Probability of Failure in BWR Reactor Coolant Piping. Volume 2: Pipe Failure Induced by Crack Growth and Failure of Intermediate Supports.

摘要

The U.S. Nuclear Regulatory Commission (NRC) contracted with the Lawrence Livermore National Laboratory (LLNL) to conduct a study to determine if the probability of occurrence of a double-ended guillotine break (DEGB) in the major coolant piping systems of nuclear power plants is large enough to warrant the current stringent design requirements of designing against the postulated effects of a DEBG. The study includes both the PWR (Pressurized Water Reactor) and the BWR (Boiling Water Reactor) plants in the United States. The results of the assessment indicated that the probability of occurrence of DEGB due to crack growth and instability is small if the problem of intergranular stress corrosion cracking (IGSCC) is resolved by the use of the replacement system. The study of intermediate support failure yielded some guidelines for significant reduction of effort in assessing the effects of seismically induced failure of intermediate supports.