Note : Les descriptions sont présentées dans la langue officielle dans laquelle elles ont été soumises.
---i` 13267~7
1 20365-2994
The invention relates to a heating reactor system,
particularly for light-water reactors, comprising a nuclear
reactor having a reactor pressure vessel, said reactor pressure
vessel containing a volume of water as primary coolant, a core o~
said nuclear reactor belng located within said volume of water and
comprising a first heat exchanger and a second heat exchanger
connected to one another via an intermediate circuit for a
secondary coolant, and an afterheat removal circuit, which
contains an afterheat removal cooler, connected to the
intermediate circuit via cooler connection pipes in the form of
influx pipes and reflux pipes and with at least one flow rate
regulating unit inserted in the cooler connection pipes.
Such heating reactor system is known and illustrated in
Figure 3 on page 29 of the periodical "Nuclear Europe", 11-
12/1987, pages 28 to 30, whereby the afterheat removal coolers,
particularly air coolers, are not connected directly to the lines
of the intermediate circuit, but indirectly via an intermediate
heat exchanger. The intermediate heat exchanger is ~or its part
connected to the hot or the cold secondary coolant line of the
intermediate circuit via an output pipe and via a return pipe in
which shut-off valves are disposed. The known heating reactor
system is intended for a thermal power output of 5 MW.
The present invention relates to heatin~ reactor systems
with a thermal power output in the range of approximately S to ~00
MW. It starts wlth the consideration that all sub~systems in such
a heating reac~or system must be designed as simply as possible
without forfeiting safety. If valves or drive pumps are provided
in an afterheat removal circuit, ~hen not only their actual price~
132B717
, \~
la 20355-299~
but also the power supply (possibly emergency power supply) and
monitoring of such units is reflected in the books. Moreover, the
safety-related contol mechanisms must be redundant.
: ,~ J
`' ~
~3~71~
2 20365-2g94
Star~ny with a heating reactor system according to the
opening paragraph, ~he present invention is based on the object of
designing the afterheat removal clrcuit in such a way that the
heating reactor can be swltched from normal operation ~o afterheat
removal operation without the conventional shut-off valves or
control valves, i.e. without valves which have so-called valve
cones or seals which are mechanically pressed against a valve seat
with a valve tappet or the like (closed position) or are lifted
from this seat (open posltion). Moreover, it should be possible
to switch the coollng of the core from normal operation to
afterheat removal operation without such fittinys ln such a way
that a so-called passive and at the same time inheren~ly safa
a~terheat removal circuit is provlded, i.e. different from the
known heating reactor sys~em according to "Nuclear Europe" wherein
by opening the conventional valves the secondary medium of ~he
intermedlate circuit is guided via the a~terheat removal cooler
during afterheat removal.
In a heating reactor system which an afterheat removal
clrcuit of the klnd defined above the ob;ect is solved in
accordance with the present invention by providing a vortex
chamber valve as the ~low ra~e regulating unit.
Vortex chambar valves are purely ~luidic elements tha~
opera~e solely on the basis of flow effect~, th~t have no movable
parts and that do no re~uire any auxiliary energy outside the
system. Reference ls made in this connec~ion to the arti~la
"Konstruktlon und Leistung von Wirbelgeraten" (Design and powar of
vortex devices) by H. ~rombach in the perlodlcal "messen ~ s~euern
- regeln", VEB Verlay Technlk Berlin, Volume 11, November 1~78,
132~717
3 203~S-2994
pages 638 - 6g2, particularly payes 641 and 642.
The advantage that can be achieved with the present
invention can be seen primarily therein ~hat so-called motor
fittings ~remote-controllable, motor-driven valves) or other
conventional valves comprising seal and valve seat in multiple
arrangement are unnecessary. The afterheat removal clrcuit with
the vortex chamber valve ensures the automatic, inherently safe
change-over by hydraulic or fluidlc means without mechanically
moved parts.
According to a preferred embodiment of the present
invention the vortex chamber valve in a heating reactor system
with a pump in the intermediate circuit is provided with a supply
connection, a control connection and an outlet connection, whereby
the supply connection is connected to the hot line, the outlet
connection is connec~ed to the cold line via the afterheat ramoval
cooler and the control connection on the delivery side of the pump
is likewise connected to the cold line of the intermediate
circuit The change-over to afterheat removal opexation according
to the prinaiple of natural circulation thereby occuræ
automatically through the vortex chamber valve when the pump in
the intermediate circuit is stopped. To this end, the vortex
chamb~r valve is advantageously lnserted in the influx pipe of the
afterheat removal cooler. Accordlng to fur~her advantag~ous
embodiments, the first heat ~xehanger is arranged in the volume of
~ater at a dlstance above the upper edge of the core and can be
heated on the primary ~ide by the primary coolant and the pipes o~
the lnterm~diate circuit connected on the secondary ~lde to the
heat exchanger tubes of the first heat exchanger ara guided to the
, . ~ .
132B717
4 20365-2994
outside through the wall of the reactor pressure vessel. If the
cover of the reactor pressure vessel is to be kept ~ree of such
penetrations, then it is advi~able that the pipes connected on the
secondary side to the heat exchanger tubes of the first heat
exchanger penetrate the casing wall of the reactor pressure vessel
below the closure head.
The arrangement for the reactor pressure vessel of the
heating reactor sys~em and the first and second heat exchangers
can be even more compac~ in tha~ the second heat exchanyer is also
arranged integrally within the space enclosed by the reactor
pressure vessel, preferably within the steam plenum. In this case
an output pipe as well as a return pipe, which are connected to
the heat exchanger tubes of the second heat exchanger, are
advisably guided to the outside through the wall of the reactor
pressure vessel and are connected to an external hea~ supply
network. To keep the cover of the reactor pressure vessel free,
it is al30 advisable that the outlet pipe and the return pipe
penetrate the caslng wall of the reactor pressure vessel below the
closure head flange
Accordiny to another broad aspect of the present
invention there ls provlded a heating reactor system, particularly
for llght-water reactors, comprising a first heat exchanger and a
second heat exchanger connec~ed to one another vla an intermediate
circult for the secondary coolant and with the additional features
of an afterheat removal circuit which contains an afterheat
removal cooler and which i5 connected to the secondary side of a
heat exchanger arranged in the reactor pressure vessel via cooler
connec~ion pipes ln the form of an influx pipe and a reflux pipe,
~3~
20365-2994
hereby a vortex chamber valve is inserted in he cooler connection
pipes as a flow rate regulating unit and whereby the heat
exchanger is a condenser arranged in the steam plenum o~ the
reactor pressure vessel.
This heating reactox system also solves ~he object on
which the present invention is based and which was explained at
the beginning. Such a heating reactor system is preferred for
smaller heating reactors with a thermal reactor output in a range
betwean approximately 5 and 50 MW, whereas the heating reactor
system according to the flr~t embodiment is suitable for heating
reactors with an average or higher thermal power output
particularly in the range of S0 to 200 MW. Even in this
embodiment of ~ha heating reactor system the lnternally
controllable current pa~h of the vortex chamber valve formed
between the control connection and the outlet connection iæ
advisably inserted in the inilux pipe of the afterheat removal
cooler.
In this embodiment of the heating reactor system two
advantageous possibilities present themselves ~or controlling the
vortex chamber valve. One embodiment provide~ that an adiustable
throttle is inserted in the return pipe of an external heat supply
network, the delivery side of this throttle belng connected to a
control pipe leading to the control connection of the vortsx
chamber valve, and that the reflux pipe of the afterheat removal
cooler is connected to a pipe branch on the side of the throttle
facing away from the delivery side. The change over to afterheat
removal operation occurs automatically in ~his case through the
vor~ex chamber valve if the pump operating normally in the
~..,
~L3~67~7
"-
6 20365-299
external heat supply network is switched off.
The second ad~antageous embodiment provi~es that a
control current pump lying in a control current path is connected
to the reflux plpe vla a suc~ion plpe and to the control
connection of the vortex chamber valve vla a pressure pipe,
whereby a control pressure blocking or sharply throttling the
internally controllable current path of the vor~ex ahamber valve
is generated by the control current pump during normal operation
of the heating reactor and whereby means are provided for ~topping
the pump during shutdown of ~he heating reactor. The pump is a
so-called continuous runnlng pump of low power and ls only
provided to generate pressure for the control current. The means
for stopping the pump during shutdown of the heatlng reactor can
preferably be realized by in~errupting the power supply ~or the
motor driving the control current pump if the control rods of the
heating reactor are in the shutdown position (fully inserted in
the reactor core).
Use o~ the afterheat removal circuit with the vortex
chamber valve o~ the first embodiment within the framework of a
first ~asic exemplary embodiment oi the heating xeac~or system for
removing decay heat in a boiling water reactor or a pressurized
water reactor which serve to generate drlving steam for a ~team
turbo generator unlt also forms the ~ubject matter of the present
invention. A pressure of approximately 15 bar normally prevails
in the reactor pressure ves3el in a heatlng reactor, a pressure of
approximately 70 bar prevails in a boiling water reactor and a
pre~sure of approxlmately 150 bar prevails in a pre~surized water
reactor. On accoun~ of the higher operatlng pressure in the
. ~
~.i ` `:
~32~7~7
7 20365-2994
reactor pressure vessel the walls of this vessel as well as the
walls of the pipiny and componen~ connected thereto which are
subjected to this pressure are thlcker. This must be taken into
consideration if, for the afterheat removal, one or a pIurality of
heat exchangers are accommodated inside a reactor pressure vessel
and the pipes on the secondary side of this heat exchanger are
guided to the outside through the wall of the reactor pressure
vessel and are also connected as influx pipe and reflux pipe to an
afterheat removal cooler together with the associated vortex
chamber valve.
If, in ~he second embodiment, a condenser is provlded
for the afterheat removal circuit of a heating reactor system and
if a separate small pump, a so-called continuous running pump, is
inserted to generate the control pressure for ~he control current
connection of the vortex chamber valve, then a further
advantageou~ use results for this embodlment for removing decay
heat in a boillng water reactor or a pressurized water reactor
which serYe to generate driving steam for a ~eam turbo-genera~or
unlt.
To further explain the sub~ect matter of the present
invention and its further advantage , reference i3 made here below
to Figures 1 to 9 of the drawings which illustrate several
exemplary embodi~ents as well as the basic design and function of
a vortex chamber valve. Shown therein in stmplified illustration
are,
:L32~7~7
~- 8 - 20365-2994
igure 1: a three-line heating reactor system in sim-
plified illustration, whereby each of the
three lines in the intermediate circuit can
be automatically connected to an afterheat
removal cooler via a vortex chamber valve in
the event of emergency cooling (first exem~
plary embodiment);
igure 2: detail of a single line for the intermediate
circuit and the afterheat removal branch con-
nected thereto with vortex chamber valve and
afterheat removal cooler, whereby the heavy
black lines denote the path o~ the secondary
coolant during normal operation and whereby
the reactor pressure vessel is illustrated
somewhat differently than in Figure l;
igure 3: the subject matter of Figure 2 during after-
heat removal operation, whereby the vortex
chamber valve is connected through and in
this case al80 the heavy black line~ denote
the path of the secondary coolant;
igure 4: a perspective-schematic view of a vortex
chamber valve with three connection pieces
for the control, supply and outlet pipe;
igure 5: flow diagxam for the vortex chamber valve
according to Figure 4;
igure 6: a common connection diagram for the vortex
chamber valve according to Figure 4;
7~7
- 9 203~5-29
Figure 7: a second exemplary embodiment for a heating
reactor system according to the inv~ntion,
whereby the intermediate circuit is illus-
trated with three lines, but for reasons of
simplification the afterheat removal branch
is illustrated with only one l;ne a3 in Fig-
ure 2 and Figure 3;
Figure 8: a third exemplary embodiment for a heating
reactor system according to the invention
which for reasons of simplification is again
Illustrated with only one line and in which
the second heat exchanger is located within
the reactor pressure vessel, as well as a
condenser to which the afterheat removal
branch can be connected via a vortex valve in
the event of emergency cooling;
:~ Figure 9: a variant of the exemplary embodiment accord- ~ :
ing to Figure 8 in section, whereby a control
: current path w~th a separate control current
pump is provided to generate the control cur-
:
rent pressure for .the vortex chamber valve.
The heating reactor ~ystem according to Figure 1 ~how3
an atomic heating reactor, identified as a whole by HR, comprising
a reactor pressur2 vQssel 1, a reactor core 2 and a primary cool-
ant in the form o light water circulated therein in natural cir-
culation, the volume 3 of this water surrounding the reactor core
2 and it9 water level 3.0 located at a distance al from and above
the upper edge ~.0 of the core. As the flow lines F1 with the
3L3~7~
- 10 - 20365-29g4
arrows fl show, the primary coolant flows in natural circulation
without special circulating pumps, although the invention is not
restricted to such an embodiment for natural circulation. Inter-
nal or external circulating pumps can also be used to increase the
amount of primary coolant circulated per unit of time. As usual,
the reactor core comprises elongated fuel elements, whereby verti-
cal cooling channels extending in the axial direction of the fuel
elements are provided in and possibly between the fuel elements,
the primary coolant flowing through these channels from bottom to
top, whereby the coolant is heated and, since it is specifically
lighter, flows upwards through the primary side of the first heat
exchangers 4 on account of lift forces.
As illustrated, these heat exchangers 4 are preferably
arranged in the volume 3 of water and, as mentioned, the primary
coolant flows through and is heated on the primary side. On the
~econdary ~ide the ~econdary coolant of an intermediate circuit ZK
which is circulated by at least one pump 5, flows through these
first heat exchangers 4 within the schematically illustrated heat
exchanger tubes 4.1 according to the direction of arrow f2. Three
first heat exchangers 4 and accordingly three lines zkl, ~k2 and
zk3, connected thereto, of the intermediate circuit ZK, each with
one circulating pump 5 for the secondary coolant and a second heat
exchanger 6 are illustrated.
To operate the heating reactor sy~tem ~R it is necessary
that at least one first heat exchanger 4 with at least one of the
line~ zkl to zk3 and one of the second heat exchangers 6 as well
as an as~ociated circulating pump 5 be provided. A triple
arrangement is illustrated in order to demonstrate that the inter-
mediate circuit ZK can have not only one, but two, three or even
~3:~7~7
~ 203~5-29~4
more lines, depending on the size of a connected external heat
supply network HN and the required quantity of heat, this also
affecting the structural size of the reactor pressure vessel 1.
The second heat exchangers 6 are thus heated on the pri-
mary side by the secondary coolant. Their heat exchanger tubes or
pipe coils are again schematically illustrated and identified by
reference numeral 6.1. A tertiary coolant of the heat supply net-
work H~ flows through said heat exchangers on the secondary side.
They are connected for this purpose on the secondary side to out-
put pipes 7a, 7b, 7c which are combined into ~ common output pipe
7 at the branch point 7.1 and are respectively connected on the
return side to return pipes 8a, 8b, 8c of a heat supply network
distributed from the common or main return pipe 8 to the individu-
al second heat exchangers 6. The individual lines zkl to zk3 of
the intermediate circuit ZK are each provided with a hot secondary
coolant line 9.1 and a cold secondary coolant line 9.2. The hot
line 9.1 connects the secondary side (or the outlet) of the heat
exchanger tubes 4.1 of the ~irst heat exchangers 4 to the influx
side or the inlets of the heat exchanger tubes 6.1 of the second
heat exchangers 6. The cold secondary coolant line 9.2 in each
case extends from the outlet of tha heat exchanger tubes 6~1 of
the second heat exchanger 6 through the circulating pump S up to
the inlet of the heat exchanger tubes 4.1 of the first heat ex-
changer 4.
Afterheat removal coolers lOa, lOb~ lOc with their in-
flux pipes 11 and reflux pipes 12 are respectively connected to
the intermediate circuit llnes kl, ~k2 and zk3 of the intermedi-
ate circuit ZK, whereby the aforenamed coolers lOa, lOb, lOc are
~32~717
- 12 - 20365-2994
identified as a whole by the afterheat removal cooler 10. The
coolers 10 or lOa, lOb, lOc are preferably designed as air
coolers, as is schematically illustrated. The influx pipe 11 of
said cooler is in each case connected to the hot lina 9.1 via the
internally controllable current path sO-eO of a vortex chamber
valve WV whose hydraulic connection cO for the control cuxrent is
connected via the control current pipe 13 to the cold secondary
coolant line 9.2 ("cold line") on the delivery side of the pump 5
of the intermediate c~rcuit ZK. The xeflux pipe 12 of the cooler
10 is in each case connected to the cold line 9.2 of the interme-
diate circuit lines zkl, zk~, zk3 on the delivery side of the pump
5. The operation of the vortex chamber valve WV will be explained
in greater detail herebelow on the basis of Figures 2 and 3. If
the heating reactor HR i5 shut down or its power reduced (absorber
rods or control rods, not illustrated, are inserted into the reac-
tor core 2 for this purpose), then it i8 the task of tha cooler 10
to remove the so-called decay heat of the heating reactor HR. It
is thereby assumed that no more heat i5 required by the external
heat supply network H~ and that the pumps 5 are no longer running.
This can be the case if the heating reactor ~R, whose fuel ale-
ments are rearranged or replaced, is inspected if the heating
reactor HR is shut down through a breakdown or if, for example,
alteration, in~pection or repair worX is carried out in the exter~
nal heat supply network HN.
The reactor pressure vessel 1 is surrounded by a reactor
containment shell 130, as is schematically indicated by the dash
line. In case the reactor pressure vessel 1 leaks, the leakage
water is collected in the contain~ent shell 130, whereby such a
~3~6717
- 13 - 20365-2994
large volume of water is selec~ed that the reactor core 2 is still
covered if the liquid level in the vessels 1 and 130 is the same.
The steam plenum 14 is located above the water level 3. The dash-
dot exterior line 15 indica~es which components and pipelines of
the illustrated heating reactor system are surrounded by a con-
crete casing of the reactor building or are accommodated under-
ground in concrete buildings, whereby these concrete buildings are
covered on the outside by heavy concrete casings and are also pro-
tected against airplane crashes.
The present invention deals in particular with a heating
reactor system with a thermal power output in the range of approx-
imately 5 to 200 MW. All sub-systems must be designed as simply
as possible in such a heating reactor system.
For the sake of clarity, the heating reactor system in
Figure 2 is illustrated with only a one line intermediate circuit
ZK. It is understood that two, three ox more lines ~kl, zk2, etc.
(as in Figure 1) could be provided. In Figure 2 and also the fol-
lowing Figures the parts with the same ~unction as those in Figure
1 are identified by the same reference numerals.
In addition to the illu3tration in Figure 1, reference
numeral~ rela ing to the cold line 9.2 were added in Figures 2 and
3 for a pipe section 9.21 between the second heat exchanger 6 and
the pump 5, for a pipe section 9.22 between the pump 5 and a
branch point 16 and for a pipe section 9~23 between the branch
point 16 and the first heat exchanger 4. It can already be seen
from Figure 1 that there are no conventional valves for the
change-over to emergency cooling operation. Figure 2 shows in
greater detail that the respective flow rate regulating units for
~3~6717
- 14 20365-29g4
the after heat removal branch 10, 11, 12 are designed as a vortex
chamber valve WV comprising a hydraulic connection sO for the
supply current sl, a connection cO or the control current cl and
a connection eO for the outlet current el. The internally con-
trollable current path sO-eO is thereby connected at the branch
point 17 to the hot line 9.1 of the intermediate circuit ZK via
the associated pipe section 11.1 of th~ influx pipe 11 of the
cooler 10 and the hydraulic connection cO for the control current
cl is connected at the branch point 18 to the delivery side of
the pump 5 of the intermediate circuit.
A single such vortex chamber valve WV is schematically
illustrated in Figures ~ to 6 for better understanding. Its hy-
draulic connections sO, cO and eO and the fluid currents, namely
the supply current sl~ control current cl and outlet current el,
are identified exactly the same as in Figure 2. The radial vor-
tex chamber valve WV illustrated by way of example in Figure 4
(there are also axial and conical vortex valves) consists of a
flat, hollow cylindrical vortex chamber housing 19 containing a
vortex chamber 19', a connection piece for the supply current sl
or suppl~ connection sO 10wing radially into the vortex chamber
19i, a connec~on piece for the control current cl or control con-
connection cO flowing tangentially into the vortex chamber 19' and
a connection piece for the outlet currentel or an outlet connection
eO arranged axially with respect to the rotational axis of the
housingl9 or the vortex chamber 19', As illustrated, the outlet
connection eO can be designed like a nozzle or Venturi tube in
order to keep the pressure drop as small as possible. The supply
current sl, illustrated by dash lines,
~26717
- 15 - 20365-2994
which is fed through the radially arranged supply connectlon sO,
leaves the vortex chamber 19' through the axial outlet connection
eO, whereby it is first of all assumed that no control current cl
is flowing yet. The throttle effect of this vortex chamber valve
WV is then relatively low and sl = el. If a control current cl,
whose control pressure is about 5 to 10% higher -than the pressure
of the supply current sl, is sent through the tangential control
connection cO, then an increasingly intensive twisting flow is
produced in the vortex chamber 19' as the quantity of control cur-
rent increases. Its centrifugal force causes the build-up of a
counterpressure in the vortex chamber 19' which can reduce and
thus control the influx of supply current sl (or increase it again
with decreasing control current cl). A relatively low maximum
control current throughput of approximately 10 to 20% of the maxi-
mum throughput of the supply current sl is enough to bring the
supply current sl to a standstill. The control current cl flows
from the tangential control connection cO in spirals to the axial
outlet connection eO and this spiral flow continues in its connec-
tion piece. The outlet current el can contain both the control
current cl as well as the supply current sl. If, however, the
throughpu~ of the control current cl reaches the designated maxi-
mum of approximate]y 10 to 20% of the supply current sl, then the
latter comes to a standstill. The outlet current el then only
contains the control current cl so that then approximately 20% of
the throughput of the to a large extent blocked supply current sl
flow3.
Figure 4 shows the general view, Figure 5 æhows a
simp]ified flow diagram and Figure 6 shows the circuit symbol
~ 3L32~7~7
- 16 - 20365-2994
obtained therefrom of the vortex chamber valve WV which can also
be simply identified as a vortex valve.
Coming back to Figure 2: It illustrates th0 "normal
operation" in which the secondary coolant of the intermediate cir-
cuit ZK is circulated by the pump 5 - see arrow f2. The control
connection cO (tangential control current cl) of the associated
vortex chamber valve WV is connected to the delivery side of the
pump 5 via pipe 13 and with its supply connection sO is connected
at the branch point to the hot line 9.1 of the intermediate cir-
cuit ZK via the pipe 11.1. If the pump 5 is running, then the
supply current sl is almost stopped by the control current cl,
i.e. flow via the cooler 10 is prevented. The low control current
cl flows via the outlet connection eO as outlet current el and via
the pipe 11.2 to the cooler 10, is cooled in the cooler 10 and
then flows back to the branch point 16 via the reflux pipe ~ F
where it mlxes with the secondary coolant in the cold line 9.2 of
the intermediate circuit ZK. Since almost no supply current sl
flows during the operating condition illustrated in Figure 2, ~he
correQponding reference numeral i8 placed in brackets and the a~-
sociated arrow is illustrated by dash lines. Furthermore, due to
the low throughput the outlet current el i8 only illustrated by
dash lines.
Figure 3 shows the operatin~ condition "afterheat remov-
al". Pump 5 is thereby switched off. The vortex chamber valve WV
has lost its blocking function since the control current cl (there
is only natural circulation) is brought to a standstill on account
of the pressure ratios. As is made clear by the arrow~ sl-el-f3,
the ~econdary coolant of the intexmediate circuit ~K circulates
132~i7~l7
- 17 ~ 20365-2994
via the cooler 10. No or almost no control current cl is flowing
any longerO Reference numeral cl is therefore placed in brackets
and the associated arrow is illustrated by dash lines. However,
the supply current sl, whose throughput is equal to that of the
outlet current el, is flowing. Since the pump 5 is stopped, the
flow stagnates at the primary side of the second heat exchanger 6
and in the pipe section 9.21 and the transfer pump (not illustrat-
ed) provided for the heat supply network HN is also no longer
working.
The heating reartor system according to Figure 7 corre-
sponds in principle to that according to Figures 1 to 3. Added to
this embodiment are two isolating valves 20a, 20b connected di-
rectly in front of and after the pump 51 pressure vessels 21 re-
spectively connected to the cold lines 9.2 of the intermediate
circuit ZK, a non-return flap 107 in the branch 9.21, and in the
six lines zkl to zk6 illustrated of the intermediate circuit ZK
motor-actuated control flaps or spool valves 105 provided in the
hot line 9.1 and control flaps or spool valves 106 provided in the
cold line 9.2. The non-return flap 107 allows a primary-side flow
through the second heat exchanger 6 only in direction f2. The
isol~ting valves 20a, 20b are used to separate the pump 5 from the
remainins network during maintenance or repair work. The first
heat exchangers 4 are modified ~omewhat in comparison to those in
Figures 1 to 3. Their heat exchanger tubes 4.1 are divided into
two partial tube bundles or pipe coils 4.11 and 4.12 connected
parallel to one another. In addition, it can be seen that the
pipes for the hot line 9.1 and the cold line 9.2 of the intermedi-
ate circuit ZK leaving the first heat exchangers 4 are guided to
~32~7~7
- 18 - 20365-2~94
the outside through the casing wall 103 of the reactor pressure
vessel 1 below its closure head flange connection 101, 102.
Flange 101 is part of the vessel base portion 1.1 and flange 102
is part of the closure 1.2.
The exemplary embodiments according to Figures 1 to 7
are based on a circuit arrangement wherein the afterheat removal
branch 11, 10, 12 is connected to the hot or cold line 9.1, 9.2 on
the secondary side of the first heat exchanger 4~ I~ the heat ex-
changers 4 are arr~nged within the reactor pressure vessel 1 at a
sufficiently large distance from the reactor core 2, then activa-
tion of the secondary coolant is relatively low and having the
secondary coolant act on the afterheat removal branch is justi-
fied. In principle, it is also possible, however, to provide
separate condensers in the steam plenum 14 of the reactor pressure
vessel 1 for afterheat removalO
The heating reactor system illustrated in Figure 8 is
preferably suitable for a thermal power output in the range of 5
to 50 MW. The reactor building is again identified by reference
numeral 15 and it is illustrated somewhat more clearly that it
consists of concrete walls. It is arranged underground in a cor-
responding chamber 22 in the ground 23. The afterheat removal
branch with its influx pipe 11, the cooler 10 and the reflux pipe
12 is connected to the hot line 25.1 of a condenser 24 via the
vortex chamber valve WV, namely its controllable current path
(sO-eO) between the supply connection sO and the outlet connection
eO, and to the cold line 25.2 of the condenser 24 at the connec-
tion point 26 of the reflux pipe 12. The condenser 24 is arranged
in the steam plenum 14 of the reactor pressure vessel 1. The path
1326717
- 19 - 20365-2994
of the steam rising in the volu~e of water 3 is schematically il-
lustrated by the flow path F2 and the direction arrows f4. The
steam flows through the primary side of the condenser 24~and, if
the condenser 24 is cooled on the secondary side, releases its
vaporization heat via the heat exchanger tubes 24.1 to the ter-
tiary medium flowing therein, whereby the steam condenses and
flows back into the volume o4 water 3 in accordance with flow
arrows f5.
The second heat exchanger 6 - in this exemplary embodi-
ment of a so called integral design - is also arranged in the
steam plenum 14, i.e. also within the space enclosed by the reac-
tor pressure vessel 1. For this reason the output pipe 7 and the
return pipe 8 of the heat supply network HN penetrate the wall of
the reactor pressure vessel 1, namely preferably the casing wall
lU3, and are connected to the outlet end or the inlet end of the
heat exchanger tubes 6.1 of the second heat exchanger 6. On their
way to or from the second heat exchanger 6 the output and return
pipe~ also penetrate the wall of the reactor containment shell 130
and the wall of the reactor building 15. The individual penetra-
tion po1nts, seen from the outside in, are identified by reference
numerals 7a, 7b and 7c for the output pipe 7 and by reference
numerals 8a, 8b and 8c for the return pipe 8. The penetration
point 7c, 8c of the output and return pipes 7, 8 are arranged
below the pressure-sealed closure head flange connection 101, 102.
The secondary side of the first heat exchanger 4, i.e. the inlet
and outlet endR of its heat exchanger tube~ 4.1, is connected to
the primary side of the second ~integral) heat exchanger 6 via the
hot and the cold secondary coolant line 9~1 or 9.2. For this
~ ~32~7~7
- 20 - ~0365-2994
reason the secondary coolant flows around the outside of the heat
exchanger tubes 6.1 of the second heat exchanger 6, the tertiary
medium of the heat supply network ~N flowing throu~h these tubes
6.1 during normal operation.
A motor-driven, remote-controllable valve 27 or 28 is
inserted in each of the two pipes 7 and 8 (output and return pipe)
within the reactor building 15 and preferably outside the contain-
ment vessel 130. These valves 27, 28 can also be isolatin~ valves
since they can completely separate the secondary side of the
second heat exchanger 6 from the heat supply network if they are
in the closed position. An adjustable throttle 29 connected in
series to the valve 28 and preceding it is located in the return
pipe 8, this throttle generating, on account of the pressure drop
formed at it, a control pressure for the control current cl during
normal heating operation. The control current comprises a partial
current of the liquid heating medium branched o~f in front of the
throttle 2g, this heating medium being fed to the control connec-
tion cO of the vortex chamber valve WV via the control pipe 30
connected at the input side of the throttle 29.
The illustration in Yigure 8, just as the illustrations
in Figures 1 to 7, is schematic, i.e. supports and holders ~or the
containment ve~sel 130, the reactor pressure vessel 1, the first
and second heat exchangers ~ and 6, the condenser 24, the valves
27l 28 and the throttle 29 as well as for the reactor core 2 are
~ot illustrated. The volume in the space 108 between the reactor
pressure vessel 1 and the reactor containment vessel 130 on the one
hand and the volume of water 3 on the other hand are determined
in such
i326717
- 21 - 20365-2994
a way that in the event of a leak in the wall of the reactor pres-
sure vessel 1 the liquid level for the (now reduced) volume of
water 3 will adjust to the volume of water in the space 108 such
that the reactor core 2 at any rate remains covered with primary
coolant.
The reflux pipe 12 ends via a pipe branch 12.1 at the
connection point 31 between the valve 28 and the throttle 29.
During normal operation, i.e. when the heating medium in the heat
supply network, not illustrated in greater detail, flows in accor-
dance with the arrows f6 ~output) and f7 (return), the throttle 29
throttles down to such an extent that the dynamic pressure at its
input side acts as control pre~gure on the control connection cO
of the vortex chamber valve WV, namely ~uch that the controllable
current path sO-eO is to a large extent blocked so that no appre-
ciable supply current sl can be built up via the hot line 25.1 of
the conden~er 24. A first portion of the heating medium thus
flows directly to the second heat exchanger 6 via the throttle 29
and the valve 28 and a second ~smaller, during normal operation)
portion flows via the control pipe 30 and the control connection-
outlet connection section cO-eO of the vortex chamber valve WV as
well as via the influx pipe 11 into the cooler 10 where it is
cooled down somewhat urther and then flows through the reflux
pipe 12 back to the connection point 31 and from there tc the
second heat exchanger 6. During this operating condition the con-
denqer ~4 contributes almost nothing or nothing appreciable to the
steam cooling since the supply current sl which can flow via the
section sO-eO of the vortex chamber valve WV is very small. The
arrows sOl in dash lines identify thi~ low power flow which is fed
~32~717
- 22 - 2~365-29
and maintained by the heating medium (tertiary medium).
If the two isolating valves 27, 28 are closed in the
course of inspection or repair work and/or if a fuel element i5
replaced and if the external pumps (not illustrated) conveying the
heating medium are thereby accordingly also switched off, then the
control pressure in the control pipe 30 drops to such an extent
that the throttle effect of the control current cl stops. The
section sO-eO of the vortex chamber valve WV is unblocked since
its flow resistance is reduced considerably, resulting in a closed
cooling circuit which i5 in addition induced by the forced
heating of the medium in the heat exchanger tubes 24.1 of the con-
denser 24, namely because the first and second heat exchangers 4
and 6 can no longer contribute to the removal of heat. The con-
trol rods are inserted into the reactor core 2 during this after-
heat removal op~ration and the condenser 24 is thus used to remove
the decay heat. The tertiary medium flows via the hot line 2S.l,
the ~ection sO-eO of the vortex chamber valve WV and the influx
pipe 11 to ~he cooler 10, is cooled ~here (the cooler can be an
air cooler or a water cooler) and, cooled of~, flows back to the
heat exchanger tubes 24.1 of the conden~er 24 via the reflux pipe
12, the connection point 26 and the cold line 25.2. As can be
seen, the removal of decay heat in the exemplary embodiment ac
cording to Figure 8 can be induced without having to open addi~
tional valves in the afterheat removal branch 10, 11, 12. The
vortex chambPr valve WV takes over the automatic change-over if
the control pres~ure alls below a minimum value at its control
connection cO and switche~ back to normal operation if the control
pressure exceeds a miniumum value at the control connection cO.
~32~717
- 23 - 20365-2994
A variant of the heating reactor system according to
Figure 8 is illustrated in Figure 9. The control pressure for the
control connection cO of the vortex chamber valve WV is thereby
generated not by throttling the flow in the return pipe 8 of the
heat supply network, but by a control current pump 40 inserted in
a control current path 41, 42, this control current pump being
connected at connection point 26 to the reflux pipe 12 via a suc-
tion pipe 41 and to the control connection cO of the vortex cham-
ber valve ~ via a pressure pipe 42. During normal heating opera-
tion of the illustrated heating reactor HR the control current
pump 40 operates as a continuous running pump. The throughput
pumped by it is relatively small so that a small control current
pump is sufficient. During normal operation of the heating reac-
tor HR a control pressure blocking or sharply throttling the in-
ternally controllable current path sO-eO of the vortex chamber
valve WV is generated by the control current pump 40. If the
heating reactor HR is shut down - this occurs when the control
rods, not illustrated, are fully inserted into the core of the
heating reactor HR - then the control current pump 4n is al~o
switched of. The means for stopping the control current pump 40
advantageou~ly depend for control on the command for insertion of
the control rods (not illustrated). For example, an electrical
command which, for example, cuts the power supply for the driYe
motor of the control current pump 40 via a relay or an electronic
switch can be derived from the electrical or hydraulic command for
the complete insertion of ~he control rods and thus for the
shutdown oE the heating reactor. On the other hand, when the
heating reactor HR is restarted the relay or electronic switch is
3L~2671~
- 24 - 20365-29g4
controlled in such a way tha~ the motor is switched on again and
the pump 40 begins to run. With the control current pump 40
switched o~f, the controllable current path sO-eO of the vortex
chamber valve WV is opened for an unthrottled flow so that, as was
already explained on the basis of Figure 8, natural circulation
flow develops via the hot line 25.1 of the condenser 24, the open
current path sO-eO, the influx pipe 11, the cooler lO, the reflux
pipe 12 and the cold line 25.2 of the condenser 24 back to the
heat exchanger tubes 24.1 of this condenser, the decay heat re-
sulting in the heating reactor HR being removed by this natural
circulation ~low. The heating reactor system according to Figure
9 corresponds otherwise to Figure 8. For this reason only one
section is illustrated.
The afterheat removal circuit according to Figure 9 with
its control current pump 40, the vortex chamber valve WV, the
afterheat removal branch ll, 10, 12 and the connected condenser 24
can be advantageously used to remove the decay heat in a boiling
water reactor or also in a pre~suri~ed water reactor, i.e. in
those light-water reactors which serve to generate driving steam
~or a steam turbo-generator unit. Such a turbo-generator unit
comprises a steam turbine on which the driving steam acts and a
turbo-generator coupled to the steam turbine for generating elec-
trical energy. In this case, one or a plurality of condensers are
arranged within the stea~ plenum of the reactor, whereby the pipes
for the hot and cold lines 25.1, 2S.2 connected to their heat ex-
changer tubes 24.1 are guided to the outside through the wall o
the reactor in corresponding pressure-3ealed penetrations.
It will be explained herebelow on the basis of Figure l
- 25 - 20365-2994
that the afterheat removal circuit illustrated in Figures 1 to 7
is also suitable for removing the decay heat in a boiling water
reactor or a pressurized water reactor. For the explanation, ref-
erence is made herebelow only to the two lines zkl of the inter-
mediate circuit ZK. It is understood, however, that more than one
pair of lines zkl can be used for afterheat removal~
According to the exemplary embodiment, the second heat
exchanger 6 on the secondary side of the first heat exchanger 4 is
replaced by a pipe section 50, illustrated by dash lines, connect-
ing the two secondary coolant lines 9.1, 9.2. As a result the
secondary coolant is circulated by the pump 5 during normal opera-
tion of the reactor (not illustrated) to generate the control
pressure for the control connection cO of the vortex chamber valve
WV. This pump 5, just as the control current pump 40, then oper-
ates as a continuous running pump to genexate the control pres-
sure. Since an external heat supply network HN is not connected
in this case, the pipes for the hot and cold line 9.1~ 9.2 can be
hortened. Ths controllable current pa~h sO-eO of the vortex
valve WV is blocked or sharply throttled, as was already e~plained
several times. A control command for ~witching off the drive
motor of the pump S is only given when the control rods in the
boiling water or pressurized water reastor are moved into the com~
pletely shutdown position and the controllable current path of the
vortex chamber valve WV is thus opened; afterheat removal opera-
tion in the natural circulation flow begins immediately. The
secondary coolant heated in the heat exchanger tubes 4.1 of the
~irst heat exchanger 4 flows via the hot line, the pipe section
11.1, the current path sO-eO of the vortex chamber valve WV, the
~326717
- 26 - 20365-~,9g4
influx pipe 11, the cooler lOa and the reflux pipe 12 back to the
cold line 9.2 and rom there to the heat exchanger 4, whereby the
secondary coolant is continuously cooled in the cooler lOa and the
decay heat is thus removed. In this exemplary embodiment the
first,heat exchanger 4, disposed in the volume of water 3 of the
boiling water or pressurized water reactor, is utilized a~ a heat
sink for the removal of decay heat. The two pipes 9.1 and 9.2 for
its hot and cold line ~ust again be guided pressure-sealed to the
outside through the wall of the reactor pressure vessel. These
pipe penetrations can be provided in the cover or the casins wall
of the reactor pressure vessel, not illustrated.
In acordance with the second embodiment for using the
afterheat removal circuit with a vortex chamber valve for boiling
water or pressurized water reactors, the pump 5 i~ dispensed with
in accordance with the exemplary embodiment according to Figure 9.
It is sufficient if the intermediate circuit lines zkl under con-
sideration extend only up to the points 61, 62 indicated by the
da~h lines. Instead of the pump 5 in the cold line 9.2, a control
current pump 60 is disposed in this embodiment in the control cur-
rent path 13. Thi~ pump 60 is lik~wise only illustrated by dash
lines ~ince it is a variant within the framework of the use. The
control current pump 60 is connected to ~he reflux pipe 12 via a
suction pipe section 13.1 of the control current path 13 (or to
the pipe section of the hot line 9.2 connected to it) and to the
control connection cO of the vortex chamber valve WV via a pres-
sure pipe section 13.2 of the control current path 13. As was
already explained on the basis of ~'igure 9, a control pre~sure
blocking or sharply throttling the internally controllable current
~326717
, ,~
- 27 - 20365-29g4
path sO-eO of the vortex chamber valve WV is generated by the con-
trol current pump 60 during normal operation of the reactor (not
illustrated). As well, means (not illustrated) which were already
explained in greater detail on the basis of Figure 9 are again
provided for stopping the control current pump 60 during shutdown
of the reactor. The advantage of this embodiment lies therein
that the throughput of the control current pump 60 amounts to ap-
proximately only 10 to 20% of the throughput which the pump 5 must
circulate. The control current pump can therefore be a relatively
small pump.
