RELIABILITY OF CRBR PRIMARY PIPING:CRITIQUE OF STRESS-STRENGTH OVERLAP METHOD FOR COLD-LEG INLET DOWNCOMER

摘要

In this report, a critique of the strength-stress overlap method for the reliability of the CRBR primary heat transport system piping was presented. The report addressed, in particular, the reliability assessment of WARD-D-0127 (Piping Integrity Status Report), which is part of the CRBR PSAR docket. It was found that the reliability assessment is extremely sensitive to the assumed shape for the probability density function for the strength (regarded as a random variable) of the cold-leg inlet downcomer section of the primary piping.