JPH0875887A - Core debris cooling apparatus for nuclear reactor - Google Patents
Core debris cooling apparatus for nuclear reactorInfo
- Publication number
- JPH0875887A JPH0875887A JP6236003A JP23600394A JPH0875887A JP H0875887 A JPH0875887 A JP H0875887A JP 6236003 A JP6236003 A JP 6236003A JP 23600394 A JP23600394 A JP 23600394A JP H0875887 A JPH0875887 A JP H0875887A
- Authority
- JP
- Japan
- Prior art keywords
- heat insulating
- reactor
- insulating material
- debris
- pressure vessel
- 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.)
- Granted
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
- Structure Of Emergency Protection For Nuclear Reactors (AREA)
Abstract
Description
【０００１】[0001]
【産業上の利用分野】本発明は、原子炉の炉心が損傷崩
壊し、これが炉内構造物に溶融混合して形成されるデブ
リの冷却装置に係り、特にデブリが原子炉圧力容器内下
部に落下した際に、原子炉圧力容器下部外壁表面に確実
に冷却水を供給し、原子炉圧力容器外壁表面で発生した
蒸気を確実に原子炉圧力容器保温材の外部に放出するこ
とができる原子炉の炉心デブリ冷却装置に関するもので
ある。BACKGROUND OF THE INVENTION 1. Field of the Invention The present invention relates to a cooling device for debris formed when a reactor core of a reactor is damaged and collapsed and melted and mixed with internal structures of the reactor. When dropped, cooling water can be reliably supplied to the outer wall surface of the lower part of the reactor pressure vessel, and steam generated on the outer wall surface of the reactor pressure vessel can be reliably discharged to the outside of the heat insulating material of the reactor pressure vessel. The present invention relates to a core debris cooling device.
【０００２】[0002]
【従来の技術】原子力発電所の設計を行う際には、設計
上の想定事故を超える事象として、炉心の損傷をも仮定
した苛酷事故対策についても検討される。この苛酷事故
対策の一つとして、従来、原子炉圧力容器下部が破損し
た後の原子炉格納容器内に落下した際の炉心デブリ冷却
装置が提案されている。ここでデブリとは、原子炉の炉
心が損傷崩壊し、これが炉内構造物に溶融混合して形成
される高温の溶融物のことである。このデブリは、原子
炉圧力容器内での冷却が十分でない場合に、原子炉圧力
容器下部を過温破損させ、原子炉圧力容器下部から原子
炉格納容器底部上に落下するおそれがある。2. Description of the Related Art When designing a nuclear power plant, countermeasures against severe accidents that also assume damage to the core are considered as events that exceed expected accidents in design. As one of measures against this severe accident, a core debris cooling device has been conventionally proposed when the lower part of the reactor pressure vessel is damaged and then dropped into the reactor containment vessel. Here, the debris is a high-temperature melt formed when the core of the nuclear reactor is damaged and collapsed, and this is melt-mixed with the internal structure of the reactor. When the cooling in the reactor pressure vessel is not sufficient, the debris may damage the lower portion of the reactor pressure vessel by overheating and may drop from the lower portion of the reactor pressure vessel onto the bottom portion of the reactor containment vessel.
【０００３】ところで、炉心の損傷崩壊の仮定そのもの
が新しい課題である。したがって、落下したデブリの冷
却に関しては、各国でその挙動を含め様々な研究が進め
られている段階であり、確立した先行技術といえるもの
は未だ存在せず、様々な研究を通してその課題が整理さ
れている段階である。したがって、現在までの知見に基
づき、炉心が損傷した場合の事象の概要を、図７に示す
加圧水型原子力発電所を例にして説明する。By the way, the assumption itself of core damage and collapse is a new subject. Therefore, regarding cooling of the debris that has fallen, various studies are underway in each country, including its behavior, and there is no established prior art yet, and the issues have been organized through various studies. It is in the stage of being. Therefore, based on the findings to date, the outline of the event when the core is damaged will be described by taking the pressurized water nuclear power plant shown in FIG. 7 as an example.
【０００４】図７において、符号１は燃料取替用水ピッ
ト２を内包する原子炉格納容器であり、この原子炉格納
容器１内には、炉心４を格納する原子炉圧力容器３が収
納されている。この原子炉格納容器１は、上部コンパー
トメント８および下部コンパートメント９と、原子炉圧
力容器３の下部に位置する原子炉キャビティ６と、燃料
取替ピット２および格納容器スプレイ１０とから構成さ
れる原子炉格納容器となっている。原子炉格納容器３
は、一次冷却材配管１１により蒸気発生器１２、一次冷
却ポンプ１３および加圧器１４に接続され、炉心４で加
熱された一次冷却材は原子炉圧力容器３から一次冷却材
配管１１を経て蒸気発生器１２へ輸送され、そこで蒸気
発生器の伝熱管を介して２次冷却材に熱交換する。そし
て蒸気発生器で冷却された１次冷却材は１次冷却材ポン
プ１３により水頭が付与され、再び原子炉圧力容器３に
供給される。原子炉圧力容器３ならびに１次冷却材配管
１１、蒸気発生器１２、１次冷却材ポンプ１３および加
圧器１４は保温材１５で覆われている。但しこの図では
原子炉圧力容器３の下部以外の保温材およびループの配
管、機器の一部を省略している。In FIG. 7, reference numeral 1 is a reactor containment vessel containing a refueling water pit 2, and in this reactor containment vessel 1, a reactor pressure vessel 3 for containing a reactor core 4 is housed. There is. The reactor containment vessel 1 is composed of an upper compartment 8 and a lower compartment 9, a reactor cavity 6 located under the reactor pressure vessel 3, a refueling pit 2 and a containment spray 10. It is a storage container. Primary containment vessel 3
Is connected to a steam generator 12, a primary cooling pump 13 and a pressurizer 14 by a primary coolant pipe 11, and the primary coolant heated in the reactor core 4 is steamed from the reactor pressure vessel 3 via the primary coolant pipe 11. It is transported to the vessel 12 where it exchanges heat with the secondary coolant via the heat transfer tubes of the steam generator. Then, the primary coolant pump 13 gives a water head to the primary coolant cooled by the steam generator, and the primary coolant is supplied again to the reactor pressure vessel 3. The reactor pressure vessel 3, the primary coolant pipe 11, the steam generator 12, the primary coolant pump 13, and the pressurizer 14 are covered with a heat insulating material 15. However, in this figure, the heat insulating material other than the lower portion of the reactor pressure vessel 3, the piping of the loop, and a part of the equipment are omitted.
【０００５】以上の構成において、炉心４が損傷し、崩
壊すると、炉心４の冷却形状が維持されないことから、
炉心４は炉内構造物とともに溶融混合し、高温の溶融物
であるデブリ５となって、原子炉圧力容器３の底部に落
下し始める。このとき、図示しない設備により、１次系
内への冷却水の注水が再開されれば、米国のスリーマイ
ルアイランドの原発事故のように、デブリ５は原子炉圧
力容器３の底部に溜まって、そのまま冷却される可能性
がある。In the above structure, when the core 4 is damaged and collapses, the cooling shape of the core 4 is not maintained,
The core 4 is melt-mixed with the internal structure of the reactor, and becomes debris 5 which is a high-temperature melt, and begins to drop to the bottom of the reactor pressure vessel 3. At this time, if cooling water injection into the primary system is restarted by equipment not shown, the debris 5 will accumulate at the bottom of the reactor pressure vessel 3 as in the nuclear accident at Three Mile Island in the United States. It may be cooled as it is.
【０００６】ところが、デブリの量が多い場合や、この
時点でも１次系内への冷却水の注水が不可能な場合に
は、デブリ５は原子炉圧力容器３の底部を破損せしめ、
やがては、原子炉圧力容器３の底部から原子炉格納容器
１の底部へと落下し始めることになる。そして、デブリ
５が原子炉格納容器１の底部に落下すると、原子炉格納
容器１の底部を形成しているコンクリート７との化学反
応（コア・コンクリート反応）により、エアロゾル状の
放射性物質（ＦＰ等）、一酸化炭素あるいは水素が多量
に発生する。この発生したガスによる内圧上昇ないしは
ガスの爆発により、原子炉格納容器１が加圧破損し、大
量のエアロゾル状の放射性物質を含むガスが、大気中に
放出されるといった最悪の事態に至るおそれがある。However, if the amount of debris is large, or if it is impossible to inject cooling water into the primary system even at this point, the debris 5 damages the bottom of the reactor pressure vessel 3,
Eventually, it will begin to fall from the bottom of the reactor pressure vessel 3 to the bottom of the reactor containment vessel 1. When the debris 5 falls to the bottom of the reactor containment vessel 1, a chemical reaction (core-concrete reaction) with the concrete 7 forming the bottom of the reactor containment vessel 1 causes the radioactive substance (FP, etc.) in the form of an aerosol. ), A large amount of carbon monoxide or hydrogen is generated. This increase in internal pressure due to the generated gas or explosion of the gas may damage the containment vessel 1 under pressure, resulting in the worst situation in which a large amount of gas containing an aerosol-like radioactive substance is released into the atmosphere. is there.
【０００７】このような事態に至る可能性は、加圧水型
原子力発電所に限らず、図８に示す沸騰水型原子力発電
所にも同様である。なお図７において、符号１８は基礎
コンクリート、１９はサプレッションプール、２０は上
部格納容器プール、２１はドライウエル、２２はウエッ
トウエル、２３は原子炉圧力容器である。The possibility of reaching such a situation is not limited to the pressurized water nuclear power plant, but is also applicable to the boiling water nuclear power plant shown in FIG. In FIG. 7, reference numeral 18 is basic concrete, 19 is a suppression pool, 20 is an upper containment vessel pool, 21 is a dry well, 22 is a wet well, and 23 is a reactor pressure vessel.
【０００８】ところで、デブリ５が原子炉圧力容器１の
底部に落下した段階において、何等かの方法でデブリ５
の冷却が可能であれば、外部への大量の放射性物質の放
出といった、最悪の事態は避けることができるものと期
待される。従来から提案されている冷却装置は、図７に
て原子炉圧力容器３が破損し原子炉キャビティ部６に落
下したあとのデブリを冷却するもので、デブリが落下す
る原子炉キャビティ部６に冷却水を導入するために、既
存のプール２と原子炉キャビティ部６とを連通するプー
ル水導入口１６を設け、かつ通常時には、プール水の導
入を防止するために、プール水導入入口の出口に遠隔操
作弁１７を配置した構造や、もともとデブリ捕獲、冷却
を目的としたコアーキャッチャー等の専用の設備が考え
られている。By the way, at the stage where the debris 5 has dropped to the bottom of the reactor pressure vessel 1, the debris 5 is somehow processed.
If it can be cooled, it is expected that the worst case such as the release of a large amount of radioactive material to the outside can be avoided. The conventionally proposed cooling device cools the debris after the reactor pressure vessel 3 is damaged in FIG. 7 and drops into the reactor cavity portion 6, and the debris drops into the reactor cavity portion 6 by cooling. In order to introduce water, a pool water inlet 16 that connects the existing pool 2 and the reactor cavity 6 is provided, and at the normal time, at the outlet of the pool water inlet to prevent the introduction of pool water. A structure in which the remote control valve 17 is arranged and a dedicated equipment such as a core catcher originally for the purpose of capturing debris and cooling are considered.
【０００９】また、ほとんどの加圧水型原子炉では、上
部コンパートメント８と原子炉キャビティ６の間には、
間隔が設けられており、事故時に燃料取替用水ピット２
ないしは原子炉格納容器外のタンクを水源とする格納容
器スプレイ１０が作動した際に、スプレイ水の一部は、
この間隙を通過して原子炉キャビティ６に蓄水し、原子
炉圧力容器３の下部領域を冠水する構造となっており、
この場合にも原子炉圧力容器破損後のデブリ冷却は達成
される。Also, in most pressurized water reactors, between the upper compartment 8 and the reactor cavity 6,
There is an interval between them, and in the event of an accident, the fuel replacement water pit 2
Or, when the containment vessel spray 10 whose water source is a tank outside the reactor containment vessel, a part of the spray water is
Water is stored in the reactor cavity 6 through this gap, and the lower region of the reactor pressure vessel 3 is flooded.
Also in this case, the debris cooling after the damage of the reactor pressure vessel is achieved.
【００１０】[0010]
【発明が解決しようとする課題】前記従来の原子炉格納
容器底部での炉心デブリ冷却装置においては、原子炉圧
力容器が破損し原子炉格納容器底部に落下した後にデブ
リを冷却するもので、原子炉圧力容器外に大量の放射性
物質を放出することになるだけでなく、デブリ落下時の
冷却水との直接接触による蒸気爆発の恐れ、および冷却
水と接触するデブリ表面は見かけ上冷却されても、デブ
リの量、形状によってはデブリ下部は冷却されずコア・
コンクリート反応が継続する恐れもある。In the conventional reactor core debris cooling system at the bottom of the containment vessel, the debris is cooled after the reactor pressure vessel is damaged and drops to the bottom of the containment vessel. Not only will a large amount of radioactive material be released outside the reactor pressure vessel, but there is also the danger of a vapor explosion due to direct contact with the cooling water when the debris falls, and the debris surface that comes into contact with the cooling water is apparently cooled. Depending on the amount and shape of the debris, the lower part of the debris is not cooled and the core
The concrete reaction may continue.
【００１１】そこで、米国等において、原子炉圧力容器
が破損する前に、原子炉圧力容器底部に落下したデブリ
を冷却することの可能性について研究が行われている。
しかしながら、一般に原子炉圧力容器は運転時の放熱に
よるロスを防ぐために保温材により覆われており、上記
デブリ冷却を阻害する要因となっている。Therefore, in the United States and the like, studies have been conducted on the possibility of cooling the debris that has dropped to the bottom of the reactor pressure vessel before the reactor pressure vessel is damaged.
However, in general, the reactor pressure vessel is covered with a heat insulating material in order to prevent loss due to heat radiation during operation, which is a factor that hinders the above debris cooling.
【００１２】本発明は、このような点を考慮してなされ
たもので、デブリが原子炉圧力容器の底部に落下した段
階で、原子炉圧力容器の保温材を通過して原子炉圧力容
器外壁表面に、大量の冷却水を効果的に導入することが
できる原子炉の炉心デブリ冷却装置を提供することを目
的とする。なお、本発明は、従来の技術により原子炉キ
ャビティは既に給水されていることを前提としている。The present invention has been made in consideration of the above point, and when debris drops to the bottom of the reactor pressure vessel, it passes through the heat insulating material of the reactor pressure vessel and the outer wall of the reactor pressure vessel. An object of the present invention is to provide a reactor core debris cooling device capable of effectively introducing a large amount of cooling water to the surface. It should be noted that the present invention is based on the assumption that the reactor cavity has already been supplied with water by the conventional technique.
【００１３】[0013]
【課題を解決するための手段】本発明は、原子炉格納容
器に収容された原子炉圧力容器下方に存在する原子炉キ
ャビティへの冷却水供給手段を有するものにおいて、前
記原子炉圧力容器の外壁を覆う保温材には、原子炉圧力
容器内の底部に落下したデブリからの熱伝導及び熱放射
により開放される複数の熱開放ブロック状保温材と、保
温材の内側と外側との圧力差で開放される複数の圧開放
ブロック状保温材とが配設されていることを特徴とす
る。According to the present invention, there is provided a means for supplying cooling water to a reactor cavity below a reactor pressure vessel housed in a reactor containment vessel, wherein an outer wall of the reactor pressure vessel is provided. The heat insulating material that covers the multiple heat release block-shaped heat insulating materials that is released by heat conduction and heat radiation from the debris that has dropped to the bottom of the reactor pressure vessel, and the pressure difference between the inside and outside of the heat insulating material. A plurality of pressure release block-shaped heat insulating materials to be released are provided.
【００１４】また、本発明の前記熱開放ブロック状保温
材の上側には、隣接する保温材と係合する接続部が、下
側には、外方に向かって下向きに傾斜した滑り面が、そ
れぞれ配設されていることを特徴とする。Further, on the upper side of the heat releasing block-like heat insulating material of the present invention, a connecting portion engaging with an adjacent heat insulating material is provided, and on the lower side, a sliding surface inclined downward toward the outside, It is characterized in that each is provided.
【００１５】また、本発明の前記接続部は、上側に隣接
する保温材とのオーバラップ部が低融点のろう付けで固
定された構造であることを特徴とする。Further, the connection portion of the present invention is characterized in that the overlap portion with the heat insulating material adjacent to the upper side is fixed by brazing with a low melting point.
【００１６】また、本発明の前記接続部は、上側に隣接
する保温材にバックル止めがね部が係止され、前記保温
材を貫通する止め軸が低融点ろう付けで固定された構造
であることを特徴とする。Further, the connection portion of the present invention has a structure in which a buckle-stopping ring portion is locked to a heat insulating material adjacent to the upper side, and a stop shaft penetrating the heat insulating material is fixed by low melting point brazing. It is characterized by
【００１７】また、本発明の前記圧開放ブロック状保温
材は、一辺に蝶番が取り付けられ、他の辺は水溶性の
糊，テープ等のシールで密封されていることを特徴とす
る。The pressure release block-shaped heat insulating material of the present invention is characterized in that a hinge is attached to one side and the other side is sealed with a seal such as water-soluble glue or tape.
【００１８】また、本発明の前記圧開放ブロック状保温
材は、各辺にストッパーである突起物が設けられると共
に、水溶性の糊，テープ等のシールで密封されているこ
とを特徴とする。Further, the pressure release block-shaped heat insulating material of the present invention is characterized in that each side is provided with a protrusion as a stopper and is sealed with a seal such as a water-soluble glue or tape.
【００１９】[0019]
【作用】本発明に係る原子炉の炉心デブリ冷却装置にお
いて、炉心領域から原子炉圧力容器の底部に落下してき
た炉心溶融デブリは、原子炉圧力容器の底部を加熱し、
原子炉圧力容器の底部外壁表面は高温状態となる。この
とき原子炉圧力容器の底部外壁表面にあらかじめ接触な
いしは近接して設置された熱開放ブロック状保温材上側
の接続部の低融点のろう付けを熱伝導ないしは熱放射に
よりとかすので、前記熱開放ブロック状保温材は下側の
滑り面にそって外方に開放され、保温材の一部あるいは
大部分は除去される。その結果、保温材の外部に滞留し
ていた冷却水は保温材が除去された領域を通って原子炉
圧力容器外壁表面に導入され、一方、原子炉圧力容器外
壁表面で加熱発生した蒸気はやはり保温材が除去された
領域を通って保温材外部に導出されることにより、原子
炉圧力容器外壁表面は良好に冷却される。In the reactor core debris cooling apparatus according to the present invention, the core molten debris that has dropped from the core region to the bottom of the reactor pressure vessel heats the bottom of the reactor pressure vessel,
The surface of the bottom outer wall of the reactor pressure vessel becomes hot. At this time, since the low melting point brazing of the upper connection portion of the heat release block-shaped heat insulating material, which is installed in advance in contact with or close to the outer surface of the bottom of the reactor pressure vessel, is melted by heat conduction or heat radiation, the heat release block The heat insulating material is opened outward along the lower sliding surface, and a part or most of the heat insulating material is removed. As a result, the cooling water staying outside the heat insulating material is introduced to the outer wall surface of the reactor pressure vessel through the area where the heat insulating material is removed, while the steam generated by heating on the outer wall surface of the reactor pressure vessel is still The surface of the outer wall of the reactor pressure vessel is satisfactorily cooled by being guided to the outside of the heat insulating material through the area where the heat insulating material has been removed.
【００２０】また原子炉圧力容器の底部外壁表面から離
れた場所で、デブリによる加熱効果を期待できないよう
な保温材については、水頭圧ないしは原子炉圧力容器外
壁表面での冷却水との接触による激しい気泡の発生、消
滅の繰り返しにともなう動圧により開放される複数の圧
開放ブロック状保温材が通常時閉の状態で配設されてい
るが、これが開放されることにより、保温材の内側と外
側との冷却水と蒸気の流通は促進され、原子炉圧力容器
外壁表面は良好に冷却される。Further, with respect to a heat insulating material which cannot be expected to have a heating effect due to debris at a place distant from the surface of the outer wall of the bottom of the reactor pressure vessel, the head pressure or contact with the cooling water on the surface of the outer wall of the reactor pressure vessel causes severe A plurality of pressure-releasing block-shaped heat insulating materials, which are opened by dynamic pressure due to repeated generation and disappearance of air bubbles, are normally placed in a closed state. The circulation of cooling water and steam between and is promoted, and the surface of the outer wall of the reactor pressure vessel is cooled well.
【００２１】[0021]
【実施例】以下、添付図に基づいて本発明の実施例を詳
細に説明する。図１は原子炉圧力容器下部領域の拡大図
である。図２は、本発明に係る原子炉の炉心デブリ冷却
装置の第１実施例を示すもので、図中符号２５は原子炉
圧力容器３を覆う保温材１５の一部を構成する熱開放ブ
ロック状保温材である。保温材１５の全体構成は、一般
に矩形のパーツをネジ、リベット、バックルあるいはバ
ンド方式により接続、組み合わせたものである。本実施
例は、この原子炉圧力容器下部領域の保温材１５の一部
を開放可能として、複数の熱開放ブロック状保温材２５
とし、この熱開放ブロック状保温材２５を図２の
（ａ），（ｂ）に示すように原子炉圧力壁側の上側の接
続部であるオーバーラップ部２７のみを低融点のろうを
用いてろう付けして固定し、かつ下端は、符号２８に示
すような角度を持たせた形状の滑り面として、上部接続
部のろうが溶融し離脱した際に、自重により符号２５の
保温材が容易に落下するようにしたものである。Embodiments of the present invention will be described in detail below with reference to the accompanying drawings. FIG. 1 is an enlarged view of the lower region of the reactor pressure vessel. FIG. 2 shows a first embodiment of a reactor core debris cooling system according to the present invention, in which reference numeral 25 denotes a heat release block shape which constitutes a part of a heat insulating material 15 which covers the reactor pressure vessel 3. It is a heat insulating material. The whole structure of the heat insulating material 15 is generally formed by connecting and combining rectangular parts by a screw, rivet, buckle or band method. In this embodiment, a part of the heat insulating material 15 in the lower region of the reactor pressure vessel can be opened, and a plurality of heat release block-shaped heat insulating materials 25 are provided.
As shown in FIGS. 2 (a) and 2 (b), the heat releasing block-shaped heat insulating material 25 is formed by using a low melting point braze only for the overlap portion 27 which is the upper connecting portion on the reactor pressure wall side. As the sliding surface is fixed by brazing and the lower end has an angled shape as shown by reference numeral 28, when the brazing material of the upper connection portion melts and separates, the heat retaining material of reference numeral 25 can be easily applied by its own weight. It is intended to fall into the.
【００２２】また、図３は本発明の第２実施例を示すも
ので、前記第１実施例におけるオーバーラップ部２７に
代え、バックル止めがね部２９の端の止め軸３０を保温
材の原子炉圧力容器３側にろう付けしたものである。な
お、その他の点については、前記第１実施例と同一構成
となっている。以上の構成において、保温材を固定して
いるバックル止めがね部２９の止め軸３０の低融点のろ
う付け部分は加熱され、原子炉圧力容器下部がクリーブ
破損する前に、ろう付けは溶融し、バックル２９は外
れ、この保温材２５は離脱、落下する。その結果、前記
第１実施例と同様に保温材１５に開口部が形成される。FIG. 3 shows a second embodiment of the present invention. Instead of the overlap portion 27 in the first embodiment, a retaining shaft 30 at the end of the buckle retaining ring portion 29 is replaced by an atom of a heat insulating material. It is brazed to the furnace pressure vessel 3 side. The other points are the same as those of the first embodiment. In the above structure, the low melting point brazed portion of the retaining shaft 30 of the buckle clasp 29 that fixes the heat insulating material is heated, and the brazing is melted before the lower part of the reactor pressure vessel is cleaved. The buckle 29 is released, and the heat insulating material 25 is detached and dropped. As a result, an opening is formed in the heat insulating material 15 as in the first embodiment.
【００２３】このような熱開放ブロック状保温材２５を
図１に示すように、ろう付け部分が原子炉圧力容器３の
外壁表面に接触ないしは近接させて設置し、原子炉圧力
容器３が高温となった場合にこのろう付け部が溶融し、
固定されていた保温材２５は離脱、落下し、保温材１５
に開口部が形成される。このような熱開放ブロック状保
温材２５を複数設置する。As shown in FIG. 1, such a heat release block-shaped heat insulating material 25 is installed such that the brazing portion is in contact with or close to the surface of the outer wall of the reactor pressure vessel 3, and the reactor pressure vessel 3 is kept at a high temperature. If this happens, the brazing part will melt,
The heat insulating material 25 that has been fixed is detached and dropped, and the heat insulating material 15
An opening is formed in the. A plurality of such heat releasing block-shaped heat insulating materials 25 are installed.
【００２４】図４は、本発明の第３実施例の圧開放ブロ
ック状保温材２６を示すもので、前記第１実施例におけ
るオーバーラップ部２７のろう付けに代え、蝶番３１を
設けたもので、僅かな保温材の内側と外側との圧力差で
開放される。ただし、通常時は、閉状態を維持するため
に、蝶番３１部分を除く周辺部３２は水溶性の糊、テー
プ等によって密封し、同時に保温機能を維持する。FIG. 4 shows a pressure releasing block-shaped heat insulating material 26 according to a third embodiment of the present invention, in which a hinge 31 is provided instead of brazing the overlap portion 27 in the first embodiment. , It is opened by a slight pressure difference between the inside and outside of the heat insulating material. However, in the normal state, in order to maintain the closed state, the peripheral portion 32 excluding the hinge 31 is sealed with water-soluble glue, tape or the like, and at the same time, the heat retaining function is maintained.
【００２５】また、図５は、本発明の第４実施例の圧開
放ブロック状保温材２６を示すもので、前記第１実施例
におけるオーバーラップ部２７のろう付けに代え、スト
ッパーである突起物３３を設けたもので、僅かな保温材
の内側と外側との圧力差で開放される。ただし、通常時
は、密閉状態を維持するために、周辺部３４を水溶性の
糊、テープ等によって密封し、保温機能を高めることも
可能である。FIG. 5 shows a pressure releasing block-shaped heat insulating material 26 according to a fourth embodiment of the present invention. Instead of brazing the overlapping portion 27 in the first embodiment, a protrusion serving as a stopper is provided. 33 is provided and is opened by a slight pressure difference between the inside and outside of the heat insulating material. However, in a normal state, in order to maintain the hermetically sealed state, it is possible to seal the peripheral portion 34 with water-soluble glue, tape or the like to enhance the heat retaining function.
【００２６】以上の構成において、原子炉圧力容器の底
部外壁表面から離れた場所で、デブリによる加熱効果を
期待できないような保温材についても、水頭圧ないしは
原子炉圧力容器外壁表面での激しい気泡の発生、消滅の
繰り返しにともなう動圧により開閉可能となり、前記第
１実施例と同様に保温材の内側と外側との冷却水と蒸気
の流通は促進され、原子炉圧力容器外壁表面は良好に冷
却される。In the above structure, even with a heat insulating material which cannot be expected to have a heating effect due to debris at a place away from the outer surface of the bottom of the reactor pressure vessel, head pressure or violent bubbles on the outer surface of the reactor pressure vessel are generated. It can be opened and closed by the dynamic pressure that accompanies repeated generation and disappearance, the circulation of cooling water and steam between the inside and outside of the heat insulating material is promoted as in the first embodiment, and the outer wall surface of the reactor pressure vessel is cooled well. To be done.
【００２７】図６は、本発明の第５実施例を示すもの
で、前記第１実施例の熱開放ブロック状保温材２５に代
えて、原子炉圧力容器外周部に熱膨張率の小さい材質、
例えばセラミックからなる止めがねリング３４および３
５を図のように組み合わせ、リング３４は上部の保温材
３６に固定し、リング３５は下部保温材３７に固定する
ことにより、上部と下部とを独立させ、かつこの２つの
リングを介して上部保温材により下部保温材を支えるこ
とを可能としたものである。このようなリングを原子炉
圧力容器下部領域に接触ないしは近接して設置すること
により、炉心溶融事故時に原子炉圧力容器下部に堆積し
たデブリからの加熱による周方向への原子炉圧力容器外
壁の熱膨張によるリング３４，３５の破壊により、下部
の保温材３７の全体が自重により容易に原子炉キャビテ
ィ下部に落下するようにしたものである。なお、前記各
実施例においては、燃料取替用水ピットを原子炉格納容
器内に設置した場合について説明したが、燃料取替用水
ピットを原子炉格納容器外に設置したプラントの場合
や、図８に示すような構造の沸騰水型原子炉にも、同様
に適用することができる。FIG. 6 shows a fifth embodiment of the present invention. Instead of the heat release block heat insulating material 25 of the first embodiment, a material having a small coefficient of thermal expansion is provided on the outer peripheral portion of the reactor pressure vessel,
Clasp rings 34 and 3 made of ceramic, for example
5 as shown in the figure, the ring 34 is fixed to the upper heat insulating material 36, and the ring 35 is fixed to the lower heat insulating material 37 so that the upper portion and the lower portion are independent, and the upper portion is connected via these two rings. The heat insulating material makes it possible to support the lower heat insulating material. By installing such a ring in contact with or in the vicinity of the lower region of the reactor pressure vessel, heat from the debris accumulated in the lower portion of the reactor pressure vessel during the core melting accident will cause the heat of the outer wall of the reactor pressure vessel in the circumferential direction. When the rings 34 and 35 are broken due to expansion, the entire lower heat insulating material 37 is easily dropped to the lower portion of the reactor cavity by its own weight. In each of the above-described embodiments, the case where the fuel replacement water pit is installed inside the reactor containment vessel has been described. It can be similarly applied to a boiling water reactor having a structure as shown in FIG.
【００２８】また、本発明は、前記各実施例に限定され
るものではなく、オーバーラップ部２７及びバックル止
めがね部２９の止め軸３０のろう付けに代えて、形状記
憶合金による止めがね等を用いるようにすることもで
き、また蝶番３１に代えて、符号３２と同様に周辺部全
体を水溶性の糊、テープ等で固定あるいは、単に脱着可
能なよう設置しておき、事故時に原子炉キャビティに給
水が行われた際、あるいは更に蒸気発生時の負荷が加わ
ることにより確実に開放可能とすることもでき、種々の
変更ないし組み合わせが可能である。The present invention is not limited to the above-mentioned embodiments, but instead of brazing the retaining shaft 30 of the overlapping portion 27 and the buckle retaining portion 29, a retaining metal made of a shape memory alloy is used. In place of the hinge 31, the entire peripheral portion is fixed with water-soluble glue, tape, or the like so that it can be easily detached in place of the hinge 31. When the water is supplied to the furnace cavity, or when a load is further applied when steam is generated, the furnace cavity can be surely opened, and various modifications and combinations are possible.
【００２９】次に本実施例の作動について説明する。原
子炉圧力容器３内に格納されている炉心が損傷し、溶融
すると原子炉圧力容器３の底部に落下しデブリ５となっ
て堆積する。すると、デブリ５内で発生する崩壊熱によ
り原子炉圧力容器３の下部は加熱され、原子炉圧力容器
の内壁はもとより外壁表面も高温状態となる。そのた
め、熱伝導ないしは放射伝熱により、熱開放ブロック状
保温材２５を固定している接続部の低融点（例えば５０
０〜６００℃）のろう付け部分は加熱され、原子炉圧力
容器３の下部がクリープ破損（１０００℃を越えると破
損のリスクが高くなる）する前に、ろう付けは外れ、こ
の保温材２５は離脱、落下する。この保温材の開口部よ
り原子炉キャビティ６に予め蓄積されている冷却水は水
頭圧により原子炉容器下部領域２４に流入し、原子炉容
器下部外壁表面は冷却される。そのため原子炉圧力容器
３の底部に堆積したデブリ５も冷却される。Next, the operation of this embodiment will be described. When the core contained in the reactor pressure vessel 3 is damaged and melts, it falls to the bottom of the reactor pressure vessel 3 and accumulates as debris 5. Then, the lower part of the reactor pressure vessel 3 is heated by the decay heat generated in the debris 5, and the surface of the outer wall as well as the inner wall of the reactor pressure vessel is in a high temperature state. Therefore, the low melting point (for example, 50) of the connection portion fixing the heat release block-shaped heat insulating material 25 is caused by heat conduction or radiation heat transfer.
(0-600 ° C.), the brazing part is heated, and before the lower part of the reactor pressure vessel 3 undergoes creep damage (above 1000 ° C., the risk of damage is high), the brazing is removed and the heat insulating material 25 Detaches and falls. The cooling water previously accumulated in the reactor cavity 6 through the opening of the heat insulating material flows into the reactor vessel lower region 24 by the water head pressure, and the surface of the reactor vessel lower outer wall is cooled. Therefore, the debris 5 deposited on the bottom of the reactor pressure vessel 3 is also cooled.
【００３０】また、原子炉圧力容器３の底部外壁面から
離れた場所で、デブリ５による加熱効果を期待できない
ような場所には、水頭圧ないしは原子炉圧力容器３外壁
表面での冷却水との接触による激しい気泡の発生、消滅
の繰り返しによる動圧により、複数の圧開放ブロック状
保温材２６が開放されるので、保温材の内側と外側との
冷却水と蒸気の流通は促進され、原子炉圧力容器３の外
壁表面は良好に冷却される。Further, at a place away from the outer wall surface of the bottom of the reactor pressure vessel 3 where the heating effect of the debris 5 cannot be expected, the head pressure or the cooling water on the outer wall surface of the reactor pressure vessel 3 Since a plurality of pressure release block-shaped heat insulating materials 26 are opened by dynamic pressure due to repeated generation and disappearance of intense bubbles due to contact, circulation of cooling water and steam between the inside and outside of the heat insulating material is promoted, and the reactor The outer wall surface of the pressure vessel 3 is cooled well.
【００３１】従って、原子炉圧力容器壁がさらに加熱す
るのを防止し、原子炉キャビティ６への給水が継続され
る限り、原子炉圧力容器下部は冷却され原子炉圧力容器
３の破損は防止される。これにより、デブリの原子炉圧
力容器外への飛散ないしは放出が防止され、放射性物質
による原子炉格納容器内汚染、蒸気爆発およびコア・コ
ンクリート反応の発生を防止することができる。Therefore, as long as the reactor pressure vessel wall is prevented from further heating and the water supply to the reactor cavity 6 is continued, the lower portion of the reactor pressure vessel is cooled and damage to the reactor pressure vessel 3 is prevented. It As a result, scattering or release of debris to the outside of the reactor pressure vessel can be prevented, and contamination of the reactor containment vessel by radioactive materials, steam explosion, and core-concrete reaction can be prevented.
【００３２】[0032]
【発明の効果】以上説明したように本発明は、デブリが
原子炉圧力容器下部に溶融落下した状態で、原子炉圧力
容器外壁の温度上昇、それによる外壁の熱膨張ないしは
原子炉キャビティへの給水を自動的に感知して、原子炉
圧力容器の保温材の一部ないしは全てを除去ないしは開
放可能とし、原子炉圧力容器外壁を直接冷却するための
冷却水導入および発生蒸気放出の十分な流路を確保する
ことにより、原子炉圧力容器の破損ならびに原子炉格納
容器内への放射性物質の大量拡散およびデブリとコンク
リートとの直接接触が防止されるので、コア・コンクリ
ート反応の発生を防ぐことができる。As described above, according to the present invention, in a state where debris is melted and dropped to the lower part of the reactor pressure vessel, the temperature rise of the outer wall of the reactor pressure vessel, the thermal expansion of the outer wall or the water supply to the reactor cavity due to the temperature rise. Of the heat insulation material of the reactor pressure vessel can be removed or opened, and a sufficient flow path for introducing cooling water and releasing steam generated for directly cooling the outer wall of the reactor pressure vessel can be detected. By securing the above, it is possible to prevent damage to the reactor pressure vessel, large amount of radioactive material diffusion into the reactor containment vessel, and direct contact between debris and concrete, so that it is possible to prevent core-concrete reaction from occurring. .
【図１】本発明に係る原子炉の炉心デブリ冷却装置を示
す説明図である。FIG. 1 is an explanatory diagram showing a reactor core debris cooling device according to the present invention.
【図２】本発明の第１実施例を示す熱開放ブロック状保
温材の図で、（ａ）は縦断面図を、（ｂ）は斜視図をそ
れぞれ表わす。2A and 2B are views of a heat release block-shaped heat insulating material showing a first embodiment of the present invention, in which FIG. 2A is a longitudinal sectional view and FIG. 2B is a perspective view.
【図３】本発明の第２実施例を示す熱開放ブロック状保
温材の縦断面図である。FIG. 3 is a vertical cross-sectional view of a heat release block-shaped heat insulating material showing a second embodiment of the present invention.
【図４】本発明の第３実施例を示す圧開放ブロック状保
温材の斜視図である。FIG. 4 is a perspective view of a pressure releasing block-shaped heat insulating material showing a third embodiment of the present invention.
【図５】本発明の第４実施例を示す圧開放ブロック状保
温材の斜視図である。FIG. 5 is a perspective view of a pressure release block-shaped heat insulating material according to a fourth embodiment of the present invention.
【図６】本発明の第５実施例を示す保温材熱開放部の断
面図である。FIG. 6 is a sectional view of a heat insulating material heat release portion showing a fifth embodiment of the present invention.
【図７】加圧水型原子力発電所におけるデブリの発生状
態を示す説明図である。FIG. 7 is an explanatory diagram showing a debris generation state in a pressurized water nuclear power plant.
【図８】沸騰水型原子力発電所におけるデブリの発生状
態わ示す説明図である。FIG. 8 is an explanatory diagram showing a debris generation state in a boiling water nuclear power plant.
１ 原子炉格納容器 ３，２３ 原子炉圧力容器 ５ デブリ ６ 原子炉キャビティ １５ 保温材 ２５ 熱開放ブロック状保温材 ２６ 圧開放ブロック状保温材 ２７ オーバラップ部 ２８ 滑り面 ２９ バックル止めがね部 ３０ 止め軸 ３１ 蝶番 ３３ 突起物 ３４ 上部保温材止めがね ３５ 下部保温材止めがね ３６ 上部保温材 ３７ 下部保温材 1 Reactor Containment Vessel 3,23 Reactor Pressure Vessel 5 Debris 6 Reactor Cavity 15 Heat Insulating Material 25 Heat Release Block-like Heat Insulation Material 26 Pressure Release Block-like Heat Insulation Material 27 Overlap 28 Slip Surface 29 Buckle Stopper 30 Stop Axis 31 Hinges 33 Protrusions 34 Upper heat insulating material retaining rings 35 Lower heat retaining material retaining rings 36 Upper heat retaining material 37 Lower heat retaining material
Claims (6)
容器下方に存在する原子炉キャビティへの冷却水供給手
段を有するものにおいて、 前記原子炉圧力容器の外壁を覆う保温材には、原子炉圧
力容器内の底部に落下したデブリからの熱伝導及び熱放
射により開放される複数の熱開放ブロック状保温材と、
保温材の内側と外側との圧力差で開放される複数の圧開
放ブロック状保温材とが配設されていることを特徴とす
る原子炉の炉心デブリ冷却装置。1. A reactor having a means for supplying cooling water to a reactor cavity located below a reactor pressure vessel housed in a reactor containment vessel, wherein the heat insulating material covering the outer wall of the reactor pressure vessel is A plurality of heat release block-shaped heat insulating material that is opened by heat conduction and heat radiation from debris that has fallen to the bottom of the furnace pressure vessel,
A core debris cooling device for a nuclear reactor, comprising: a plurality of pressure release block-shaped heat insulating materials that are opened by a pressure difference between the inside and outside of the heat insulating material.
は、隣接する保温材と係合する接続部が、下側には、外
方に向かって下向きに傾斜した滑り面が、それぞれ配設
されていることを特徴とする請求項１記載の原子炉の炉
心デブリ冷却装置。2. The heat-releasing block-shaped heat insulating material is provided with a connecting portion engaged with an adjacent heat insulating material on the upper side, and a sliding surface inclined downward toward the outside on the lower side. The core debris cooling device for a nuclear reactor according to claim 1, wherein
のオーバラップ部が低融点のろう付けで固定された構造
であることを特徴とする請求項２記載の原子炉の炉心デ
ブリ冷却装置。3. The reactor core debris cooling according to claim 2, wherein the connecting portion has a structure in which an overlapping portion with a heat insulating material adjacent to the upper side is fixed by brazing with a low melting point. apparatus.
バックル止めがね部が係止され、前記保温材を貫通する
止め軸が低融点ろう付けで固定された構造であることを
特徴とする請求項２記載の原子炉の炉心デブリ冷却装
置。4. The connecting portion has a structure in which a buckle retaining ring is engaged with a heat insulating material adjacent to the upper side, and a retaining shaft penetrating the heat insulating material is fixed by low melting point brazing. The reactor core debris cooling device according to claim 2.
蝶番が取り付けられ、他の辺は水溶性の糊，テープ等の
シールで密封されていることを特徴とする請求項１記載
の原子炉の炉心デブリ冷却装置。5. The atom according to claim 1, wherein the pressure release block heat insulating material has a hinge attached to one side and is sealed with a seal such as a water-soluble glue or tape on the other side. Cooling device for core debris of the reactor.
トッパーである突起物が設けられると共に、水溶性の
糊，テープ等のシールで密封されていることを特徴とす
る請求項１記載の原子炉の炉心デブリ冷却装置。6. The pressure releasing block-shaped heat insulating material is provided with protrusions serving as stoppers on each side, and is sealed with a seal such as water-soluble glue or tape. Debris cooling system for nuclear reactors.
Priority Applications (1)
| Application Number | Priority Date | Filing Date | Title |
|---|---|---|---|
| JP23600394A JP3160476B2 (en) | 1994-09-05 | 1994-09-05 | Reactor core debris cooling system |
Applications Claiming Priority (1)
| Application Number | Priority Date | Filing Date | Title |
|---|---|---|---|
| JP23600394A JP3160476B2 (en) | 1994-09-05 | 1994-09-05 | Reactor core debris cooling system |
Publications (2)
| Publication Number | Publication Date |
|---|---|
| JPH0875887A true JPH0875887A (en) | 1996-03-22 |
| JP3160476B2 JP3160476B2 (en) | 2001-04-25 |
Family
ID=16994360
Family Applications (1)
| Application Number | Title | Priority Date | Filing Date |
|---|---|---|---|
| JP23600394A Expired - Fee Related JP3160476B2 (en) | 1994-09-05 | 1994-09-05 | Reactor core debris cooling system |
Country Status (1)
| Country | Link |
|---|---|
| JP (1) | JP3160476B2 (en) |
Cited By (5)
| Publication number | Priority date | Publication date | Assignee | Title |
|---|---|---|---|---|
| JPH10319166A (en) * | 1997-05-06 | 1998-12-04 | Commiss Energ Atom | Water reactor containing core recovery device operating in accidental meltdown |
| EP0993000A2 (en) * | 1998-10-07 | 2000-04-12 | Forschungszentrum Jülich Gmbh | Apparatus for cooling and protecting a reactor pressure vessel in the event of a core melting accident |
| WO2001016962A1 (en) * | 1999-08-27 | 2001-03-08 | Hitachi, Ltd. | Reactor safety equipment |
| KR20190073861A (en) * | 2017-12-19 | 2019-06-27 | 한국원자력연구원 | Passive reactor external vessel cooling system |
| JP7082253B1 (en) * | 2021-09-25 | 2022-06-07 | 強 松岡 | Reactor capable of responding to core meltdown accidents aimed at preventing the release of radioactivity |
-
1994
- 1994-09-05 JP JP23600394A patent/JP3160476B2/en not_active Expired - Fee Related
Cited By (8)
| Publication number | Priority date | Publication date | Assignee | Title |
|---|---|---|---|---|
| JPH10319166A (en) * | 1997-05-06 | 1998-12-04 | Commiss Energ Atom | Water reactor containing core recovery device operating in accidental meltdown |
| EP0993000A2 (en) * | 1998-10-07 | 2000-04-12 | Forschungszentrum Jülich Gmbh | Apparatus for cooling and protecting a reactor pressure vessel in the event of a core melting accident |
| EP0993000A3 (en) * | 1998-10-07 | 2000-12-13 | Forschungszentrum Jülich Gmbh | Apparatus for cooling and protecting a reactor pressure vessel in the event of a core melting accident |
| EP1233423A1 (en) * | 1998-10-07 | 2002-08-21 | Forschungszentrum Jülich Gmbh | Apparatus for cooling and protecting a reactor pressure vessel in the event of a core melting accident |
| WO2001016962A1 (en) * | 1999-08-27 | 2001-03-08 | Hitachi, Ltd. | Reactor safety equipment |
| KR20190073861A (en) * | 2017-12-19 | 2019-06-27 | 한국원자력연구원 | Passive reactor external vessel cooling system |
| JP7082253B1 (en) * | 2021-09-25 | 2022-06-07 | 強 松岡 | Reactor capable of responding to core meltdown accidents aimed at preventing the release of radioactivity |
| WO2023047555A1 (en) * | 2021-09-25 | 2023-03-30 | 強 松岡 | Nuclear reactor capable of coping with core meltdown accident for purpose of preventing release of radioactivity |
Also Published As
| Publication number | Publication date |
|---|---|
| JP3160476B2 (en) | 2001-04-25 |
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Legal Events
| Date | Code | Title | Description |
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| A01 | Written decision to grant a patent or to grant a registration (utility model) |
Free format text: JAPANESE INTERMEDIATE CODE: A01 Effective date: 20010116 |
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| LAPS | Cancellation because of no payment of annual fees |