| 摘要 |
PURPOSE:To move neutron absorbers to a fuel region without using a driving power source or control driving device when an abnormal temp. of a reactor core arises by using materials which are thermally deformed or deteriorated in property for structural materials to support the neutron absorbers. CONSTITUTION:The neutron absorbers 13, 14 are supported by supporting members in ordinary operating positions 17, 18 on the outside of a core fuel region 19 on the side inner than the top end face 15 and bottom end face 16 of a fuel assembly. The materials which are thermally deformed or deteriorated in property, for example, springs consisting of shape memory alloys or bimetals, metal fuse plugs, and ferromagnetic materials of which the magnetism is annihilated at a certain temp. (Curie point) are used alone or in combination as said supporting members. The increase of the core temp. up to the emergency stop temp. is thus self-detected by the thermal deformation or deterioration in properties of the structural materials supporting the neutron absorbers and the neutron absorbers are moved to the core fuel region and, therefore, the need for the control driving device and driving power source is eliminated and the initial cost is reduced. In addition, the malfunction by human cause is eliminated.
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