CA1066435A - Reactor plant for a district heating plant - Google Patents
Reactor plant for a district heating plantInfo
- Publication number
- CA1066435A CA1066435A CA254,400A CA254400A CA1066435A CA 1066435 A CA1066435 A CA 1066435A CA 254400 A CA254400 A CA 254400A CA 1066435 A CA1066435 A CA 1066435A
- Authority
- CA
- Canada
- Prior art keywords
- reactor
- pool
- water
- outlet
- space
- Prior art date
- Legal status (The legal status is an assumption and is not a legal conclusion. Google has not performed a legal analysis and makes no representation as to the accuracy of the status listed.)
- Expired
Links
Classifications
-
- G—PHYSICS
- G21—NUCLEAR PHYSICS; NUCLEAR ENGINEERING
- G21C—NUCLEAR REACTORS
- G21C15/00—Cooling arrangements within the pressure vessel containing the core; Selection of specific coolants
- G21C15/18—Emergency cooling arrangements; Removing shut-down heat
-
- G—PHYSICS
- G21—NUCLEAR PHYSICS; NUCLEAR ENGINEERING
- G21C—NUCLEAR REACTORS
- G21C1/00—Reactor types
- G21C1/04—Thermal reactors ; Epithermal reactors
- G21C1/06—Heterogeneous reactors, i.e. in which fuel and moderator are separated
- G21C1/14—Heterogeneous reactors, i.e. in which fuel and moderator are separated moderator being substantially not pressurised, e.g. swimming-pool reactor
-
- Y—GENERAL TAGGING OF NEW TECHNOLOGICAL DEVELOPMENTS; GENERAL TAGGING OF CROSS-SECTIONAL TECHNOLOGIES SPANNING OVER SEVERAL SECTIONS OF THE IPC; TECHNICAL SUBJECTS COVERED BY FORMER USPC CROSS-REFERENCE ART COLLECTIONS [XRACs] AND DIGESTS
- Y02—TECHNOLOGIES OR APPLICATIONS FOR MITIGATION OR ADAPTATION AGAINST CLIMATE CHANGE
- Y02E—REDUCTION OF GREENHOUSE GAS [GHG] EMISSIONS, RELATED TO ENERGY GENERATION, TRANSMISSION OR DISTRIBUTION
- Y02E30/00—Energy generation of nuclear origin
- Y02E30/30—Nuclear fission reactors
Abstract
ABSTRACT OF THE DISCLOSURE:
Reactor plant comprising a light-water-cooled reactor core with vertical fuel assemblies, a reactor vessel with an inlet space and an outlet space, separated from the inlet space, for cooling water flowing through the reactor core, a heat-exchanger, a circulating pump for the primary circuit of the heat-exchanger, and a water-filled pool. The inlet and outlet spaces are provided each with at least one hydraulic connection with the heat-exchanger. The reactor core is enclosed in the reactor vessel and the reactor vessel arranged in the pool. The coolant of the primary coolant circuit during normal operation is blocked from the pool water by means of a blocking device with a liftable blocking effect. The primary coolant circuit, through an outlet opening and an inlet opening in the defining walls of the primary coolant circuit, is constantly in an open connection with the pool space and the outlet opening is provided with a connecting means for this purpose in the form of a gas lock tube.
Reactor plant comprising a light-water-cooled reactor core with vertical fuel assemblies, a reactor vessel with an inlet space and an outlet space, separated from the inlet space, for cooling water flowing through the reactor core, a heat-exchanger, a circulating pump for the primary circuit of the heat-exchanger, and a water-filled pool. The inlet and outlet spaces are provided each with at least one hydraulic connection with the heat-exchanger. The reactor core is enclosed in the reactor vessel and the reactor vessel arranged in the pool. The coolant of the primary coolant circuit during normal operation is blocked from the pool water by means of a blocking device with a liftable blocking effect. The primary coolant circuit, through an outlet opening and an inlet opening in the defining walls of the primary coolant circuit, is constantly in an open connection with the pool space and the outlet opening is provided with a connecting means for this purpose in the form of a gas lock tube.
Description
~06643S
The present invention relates to a reactor plant comprising a light-water-cooled reactor core with vertical fuel assemblies, a reactor vessel with an inlet space and an outlet space for cooling water flowing through the reactor core, a heat-exchanger, a circulating pump for the primary circuit of the heat-exchanger, and a water-filled pool, said inlet and outlet spaces each being provided with at least one hydraulic connection with the heat-exchanger, the reactor core being contained in the reactor vessel and the reactor vessel arranged in said pool, the coolant of the primary coolant circuit during normal reactor operation being blocked from the pool water by means of a blocking device with a liftable blocking effect.
In particular a nuclear reactor is aimed at which can suitably be used in a district heating plant. Such a reactor is described in "The American Nuclear Society Transactions", Vol. 20, pp. 733-734. In the known reactor it is possible to achieve emergency cooling with the pool as a heat sink. This is done by operating two valves, by means of which the pool water flows in through an inlet opening in the primary coolant circuit of the reactor and steam and hot water flow out from this through an outlet opening.
However, it is a disadvantage in the known device that the emergency cooling function is dependent on the transport and correct positioning of solid bodies, namely the valve bodies included in the above-mentioned valves. A construction according to the invention aims at avoiding this drawback.
Instead of valves with movable parts, a number of so-called "gas lock tubes" are used according to the invention. In the following, the term "gas lock tube" refers to a bent tube which is immersed in a liquid and arranged with both its ends below an intermediate tube portion, in which an amount of gas is contained, or a device equivalent thereto.
' 1066435 ~ s herein claimed, a reactor plant according to the invention is characterized in that the primary coolant circuit, through an outlet opening and an inlet opening in the walls defining the primary coolant circuit, is constantly in an open connection with the pool space, at least the outlet opening being provided with a connecting means for this purpose in the form of a gas lock tu~e.
.. . . . . .
- la -In the following the invention will be described with reference to the accompanying schematic drawings in which Figures 1 and 2 show two different embodiments of the invention in vertical section and Figure 3 a partial section along III-III
of Figure 2~ Figure 2 is a section along II-II of Figure 3.
The reactors shown are of the pressurized water type, i.e.
boiling does not occur during normal operation since problems of stability could arise at the low pressures which are used in this connection.
In Figure 1, 1 designates a water-filled pool which may suitably be designed with a maximum depth of about 25 metres. Near the bottom of the pool a reactor vessel 2 is arranged, which contains a reactor core 3 and a plurality of control rods 4. The reactor vessel is connected to the primary side of a heat-exchanger 5 by means of a conduit 7 for relatively cold water flowing into the reactor vessel, and a conduit 6 for relatively hot water which leaves the reactor core 3, a circulating pump 8 being included in the conduit 7.
The conduit 6 opens out into an inlet chamber 9 and the conduit 7 comes out from an outlet chamber 10 of the heat-exchanger.
From the inlet chamber 9 the water flows through vertical tubes 11 and up to a turning chamber 12 from which it 10ws bask through vertical tubes 13 to the outlet chamber 10 of the heat-exchanger. The parts 2, 6, 9, 11, 12, 13, 10, 7 and 8 together form the primary coolant circuit of the core 3 which contains only pure water. The corresponding secondary coolant circuit consists of the spaces between the tubes 11 and 13, an outgoing conduit 14 and a return conduit 15 and a number of consumers connected to the conduits 14 and 15, preferably directly connected heating-plants for room heating of houses and work places. The secondary coolant circuit preferably has higher water pressure than the primary circuit. The lower part of ~066435 the reactor vessel 2 is the inlet space and its upper part the outlet space for the reactor core 3.
The primary coolant circuit is constructed with an outlet opening 16 and an inlet opening 17, through which it is in a permanent open communication with the pool space by way of two gas lock tubes 18 and 19, which are connected to the openings 16 and 17, respectively. As indicated in the drawing, the gas lock tubes 18 and 19 each contains an enclosed amount of gas, which are connected each to a pressure-regulated gas tank 22 and 23 by way of relatively thin tubes 20 and 21, respectively. The gas pressure in the gas tank 22 is chosen approximately equal to the water pressure at the lower opening of the gas lock tube 18, i.e. only so much higher than a slight bubbling out of air can be observed at this opening. This will give an indication that an even pressure is maintained in the gas lock tube. Alternatively, the pressure in the gas tanks 22 and 23 can be chosen much higher, for example more than 150% of said water pressure, the pipes 20 and 21 then being provided each with a throttling means.
In order for the water levels of the two gas lock tu~es to adjust themselves as indicated in the drawing, the tube 19 must be supplied with gas, the pressure of which - counting in water columns - is equal to the gas pressure in the tube 18 plus the difference hl between the water levels of the `two tubes. As indicated in the drawing, such a high pressuriza-tion can be used that the water pressure at the outlet of the core 3 will be considerably greater than what corresponds to the water pressure in the pool. The vertical dimension of the gas lock tube 18 can be chosen greater than, e.g. one-fourth of the maximum water depth in the pool, thus achieving a considerable increase in the water pressure in the core, which means that a higher water temperature can be allowed at ~ _ 3 _ a given pool depth without getting too close to the boiling point.
Also in the event that the gas amount contained in the gas locks has a very small vertical dimension, the air lock tubes have an important function since in normal operation they effectively prevent the reactor water and the pool water from being intermixed. When level variations occur, among other things since the difference between the water levels of the air lock tubes is greater when the pump 3 is in operation than in the purely static case, the vertical dimensions of the gas lock tubes must, however, be chosen so large that the contained amount of air does not leave the gas lock tube during normal operation. As a rule, it may be taken into account that the gas lock tube shall be dimensioned to allow a contained amount of air whose vertical dimension is greater than one metre.
A reactor according to the invention is designed to fulfil extrem~ security demands. Even in the very hypothetical case that the circulating pump 8 seizes and the control rods 4 for some reason are jam~ed outside the core at the same time, it may be counted on, with a great degree of security, that no radioactive discharge will take place, and that there will be no risk that the fuel rods will melt down.
If a sudden boiling takes place in the reactor core 3, for example because of an intentional or unintentional faulty drawing of the control rods or an instantaneous pump stop without a subsequent reactor trip, the steam formation will first result in part of the water of the primary system being pressed out through the gas lock tube 18. This does not necessarily lead to a breakdown of the air locks. Since we assume that there are negative void coefficients of reactivity, the void contents will then result in the power being rapidly ~ - 3a -reduced to less than 5 % of the normal power. The evaporation continues and the gas lock tube 18 is filled with steam while the water level slowly sinks.
- 3b -.
~066435 B~ openlng the valves 24 ana 25 RO that the ~as pressure aiæappears ln the tanks 22 snd 23, lt ~ould be pos~lble to aohie~e a relatirel~ rapid inno~
of pool ~ater into the primary ooolant olrouit of the reaotor. ~o~ver, slnce the behaviour of the resotor under the ~orst i~agiDable condit~ons 18 of intere~t, ~c assu~e that the valves 24 and 25 are not operating.
If an evaporatlon ooours ln the reaotor oore, the dlfferenoe bet~een the l~ el ln the heat-eschan~er ana the level in a connected branoh Or the lo~er gas look tub~ ~ill deorease Rlo~ly, ~hioh eans that the pool water ~111 rlse to such an e%tent ln the long branch of the lo~er &a8 loc~ tube that the pool ~ater finally passes the horlzontal part of bhe gas loc}s ana 18 suppllea to the pri~ar1 coolant clrcuit of the reactor. Such replenishment oan be repeated several times, but the water level in the heat-e%chan~er can n~rer rlse hiBher than to a certain ~a~imu~ level, namel~ bhat ~hich coinclaes ~ith the lo~er openlng of the upper ~as lock tube. It 18 i~portant that the ~hole reactor core 18 arranBea belo~ this oa2imu~ level. Further, lt 18 es~ential that the upper edg~ of the lo~er eas look tube 1~ arran~ea belo~ the abo e-ntlond a~l~uo le~d , since other~ise lt ~ould be i~po~slble to flll lt ~lth ~ater co pletd ~ ~hen ~ater le flll d ln after ch nsln6~ which ~ould inrolve that a per a~nent ~as plug ~Oula oocur at the upper ost part o~ th-Bas loc~ tuOe 19, ~hlch ~Oula pr ront th fbrth r supply Or pool ~ater to the r aotor. ~8 ~8 shown ln the ara~ing, both the Op~nln68 of the pri~ary s~te , which arQ pro ldel ~lth Ras loc~s, are arransea in such a ~a~ that the outl-t op nlng - coN~ting in th clrcul-tlng alr otlon of th prl-ary clroult - has relatl~el~ ~hort alstance and the iDlet oponlng a relatlr ly long alstan~- ~ror th space abo~e the reaotor core. The lnlet opeul~6 17 ~houla Oe arran pa a~ ~ar down as posslbl-~ ho~er r lt shoula be aOo - th oore . aounting~ln the clrcul-tlng alreotlon o~ th prl-ary ooolant olrcult, th purp 8 18 looatd aft r the lnlet oponlng 17an~ before the oore ~, and therefore the pressurlsatlon ocourrin6 ~hen th pu p 18 ~or~lng oaus-s an equally ~reat lncr~ se ln th pres~ure of th coro 3, ~hereas th l- el ln the Bas loo~ tube 19 18 lnfluenosa to a r-la-tl~el~ d l ae6re- ~h n the sps~a of the pu p 1~ o _ . _ _ _ In Flgures 2 ana 3~ 30 18 a reaotor oore ~hloh 18 arrsDBod ln a ~ater-fllld r aotor essel 34 ana oonstruotsa fro a plurallt~ of ~ertloallJ arran~ea fuol a~se~blle~. ~he r actor ssd 18 arraneed ln a ~ator-rilld pool spao-31. ~he ~at r l~ el ln th- pool ~8 ~ho~n by the sy~bol J.
The reaotor oore 30 18 surrouna d by a flo w ontrolllng oadn6 32, the upp r dge of ~hioh 1~ fastenea to a ooDlcal~ annular sore n 33~ th out-r dge o~
~hloh 18 attaoh~a to th reaotor essel 34 ~n a pressure-tlght ~nn r. Th soreen 33 aeflnes an inlet space 35 bJ its under slae and b~ lts upper slde it a-rines an outlet spaoe 36 for the cooling ~ater flo~g tbrough the reac-tor core. The outlet space 36 1~ pro lded at its lo~er end ~ith a lo~er gaJ
loo~ tub- 37, the short branch 37' of ~hlch 18 ~ater-flllea, ~hereas the long branch 37~ aurins nor~al operation is gas-flllea and arran6ea ~ith a predo l-na~t part of lts length in a ~ell 58 the aepth of ~hich countlng ~ro the pool botto 18 Breater th~n one-~ourth o~ the aqp~h of the pool.
The outlet ~pace 36 is ~urther pro~idea ~ith ~wo upper gas loo} tubes 3~, of ~hich the branch connect d to the r actor ~essel is in nor~al operation ~ater-filled ana the other branch gas-fillea.
~t th upper end of the reactor es~el an annnlar pump cha~ber 39 i8 definea b~ mean~ of an annular pu~p ~ o~ 40 ana a hollo~ c~llnarloal ~11 41. ~t lea~t on~ ~usp 57 1~ arrangea to pu~p ~ater ~ro~ the outlet spao- 36 to the pu p ohu b r 39.
....
A plurallt~ Or heat-~ch~n~ru, Or ~hich only ona 18 ~ho~n ln Flgure 2, ar arrane~a ln th reaotor -88-L ~ach h at-e~changer con d st~ of a tub- 42, the upper end of ~hlch 1~ e~led ana pro id d ~it]h t~o conneotlon ~oo~ ts 43 ror ooonootlon Or tho lnlot a~a outl-t oondultc of th seoond~rJ olrc~lt, ~hioh are lnalcat d 1~ Flgur- 3 b~ th ~ots ~na da~he~ a-d4n~t d ~ and 45.
Th ~ ooJ~ar~ of th h at_~cotuo46~r oooslsts o~ a plurall b orLloo~ 46 arr ng d 1~ th tub- 42 and th ~rl~rr c~- of th 8paO- urroq~ d b~ th tub- 42 and t oooupl d b~ t]h tub- loopc 46. Th tub- 42 ha- a yr~-s~r--tlght pb~-ag thrcugh th r ~otor e-8 d 34, the snnular pu p d o~ 40 aod th oooloal or- n 33 na OponJ out ~lth lt~ lower en~ into th lDl-t pac-35~ th retur~ ~at r ~ro- tho pri brr ala- of the heat-~loh~D~r n o~ioB o~t lnto th p o- 35. ~her tror th ~ator n 0~8 thso~gh th oore ~0 a~a lt~ o~t-l-t oha ber 36 ~ro- ~h r~ lt pa~ th puap 57 an~ th pu p ohaab r 39 ana then rlo~ at th upy r ~D~ of the Wbo 42 throogh a plurallt;r Or hol- 47 ~hloh, tog ther ~lth th pu p oha ber, oo~stltut- a kvdsawllo oonn~otlon bot~e~ the prl rr lde Or th heat-e~#h ry~r ana th o~tl-t ~pao- 36 o~
th roaotor es~-l.
pl~rallt~ Or oontrol roa eU~a tubos 48 ar- ~opt 1~ th- oorr ct posltlon b~ eaDs Or ~ rlAg 49 whloh 1- ittaoh d to th- reaotor ess-l ~lth t~e h lp of a plusallt~ Or ~t~o 50. ~ plursllt;r Or oontrol roas ar- oh faJt nea to a oontrol ro~ sbart 51 ~r ~eans Or an ol otro~agnet, not ho~, th- ~lnd-in~ of ~hloh 18 oerl-~-oonnsot d to a t~pera~uro fu~e in th for~ of a lt-ing body ~hloh elt~ ana br a~- th ourront lf th te per~t~ in th ~at r o~ tho re~otor 088-l tond~ to b oo e too hlgh, th t 1~, lr th r- 1B ~ rl-~o~ bolling ooourrlDs ln th re~otor ese-l.
- .~ 1066435 ~a¢h of the ¢ontrol rod shafts i8 conneotea to a control rd drl~e 53 attached to the reactor ~essel co~er 52 wbich control rod dri~es are oon-neoted eaoh to an eleotric ~otor 55 b~ ~ay Or a plurality of shafts 54.
The motors are supported b~ a stana not sho~n attachd to the reactor ~essel oo~er. ~h oo ponents 48 51 52 53 54 ana 55 can be llftea as o unlt in th oase o~ a refuelling.
The oonneotlon of the uppsr 8as lock tube to the vessel i~ dlr~ctl~ beloN
the pump deck To lid t the depth of the ~ell 58 of the lo~er 8as lock tube this i8 oonneotea to the ~essel abo-e the core. During nor al operatlon this requires a d l by-paJs flow pa~t the oore. During deca~ heat ooollng the ~ater supplied throu~h the lo~er 8as look then ~10N8 through a b~-pass ope-nlD~ 56 ~sde for thls purpose to the iolet of the oore.
.
In th o~ont of a pu p stop ~ith falllng r aotor trlp the to p~rature of the oor- o~tlot ~lll rl-- at th _ tl e a- th pr~ssu aiOps in a anner a ter ~nd b~ th ¢o Jt do~n ¢hasaoterlstios of the pu p. For ~a pl- boil-iog a~ ooour ft r about 6 second~ at about 4 bar and 145C in the oor~ out-let. Thi~ te p~rature 18 far abov- the rolease temp~r~tur- of th fu~-- but beoause of thelr lnertia th ~ are not l e~lat l~ r-leasd. Th pressure and tho to p~rature ~lll ther~ror rlse ~h~ boiliog o¢ours #na Br~at a ounts of ~ator ana/or ~tea ar- pr~s~ d out through tho upper Ba8 l00~8. Tho pr esuro arOp io these 18 UJUa~ 0 er at that oo r plenlsh- nt throu~h th- lo~r o~8 look oan bo oou~t d on. B oaus- of th ~olalDg tho po~r of th oor rall~
O oonJ~ rabl- ~nor J- of th fu l te~perature ooours. Th ~ater oon_ tonts of th r~ otor nsd abo e th oor aro unu~uall~ Br~at aoa a looB
tl~e before all thls oan be pressed out through th upper gas looks booau~e of th- st _ doneloyo~nt~ the fcJ-s r l~s-~ the oontrol roa- fall do~n into th oor ana onlJ the ~eoa~ po~er of th oore neea be ooold off I~ a rea¢tor ~e~sel of the t~pe sho~n 1~ uros 2 aD~ ~ the alstanoe fro-tho upper de- of the oor to the essd oo~er shoula b- at le Jt 60%
preferabl~ re than ?o% of the total heieht of tho reactor ~ess~ t tho sa e tl e th- a~a eter of the ess d shoula be at lea~t 160~ pr f r-abl~ re than 190% of th- ala eter o~ the reaotor oore. Beoaus- of the Broat ala~eter an~ holdhe of the e88d a ~od separatl of st-an ana ~ater 18 obtaln~a ana ool~ 8 al1 prossure alffer~noos a regulrsa to pre~s out the st~a~ throu~h th~ ~pper ou looks~ Thss th Yator upyl~
through the lo~er eaJ loo~ tub- 37 18 seourd.
The Bas of at least ono ~aJ look tubo ~a~ be vater stea~ upplld b~ a speolal boller~ for -~ ple ~ a 8 al1 st~u~ oonkult.
The present invention relates to a reactor plant comprising a light-water-cooled reactor core with vertical fuel assemblies, a reactor vessel with an inlet space and an outlet space for cooling water flowing through the reactor core, a heat-exchanger, a circulating pump for the primary circuit of the heat-exchanger, and a water-filled pool, said inlet and outlet spaces each being provided with at least one hydraulic connection with the heat-exchanger, the reactor core being contained in the reactor vessel and the reactor vessel arranged in said pool, the coolant of the primary coolant circuit during normal reactor operation being blocked from the pool water by means of a blocking device with a liftable blocking effect.
In particular a nuclear reactor is aimed at which can suitably be used in a district heating plant. Such a reactor is described in "The American Nuclear Society Transactions", Vol. 20, pp. 733-734. In the known reactor it is possible to achieve emergency cooling with the pool as a heat sink. This is done by operating two valves, by means of which the pool water flows in through an inlet opening in the primary coolant circuit of the reactor and steam and hot water flow out from this through an outlet opening.
However, it is a disadvantage in the known device that the emergency cooling function is dependent on the transport and correct positioning of solid bodies, namely the valve bodies included in the above-mentioned valves. A construction according to the invention aims at avoiding this drawback.
Instead of valves with movable parts, a number of so-called "gas lock tubes" are used according to the invention. In the following, the term "gas lock tube" refers to a bent tube which is immersed in a liquid and arranged with both its ends below an intermediate tube portion, in which an amount of gas is contained, or a device equivalent thereto.
' 1066435 ~ s herein claimed, a reactor plant according to the invention is characterized in that the primary coolant circuit, through an outlet opening and an inlet opening in the walls defining the primary coolant circuit, is constantly in an open connection with the pool space, at least the outlet opening being provided with a connecting means for this purpose in the form of a gas lock tu~e.
.. . . . . .
- la -In the following the invention will be described with reference to the accompanying schematic drawings in which Figures 1 and 2 show two different embodiments of the invention in vertical section and Figure 3 a partial section along III-III
of Figure 2~ Figure 2 is a section along II-II of Figure 3.
The reactors shown are of the pressurized water type, i.e.
boiling does not occur during normal operation since problems of stability could arise at the low pressures which are used in this connection.
In Figure 1, 1 designates a water-filled pool which may suitably be designed with a maximum depth of about 25 metres. Near the bottom of the pool a reactor vessel 2 is arranged, which contains a reactor core 3 and a plurality of control rods 4. The reactor vessel is connected to the primary side of a heat-exchanger 5 by means of a conduit 7 for relatively cold water flowing into the reactor vessel, and a conduit 6 for relatively hot water which leaves the reactor core 3, a circulating pump 8 being included in the conduit 7.
The conduit 6 opens out into an inlet chamber 9 and the conduit 7 comes out from an outlet chamber 10 of the heat-exchanger.
From the inlet chamber 9 the water flows through vertical tubes 11 and up to a turning chamber 12 from which it 10ws bask through vertical tubes 13 to the outlet chamber 10 of the heat-exchanger. The parts 2, 6, 9, 11, 12, 13, 10, 7 and 8 together form the primary coolant circuit of the core 3 which contains only pure water. The corresponding secondary coolant circuit consists of the spaces between the tubes 11 and 13, an outgoing conduit 14 and a return conduit 15 and a number of consumers connected to the conduits 14 and 15, preferably directly connected heating-plants for room heating of houses and work places. The secondary coolant circuit preferably has higher water pressure than the primary circuit. The lower part of ~066435 the reactor vessel 2 is the inlet space and its upper part the outlet space for the reactor core 3.
The primary coolant circuit is constructed with an outlet opening 16 and an inlet opening 17, through which it is in a permanent open communication with the pool space by way of two gas lock tubes 18 and 19, which are connected to the openings 16 and 17, respectively. As indicated in the drawing, the gas lock tubes 18 and 19 each contains an enclosed amount of gas, which are connected each to a pressure-regulated gas tank 22 and 23 by way of relatively thin tubes 20 and 21, respectively. The gas pressure in the gas tank 22 is chosen approximately equal to the water pressure at the lower opening of the gas lock tube 18, i.e. only so much higher than a slight bubbling out of air can be observed at this opening. This will give an indication that an even pressure is maintained in the gas lock tube. Alternatively, the pressure in the gas tanks 22 and 23 can be chosen much higher, for example more than 150% of said water pressure, the pipes 20 and 21 then being provided each with a throttling means.
In order for the water levels of the two gas lock tu~es to adjust themselves as indicated in the drawing, the tube 19 must be supplied with gas, the pressure of which - counting in water columns - is equal to the gas pressure in the tube 18 plus the difference hl between the water levels of the `two tubes. As indicated in the drawing, such a high pressuriza-tion can be used that the water pressure at the outlet of the core 3 will be considerably greater than what corresponds to the water pressure in the pool. The vertical dimension of the gas lock tube 18 can be chosen greater than, e.g. one-fourth of the maximum water depth in the pool, thus achieving a considerable increase in the water pressure in the core, which means that a higher water temperature can be allowed at ~ _ 3 _ a given pool depth without getting too close to the boiling point.
Also in the event that the gas amount contained in the gas locks has a very small vertical dimension, the air lock tubes have an important function since in normal operation they effectively prevent the reactor water and the pool water from being intermixed. When level variations occur, among other things since the difference between the water levels of the air lock tubes is greater when the pump 3 is in operation than in the purely static case, the vertical dimensions of the gas lock tubes must, however, be chosen so large that the contained amount of air does not leave the gas lock tube during normal operation. As a rule, it may be taken into account that the gas lock tube shall be dimensioned to allow a contained amount of air whose vertical dimension is greater than one metre.
A reactor according to the invention is designed to fulfil extrem~ security demands. Even in the very hypothetical case that the circulating pump 8 seizes and the control rods 4 for some reason are jam~ed outside the core at the same time, it may be counted on, with a great degree of security, that no radioactive discharge will take place, and that there will be no risk that the fuel rods will melt down.
If a sudden boiling takes place in the reactor core 3, for example because of an intentional or unintentional faulty drawing of the control rods or an instantaneous pump stop without a subsequent reactor trip, the steam formation will first result in part of the water of the primary system being pressed out through the gas lock tube 18. This does not necessarily lead to a breakdown of the air locks. Since we assume that there are negative void coefficients of reactivity, the void contents will then result in the power being rapidly ~ - 3a -reduced to less than 5 % of the normal power. The evaporation continues and the gas lock tube 18 is filled with steam while the water level slowly sinks.
- 3b -.
~066435 B~ openlng the valves 24 ana 25 RO that the ~as pressure aiæappears ln the tanks 22 snd 23, lt ~ould be pos~lble to aohie~e a relatirel~ rapid inno~
of pool ~ater into the primary ooolant olrouit of the reaotor. ~o~ver, slnce the behaviour of the resotor under the ~orst i~agiDable condit~ons 18 of intere~t, ~c assu~e that the valves 24 and 25 are not operating.
If an evaporatlon ooours ln the reaotor oore, the dlfferenoe bet~een the l~ el ln the heat-eschan~er ana the level in a connected branoh Or the lo~er gas look tub~ ~ill deorease Rlo~ly, ~hioh eans that the pool water ~111 rlse to such an e%tent ln the long branch of the lo~er &a8 loc~ tube that the pool ~ater finally passes the horlzontal part of bhe gas loc}s ana 18 suppllea to the pri~ar1 coolant clrcuit of the reactor. Such replenishment oan be repeated several times, but the water level in the heat-e%chan~er can n~rer rlse hiBher than to a certain ~a~imu~ level, namel~ bhat ~hich coinclaes ~ith the lo~er openlng of the upper ~as lock tube. It 18 i~portant that the ~hole reactor core 18 arranBea belo~ this oa2imu~ level. Further, lt 18 es~ential that the upper edg~ of the lo~er eas look tube 1~ arran~ea belo~ the abo e-ntlond a~l~uo le~d , since other~ise lt ~ould be i~po~slble to flll lt ~lth ~ater co pletd ~ ~hen ~ater le flll d ln after ch nsln6~ which ~ould inrolve that a per a~nent ~as plug ~Oula oocur at the upper ost part o~ th-Bas loc~ tuOe 19, ~hlch ~Oula pr ront th fbrth r supply Or pool ~ater to the r aotor. ~8 ~8 shown ln the ara~ing, both the Op~nln68 of the pri~ary s~te , which arQ pro ldel ~lth Ras loc~s, are arransea in such a ~a~ that the outl-t op nlng - coN~ting in th clrcul-tlng alr otlon of th prl-ary clroult - has relatl~el~ ~hort alstance and the iDlet oponlng a relatlr ly long alstan~- ~ror th space abo~e the reaotor core. The lnlet opeul~6 17 ~houla Oe arran pa a~ ~ar down as posslbl-~ ho~er r lt shoula be aOo - th oore . aounting~ln the clrcul-tlng alreotlon o~ th prl-ary ooolant olrcult, th purp 8 18 looatd aft r the lnlet oponlng 17an~ before the oore ~, and therefore the pressurlsatlon ocourrin6 ~hen th pu p 18 ~or~lng oaus-s an equally ~reat lncr~ se ln th pres~ure of th coro 3, ~hereas th l- el ln the Bas loo~ tube 19 18 lnfluenosa to a r-la-tl~el~ d l ae6re- ~h n the sps~a of the pu p 1~ o _ . _ _ _ In Flgures 2 ana 3~ 30 18 a reaotor oore ~hloh 18 arrsDBod ln a ~ater-fllld r aotor essel 34 ana oonstruotsa fro a plurallt~ of ~ertloallJ arran~ea fuol a~se~blle~. ~he r actor ssd 18 arraneed ln a ~ator-rilld pool spao-31. ~he ~at r l~ el ln th- pool ~8 ~ho~n by the sy~bol J.
The reaotor oore 30 18 surrouna d by a flo w ontrolllng oadn6 32, the upp r dge of ~hioh 1~ fastenea to a ooDlcal~ annular sore n 33~ th out-r dge o~
~hloh 18 attaoh~a to th reaotor essel 34 ~n a pressure-tlght ~nn r. Th soreen 33 aeflnes an inlet space 35 bJ its under slae and b~ lts upper slde it a-rines an outlet spaoe 36 for the cooling ~ater flo~g tbrough the reac-tor core. The outlet space 36 1~ pro lded at its lo~er end ~ith a lo~er gaJ
loo~ tub- 37, the short branch 37' of ~hlch 18 ~ater-flllea, ~hereas the long branch 37~ aurins nor~al operation is gas-flllea and arran6ea ~ith a predo l-na~t part of lts length in a ~ell 58 the aepth of ~hich countlng ~ro the pool botto 18 Breater th~n one-~ourth o~ the aqp~h of the pool.
The outlet ~pace 36 is ~urther pro~idea ~ith ~wo upper gas loo} tubes 3~, of ~hich the branch connect d to the r actor ~essel is in nor~al operation ~ater-filled ana the other branch gas-fillea.
~t th upper end of the reactor es~el an annnlar pump cha~ber 39 i8 definea b~ mean~ of an annular pu~p ~ o~ 40 ana a hollo~ c~llnarloal ~11 41. ~t lea~t on~ ~usp 57 1~ arrangea to pu~p ~ater ~ro~ the outlet spao- 36 to the pu p ohu b r 39.
....
A plurallt~ Or heat-~ch~n~ru, Or ~hich only ona 18 ~ho~n ln Flgure 2, ar arrane~a ln th reaotor -88-L ~ach h at-e~changer con d st~ of a tub- 42, the upper end of ~hlch 1~ e~led ana pro id d ~it]h t~o conneotlon ~oo~ ts 43 ror ooonootlon Or tho lnlot a~a outl-t oondultc of th seoond~rJ olrc~lt, ~hioh are lnalcat d 1~ Flgur- 3 b~ th ~ots ~na da~he~ a-d4n~t d ~ and 45.
Th ~ ooJ~ar~ of th h at_~cotuo46~r oooslsts o~ a plurall b orLloo~ 46 arr ng d 1~ th tub- 42 and th ~rl~rr c~- of th 8paO- urroq~ d b~ th tub- 42 and t oooupl d b~ t]h tub- loopc 46. Th tub- 42 ha- a yr~-s~r--tlght pb~-ag thrcugh th r ~otor e-8 d 34, the snnular pu p d o~ 40 aod th oooloal or- n 33 na OponJ out ~lth lt~ lower en~ into th lDl-t pac-35~ th retur~ ~at r ~ro- tho pri brr ala- of the heat-~loh~D~r n o~ioB o~t lnto th p o- 35. ~her tror th ~ator n 0~8 thso~gh th oore ~0 a~a lt~ o~t-l-t oha ber 36 ~ro- ~h r~ lt pa~ th puap 57 an~ th pu p ohaab r 39 ana then rlo~ at th upy r ~D~ of the Wbo 42 throogh a plurallt;r Or hol- 47 ~hloh, tog ther ~lth th pu p oha ber, oo~stltut- a kvdsawllo oonn~otlon bot~e~ the prl rr lde Or th heat-e~#h ry~r ana th o~tl-t ~pao- 36 o~
th roaotor es~-l.
pl~rallt~ Or oontrol roa eU~a tubos 48 ar- ~opt 1~ th- oorr ct posltlon b~ eaDs Or ~ rlAg 49 whloh 1- ittaoh d to th- reaotor ess-l ~lth t~e h lp of a plusallt~ Or ~t~o 50. ~ plursllt;r Or oontrol roas ar- oh faJt nea to a oontrol ro~ sbart 51 ~r ~eans Or an ol otro~agnet, not ho~, th- ~lnd-in~ of ~hloh 18 oerl-~-oonnsot d to a t~pera~uro fu~e in th for~ of a lt-ing body ~hloh elt~ ana br a~- th ourront lf th te per~t~ in th ~at r o~ tho re~otor 088-l tond~ to b oo e too hlgh, th t 1~, lr th r- 1B ~ rl-~o~ bolling ooourrlDs ln th re~otor ese-l.
- .~ 1066435 ~a¢h of the ¢ontrol rod shafts i8 conneotea to a control rd drl~e 53 attached to the reactor ~essel co~er 52 wbich control rod dri~es are oon-neoted eaoh to an eleotric ~otor 55 b~ ~ay Or a plurality of shafts 54.
The motors are supported b~ a stana not sho~n attachd to the reactor ~essel oo~er. ~h oo ponents 48 51 52 53 54 ana 55 can be llftea as o unlt in th oase o~ a refuelling.
The oonneotlon of the uppsr 8as lock tube to the vessel i~ dlr~ctl~ beloN
the pump deck To lid t the depth of the ~ell 58 of the lo~er 8as lock tube this i8 oonneotea to the ~essel abo-e the core. During nor al operatlon this requires a d l by-paJs flow pa~t the oore. During deca~ heat ooollng the ~ater supplied throu~h the lo~er 8as look then ~10N8 through a b~-pass ope-nlD~ 56 ~sde for thls purpose to the iolet of the oore.
.
In th o~ont of a pu p stop ~ith falllng r aotor trlp the to p~rature of the oor- o~tlot ~lll rl-- at th _ tl e a- th pr~ssu aiOps in a anner a ter ~nd b~ th ¢o Jt do~n ¢hasaoterlstios of the pu p. For ~a pl- boil-iog a~ ooour ft r about 6 second~ at about 4 bar and 145C in the oor~ out-let. Thi~ te p~rature 18 far abov- the rolease temp~r~tur- of th fu~-- but beoause of thelr lnertia th ~ are not l e~lat l~ r-leasd. Th pressure and tho to p~rature ~lll ther~ror rlse ~h~ boiliog o¢ours #na Br~at a ounts of ~ator ana/or ~tea ar- pr~s~ d out through tho upper Ba8 l00~8. Tho pr esuro arOp io these 18 UJUa~ 0 er at that oo r plenlsh- nt throu~h th- lo~r o~8 look oan bo oou~t d on. B oaus- of th ~olalDg tho po~r of th oor rall~
O oonJ~ rabl- ~nor J- of th fu l te~perature ooours. Th ~ater oon_ tonts of th r~ otor nsd abo e th oor aro unu~uall~ Br~at aoa a looB
tl~e before all thls oan be pressed out through th upper gas looks booau~e of th- st _ doneloyo~nt~ the fcJ-s r l~s-~ the oontrol roa- fall do~n into th oor ana onlJ the ~eoa~ po~er of th oore neea be ooold off I~ a rea¢tor ~e~sel of the t~pe sho~n 1~ uros 2 aD~ ~ the alstanoe fro-tho upper de- of the oor to the essd oo~er shoula b- at le Jt 60%
preferabl~ re than ?o% of the total heieht of tho reactor ~ess~ t tho sa e tl e th- a~a eter of the ess d shoula be at lea~t 160~ pr f r-abl~ re than 190% of th- ala eter o~ the reaotor oore. Beoaus- of the Broat ala~eter an~ holdhe of the e88d a ~od separatl of st-an ana ~ater 18 obtaln~a ana ool~ 8 al1 prossure alffer~noos a regulrsa to pre~s out the st~a~ throu~h th~ ~pper ou looks~ Thss th Yator upyl~
through the lo~er eaJ loo~ tub- 37 18 seourd.
The Bas of at least ono ~aJ look tubo ~a~ be vater stea~ upplld b~ a speolal boller~ for -~ ple ~ a 8 al1 st~u~ oonkult.
Claims (11)
1. Reactor plant comprising: a light-water-cooled reactor core with vertical fuel assemblies; a reactor vessel with an inlet space and an outlet space, separated from said inlet space, for cooling water flowing through the reactor core; a heat-exchanger having walls defining a primary coolant circuit and a secondary coolant circuit; a circulating pump for the primary circuit of the heat-exchanger, and a water-filled pool; said inlet and outlet spaces being provided each with at least one hydraulic connection with the heat-exchanger; the reactor core being enclosed in the reactor vessel and the reactor vessel arranged in said pool; the coolant of the primary coolant circuit during normal operation being blocked from the pool water by means of a blocking device with a liftable blocking effect, characterized in that the primary coolant circuit, through an outlet opening and an inlet opening in the walls defining the primary coolant circuit, is constantly in an open connection with the pool space, at least the outlet opening being provided with a connecting means for this purpose in the form of a gas lock tube.
2. Reactor plant according to claim 1, characterized in that the outlet opening is provided with an upper gas lock tube and that the inlet opening is provided with a lower gas lock tube, the outlet end of the upper gas lock tube being at a higher level than the upper edge of the reactor core and also higher than the upper edge of the lower gas lock tube.
3. Reactor plant according to claim 2, characterized in that the amounts of gases enclosed in said gas lock tubes communicate with separate gas containers by way of gas tubes.
4. Reactor plant according to claim 1, characterized in that said heat-exchanger is arranged inside said reactor vessel.
5. Reactor plant according to claim 4, characterized in that the heat-exchanger contains a cooling coil, included in its secondary circuit, and a vertical tube in which the cooling coil is arranged, the lower end of the tube opening out into said inlet space, the tube at its upper end being provided with at least one inlet opening communicating with said outlet space.
6. Reactor plant according to claim 5, characterized in that said inlet opening communicates with said outlet space through a pump chamber, at least one circulating pump being arranged to pump water from the outlet space to the pump chamber.
7. Reactor plant according to claim 4, characterized in that a lower gas lock tube is connected to a lower part of said outlet space and an upper gas lock tube to an upper part of said outlet space.
8. Reactor plant according to claim 7, characterized in that the pool is designed with a well located below the pool bottom, the depth of said well being greater than one-fourth of the pool depth, in which a predominant part of the lower gas lock tube is arranged.
9. Reactor plant according to claim 7, characterized in that the uppermost point of the upper gas lock tube is located considerably higher than the water level in the pool.
10. Reactor plant according to claim 1, characterized in that the gas of said gas lock tube is water steam.
11. Reactor plant according to claims 1, 2 or 3, characterized in that the pool water during normal operation contains a neutron-absorbing agent in a relatively high concentration, whereas the water contained in the reactor vessel during normal operation is relatively pure.
Applications Claiming Priority (1)
| Application Number | Priority Date | Filing Date | Title |
|---|---|---|---|
| SE7506607A SE391059B (en) | 1975-06-10 | 1975-06-10 | NUCLEAR REACTOR WITH A PRIMER COOLING CIRCUIT IN A LIQUID-FILLED POOL |
Publications (1)
| Publication Number | Publication Date |
|---|---|
| CA1066435A true CA1066435A (en) | 1979-11-13 |
Family
ID=20324814
Family Applications (1)
| Application Number | Title | Priority Date | Filing Date |
|---|---|---|---|
| CA254,400A Expired CA1066435A (en) | 1975-06-10 | 1976-06-09 | Reactor plant for a district heating plant |
Country Status (7)
| Country | Link |
|---|---|
| CA (1) | CA1066435A (en) |
| CH (1) | CH602993A5 (en) |
| DE (1) | DE2625542A1 (en) |
| DK (1) | DK258476A (en) |
| FI (1) | FI761657A (en) |
| FR (1) | FR2314560A1 (en) |
| SE (1) | SE391059B (en) |
Families Citing this family (4)
| Publication number | Priority date | Publication date | Assignee | Title |
|---|---|---|---|---|
| SE428611B (en) * | 1979-12-17 | 1983-07-11 | Asea Atom Ab | COOLING WATER REACTOR REQUIRER |
| FR2985847B1 (en) * | 2012-01-18 | 2014-03-14 | Dcns | UNDERWATER MODULE FOR THE PRODUCTION OF ELECTRICAL ENERGY |
| FR2985844B1 (en) * | 2012-01-18 | 2014-03-14 | Dcns | IMMERSE ENERGY PRODUCTION MODULE |
| FR2985848B1 (en) * | 2012-01-18 | 2014-03-14 | Dcns | SUBMARINE OR SUBMARINE MODULE FOR GENERATING ELECTRICAL ENERGY |
Family Cites Families (6)
| Publication number | Priority date | Publication date | Assignee | Title |
|---|---|---|---|---|
| NL113562C (en) * | 1959-02-24 | |||
| GB1026474A (en) * | 1963-05-23 | 1966-04-20 | Babcock & Wilcox Ltd | Improvements in nuclear reactors |
| US3394051A (en) * | 1965-12-20 | 1968-07-23 | Babcock & Wilcox Co | Integral nuclear reactor-steam generator arrangement |
| FR1525183A (en) * | 1967-03-28 | 1968-05-17 | Commissariat Energie Atomique | Nuclear reactor |
| US3454466A (en) * | 1967-12-29 | 1969-07-08 | Atomic Energy Commission | Nuclear reactor containment system for metropolitan sites |
| US3718539A (en) * | 1971-03-31 | 1973-02-27 | Combustion Eng | Passive nuclear reactor safeguard system |
-
1975
- 1975-06-10 SE SE7506607A patent/SE391059B/en unknown
-
1976
- 1976-06-01 CH CH684476A patent/CH602993A5/xx not_active IP Right Cessation
- 1976-06-05 DE DE19762625542 patent/DE2625542A1/en active Pending
- 1976-06-09 FI FI761657A patent/FI761657A/fi not_active Application Discontinuation
- 1976-06-09 CA CA254,400A patent/CA1066435A/en not_active Expired
- 1976-06-10 FR FR7617496A patent/FR2314560A1/en active Granted
- 1976-06-10 DK DK258476A patent/DK258476A/en unknown
Also Published As
| Publication number | Publication date |
|---|---|
| DE2625542A1 (en) | 1976-12-16 |
| FI761657A (en) | 1976-12-11 |
| DK258476A (en) | 1976-12-11 |
| FR2314560B1 (en) | 1979-07-27 |
| CH602993A5 (en) | 1978-08-15 |
| FR2314560A1 (en) | 1977-01-07 |
| SE7506607L (en) | 1976-12-11 |
| SE391059B (en) | 1977-01-31 |
Similar Documents
| Publication | Publication Date | Title |
|---|---|---|
| US4526742A (en) | Nuclear reactor plant | |
| EP0405720B1 (en) | Passive safety injection system using borated water | |
| US4753771A (en) | Passive safety system for a pressurized water nuclear reactor | |
| US3168445A (en) | Safety equipment for nuclear powerreactor plants | |
| US11043310B2 (en) | Valve assembly with isolation valve vessel | |
| US4986956A (en) | Passive nuclear power plant containment system | |
| EP0359716B1 (en) | Intrinsic-safety nuclear reactor of the pressurized water type | |
| US4056436A (en) | System for mitigating the effects of an accident at a nuclear power plant | |
| US4587079A (en) | System for the emergency cooling of a pressurized water nuclear reactor core | |
| DE2013586A1 (en) | Liquid-cooled nuclear reactor | |
| CA1066435A (en) | Reactor plant for a district heating plant | |
| US5579355A (en) | Heat dissipation system for a nuclear reactor, in particular a pressurized water reactor | |
| US4187147A (en) | Recirculation system for nuclear reactors | |
| FI63128B (en) | REAKTORANLAEGGNING | |
| US3580806A (en) | Pressure suppressing arrangement | |
| US3321374A (en) | Containment system for pressurized nuclear reactor installation | |
| US4816210A (en) | Passive filtered containment vent | |
| US5295170A (en) | Nuclear reactor with passive means of adjusting the pH of post accident water | |
| GB1491232A (en) | Nuclear reactors | |
| US5642389A (en) | Light water reactor in particular a boiling water reactor with a high degree of inherent safety | |
| CN212990694U (en) | Overpressure protection device of waste heat discharge system and waste heat discharge system | |
| CN113661547B (en) | Nuclear power plant serious accident handling safety system and control method thereof | |
| US3383288A (en) | Liquid cooled nuclear reactor | |
| ITMI951567A1 (en) | DEPRESSURIZATION SYSTEM FOR PLANTS OPERATING WITH PRESSURE STEAM | |
| JP2918353B2 (en) | Reactor containment vessel |