Protecting People and the EnvironmentUNITED STATES NUCLEAR REGULATORY COMMISSION
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.
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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
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