JP2011174774A

JP2011174774A - Isolation cooling system in nuclear power plant

Info

Publication number: JP2011174774A
Application number: JP2010038114A
Authority: JP
Inventors: Tomohiro Kiguchi; 知大木口; Tomohiro Wada; 知弘和田
Original assignee: Hitachi GE Nuclear Energy Ltd
Current assignee: Hitachi GE Nuclear Energy Ltd
Priority date: 2010-02-24
Filing date: 2010-02-24
Publication date: 2011-09-08

Abstract

<P>PROBLEM TO BE SOLVED: To achieve the control over the pressure or temperature of a reactor even in the occurrence of a reactor isolation event by making the amount of heat removed by a reactor isolation cooling system adjustable. <P>SOLUTION: In an isolation cooling system including an introduction pipe for introducing the steam from a reactor pressure vessel, a heat exchanger for removing the heat from the steam introduced from the introduction pipe and a return pipe for returning the condensate condensed by the heat removal in the heat exchanger, the return pipe includes a regulating valve. <P>COPYRIGHT: (C)2011,JPO&INPIT

Description

本発明は、原子力発電プラントの隔離時冷却設備に関する。 The present invention relates to an isolation cooling facility for a nuclear power plant.

特許文献１には、原子炉隔離時に原子炉一次系または原子炉二次系の熱を除去する隔離時冷却設備を開示する。そして、特許文献１の隔離時冷却設備は、復水器の復水を原子炉圧力容器へ戻す復水配管に、通常運転時には閉鎖される隔離弁を設置している。 Patent Document 1 discloses an isolation cooling facility that removes heat from a primary reactor system or a secondary reactor system during isolation of a reactor. And the cooling system at the time of isolation of patent document 1 has installed the isolation valve closed at the time of normal operation in the condensate piping which returns the condensate of a condenser to a reactor pressure vessel.

特開平３−２４６４９２号公報JP-A-3-246492

しかし、特許文献１の隔離時冷却設備は、復水配管に隔離弁を使用するため、冷却設備による除熱量を調節することができないという課題があった。 However, since the cooling system at the time of isolation of patent document 1 uses an isolation valve for condensate piping, there existed a subject that the amount of heat removal by a cooling system could not be adjusted.

そこで本発明は、原子炉隔離時冷却設備の除熱量を調整可能とすることにより、原子炉隔離事象発生時にも原子炉の圧力または温度を制御することを目的とする。 Accordingly, an object of the present invention is to control the pressure or temperature of a nuclear reactor even when a nuclear reactor isolation event occurs, by making it possible to adjust the heat removal amount of the cooling facility during the nuclear reactor isolation.

本発明の隔離時冷却設備は、戻り配管に調整弁を備えることを特徴とする。 The isolation cooling facility according to the present invention is characterized in that a return valve is provided with a regulating valve.

本発明によれば、原子炉隔離時冷却設備の除熱量を調整可能とすることにより、原子炉隔離事象発生時にも原子炉の圧力または温度を制御することが可能になる。 According to the present invention, it becomes possible to control the pressure or temperature of a nuclear reactor even when a nuclear reactor isolation event occurs, by making it possible to adjust the heat removal amount of the cooling equipment at the time of nuclear reactor isolation.

実施例１に係る隔離時冷却設備の概略構成図である。It is a schematic block diagram of the cooling system at the time of isolation which concerns on Example 1. FIG.

以下、実施例を詳細に説明する。但し、この実施例に記載される構成要素，種類，組み合わせ，形状、その相対配置などは特定的な記載がない限り、この発明の範囲をそれのみに限定する主旨ではなく単なる説明例に過ぎない。 Examples will be described in detail below. However, unless otherwise specified, the components, types, combinations, shapes, relative arrangements, and the like described in this embodiment are merely illustrative examples and not intended to limit the scope of the present invention. .

図１は本実施例に係る隔離時冷却設備の概略構成図である。この隔離時冷却設備は、原子炉圧力容器１からの蒸気を取り入れる導入配管６と、導入配管６から流入する蒸気を除熱する熱交換器３と、蒸気が熱交換器３で除熱されることによって発生した凝縮水を原子炉圧力容器１に戻す戻り配管７と、戻り配管７に設けられた、開度調整が可能な調整弁５と、熱交換器３の胴側で発生した蒸気を屋外（建物外壁１４の外側）へ導く、上り勾配の排気配管１２と、外部からの異物混入を防止するメッシュ１３とを備えている。また、熱交換器３は原子炉圧力容器１からの蒸気を流す伝熱管１５を有している。なお、熱交換器３の胴側には、熱交換器内に存在する水の水位・温度をそれぞれ計測する水位計９と温度計１１を備えている。また、熱交換器３と原子炉圧力容器１とを接続する戻り配管７には、水位計８と温度計１０を備えている。 FIG. 1 is a schematic configuration diagram of an isolation cooling facility according to the present embodiment. This isolation cooling facility includes an introduction pipe 6 for taking in steam from the reactor pressure vessel 1, a heat exchanger 3 for removing heat flowing from the introduction pipe 6, and the steam being removed by the heat exchanger 3. The return pipe 7 that returns the condensed water generated by the reactor to the reactor pressure vessel 1, the adjustment valve 5 provided in the return pipe 7 that can adjust the opening degree, and the steam generated on the trunk side of the heat exchanger 3 are outdoors. An exhaust pipe 12 having an upward slope leading to (outside the building outer wall 14) and a mesh 13 for preventing foreign matter from entering from outside are provided. The heat exchanger 3 has a heat transfer tube 15 through which steam from the reactor pressure vessel 1 flows. The trunk side of the heat exchanger 3 is provided with a water level meter 9 and a thermometer 11 for measuring the water level and temperature of the water present in the heat exchanger, respectively. The return pipe 7 connecting the heat exchanger 3 and the reactor pressure vessel 1 is provided with a water level meter 8 and a thermometer 10.

次に、本実施例の隔離時冷却設備による作用効果について説明する。 Next, the effects of the isolation cooling facility of this embodiment will be described.

原子炉圧力容器からタービンに蒸気を供給することができない原子炉隔離事象発生時、原子炉圧力容器からタービンへの蒸気供給が遮断され、一時的に発電を停止することがある。早期に復旧が見込まれる場合、原子力発電プラントは原子炉圧力容器を高温状態としたまま、発電再開に向けて待機する（高温待機）。この際、原子炉のスクラムにより熱出力は低下するが、原子炉格納容器から崩壊熱が継続して発生する。そのため、原子炉隔離事象が発生して高温待機させている場合、隔離時冷却設備は崩壊熱の除去を行う。 In the event of a reactor isolation event in which steam cannot be supplied from the reactor pressure vessel to the turbine, steam supply from the reactor pressure vessel to the turbine may be interrupted and power generation may be temporarily stopped. When recovery is expected early, the nuclear power plant waits for resuming power generation while keeping the reactor pressure vessel in a high temperature state (high temperature standby). At this time, although the heat output is lowered by the scram of the reactor, decay heat is continuously generated from the reactor containment vessel. Therefore, when a reactor isolation event occurs and the reactor is kept at high temperature, the isolation cooling facility removes decay heat.

一方、発電の再開を考慮すると、待機中の原子炉圧力容器は、内部の圧力・温度をできるだけ通常運転条件に近くしておけば、復旧にかかる時間・エネルギーが少なくて済む。しかし、特許文献１の隔離時冷却設備は、戻り配管に隔離弁を使用していた。この隔離弁は、基本的に全開・全閉状態で使用することを想定しており、流体の流れやすさを定常的に調節することは何ら目的としていない。そのため、原子炉隔離事象の発生時に、除熱量を調節することができなかった。そして、除熱量は原子炉圧力容器内の蒸気の圧力および温度で決まり、結果的に原子炉格納容器の圧力・温度は必要以上に低下していた。 On the other hand, considering the restart of power generation, the standby reactor pressure vessel requires less time and energy to recover if the internal pressure and temperature are kept as close to normal operating conditions as possible. However, the isolation cooling facility of Patent Document 1 uses an isolation valve in the return pipe. This isolation valve is basically assumed to be used in a fully open / fully closed state, and has no purpose of constantly adjusting the ease of fluid flow. Therefore, the amount of heat removal could not be adjusted when the reactor isolation event occurred. The amount of heat removal was determined by the pressure and temperature of the steam in the reactor pressure vessel. As a result, the pressure and temperature of the reactor containment vessel were reduced more than necessary.

本実施例において原子炉隔離事象が発生すると、原子炉圧力容器１からの飽和蒸気は導入配管６に流入し、熱交換器３で除熱される。熱交換器３で除熱されて凝縮した凝縮水（復水）は、戻り配管７を通して原子炉圧力容器１に戻る。 In this embodiment, when a reactor isolation event occurs, saturated steam from the reactor pressure vessel 1 flows into the introduction pipe 6 and is removed by the heat exchanger 3. Condensed water (condensate) condensed by removing heat from the heat exchanger 3 returns to the reactor pressure vessel 1 through the return pipe 7.

このとき、原子炉圧力容器１の温度は、熱交換器３による除熱量と、炉心の崩壊熱，接続機器との熱伝導，放射等が平衡する状態に向かう。つまり、原子炉圧力容器１の内部温度は、熱交換器３による除熱量に依存して変化する。そして、原子炉圧力容器１の内部は飽和状態であるため、圧力は温度に連動して変化する。 At this time, the temperature of the reactor pressure vessel 1 is in a state where the amount of heat removed by the heat exchanger 3 is balanced with the decay heat of the core, heat conduction with the connected equipment, radiation, and the like. That is, the internal temperature of the reactor pressure vessel 1 changes depending on the amount of heat removed by the heat exchanger 3. And since the inside of the reactor pressure vessel 1 is in a saturated state, the pressure changes in conjunction with the temperature.

また、戻り配管７に設けた調整弁５の操作によって、伝熱管１５の内部水位を調整することができる。 Further, the internal water level of the heat transfer tube 15 can be adjusted by operating the adjustment valve 5 provided in the return pipe 7.

ここで、熱交換器３が原子炉圧力容器１から流入する蒸気を除熱する量は、蒸気の潜熱が大部分を占めている。また、蒸気が凝縮する領域は、伝熱管１５の内部水位と熱交換器３の胴側水位との間の領域が大部分を占める。そのため、調整弁５を開く方向に操作すると、伝熱管１５の内部水位は低下する。そして、伝熱管１５の内部水位と熱交換器３の胴側水位との間の領域が大きくなり、除熱量は増加する。逆に、調整弁５を閉じる方向に操作すると、伝熱管１５の内部水位と熱交換器３の胴側水位との間の領域が縮小し、凝縮量および除熱量は減少する。 Here, the amount of heat removed from the steam that flows from the reactor pressure vessel 1 by the heat exchanger 3 is mostly latent heat of the steam. Further, the region where the steam condenses occupies most of the region between the internal water level of the heat transfer tube 15 and the trunk side water level of the heat exchanger 3. Therefore, if the adjustment valve 5 is operated in the opening direction, the internal water level of the heat transfer tube 15 is lowered. And the area | region between the internal water level of the heat exchanger tube 15 and the trunk | drum side water level of the heat exchanger 3 becomes large, and the amount of heat removal increases. On the contrary, when the adjustment valve 5 is operated in the closing direction, the region between the internal water level of the heat transfer tube 15 and the trunk side water level of the heat exchanger 3 is reduced, and the amount of condensation and the amount of heat removal are reduced.

このように、本実施例の隔離時冷却装置は、戻り配管に調整弁を備えている。この調整弁は、開度を調整することで復水の流れやすさを変えることができ、中間開度での制御を定常的に行うことが可能である。そのため、原子炉隔離事象発生時にも原子炉の圧力または温度を制御して、復旧にかかる時間・エネルギーを少なくすることが可能である。 As described above, the isolation cooling device of the present embodiment includes the adjustment valve in the return pipe. This adjustment valve can change the ease of flow of the condensate by adjusting the opening, and can perform control at an intermediate opening constantly. Therefore, it is possible to reduce the time and energy required for recovery by controlling the pressure or temperature of the reactor even when the reactor isolation event occurs.

また、熱交換器及び戻り配管に水位計を設けることにより、熱交換器３の胴側水位と伝熱管１５の内部水位の水位差を常時監視する。そして、調整弁５の操作によって、伝熱管１５の内部水位を変化させ、除熱量を調整することができる。 Further, by providing a water level meter in the heat exchanger and the return pipe, the water level difference between the trunk side water level of the heat exchanger 3 and the internal water level of the heat transfer tube 15 is constantly monitored. Then, the amount of heat removal can be adjusted by changing the internal water level of the heat transfer tube 15 by operating the adjustment valve 5.

さらに、熱交換器及び戻り配管に温度計を設けることにより、熱交換器３の水と伝熱管１５の復水の温度差を監視し、除熱量の評価精度を高めることが可能である。 Furthermore, by providing a thermometer in the heat exchanger and the return pipe, it is possible to monitor the temperature difference between the water in the heat exchanger 3 and the condensate in the heat transfer tube 15 and improve the accuracy of evaluating the heat removal amount.

１原子炉圧力容器
２炉水
３熱交換器
４冷却水
５調整弁
６導入配管
７戻り配管
８，９水位計
１０，１１温度計
１２排気配管
１３メッシュ
１４建物外壁
１５伝熱管 DESCRIPTION OF SYMBOLS 1 Reactor pressure vessel 2 Reactor water 3 Heat exchanger 4 Cooling water 5 Control valve 6 Introducing piping 7 Return piping 8, 9 Water level meter 10, 11 Thermometer 12 Exhaust piping 13 Mesh 14 Building outer wall 15 Heat transfer tube

Claims

原子炉圧力容器からの蒸気を導く導入配管と、前記導入配管から導かれた蒸気を除熱する熱交換器と、前記熱交換器での除熱によって凝縮された復水を前記原子炉圧力容器に戻す戻り配管とを備えた隔離時冷却設備において、
前記戻り配管に調整弁を備えることを特徴とする隔離時冷却設備。 An introduction pipe for introducing steam from the reactor pressure vessel; a heat exchanger for removing heat from the steam introduced from the introduction pipe; and the condensate condensed by heat removal in the heat exchanger In isolation cooling equipment with return piping to return to
The isolation cooling facility, wherein the return pipe is provided with a regulating valve.

請求項１記載の隔離時冷却設備において、
前記熱交換器及び前記戻り配管に水位計を設けることを特徴とする隔離時冷却設備。 The isolation cooling facility according to claim 1,
An isolation cooling system, wherein a water level gauge is provided in the heat exchanger and the return pipe.

請求項２記載の隔離時冷却設備において、
前記熱交換器及び前記戻り配管に温度計を設けることを特徴とする隔離時冷却設備。 In the isolation cooling facility according to claim 2,
The isolation cooling facility, wherein a thermometer is provided in the heat exchanger and the return pipe.