Abstract
Studies of accident and malfunction analyses are important because their conclusive results derived by engineering analyses are applied to nuclear power plant operation. In this paper, limiting the consideration to light water reactor, the factors that govern the design conditions of such reactors are first summarized. This is followed by an examination of the destruction mechanism of equipments and fittings such as piping, through analyses of such phenomena as cracking from highly-cycled thermal or mechanical fatigue, stress corrosion cracking, and fracture from corrosion and ductile straining, applying as basis the ASME technical standards and the thermohydrautic codes. Circumstances affecting instances of actual accidents and mulfunctions are then taken into account with the considerations required to be given from the engineering standpoint in applying the results of the present study to safety regulations and to practical plant operation.
