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Title: Cobalt Reduction Guidelines, Revision 1. Final report

Technical Report ·
OSTI ID:10108712

This report, which updates and supersedes an earlier report (EPRI NP-6737) on the same subject, describes methods for establishing a program to identify nuclear power plant valves with high-cobalt hardfacing that are potential significant contributors to the cobalt inventory that is irradiated in the reactor core. The resulting radioactive cobalt isotope, cobalt-60, is a major contributor to plant radiation levels and therefore occupational doses received by plant operational and maintenance personnel. A methodology to determine whether hardfacing is actually required on specific valves is also described as is the physical, mechanical and wear properties of high-cobalt and potential replacement cobalt-free hardfacing and trim alloys. Discussions are presented of the general and specific design requirements for valve hardfacing in nuclear service. Current world-wide nuclear utility experience with cobalt-free hardfacing alloys is described. The regulatory and industry code issues related to replacing and/or changing valve hardfacing materials are discussed. The actions and responsibilities of utility management in implementing an effective cobalt-reduction program are also delineated.

Research Organization:
Electric Power Research Inst., Palo Alto, CA (United States)
Sponsoring Organization:
Electric Power Research Inst., Palo Alto, CA (United States)
OSTI ID:
10108712
Report Number(s):
EPRI-TR-103296; ON: UN94004424; TRN: 94:002185
Resource Relation:
Other Information: PBD: Dec 1993
Country of Publication:
United States
Language:
English