Nuclear reactor pressure vessel stabilizer

Stabilizer brackets are disposed on the lateral side of a nuclear reactor pressure vessel. A yokes are attached to a sole plate disposed to the upper portion of a reactor shielding wall for supporting the stabilizer brackets. A shim made of a shape memory alloy is disposed between the lateral side of each stabilizer bracket and the yoke. The shim has a memory of a shape on the condition that the height thereof is increased at a high temperature. The shim restores its shape at a high temperature to increase the height during reactor operation. The height of the shim is restrained by the inner surface of the yoke. Horizontal loads upon earthquakes exerted on the reactor pressure vessel are supported by a friction force between the shim and the inner circumferential surface of the yoke, to disperse oscillation energy. This can decrease an earthquake response of the reactor pressure vessel to improve the earthquake proofness. (I.N.)