A failure probability estimate of Type 304 stainless steel piping

The large break frequency resulting from intergranular stress corrosion cracking in the main circulation piping of the Savannah River Site (SRS) production reactors has been estimated. Four factors are developed to describe the likelihood that a crack exists that is not identified by ultrasonic inspection and that grows to instability prior to becoming through-wall and being detected by the ensuing leakage. The estimated large break frequency is 3.4 {times} 10{sup {minus}8} per reactor year. This result compares favorably to similar estimates made for commercial boiling water reactors. 9 refs., 8 figs.