AECL/EPRI valve hardfacing program loop cycling interim (1400 cycle) report

Atomic Energy of Canada Limited (AECL) has been conducting, under contract to EPRI, stroke cycling tests on valves hardsurfaced with four cobalt-free alloys. The first phase of the program, in which pressurized water reactor (PWR) primary heat transport conditions were simulated in AECL's valve test loop, has reached the 1400 cycle mark. This represents approximately 70 percent of the target life of the valves. The candidate alloys are NOREM B1, MOREM B4, EB 5183 and EVRIT 50. One valve with Stellite 6 trim serves as the control. Prior to loop testing, a baseline inaugural inspection was performed. During the loop testing, the loop was shutdown at approximately 500 cycle intervals and the valves were disassembled for examination. The examinations included leak tests, profilometry and nondestructive inspection. Corrosion coupons were used to monitor any material loss due to corrosion alone. The examination results are summarized, and the relative performances of the candidate alloys are discussed in this paper