NUCLEAR REACTOR SHUTDOWN SYSTEM AND NUCLEAR REACTOR SHUTDOWN METHOD

To provide a nuclear reactor shutdown system and nuclear reactor shutdown method for emergency shutdown, which are applicable to small reactors while maintaining safety and speed.SOLUTION: A nuclear reactor shutdown system is provided, comprising: a shielded passage extending through between reactor core fuels hermetically contained in a reactor vessel and arranged such that one end thereof is open and the other end is closed; neutron absorbers that can be introduced into the shielded passage from the opening; an elastic member designed to push the neutron absorbers into the shielded passage through the opening when released form a compressed state; and control unit disposed to maintain the compressed state of the elastic member and configured to cause the elastic member to be released from the compressed state when the temperature rises to a threshold temperature or above.SELECTED DRAWING: Figure 3 【課題】安全性及び迅速性を維持しつつ、小型の原子炉に適用可能な緊急停止用の原子炉停止システム及び原子炉停止方法を提供する。【解決手段】原子炉停止システムは、原子炉容器に密閉状態に格納される炉心燃料の間を通り、一方の端部が開口し他方の端部が閉塞する遮へい通路と、遮へい通路の開口から進入可能な中性子吸収材と、圧縮した状態から解放されることで中性子吸収材を遮へい通路の開口から内部に進入する方向へ付勢する弾性部材と、弾性部材の圧縮状態を維持するように配置され、閾値温度以上になった場合に弾性部材の圧縮状態を解放する制動部と、を備える。【選択図】図３