Investigation and Evaluation of Cracking in Austenitic Stainless Steel Piping of Boiling Water Reactor Plants.

摘要

The report covers the investigations of a series of cracks that occurred in the austenitic stainless steel bypass pipes around the discharge valves in the main recirculation loops of six domestic boiling water reactor plants and in the core spray pipes of one boiling water reactor plant. The report describes the recent cracking occurrences as well as similar occurrences in boiling water reactors in the past. The report concludes that the cracks that occurred in six domestic boiling water reactor plant units were the result of intergranular stress corrosion cracking caused by the combination of high residual stresses,light sensitization of the heat affected zones of welds,and the oxygen level normally found in the coolant for this type of reactor.