Information Notice No. 90-52: Retention of Broken Charpy Specimens
UNITED STATES NUCLEAR REGULATORY COMMISSION OFFICE OF NUCLEAR REACTOR REGULATION WASHINGTON, D.C. 20555 August 14, 1990 Information Notice No. 90-52: RETENTION OF BROKEN CHARPY SPECIMENS Addressees: All holders of operating licenses or construction permits for nuclear power reactors. Purpose: This information notice is intended to alert addressees to the potential value of the broken Charpy specimens and other test materials from their reactor vessel material surveillance program. It is expected that recipients will review the information for applicability to their facilities and consider appropriate actions. However, suggestions contained in this information notice do not constitute NRC requirements; therefore, no specific action or written response is required. Description of Circumstances: The NRC has received information that, in order to avoid the costs and burden of long-term storage of such irradiated materials, some licensees are discarding broken Charpy specimens and other surveillance materials remaining from surveillance test programs conducted years ago. However, broken Charpy specimens, particularly those from reactor vessels having radiation sensitive materials, may provide useful information such as specific material embrittlement data. Without specific data, the alternative for the licensee is often the imposition of conservative assumptions. Discussion: Charpy specimens may be reconstituted by trimming off the fractured ends and then welding end tabs onto the broken halves. Although this fabrication process involves problems such as assuring proper alignment and temperature control in the center region where the new notch is to be placed, the technology of reconstituting broken Charpy specimens is sufficiently developed to permit the writing of ASTM E 1253-88, "Standard Guide for Reconstitution of Irradiated Charpy Specimens." An ASTM Committee E-10 workshop on the techniques for reconstitution is scheduled for January 1991 and is expected to provide a basis for updating the Guide. 9008080246 . IN 90-52 August 14, 1990 Page 2 of 2 Some broken Charpy specimens consist of unique material. Depending on lead factors and the time of withdrawal, the fluence exposure may be fairly representative of the fluence at the 1/4 t and 3/4 t locations in the vessel wall near the end of the operating license period. When reconstituted, these specimens should provide extremely useful information for a surveillance program regarding a license renewal period or for the determination of the degree of annealing recovery and the rate of reembrittlement. Furthermore, tests of reconstituted Charpy specimens might provide needed measurements of the level of embrittlement for use in the pressurized thermal shock (PTS) studies required by Regulatory Guide 1.154. This information notice requires no specific action or written response. If you have any questions about the information in this notice, please contact one of the technical contacts listed below or the appropriate NRR project manager. Charles E. Rossi, Director Division of Operational Events Assessment Office of Nuclear Reactor Regulation Technical Contacts: Pryor N. Randall, NRR (301) 492-1311 Keith R. Wichman, NRR (301) 492-0757 Attachment: List of Recently Issued NRC Information Notices .ENDEND
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