closed and
the multi-way valve 60 is switched into the first switch position in order to
connect the storage
branch 20 to the reactor branch 10. By switching over the valve 97, transport
gas from the first
transport gas line 92 is then let into the storage branch 20 in order to
transfer the intermediately
parked targets from there to the instrumentation finger 110 via the multi-way
valve 60 and the
reactor branch 20 via the opened magnetic stop 112. For reducing the transport
gas pressure in
the instrumentation finger 110, the latter is connected to the exhaust gas
filter 89 via the transport
gas line 91, the exhaust gas line 81, the valve 87 and the exhaust gas line
88.
For activation of the targets, that is to say conversion of the targets into
radionuclides, the targets
are held in the instrumentation finger, typically for a period of from several
days to several weeks.
If, during that time, operational safety regulations necessitate, for example,
an aeroball
measurement, the targets may be temporarily intermediately parked in the
storage branch 20. For
that purpose transport gas is let into the finger gas line 120 via the
transport gas line 91 in reverse
23892585i
Date Recue/Date Received 2020-04-23
CA Application
Blakes Ref.: 23211/00001
- 31 -
order by closing the valve 87 and opening the valve 96, with the result that
the partly activated
targets are transferred from the instrumentation finger 110 to the storage
branch 20 via the reactor
branch 10 and the multi-way valve 60. For reducing pressure in the storage
branch 20, the latter
is in turn connected to the exhaust gas filter 89 via the valve 97 and the
exhaust gas line 82. For
reasons of radiation protection, that section 22 of the storage branch 20 in
which the partly
irradiated targets are intermediately parked, is preferably ¨ as shown in Fig.
1 ¨ provided with a
shield 23 against ionising radiation.
For the upcoming aeroball measurement, the multi-way valve 60 is then moved
into the second
switch position. Transport gas is then let into the measuring device 300 via
the valve 96 and the
transport gas line 93 in order to transfer the measuring bodies to the
instrumentation finger 110
via the measuring branch 30, the multi-way valve 60 and the reactor branch 10.
For reducing
pressure in the instrumentation finger 110, the latter is in turn connected to
the exhaust gas
filter 89 via the transport gas line 91, the exhaust gas line 81, the valve 87
and the exhaust gas
line 88. Once irradiation of the measuring bodies is complete, by closing the
valve 87 and opening
the valve 96 the measuring bodies are transferred by means of transport gas
from the
instrumentation finger 110 back to the measuring device 300 in reverse order
via the reactor
branch 10, the multi-way valve 60 and the measuring branch 30. In the
measuring device it is
possible to measure the activity of the irradiated measuring bodies for
determination of the power
density profile of the reactor. For the purpose of reducing pressure, during
the return transfer of
the measuring bodies the measuring device 300 is connected to the exhaust gas
filter 89 via the
transport gas line 93, the exhaust gas line 83, the valve 87 and the exhaust
gas line 88.
As soon as the measuring bodies are located in the measuring device 300, the
activation of the
partly irradiated targets may be continued. For that purpose the targets ¨ in
accordance with the
procedure already described hereinabove ¨ are transferred from the storage
branch 20 back to
the instrumentation finger 110.
Once the activation of the targets is complete, for the purpose of removal
from the line system
the targets are first transferred to the monotonically falling delivery
section 12 of the reactor
branch 10, the length of which section corresponds at least to the length of
the chain of targets
arranged in a row one after the other in the line system. For that purpose the
valve 87 is closed
23892585i
Date Recue/Date Received 2020-04-23
CA Application
Blakes Ref.: 23211/00001
- 32 -
and the valve 96 is opened in order to let transport gas into the
instrumentation finger 110 via the
transport gas line 91 and the finger gas line 120. For reducing pressure in
the reactor branch 10,
the multi-way valve 60 is in the sixth switch position in order to connect the
reactor branch 10 to
the exhaust gas line 88 and the exhaust gas filter 89. In that switch position
the targets are held
back by the multi-way valve 60 acting as a stop. Once the transport gas supply
has been closed
via the valve 96 and the reduction in pressure in the reactor branch 10 is
complete, the multi-way
valve 60 is moved into the third switch position, with the result that the
reactor branch 10 is
connected to the removal branch 40. In that way the targets may be transferred
pressurelessly
and exclusively under the force of gravity from the monotonically falling
delivery section 12 of the
reactor branch 10 via the multi-way valve 60 and via the likewise
monotonically falling removal
branch 40 arranged vertically therebelow to the allocated removal vessel 400.
In the present exemplary embodiment, the device 1 comprises a shut-off valve
42 in the removal
branch 40 for gas-tight shutting-off of the removal branch 40. This
advantageously minimises the
risk of contamination.
As can also be seen from Fig. 1, the device 1 has a shut-off valve 4 in the
reactor branch 10 for
gas-tight shutting-off of the reactor branch 10. In the event of a reactor-
side leakage into the line
system 2, the shut-off valve 4 advantageously serves for immediately closing
off the other parts
of the line system that are associated with the regions of the device 1 remote
from the reactor
and situated on the other side of the shut-off valve 4.
For separating any dummy targets used it is possible ¨ as explained
hereinabove and likewise
shown in Fig. 1 ¨ for one or more electromagnets 7 to be arranged along the
delivery section 12,
which electromagnets serve for holding magnetic targets or dummy targets in
place.
Fig. 3 shows a second exemplary embodiment of the transfer device 1 according
to the invention
which differs from the exemplary embodiment according to Fig. 1 essentially
only by the additional
presence of an intermediate removal device 70 in the reactor branch 10 and
therefore only that
difference will be discussed below. Otherwise in Fig. 1 and 3 the same
reference numerals are
used for identical or similar features in respect of both embodiments.
23892585i
Date Recue/Date Received 2020-04-23
CA Application
Blakes Ref.: 23211/00001
- 33 -
The intermediate removal device 70 present in the second exemplary embodiment
according to
Fig. 3 comprises an intermediate removal valve 71 into which connect a reactor-
side section 13
of the reactor branch 12, an intermediate removal section 14 of the reactor
branch 10 extending
in the direction of the multi-way valve 60, an intermediate removal branch 72
and an exhaust gas
line 85. The exhaust gas line 85 is connected to the exhaust gas filter 89 via
the exhaust gas
line 88. In a first switch position the intermediate removal valve 71 connects
the reactor-side
section 13 to the intermediate removal section 14 of the reactor branch 10, in
a second switch
position the intermediate removal section 14 to the intermediate removal
branch 72, and in a third
switch position, for the purpose of reducing pressure, the intermediate
removal section 14 to the
exhaust gas line 85. In a fourth switch position the intermediate removal
valve 71 effects complete
shut-off.
For separating a (sub-)quantity of dummy targets or targets, the intermediate
removal section 14
has an apex 17 in the transition between a first and a second monotonically
falling sub-
section 15, 16. By transferring the entire target chain into the intermediate
removal section 14
until it strikes against the (closing-off) intermediate removal valve 71, the
(sub-)quantity of dummy
targets or targets to be separated or removed collect in the first sub-section
15, while the (sub-
)quantity that is not to be removed is located on the other side of the apex
17 in the second sub-
section 16. By switching over into the second switch position, the (sub-
)quantity to be separated
-- or removed may be transferred under the force of gravity to the
intermediate removal branch 72
and further to an intermediate removal vessel 700, while the (sub-)quantity
that is not to be
removed remains in the second sub-section 16. From there the (sub-)quantity
that is not to be
removed may be transferred purposively to a different location in the line
system 2.
Fig. 4 shows a third exemplary embodiment of the transfer device 1001
according to the invention
which differs from the exemplary embodiments according to Fig. 1 and Fig. 3 in
that the line
system associated with an instrumentation finger does not comprise a separate
introduction
branch and removal branch which each connect into the multi-way valve.
Instead, in this
exemplary embodiment the introduction of the unirradiated targets and the
removal of the
irradiated or activated targets in each case take place via the storage branch
1020a, 1020b
associated with an instrumentation finger. For that purpose, the storage
branch 1020a, 1020b
23892585i
Date Recue/Date Received 2020-04-23
CA Application
Blakes Ref.: 23211/00001
- 34 -
associated with a respective instrumentation finger may be coupled at its end
remote from the
multi-way valve to a combined introduction/removal device which comprises a
shielding transfer
vessel 1400. From that vessel 1400, unirradiated targets may be introduced
into the storage
branch, for example by means of compressed air, and vice versa, after the
irradiation, activated
-- targets may be delivered from the storage branch to the transfer vessel
1400. As in the first and
second exemplary embodiments, the storage branches 1020a, 1020b associated
with a
respective instrumentation finger comprise a shielded section 1022a, 1022b in
which targets may
be stored intermediately. In the present case the transfer device comprises
for that purpose a
common shield 1023 against ionising radiation which surrounds the shielded
-- sections 1022a, 1022b of all storage branches.
In the end region in front of the coupling, each storage branch 1020a, 1020b
may further comprise
a blocking device (not shown), for example a magnetically operable stop, for
example a pin, peg
or bolt, for blocking the transport path through the storage branch. In
addition, in the storage
-- branches 1020a, 1020b, especially in the shielded sections 1022a, 1022b,
there may be arranged
electromagnets (not shown) which serve for holding magnetic targets or dummy
targets in place
and accordingly enable targets and dummy targets to be separated.
By dispensing with separate removal and introduction branches, a single multi-
way valve may
-- advantageously be used to serve a plurality of instrumentation fingers. In
the exemplary
embodiment according to Fig. 4, two instrumentation fingers 1110a, 1110b are
served by a single
multi-way valve 1060. As shown in detail especially in Fig. 5, the multi-way
valve 1060 according
to the present exemplary embodiment is in the form of a rotary valve which
comprises a valve
body 1067 having six ports and a control element 1066 rotatably mounted
therein. In the control
-- element 1066 there are provided a first through-channel 1068 and a second
through-
channel 1069 which each run in a 120 arc and are arranged mirror-
symmetrically with respect to
one another. Two reactor branches 1010a, 1010b, two storage branches 1020a,
1020b and two
measuring branches 1030a, 1030b are connected to respective oppositely located
ports, with one
reactor branch 1010a, 1010b, one storage branch 1020a, 1020b and one measuring
-- branch 1030a, 1030b being associated with each of the instrumentation
fingers 1110a, 1110b
and in that respect forming a sub-line system 1002a, 1002b. In different
switch positions, this
23892585i
Date Recue/Date Received 2020-04-23
CA Application
Blakes Ref.: 23211/00001
- 35 -
multi-way valve 1060 connects a reactor branch 1010a, 1010b selectively to an
associated
storage branch 1020a, 1020b or to an associated measuring branch 1030a, 1030b.
In addition,
an exhaust gas line for removing gas from the valve body connects into the
multi-way valve.
Furthermore, the transfer device 1001 according to Fig. 4 differs from those
of Fig. 1 and 3 in that
the device 1001 comprises, in the measuring branches 1030a, 1030b, respective
parking
sections 1032a, 1032b for intermediate parking of the measuring bodies or
targets. In addition,
the device 1001 comprises a shield 1033 against ionising radiation along the
parking
sections 1032a, 1032b. This provides an alternative way of intermediately
parking the measuring
bodies in the parking section 1032a, 1032b associated with a respective
instrumentation
finger 1110a, 1110b under shielded conditions during those periods in which no
measurement is
being carried out. In the end region of the parking sections 1032a, 1032b
remote from the multi-
way valve 1060, a respective blocking device or holding device (not shown) may
be provided, for
example a magnetically operable stop or an electromagnet, in order to block
the transport path
from the parking sections 1032a, 1032b to the sections of the measuring
branches 1030a, 1030b
remote from the multi-way valve 1060 and thus hold the measuring bodies in the
parking
sections 1032a, 1032b, for example under the action of gravity against a
mechanical stop or
against a magnetic holding force.
Like the devices according to Fig. 1 and 3, the transfer device 1001 according
to Fig. 4 also
comprises a shut-off valve 1004a, 1004b in each of the reactor branches 1010a,
1010b for gas-
tight shutting-off of the respective reactor branch 1010a, 1010b. Similarly,
the transfer
device 1001 according to Fig. 4, like the two other embodiments, comprises a
preferably common
pneumatic transport device 1090 and a preferably common exhaust gas device
1080 for
transporting the measuring bodies and targets through the sub-line systems
1002a, 1002b.
23892585i
Date Recue/Date Received 2020-04-23
