Recent Japanese Probabilistic Fracture Mechanics Researches Related to Failure Probability of Aged RPV

Abstract

In order to prepare for the need of probabilistic methodology in design, inspection and maintenance of nuclear components, JAERI (The Japan Atomic Energy Research Institute) has conducted PFM (Probabilistic Fracture Mechanics) researches of Phase 1 and Phase 2 since late 1980s. In order to establish the standard procedure, Phase 1 had been conducted from 1988 to 1994 by entrusting contract researches to JWES (The Japan Welding Engineering Society), MRI (Mitsubishi Research Institute Incorporation) and JSME (The Japan Society of Mechanical Engineers). Subsequently, JAERI initiated Phase 2 in 1996 aiming at more practical application. JAERI had entrusted contract researches from 1996 to 2000 to JWES. JAERI also initiated a development of a PFM Code PASCAL (PFM Analysis of Structural Components in Aging LWR) as well as the contract research. The development of PASCAL-Ver.1 was completed in 2000. PASCAL-Ver.1 was released in 2001. Using PASCAL-Ver. 1, round robin analyses on the usability of the code, the effect of annealing on the failure probability of an RPV, the probabilistic evaluation of the flaw acceptance standard in ASME ( or JSME) Code have been performed within the contract research. This paper presents the overview of activities related to RPV and some results of round robin analyses conducted in PFM Sub-Committee in JWES. In addition, the outline of PASCAL-Ver.1 is also introduced.