ML20129G270

Forwards Engineering Evaluation Rept AEOD/E506, Valve Stem Susceptibility to IGSCC Due to Improper Heat Treatment

ML20129G270
Person / Time
Site:	Brunswick
Issue date:	05/20/1985
From:	Caroline Hsu NRC OFFICE FOR ANALYSIS & EVALUATION OF OPERATIONAL DATA (AEOD)
To:	Seyfrit K NRC OFFICE FOR ANALYSIS & EVALUATION OF OPERATIONAL DATA (AEOD)
Shared Package
ML20129G226	List: ML20129G221 ML20129G270 ML20129G303
References
AEOD-E506, NUDOCS 8506070209
Download: ML20129G270 (2)

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MAY 2 0190s AE0D/E506 HEMORANDUM FOR: Karl V. Seyfrit, Chief Reactor Operations Analysis Branch Office for Analysis and Evaluation of Operational Data THRU: Hatthew Chiramal, Chief Engineering Section Reactor Operations Analysis Branch Office for Analysis and Evaluation of Operational Data FR0f t: Chuck Hsu Engineer Engineering Section Reactor Operations Analysis Branch Office for Analysis and Evaluation of Operational Data

SUBJECT:

VALVE STEM SUSCEPTIBILITY TO IGSCC DUE TO IMPROPER HEAT TREATHENT The enclosed Engineering Evaluation Peport is forwarded for your information and further consideration. This review indicates that the intergranular stress' corrosion cracking (IGSCC) damage to valve stems, made of 400 series stainless steel, was attributed to excessive hardness caused by improper heat treatment of the material. The excessive hardness resulting from improper heat treatment may not be detected in either the licensee's or the supplier's QA programs. Since stress corrosion indication on a valve stea can only be observed by close inspections after disassembly of the valve, the plant routine valve operability test progran cannot detect valve stem degradation. It is likely that valve stem IGSCC would go undetected until failures evidenced by a sudden shear of the stem upon actuation of the valve. This appears to represent a generic problem with this sten naterial . Therefore, this report suggests that RES and IE consider the following actions:

1. RES should consider the adequacy of the existing code requirenents with regard to assurance of proper hardness of martensitic stainless steel following the heat treatment process. If appropriate, RES should attempt to have such requirements included in the applicable code.

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2. IE should consider issuing an Infomation Notice to inform licensees of the potential problem concerning improper heat treatment of stem material made of 400 series stainless steel which results in a high susceptibility to IGSCC.

S Chuck Hsu, Engineer Engineering Section Reactor Operations Analysis Branch Office for Analysis and Evaluation of Operational Data

Enclosure:

As stated cc: w/ enclosure R. Baer, IE P. Claudlin, IE J. B. Henderson, IE W. S. Hazelton, NRR DIST BUTION:

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