Leak behavior through EPAs under severe accident conditions

The leakage behavior of electrical penetration assemblies (EPAs) is being evaluated by varying the penetration type, manufacturer, and hypothetical temperature and pressure accident profile. Nuclear qualified EPAs were procured from D.G. O'Brien, Westinghouse, and Conax. Severe accident sequence analysis was used to generate the severe accident conditions (SAC) for a large dry PWR, a BWR Mark I drywell, and a BWR Mark III wetwell. The EPA manufacturers were matched to the reactor type based on a survey of EPAs used in reactors. The D.G. O'Brien EPA was chosen for the PWR SAC, the Westinghouse was chosen for the BWR Mark III, and the Conax was chosen for the BWR Mark I. The EPAs were radiation and thermal aged to a 40-year service life before the SAC test was conducted. For the D.G. O'Brien EPA SAC test, while there was no detectable leakage during the SAC test, there was a 0.13 scc/sec leak measured during the posttest inspection. For the Westinghouse EPA SAC test, there was no detectable leakage during or after the SAC test. The Conax EPA SAC test is scheduled for completion in July 1986