JPH1123773A - Core cooling structure of fast breeder reactor - Google Patents
Core cooling structure of fast breeder reactorInfo
- Publication number
- JPH1123773A JPH1123773A JP9179296A JP17929697A JPH1123773A JP H1123773 A JPH1123773 A JP H1123773A JP 9179296 A JP9179296 A JP 9179296A JP 17929697 A JP17929697 A JP 17929697A JP H1123773 A JPH1123773 A JP H1123773A
- Authority
- JP
- Japan
- Prior art keywords
- core
- core tank
- heat exchanger
- coolant
- upper plenum
- 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.)
- Pending
Links
Classifications
-
- 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
Landscapes
- Heat-Exchange Devices With Radiators And Conduit Assemblies (AREA)
Abstract
Description
【0001】[0001]
【発明の属する技術分野】本発明は、冷却材に熱伝導性
の高い液体金属を用いていることを活用し、全交流電源
が喪失された場合でも冷却材の自然循環により炉心の崩
壊熱を除去し、事象を安全に収束させる設計を行う高速
増殖炉に係り、崩壊熱除去系に直接炉心冷却系を採用し
た場合に、炉心のラッパ管とラッパ管の間に存在する流
体の自然対流(インターラッパーフロー:以下IWFと
略)を促進させ、ラッパ管の外から内部にある燃料から
発せられる崩壊熱を除去させる高速増殖炉炉心構造に関
する。BACKGROUND OF THE INVENTION 1. Field of the Invention The present invention makes use of the use of a liquid metal having high thermal conductivity as a coolant, and reduces the decay heat of the core by natural circulation of the coolant even when all AC power is lost. In a fast breeder reactor designed to remove and safely converge events, the natural convection of fluid existing between the wrapper pipes of the core (when a core cooling system is directly used for the decay heat removal system) The present invention relates to a fast breeder reactor core structure that promotes interwrapper flow (hereinafter abbreviated as IWF) and removes decay heat generated from fuel inside and outside the wrapper tube.
【0002】[0002]
【従来の技術】高速増殖炉においては、原子炉の運転を
継続しても炉心では所定の時間にわたって発熱を継続す
る。このような発熱を崩壊熱と呼んでいる。従来より、
この崩壊熱を除去するためにさまざまな装置が提案され
ており、その1つに原子炉容器内の冷却材中に熱交換器
を浸漬させて炉心からの崩壊熱を直接除去する直接炉心
冷却系がある。この浸漬型炉内熱交換器を含む直接炉心
冷却系を採用した高速増殖炉原子炉構造例を図1に、炉
心部の集合体配置例を図2に示す。2. Description of the Related Art In a fast breeder reactor, even if the operation of the reactor is continued, the core continuously generates heat for a predetermined time. Such heat generation is called decay heat. Conventionally,
Various devices have been proposed to remove this decay heat. One of them is a direct core cooling system in which a heat exchanger is immersed in a coolant in a reactor vessel to directly remove decay heat from the core. There is. FIG. 1 shows an example of the structure of a fast breeder reactor that employs a direct core cooling system including the submerged in-furnace heat exchanger, and FIG. 2 shows an example of an arrangement of core assemblies.
【0003】図1において、原子炉容器1の中央部には
複数の燃料集合体2が装荷された炉心槽3があり、原子
炉容器入口配管18から供給された冷却材は炉心入口プ
レナムを介して各燃料集合体内に配分され、炉心上部プ
レナム9に出て合流した後原子容器出口配管17から出
ていき再び入口配管に戻る。In FIG. 1, there is a core tank 3 in which a plurality of fuel assemblies 2 are loaded at a central portion of a reactor vessel 1, and a coolant supplied from a reactor vessel inlet pipe 18 passes through a core inlet plenum. After being distributed to each fuel assembly, and coming out of the reactor core upper plenum 9 and merging, it exits from the reactor vessel outlet pipe 17 and returns to the inlet pipe again.
【0004】全交流電源喪失のような事故が発生する
と、1次冷却材の強制循環力が無くなり、直接炉心冷却
系の自然循環除熱により崩壊熱除去を行う。この時、直
接炉心冷却系の炉内熱交換器8は崩壊熱によって加熱さ
れた上部プレナム9の冷却材を上部の窓から取込み熱交
換した後下部の窓から流出させている。この方式では、
熱交換器での除熱が直接1次系の自然循環力に働くわけ
ではないため、炉心を流れる冷却材流量を大幅には増や
せず、燃料集合体の冷却能力が小さいのが大きな欠点で
となっている。When an accident such as loss of all AC power occurs, the forced circulation force of the primary coolant is lost, and decay heat is removed directly by natural circulation heat removal of the core cooling system. At this time, the in-furnace heat exchanger 8 of the direct core cooling system takes in the coolant of the upper plenum 9 heated by the decay heat from the upper window, exchanges heat, and then flows out from the lower window. In this scheme,
The major drawback is that the heat removal in the heat exchanger does not directly affect the natural circulation force of the primary system, so the coolant flow rate through the reactor core cannot be increased significantly and the cooling capacity of the fuel assembly is small. Has become.
【0005】従来、この欠点を解決する方策として、燃
料集合体ラッパ管13とラッパ管の間に存在する冷却材
を利用し、この部分の自然対流を促進させることで、ラ
ッパ管の外から集合体内部を冷却する方法が考えられて
いる。Conventionally, as a measure for solving this drawback, a coolant existing between the fuel assembly wrapper tube 13 and the wrapper tube is used to promote natural convection in this portion, so that the fuel assembly is collected from outside the wrapper tube. Methods for cooling the inside of the body have been considered.
【0006】図2に示す炉心配置においては、内側炉心
35及び外側炉心36において崩壊熱を発しており、径
方向ブランケット37、ガス膨張機構(GEMと略す)
40及び中性子遮へい体38においては発熱量が小さい
か発熱が全く無い領域なので、炉心槽内で中心部が高
温、外周部が低温という半径方向の温度分布が付き、本
来停留状態となっているラッパ管とラッパ管の間の領域
の冷却材が対流によって循環することになる。In the core arrangement shown in FIG. 2, decay heat is generated in the inner core 35 and the outer core 36, and a radial blanket 37, a gas expansion mechanism (abbreviated as GEM).
The wrapper 40 and the neutron shield 38 are in a region where the calorific value is small or there is no heat at all, so that the temperature distribution in the radial direction is high in the central part and low in the outer peripheral part in the core tank, and the wrapper which is originally in a stationary state is provided. The coolant in the area between the tube and the flaring tube will circulate by convection.
【0007】この、ラッパ管間の冷却材の自然対流はイ
ンターラッパーフロー(IWF)と呼ばれる。IWFを
促進させる方法としては、ラッパ管のスペーサとして上
部と中間部に取り付けられているパッドの隙間を大きく
するか、パッドに流路を設けることが考えられる。[0007] This natural convection of the coolant between the wrapper tubes is called an interwrapper flow (IWF). As a method of accelerating the IWF, it is conceivable to increase the gap between the pads attached to the upper part and the intermediate part as spacers of the flapper tube, or to provide a flow path in the pads.
【0008】このようなラッパ管形状を採用した場合、
炉内熱交換器で冷却された冷却材は、密度の関係で上部
プレナム下部に成層化して炉心上部に覆い被さり、パッ
ドの隙間を潜り込んで低温冷却材がラッパ管ギャップに
入り込むため、IWFによる燃料集合体内の除熱が期待
できる。特開昭59−44694 号,特開平8−240686 号にお
いて、このラッパ管パッドに開口を設けることを前提と
して、崩壊熱除去機能を促進させる方策が提案されてい
る。When such a trumpet tube shape is adopted,
The coolant cooled by the in-furnace heat exchanger is stratified below the upper plenum in relation to the density and covers the upper part of the core, and enters the gap between the pads to allow the low-temperature coolant to enter the gap of the trumpet pipe. The heat removal inside the assembly can be expected. In JP-A-59-44694 and JP-A-8-240686, measures are proposed to promote the decay heat removal function on the premise that an opening is provided in the wrapper tube pad.
【0009】一方、特開平8−62374号では、上部プレナ
ムから炉心槽外部(中間プレナム)あるいは炉心槽容器
を介して炉心槽内部につながる流路パスを設ける方法,
炉内熱交換器の1次側出口部を中間プレナムに貫通させ
て更に中間プレナムと炉心槽の間に貫通孔を設ける方
法,炉心外周部に設置されている非発熱集合体である中
性子遮へい体に逆流流路を設ける方法が提案されてい
る。On the other hand, JP-A-8-62374 discloses a method of providing a flow path from the upper plenum to the outside of the core tank (intermediate plenum) or to the inside of the core tank via the core tank vessel.
A method in which a primary outlet of an in-furnace heat exchanger is penetrated through an intermediate plenum and a through-hole is further provided between the intermediate plenum and a core tank, and a neutron shield as a non-heating assembly installed on the outer periphery of the core There has been proposed a method of providing a backflow channel in the apparatus.
【0010】[0010]
【発明が解決しようとする課題】日本は世界有数の地震
国であり、実証炉以降に予定されている大型炉心では、
特にパッド部の耐震設計条件が厳しくなることから、燃
料集合体ラッパ管の6角形状に合わせた鉢巻き型のパッ
ドが現状では採用されている。このパッド形状では、パ
ッド間の隙間は殆ど無いため、炉内熱交換器からの低温
流体は炉心槽に入りにくく、炉心槽内のIWFは図1に
示すように、炉心槽内の閉じた空間での対流となるた
め、大きな除熱効果は期待できない。[Problems to be Solved by the Invention] Japan is one of the world's leading earthquake nations.
Particularly, since the seismic design conditions of the pad portion become severe, a head-wound pad adapted to the hexagonal shape of the fuel assembly wrapper tube is currently used. In this pad shape, since there is almost no gap between the pads, the low-temperature fluid from the in-furnace heat exchanger hardly enters the core tank, and the IWF in the core tank is a closed space in the core tank as shown in FIG. Therefore, a large heat removal effect cannot be expected.
【0011】一方、特開平8−62374号に提案されている
方法は、炉内熱交換器からの低温流体を炉心槽内に送り
込む方法としては有効であるが、送り込まれた冷却材が
炉心で暖められて上部プレナムに戻るための流路パスに
ついては提案されておらず、IWFを有効に活用するた
めには入口側の配慮だけでは不十分である。On the other hand, the method proposed in Japanese Patent Application Laid-Open No. 8-62374 is effective as a method for feeding a low-temperature fluid from a heat exchanger in a furnace into a core vessel, but the supplied coolant is cooled in the core. There is no proposal for a flow path to return to the upper plenum after it has been warmed, and considerations on the inlet side alone are not enough to make effective use of IWF.
【0012】本発明は、直接炉心冷却方式の高速増殖炉
において、炉心の耐震性を損なうことなく、IWFを積
極的かつ有効に利用して自然循環時の崩壊熱除去機能を
促進させる炉心構造を提供することを目的とする。The present invention relates to a core structure in a direct core cooling type fast breeder reactor which promotes a function of removing decay heat during natural circulation by actively and effectively utilizing IWF without impairing the seismic resistance of the core. The purpose is to provide.
【0013】[0013]
【課題を解決するための手段】前記目的を達成するため
の第1手段は、炉心槽内の中央部に燃料集合体、周辺部
にブランケット集合体と中性子遮へい体を、スペーサ用
のパッドを介在させて配置し、炉心槽に取り付けた側部
支持板によって中性子遮へい体を支持し、炉心槽より上
方の上部プレナム内に冷却装置と接続された炉内熱交換
器を備えた高速増殖炉において、炉心槽と中性子遮へい
体との間に設けられている側部炉心支持板にフローホー
ルを設けるとともに、炉心槽内に複数設けられている制
御棒集合体のラッパ管に開口部を設け、上部プレナム〜
炉内熱交換器〜炉心槽ラッパ管ギャップ領域の明確な流
路パスを形成させることを特徴とした高速増殖炉の炉心
冷却構造である。The first means for achieving the above object is that a fuel assembly is provided at a central portion in a core tank, a blanket assembly and a neutron shield are provided at a peripheral portion, and a pad for a spacer is provided. In a fast breeder reactor equipped with an in-furnace heat exchanger connected to a cooling device in the upper plenum above the core tank, supporting the neutron shield by a side support plate attached to the core tank, A flow hole is provided in a side core support plate provided between a core tank and a neutron shield, and an opening is provided in a wrapper tube of a plurality of control rod assemblies provided in the core tank, and an upper plenum is provided. ~
This is a core cooling structure of a fast breeder reactor characterized by forming a clear flow path from the in-reactor heat exchanger to the core tank trumpet tube gap region.
【0014】また、前記目的を達成するための第2手段
は、炉心槽内の中央部に燃料集合体、周辺部にブランケ
ット集合体とガス膨張機構(GEM)と中性子遮へい体
を、スペーサ用のパッドを介在させて配置し、炉心槽に
取り付けた側部支持板によって中性子遮へい体を支持
し、炉心槽より上方の上部プレナム内に冷却装置と接続
された炉内熱交換器を備えた高速増殖炉において、炉心
槽と中性子遮へい体との間に設けられている側部炉心支
持板にフローホールを設けるとともに、炉心槽内に設け
られているGEM領域の一部を炉心槽内ラッパ管ギャッ
プ領域と上部プレナムとの連通機構に変えることで、上
部プレナム〜炉内熱交換器〜炉心槽ラッパ管ギャップ領
域の明確な自然循環パスを形成させることを特徴とした
高速増殖炉の炉心冷却構造である。A second means for achieving the above object is that a fuel assembly is provided at a central portion in a core vessel, a blanket assembly, a gas expansion mechanism (GEM) and a neutron shield are provided at a peripheral portion, and a spacer for a spacer is provided. High-speed breeder with neutron shields supported by side support plates attached to the core tank with pads interposed, and an internal heat exchanger connected to a cooling device in the upper plenum above the core tank In the furnace, a flow hole is provided in a side core support plate provided between a core tank and a neutron shield, and a part of a GEM area provided in the core tank is defined as a wrapper tube gap area in the core tank. Core cooling of a fast breeder reactor characterized by forming a clear natural circulation path from the upper plenum to the heat exchanger in the furnace to the core tank wrapper tube gap area by changing the communication mechanism between the upper plenum and the upper plenum. It is a structure.
【0015】前記第1手段によれば、上部プレナム内の
冷却材が炉内熱交換器で冷却されたのち、炉心上部に覆
い被さり、炉心槽の外周部に設置されている側部炉心支
持板に設けられた開口部の上が低温で密度の大きい流
体、下が高温で密度の小さい流体となることから、浮力
の関係で側部支持板上部の低温流体が炉心槽内部に潜り
込む。この低温冷却材の潜り込みが炉心槽内のラッパ管
ギャップ領域冷却材の自然対流を促進させ、崩壊熱が発
生している中央部の燃料集合体の冷却に寄与する作用が
得られる。[0015] According to the first means, after the coolant in the upper plenum is cooled by the in-furnace heat exchanger, it is covered over the upper part of the core, and the side core supporting plate installed on the outer peripheral portion of the core tank. The upper part of the opening provided in the lower part becomes a fluid having a low temperature and a high density, and the lower part becomes a fluid having a high temperature and a low density. This infiltration of the low-temperature coolant promotes the natural convection of the coolant in the flared tube gap region in the core tank, and has an effect of contributing to the cooling of the fuel assembly in the center where the decay heat is generated.
【0016】制御棒集合体ラッパ管に設けた炉心槽内部
と上部プレナムとの連通パスにより、炉心中央部で高温
化されたIWFが制御棒集合体を介して上部プレナムに
抜けるため、上部プレナム〜炉内熱交換器〜炉心槽ラッ
パ管ギャップ領域の明確な自然循環パスが形成され、炉
内熱交換器を介したIWFにより効率的に炉心を冷却す
る作用が得られる。The communication path between the inside of the core tank provided in the control rod assembly wrapper tube and the upper plenum allows the IWF heated at the center of the core to pass through the control rod assembly to the upper plenum. A clear natural circulation path is formed between the in-furnace heat exchanger and the core tank wrapper tube gap region, and the core can be efficiently cooled by the IWF through the in-furnace heat exchanger.
【0017】前記第2手段によれば、GEMを採用した
高速増殖炉の炉心において、第1手段と同様に側部支持
板上部の低温流体が側部支持板に設けられた開口部によ
り炉心槽内部に潜り込みやすくしており、GEM領域の
一部を炉心槽内ラッパ管ギャップ領域と上部プレナムと
の連通機構に変えることで、炉心中央部で高温化された
IWFが制御棒集合体を介して上部プレナムに抜けるた
め、第1手段と同様の作用が得られる。According to the second means, in the core of the fast breeder reactor employing the GEM, the low temperature fluid in the upper portion of the side support plate is supplied to the core tank by the opening provided in the side support plate, as in the first means. By changing part of the GEM region into a communication mechanism between the wrapper tube gap region in the core tank and the upper plenum, the IWF heated at the center of the core through the control rod assembly Since the upper plenum exits, the same operation as the first means is obtained.
【0018】[0018]
【発明の実施の形態】以下、本発明の実施例を図2〜図
11により説明する。DESCRIPTION OF THE PREFERRED EMBODIMENTS An embodiment of the present invention will be described below with reference to FIGS.
【0019】〔実施例1〕図4は発明の第1手段に係る
高速増殖炉原子炉構造の一実施例を示す縦断面図図であ
る。同図において、原子炉容器1の中央部に燃料集合体
2を内包する炉心槽3があり、自然循環時に炉心を出た
冷却材は炉心上部機構7,炉内熱交換器8,冷却材原子
炉出口配管17等を内包する上部プレナム9に流れ、冷
却材原子炉出口配管17から冷却系機器(図示せず)へ
移行した後、冷却材原子炉入口配管18に戻り、炉心入
口プレナム5を介して炉心部へ流入する流れとなる。Embodiment 1 FIG. 4 is a longitudinal sectional view showing an embodiment of a fast breeder reactor structure according to the first means of the present invention. In the figure, a core tank 3 containing a fuel assembly 2 is provided at a central portion of a reactor vessel 1, and a coolant that has exited the core during natural circulation is a core upper mechanism 7, an in-core heat exchanger 8, a coolant atomizer. After flowing into the upper plenum 9 including the reactor outlet pipe 17 and the like, and moving from the coolant reactor outlet pipe 17 to cooling system equipment (not shown), the flow returns to the coolant reactor inlet pipe 18 and the core inlet plenum 5 is removed. Through the reactor core.
【0020】自然循環時においては、原子炉容器内に設
置された炉内熱交換器8の2次側も自然循環で流れてお
り、これによって上部プレナム9内の冷却材を自然循環
によって冷却される。この特、冷却材は炉内熱交換器の
上方にある入口窓から炉内熱交換器の伝熱部に行き、2
次側との熱交換で冷却された後炉内熱交換器下方にある
出口窓から上部プレナム内に排出される。At the time of natural circulation, the secondary side of the in-furnace heat exchanger 8 installed in the reactor vessel also flows by natural circulation, whereby the coolant in the upper plenum 9 is cooled by natural circulation. You. In particular, the coolant flows from the entrance window above the in-furnace heat exchanger to the heat transfer section of the in-furnace heat exchanger,
After being cooled by heat exchange with the next side, it is discharged into the upper plenum from an outlet window below the in-furnace heat exchanger.
【0021】図4に燃料集合体部の部分縦断面図を示
す。炉心槽内では、6角形状断面のラッパ管13に収め
られた燃料集合体が多数設置されており、ラッパ管には
上端近傍及び燃料集合体発熱部14の上端近傍に耐震サ
ポート用のためのスペーサとして上部パッド15及び中
間パッド16が設置されている。FIG. 4 is a partial longitudinal sectional view of the fuel assembly. In the core tank, a large number of fuel assemblies housed in a hexagonally-shaped cross-section wrapper tube 13 are installed, and the wrapper tube is provided near the upper end and near the upper end of the fuel-assembly heat generating portion 14 for seismic support. Upper pads 15 and intermediate pads 16 are provided as spacers.
【0022】燃料集合体部のパッドがある部分の水平断
面を図6、パッドが無い部分の水平断面を図7に示す。
燃料集合体廻りのラッパ管13は6角形状となってお
り、図7に示すようにラッパ管とラッパ管の間には隙間
領域が存在し、この領域にも冷却材が充填されている。FIG. 6 shows a horizontal cross section of a portion of the fuel assembly where a pad is provided, and FIG. 7 shows a horizontal cross section of a portion where no pad is provided.
The wrapper tube 13 around the fuel assembly has a hexagonal shape. As shown in FIG. 7, a gap region exists between the wrapper tubes, and this region is also filled with the coolant.
【0023】パッドのある領域では、図6に示すように
その隙間は非常に狭くなっている。また、図2に示した
ように燃料集合体の配置は6角形状となっており、炉心
槽の容器は円筒となっているため、燃料集合体の最外層
部と炉心槽の間には、上部パッド及び中間パッドと同じ
レベルに炉心側部支持板4が設置されており、燃料集合
体の水平方向のサポートを確保している。In the area where the pad is located, the gap is very narrow as shown in FIG. Further, as shown in FIG. 2, the arrangement of the fuel assemblies is hexagonal, and the container of the core tank is cylindrical. Therefore, between the outermost layer portion of the fuel assembly and the core tank, A core side support plate 4 is installed at the same level as the upper pad and the intermediate pad, and secures horizontal support of the fuel assembly.
【0024】図5はこの炉心側部支持板の水平断面を示
したものであり、外周部の集合体のラッパ管の面に沿う
ようなジグザグ上の支持板となっている。スペーサパッ
ドとスペーサパッドの隙間は設計寸法でも1mm以下と非
常に狭く、冷却材充填時には高温となっており中心部の
集合体に比べて周辺部の集合体は熱膨張によって半径方
向にずれることになり、外周部のパッド間の隙間は殆ど
塞がれているものと考えられる。FIG. 5 shows a horizontal cross section of the core side support plate, which is a zigzag support plate along the surface of the wrapper tube of the outer peripheral assembly. The gap between the spacer pad and the spacer pad is extremely narrow, less than 1 mm in design dimension, and the temperature is high when the coolant is filled. The aggregates in the peripheral part are displaced in the radial direction due to thermal expansion compared to the aggregate in the center. It is considered that the gap between the pads on the outer peripheral portion is almost completely closed.
【0025】炉内熱交換器は通例図3に示すように上部
プレナムの外周側に設置されるので、炉内熱交換器で冷
却された冷却材は外周部から中心部に向かって広がる。
この低温化された冷却材を炉心槽内に潜り込ませるため
には、炉心槽の中で比較的低温な領域となっている外周
部から潜り込ませる必要があるが、上記で述べたように
隙間が殆ど塞がれているのでこのままでは潜り込むこと
が困難である。Since the in-furnace heat exchanger is usually installed on the outer periphery of the upper plenum as shown in FIG. 3, the coolant cooled by the in-furnace heat exchanger spreads from the outer periphery toward the center.
In order to allow the cooled coolant to enter the core tank, it is necessary to sink from the outer peripheral portion, which is a relatively low-temperature region in the core tank. It is difficult to dive as it is because it is almost blocked.
【0026】本実施例では、この炉心側部支持板に上部
プレナムと炉心槽内の冷却材が連通しやすいようにフロ
ーホール4aを設けている。In this embodiment, a flow hole 4a is provided in the core side support plate so that the upper plenum and the coolant in the core tank can easily communicate with each other.
【0027】また、炉心槽の中には発熱集合体である内
側炉心及び外側炉心には運転中の熱出力を制御する制御
棒を挿入させるための制御棒集合体32が数箇所設置さ
れており、本実施例においては図4に示すように制御棒
集合体のラッパ管に開口部20を設けて炉心槽内のIW
Fによって暖められた冷却材が制御棒集合体の中を通っ
て上部プレナムへ抜けやすくしている。In the core tank, several control rod assemblies 32 for inserting control rods for controlling the heat output during operation are installed in the inner core and the outer core which are the heat generating assemblies. In the present embodiment, as shown in FIG. 4, an opening 20 is provided in the wrapper tube of the control rod assembly so that the IW
The coolant heated by F facilitates the passage through the control rod assembly to the upper plenum.
【0028】図8はIWF流出機構を設けた制御棒集合
体の構造概念を示した縦断面図である。制御棒集合体は
同図に示すように外周部はハンドリングヘッド23,ラ
ッパ管13,上部パッド15,中間パッド16及びエン
トランスノズル24から構成され、内部は制御棒案内管
21,制御棒要素22及び各種流路構成要素から構成さ
れている。燃料からの中性子を受けて制御棒要素が発す
る熱を除熱するために通常時は少量の冷却材を内部に流
している。FIG. 8 is a longitudinal sectional view showing the structural concept of a control rod assembly provided with an IWF outflow mechanism. As shown in the figure, the control rod assembly is composed of a handling head 23, a wrapper tube 13, an upper pad 15, an intermediate pad 16, and an entrance nozzle 24 at the outer peripheral portion, and the control rod guide tube 21, the control rod element 22, It is composed of various flow path components. In order to remove the heat generated by the control rod elements in response to neutrons from the fuel, a small amount of coolant is usually flowed inside the control rod elements.
【0029】本実施例では、上部パッド15の下部及び
中間パッドの下部のラッパ管に開口部20を設けてい
る。自然循環時にはIWFによって発熱集合体で暖めら
れた流体は上方に移動し、各パッドの下の位置が最も高
温になると予想されるので、この位置に開口があれば、
制御棒集合体ラッパ管内部に流入し、図8中に示した流
路25,26で上部プレナムへ流出しやすくなる。In this embodiment, an opening 20 is provided in the wrapper tube below the upper pad 15 and below the intermediate pad. At the time of natural circulation, the fluid heated by the heat generating assembly by the IWF moves upward, and the position under each pad is expected to be the hottest.
The control rod assembly easily flows into the wrapper tube and flows out to the upper plenum through the flow paths 25 and 26 shown in FIG.
【0030】この位置に開口があると通常運転時にこの
穴からラッパ管外へ流出する流れも発生するが、制御棒
要素の上部にある上部パッド下部の開口については流出
しても全く問題無い。中間パッド下方の開口については
ラッパ管外へ抜ける流量が多いと制御棒要素の除熱機能
が低下するので流出時と流入時の抵抗比が異なるような
流路形状としてテーパを付けている。If there is an opening at this position, a flow will flow out of this hole to the outside of the trumpet tube during normal operation, but there is no problem if the flow goes out of the opening at the lower part of the upper pad above the control rod element. The opening below the intermediate pad is tapered as a flow path shape that has a different resistance ratio between the outflow and the inflow since the heat removal function of the control rod element is reduced if the flow rate flowing out of the wrapper tube is large.
【0031】本実施例においては、自然循環時には炉内
熱交換器から流出された低温の冷却材は、浮力によって
炉心側部支持板に取り付けたフローホールから炉心槽内
部に潜り込む流れとなり、更に中間パッドのレベルにあ
る下段の側部炉心支持板からも下に潜り込む流れもでき
る。炉心槽に潜り込んだ冷却材は、中間パッドあるいは
炉心槽下面に沿って炉心中心部に移動し、炉心中心部の
崩壊熱を発している燃料集合体部に達すると熱伝導及び
熱伝達により集合体内部の冷却材と熱交換するため高温
化し、上昇流となって中間部及び上部パッドの下端領域
に達し、制御棒集合体の開口部を通って制御棒集合体内
に入った後上部プレナムに流出する。これにより図3中
の10及び11に示すような炉内自然循環流路が形成さ
れ、炉内熱交換器が燃料集合体の崩壊熱除去に効果的に
作用させることができる。In this embodiment, at the time of natural circulation, the low-temperature coolant flowing out of the in-furnace heat exchanger flows into the core tank from the flow hole attached to the core side support plate by buoyancy. There is also a flow that can sink below from the lower side core support plate at the level of the pad. The coolant that has sunk into the core tank moves to the center of the core along the intermediate pad or the lower surface of the core tank, and reaches the fuel assembly that emits decay heat in the center of the core, where it is assembled by heat conduction and heat transfer. The temperature rises due to heat exchange with the coolant inside, rises as an upflow, reaches the middle and lower end regions of the upper pad, passes through the opening of the control rod assembly, enters the control rod assembly, and then flows out to the upper plenum I do. Thereby, a natural circulation channel in the furnace as shown by 10 and 11 in FIG. 3 is formed, and the in-furnace heat exchanger can effectively act on the decay heat removal of the fuel assembly.
【0032】〔実施例2〕図9は発明の第2手段に係る
高速増殖炉の一実施例を示す縦断面図である。同図にお
いては、発明の第1手段と同様に炉内熱交換器8からの
低温冷却材を炉心槽に流入させるための側部炉心支持板
内フローホール4aを設けている。Embodiment 2 FIG. 9 is a longitudinal sectional view showing an embodiment of the fast breeder reactor according to the second means of the present invention. In the same drawing, a flow hole 4a in the side core support plate for allowing the low-temperature coolant from the in-furnace heat exchanger 8 to flow into the core tank as in the first means of the invention is provided.
【0033】更に本発明においては、原子炉停止時にス
クラムを失敗した場合に炉心の安全性を確保するための
手段であるガス膨張機構(GEM)33を設けた炉心構
造において、GEM領域の一部にIWF流出流路促進構
造を設置した炉心冷却構造としている。Further, according to the present invention, in a reactor core structure provided with a gas expansion mechanism (GEM) 33 which is a means for ensuring the safety of the reactor core when a scram fails when the reactor is stopped, a part of the GEM region is provided. A core cooling structure is provided with an IWF outflow channel promoting structure.
【0034】GEMは原子炉トリップ時に制御棒挿入に
失敗した場合に、GEM内のガス層によって中性子の半
径方向への漏れを大きくして炉心の反応度を低下させ、
燃料の健全性を保つための安全機構である。When the control rod insertion fails during the reactor trip, the gas layer in the GEM increases the neutron leakage in the radial direction and reduces the reactivity of the core,
It is a safety mechanism to maintain fuel integrity.
【0035】図10はGEMの構造概念を示す縦断面図
である。GEMは同図に示すようにハンドリングヘッド
23,エントランスノズル24,ラッパ管及び上部/中
間パッドから構成されており、内部にはガスを封入した
冷却材27が入っている。FIG. 10 is a longitudinal sectional view showing the structure concept of the GEM. The GEM includes a handling head 23, an entrance nozzle 24, a wrapper tube, and upper / middle pads as shown in FIG.
【0036】内部の冷却材の液面は運転時には炉心の燃
料集合体発熱部レベルより上方になるようにしており、
冷却材は炉心入口プレナムと連通している。原子炉停止
時にはポンプ吐出圧が下がるため、内部の液位が炉心の
燃料集合体発熱部より下がって、発熱部廻りがガス領域
となることで中性子の外周部への漏れを大きくして反応
度を下げるものである。最近の設計検討によると、GE
Mは必ずしも発熱集合体の廻りに全周に配置する必要は
なく、一部はガス層を設けないダミーとする設計も採り
うる。During operation, the liquid level of the internal coolant is higher than the level of the fuel assembly heating section of the core.
Coolant is in communication with the core inlet plenum. When the reactor is shut down, the pump discharge pressure drops, so the internal liquid level drops below the fuel assembly heating part in the core, and the area around the heating part becomes a gas region, increasing leakage of neutrons to the outer periphery and increasing reactivity. It lowers. According to recent design considerations, GE
M need not necessarily be arranged on the entire circumference around the heat generating assembly, and a part may be designed as a dummy having no gas layer.
【0037】本実施例は、このダミーのGEM領域を有
効に活用する観点から、図11の縦断面図に示すように
IWFを炉上部プレナムへ流出させるための機構にする
ことで発明の第1手段と同様の効果を得ることを狙いと
している。図11のIWF流出促進機構は、上部プレナ
ムと内部の冷却材との連通部となるハンドリングヘッド
23と、IWFを内部に流入させるために上部パッド下
方と中間パッド下方にそれぞれ開口部20を設けたラッ
パ管から構成され、エントランスノズルには下部の炉心
入口プレナムとの連通口がないのが大きな特徴である。In the present embodiment, from the viewpoint of effectively utilizing the dummy GEM region, a mechanism for discharging IWF to the upper plenum of the furnace as shown in a vertical sectional view of FIG. It aims to obtain the same effect as the means. The IWF outflow promotion mechanism of FIG. 11 has a handling head 23 serving as a communication portion between the upper plenum and the internal coolant, and openings 20 provided below the upper pad and the lower intermediate pad for flowing the IWF into the inside. The main feature is that the entrance nozzle has no communication port with the lower core inlet plenum.
【0038】通常時にはラッパ管内に強制的な流れを設
ける必要がないため、開口部20に対する制約条件が余
り無く、強度上許す限りの開口を設けることが可能とな
る。自然循環時には、炉心の発熱領域で高温化されたI
WFがこの開口部を通って、同図の30,31に示すよ
うな流路を通って上部プレナムに抜ける。ラッパ管内に
は制御棒集合体のように内部構造物を殆ど設ける必要が
ないため、流路30や31を冷却材が流れる際の流動抵
抗は非常に小さくできる。Normally, it is not necessary to provide a forced flow in the wrapper tube, so that there are few restrictions on the opening 20 and it is possible to provide as many openings as the strength allows. During natural circulation, the temperature of I
The WF passes through this opening and into the upper plenum through channels such as 30 and 31 in the figure. Since there is almost no need to provide an internal structure like a control rod assembly in the wrapper tube, the flow resistance when the coolant flows through the flow passages 30 and 31 can be extremely small.
【0039】本実施例においては、自然循環時には炉内
熱交換器から流出された低温の冷却材は、浮力によって
炉心側部支持板に取り付けたフローホールから炉心槽内
部に潜り込む流れとなり、更に中間パッドのレベルにあ
る下段の側部炉心支持板からも下に潜り込む流れもがで
きる。炉心槽に潜り込んだ冷却材は、中間パッドあるい
は炉心槽下面に沿って炉心中心部に移動し、炉心中心部
の崩壊熱を発している燃料集合体部に達すると熱伝導及
び熱伝達により集合体内部の冷却材と熱交換するため高
温化し、上昇流となって中間部及び上部パッドの下端領
域に達し、GEM領域の一部に設置したIWF流出流路促
進機構の開口部を通って上部プレナムに流出する。In this embodiment, at the time of natural circulation, the low-temperature coolant flowing out of the in-furnace heat exchanger flows into the core tank from the flow hole attached to the core side support plate by buoyancy. There is also a flow that sinks down from the lower side core support plate at the level of the pad. The coolant that has sunk into the core tank moves to the center of the core along the intermediate pad or the lower surface of the core tank, and reaches the fuel assembly that emits decay heat in the center of the core, where it is assembled by heat conduction and heat transfer. The temperature rises to exchange heat with the internal coolant, and the temperature rises to reach the middle part and the lower end area of the upper pad. The upper plenum passes through the opening of the IWF outflow channel promotion mechanism installed in a part of the GEM area. Leaked to
【0040】これにより図9中の10及び11に示すよ
うな炉内自然循環流路が形成され、炉内熱交換器が燃料
集合体の崩壊熱除去に効果的に作用させることができ
る。As a result, a natural circulation flow path in the furnace as shown by 10 and 11 in FIG. 9 is formed, and the heat exchanger in the furnace can effectively act to remove decay heat of the fuel assembly.
【0041】IWF流出流量促進機構内の流動抵抗が非
常に小さくできるため、炉内自然循環流路全体の流動抵
抗も小さくなり、よりIWFが流れやすい炉心構造とな
っている。Since the flow resistance in the IWF outflow flow rate promoting mechanism can be made very small, the flow resistance of the entire natural circulation passage in the furnace also becomes small, and the core structure has a structure in which the IWF flows more easily.
【0042】[0042]
【発明の効果】本発明によれば、炉心側部支持構造にフ
ローホールを設けたことにより炉内熱交換器からの低温
流体が炉心槽内に流れやすくなり、また、制御棒ラッパ
管を介した炉心槽と上部プレナムと連通パスを設けたこ
とにより炉心槽内の対流現象で高温化された冷却材が上
部プレナムに流出しやすくなり、炉内熱交換器〜炉心槽
〜上部プレナムを流路パスとしたIWFが促進され、高
速増殖炉の自然循環時の炉心崩壊熱除熱性能を向上させ
る効果が得られる。According to the present invention, by providing a flow hole in the core side support structure, the low temperature fluid from the in-furnace heat exchanger can easily flow into the core tank, and the control rod wrapper tube can be used. By providing a communication path between the core tank and the upper plenum, the coolant heated by the convection phenomenon in the core tank easily flows out to the upper plenum, and flows through the heat exchanger in the furnace to the core tank to the upper plenum. The IWF as a pass is promoted, and the effect of improving the core decay heat removal performance during the natural circulation of the fast breeder reactor is obtained.
【0043】また、炉心側部支持構造にフローホールを
設けることにより炉内熱交換器からの低温流体が炉心槽
内に流れやすくなり、また、GEM領域の一部に炉心槽
と上部プレナムと連通パスを備えたIWF流出流量促進
機構を設けることにより、炉心槽内のIWFで高温化さ
れた冷却材が上部プレナムに流出しやすくなり、炉内熱
交換器〜炉心槽〜上部プレナムを流路パスとしたIWF
が促進され、高速増殖炉の自然循環時の炉心崩壊熱除熱
性能を向上させる効果が得られる。IWF流出流量促進
機構内の流路抵抗は非常に小さくできるので、これによ
りIWF効果が更に向上することが期待できる。By providing a flow hole in the core side support structure, the low temperature fluid from the in-furnace heat exchanger can easily flow into the core tank, and a part of the GEM region communicates with the core tank and the upper plenum. By providing an IWF outflow flow rate promotion mechanism provided with a path, the coolant heated by the IWF in the core tank easily flows out to the upper plenum, and the flow path passes through the heat exchanger in the furnace, the core tank, and the upper plenum. IWF
Is promoted, and the effect of improving the core decay heat removal performance during the natural circulation of the fast breeder reactor is obtained. Since the flow resistance in the IWF outflow flow rate promoting mechanism can be made extremely small, it is expected that the IWF effect will be further improved.
【図1】従来の高速増殖炉原子炉構造例。FIG. 1 shows an example of a conventional fast breeder reactor structure.
【図2】従来の高速増殖炉燃料集合体配置例。FIG. 2 shows an example of a conventional fast breeder reactor fuel assembly arrangement.
【図3】本発明の第1実施例の模式縦断面図。FIG. 3 is a schematic longitudinal sectional view of the first embodiment of the present invention.
【図4】本発明の第1実施例の燃料集合体部分縦断面
図。FIG. 4 is a partial longitudinal sectional view of a fuel assembly according to the first embodiment of the present invention.
【図5】本発明の第1実施例の炉心槽容器部水平部分断
面図。FIG. 5 is a horizontal partial cross-sectional view of a core vessel container according to the first embodiment of the present invention.
【図6】燃料集合体水平部分断面図(パッド部)。FIG. 6 is a horizontal partial sectional view of a fuel assembly (pad portion).
【図7】燃料集合体水平部分断面図(パッド無し部)。FIG. 7 is a horizontal partial sectional view of a fuel assembly (portion without a pad).
【図8】本発明の第1実施例の制御棒集合体構造縦断面
図。FIG. 8 is a longitudinal sectional view of a control rod assembly structure according to the first embodiment of the present invention.
【図9】本発明の第2実施例の模式縦断面図。FIG. 9 is a schematic longitudinal sectional view of a second embodiment of the present invention.
【図10】ガス膨張機構(GEM)構造縦断面図。FIG. 10 is a longitudinal sectional view of a gas expansion mechanism (GEM) structure.
【図11】本発明の第2実施例のIWF促進構造物縦断
面図。FIG. 11 is a longitudinal sectional view of an IWF-accelerated structure according to a second embodiment of the present invention.
1…原子炉容器、2…燃料集合体、3…炉心槽壁、4…
側部炉心支持板、4a…側部炉心支持板内フローホー
ル、5…炉心入口プレナム、6…下部プレナム、7…炉
心上部機構(UIS)、8…炉内熱交換器(DHX)、
9…上部プレナム、10…DHXの流路パス、11…炉
心槽内インターラッパーフロー、12…集合体内流路パ
ス、13…燃料集合体ラッパ管、14…燃料集合体発熱
部、15…ラッパ管上部パッド、16…ラッパ管中間パ
ッド、17…冷却材原子炉出口配管、18…冷却材原子
炉入口配管、19…水平隔壁、20…IWF流出流路
口、21…制御棒案内管、22…制御棒要素、23…ハ
ンドリングヘッド、24…エントランスノズル、25…
制御棒集合体内上部IWF流出流路、26…制御棒集合
体内中間部IWF流出流路、27…GEM内液体金属、
28…GEM内不活性ガス、29…GEM内液体金属流
入口、30…上部IWF流出流路、31…中間部IWF
流出流路、32…IWF促進型制御棒集合体、33…G
EM部IWF流出流量促進機構、34…遮へい集合体、
35…内側炉心、36…外側炉心、37…径方向ブラン
ケット、38…中性子遮へい体、39…制御棒集合体、
40…GEM(ガス膨張機構)。DESCRIPTION OF SYMBOLS 1 ... Reactor vessel, 2 ... Fuel assembly, 3 ... Core tank wall, 4 ...
Side core support plate, 4a: flow hole in side core support plate, 5: core inlet plenum, 6: lower plenum, 7: upper core mechanism (UIS), 8: in-core heat exchanger (DHX),
Reference numeral 9: upper plenum, 10: DHX flow path, 11: core tank inter-wrapper flow, 12: flow path in the assembly, 13: fuel assembly wrapper tube, 14: fuel assembly heating section, 15: wrapper tube Upper pad, 16 ... middle pad of wrapper pipe, 17 ... coolant reactor outlet pipe, 18 ... coolant reactor inlet pipe, 19 ... horizontal bulkhead, 20 ... IWF outlet channel, 21 ... control rod guide pipe, 22 ... control Rod element, 23 ... Handling head, 24 ... Entrance nozzle, 25 ...
Upper IWF outflow channel in the control rod assembly, 26 ... Middle IWF outflow channel in the control rod assembly, 27 ... Liquid metal in GEM,
28: inert gas in GEM, 29: inlet of liquid metal in GEM, 30: outflow channel of upper IWF, 31: intermediate IWF
Outflow channel, 32 ... IWF-promoted control rod assembly, 33 ... G
EM part IWF outflow flow rate promotion mechanism, 34 ... shielding assembly,
35: inner core, 36: outer core, 37: radial blanket, 38: neutron shield, 39: control rod assembly,
40 ... GEM (gas expansion mechanism).
Claims (2)
ブランケット集合体と中性子遮へい体を、スペーサ用の
パッドを介在させて配置し、炉心槽に取り付けた側部支
持板によって中性子遮へい体を支持し、炉心槽より上方
の上部プレナム内に冷却装置と接続された浸漬型炉内熱
交換器を備えた高速増殖炉において、炉心槽と中性子遮
へい体との間に設けられている側部炉心支持板にフロー
ホールを設けることにより、炉内熱交換器から上部プレ
ナムに排出された低温の冷却材が炉心槽内の各集合体間
の隙間領域に流れ込みやすくし、炉心槽内に複数設けら
れている制御棒集合体のラッパ管に開口部を設け、炉心
槽内ラッパ管ギャップ部の冷却材がIWFによって暖めら
れた後、制御棒ラッパ管開口部を介してラッパ管内に流
れ、上部プレナムに流出させることで、上部プレナム〜
炉内熱交換器〜炉心槽ラッパ管ギャップ領域の明確な自
然循環パスを形成させることを特徴とした高速増殖炉の
炉心冷却構造。1. A fuel assembly is provided at a central portion in a core tank, and a blanket assembly and a neutron shield are provided at peripheral portions thereof with spacer pads interposed therebetween, and neutrons are provided by side support plates attached to the core tank. A fast breeder reactor that supports a shield and has a submerged-type in-furnace heat exchanger connected to a cooling device in the upper plenum above the core tank, provided between the core tank and the neutron shield. By providing a flow hole in the side core support plate, the low-temperature coolant discharged from the in-furnace heat exchanger to the upper plenum can easily flow into the gap area between the assemblies in the core tank, and into the core tank. An opening is provided in the wrapper tube of the plurality of control rod assemblies, and after the coolant in the wrapper tube gap in the core tank is heated by the IWF, the coolant flows into the wrapper tube through the control rod wrapper tube opening, In the upper plenum By order issued, the upper plenum -
A core cooling structure for a fast breeder reactor, characterized in that a clear natural circulation path is formed between a heat exchanger in a reactor and a core tank wrapper tube gap region.
ブランケット集合体とガス膨張機構(GEM)と中性子
遮へい体を、スペーサ用のパッドを介在させて配置し、
炉心槽に取り付けた側部支持板によって中性子遮へい体
を支持し、炉心槽より上方の上部プレナム内に冷却装置
と接続された浸漬型炉内熱交換器を備えた高速増殖炉に
おいて、炉心槽と中性子遮へい体との間に設けられてい
る側部炉心支持板にフローホールを設けることにより、
炉内熱交換器から上部プレナムに排出された低温の冷却
材が炉心槽内の各集合体間の隙間領域に流れ込みやすく
し、炉心槽内に設けられているGEM領域の一部を炉心
槽内ラッパ管ギャップ領域と上部プレナムとの連通機構
に変えることで、炉心槽内ラッパ管ギャップ部の冷却材
がIWFによって暖められた後、上記連通機構を介して
上部プレナムに流出させ、上部プレナム〜炉内熱交換器
〜炉心槽ラッパ管ギャップ領域の明確な自然循環パスを
形成させることを特徴とした高速増殖炉の炉心冷却構
造。2. A fuel assembly is disposed at a central portion in a core tank, and a blanket assembly, a gas expansion mechanism (GEM) and a neutron shield are disposed at a peripheral portion with a spacer pad interposed therebetween.
In a fast breeder reactor equipped with a submerged-type in-furnace heat exchanger that supports a neutron shield by a side support plate attached to a core tank and is connected to a cooling device in an upper plenum above the core tank, By providing a flow hole in the side core support plate provided between the neutron shield and
The low-temperature coolant discharged from the in-furnace heat exchanger to the upper plenum easily flows into the gap area between the assemblies in the core tank, and a part of the GEM area provided in the core tank is removed from the core tank. By changing to a communication mechanism between the trumpet pipe gap region and the upper plenum, the coolant in the trumpet pipe gap in the core tank is heated by the IWF, and then flows out to the upper plenum via the communication mechanism, and the upper plenum to the furnace A core cooling structure for a fast breeder reactor, wherein a clear natural circulation path is formed between the internal heat exchanger and the core tank trumpet tube gap region.
Priority Applications (1)
Application Number | Priority Date | Filing Date | Title |
---|---|---|---|
JP9179296A JPH1123773A (en) | 1997-07-04 | 1997-07-04 | Core cooling structure of fast breeder reactor |
Applications Claiming Priority (1)
Application Number | Priority Date | Filing Date | Title |
---|---|---|---|
JP9179296A JPH1123773A (en) | 1997-07-04 | 1997-07-04 | Core cooling structure of fast breeder reactor |
Publications (1)
Publication Number | Publication Date |
---|---|
JPH1123773A true JPH1123773A (en) | 1999-01-29 |
Family
ID=16063356
Family Applications (1)
Application Number | Title | Priority Date | Filing Date |
---|---|---|---|
JP9179296A Pending JPH1123773A (en) | 1997-07-04 | 1997-07-04 | Core cooling structure of fast breeder reactor |
Country Status (1)
Country | Link |
---|---|
JP (1) | JPH1123773A (en) |
Cited By (1)
Publication number | Priority date | Publication date | Assignee | Title |
---|---|---|---|---|
JP2018071997A (en) * | 2016-10-25 | 2018-05-10 | 日立Geニュークリア・エナジー株式会社 | Fast reactor core |
-
1997
- 1997-07-04 JP JP9179296A patent/JPH1123773A/en active Pending
Cited By (1)
Publication number | Priority date | Publication date | Assignee | Title |
---|---|---|---|---|
JP2018071997A (en) * | 2016-10-25 | 2018-05-10 | 日立Geニュークリア・エナジー株式会社 | Fast reactor core |
Similar Documents
Publication | Publication Date | Title |
---|---|---|
KR100597722B1 (en) | Stable and passive decay heat removal system for liquid metal reator | |
JPH08160179A (en) | Liquid-metal cooling-type nuclear reactor | |
JP2009150860A (en) | Passive safety grade residual heat removal system of eliminated sodium solidification possibility in intermediate sodium loop for removing remaining heat in sodium cooled fast reactor | |
US20110075786A1 (en) | Heat exchanger, methods therefor and a nuclear fission reactor system | |
GB2031642A (en) | Nuclear reactor | |
US20220051816A1 (en) | Heat exchanger configuration for nuclear reactor | |
WO2012150699A1 (en) | Fuel assembly, reactor core and water-cooled nuclear reactor | |
US9221093B2 (en) | Heat exchanger, methods therefor and a nuclear fission reactor system | |
US9275760B2 (en) | Heat exchanger, methods therefor and a nuclear fission reactor system | |
US4302296A (en) | Apparatus for insulating hot sodium in pool-type nuclear reactors | |
WO2011078870A2 (en) | A heat exchanger, methods therefor and a nuclear fission reactor system | |
JP2003139881A (en) | Reactor cooled with supercritical pressure water, channel box, water rod and fuel assembly | |
JPH1123773A (en) | Core cooling structure of fast breeder reactor | |
WO2023087501A1 (en) | Passive residual heat removal device and miniature horizontal reactor system | |
EP0200111B1 (en) | Improved boiling water nuclear reactor fuel assembly | |
EP4250315A1 (en) | Safety system and safety control method for preventing molten corium from melting through rpv | |
JPH06160570A (en) | Fuel aggregate | |
CN116982120B (en) | Nuclear reactor with heavy liquid metal coolant | |
JPS6055796B2 (en) | pressure tube reactor | |
JP4316119B2 (en) | Fuel assembly | |
CN116189933A (en) | Submerged containment vessel with active water cooled heat sink | |
JPS59150374A (en) | Thermal shield device in fast breeder | |
CN114220571A (en) | Natural circulation waste heat discharge system and fast neutron reactor | |
JPH0363714B2 (en) | ||
JPH08297186A (en) | Core for fast reactor |