Basis safety - a challenge to nuclear technology

The need to ensure an utmost degree of safety of reactor pressure components demands a consequent analysis of the decisive parameters such as materials, design, manufacturing and testing. According to the state of the art in pressure vessel and piping technology defects cannot generally be excluded. For this reason, at an early stage of the German light water reactor technology, extensive material investigations on actual components were carried out. Because of the defects detected, new requirements had to be established for materials and design for components and systems (a) to be manufactured, (b) to be improved (assembling stage), and (c) to be replaced (assembling or service stage). For an unimpeachable safety concept with a low failure probability, design and materials have to be optimised so that the problems of manufacturing and testing ease off and testing will become a more redundant measure. Materials and design can be optimised to such a degree that at least catastrophic failure of components and systems can be excluded by a deterministic respectively mechanistic safety analysis. The requirements of a so-called Basis Safety Concept have become a part of the newest edition of the German RSK-Guidelines for Pressurised Light Water Reactors. (author)