Experience with noble metal chemical addition in BWRs

摘要

The specification for hydrogen water chemistry (HWC) is to establish an electrochemical corrosion potential (ECP) of less than 230 mV(SHE) for mitigating intergranular stress corrosion cracking susceptibility. This paper describes a noble metal chemical addition process, called NobleChem, that treats all the wetted internals of a BWR and produces a thin (on the order of a mono layer) deposit of Pt and Rh. After NobleChem treatment, the ECP specification can be achieved at very low hydrogen addition rates without a steady state increase in operating dose rates. This new technology was applied for the first time at the Duane Arnold Energy Center (Duane Arnold) BWR in October of 1996. The results to date from this reactor are discussed in detail. In addition to Duane Arnold, three other BWRs have applied NobleChem at this writing and a total of nine did so by the end of 2000. The similarities and differences observed between the recently treated BWRs and the Duane Arnold reactor are also discussed in detail.