Protecting People and the EnvironmentUNITED STATES NUCLEAR REGULATORY COMMISSION
UNITED STATES
NUCLEAR REGULATORY COMMISSION
OFFICE OF NUCLEAR REACTOR REGULATION
WASHINGTON, D.C. 20555-0001
August 7, 1997
NRC INFORMATION NOTICE 97-63: STATUS OF NRC STAFF'S REVIEW OF BWRVIP-05
Addressees
All holders of operating licenses for construction permits for boiling water
reactors (BWRs).
Purpose
The U.S. Nuclear Regulatory Commission (NRC) is issuing this information
notice to inform addressees about the status of NRC staff's review of "BWR
Vessel and Internals Project, BWR Reactor Pressure Vessel Shell Weld
Inspection Recommendations (BWRVIP-05)." This information notice does not
transmit or imply any new or changed requirements or staff positions. No
specific action or written response is required.
Discussion
On May 12, 1997, the NVIP) met with the Commission to discuss the NRC
staff's review of the BWRVIP's proprietary report, "BWR Vessel and Internals
Project, BWR Reactor Pressure Vessel Shell Weld Inspection Recommendations
(BWRVIP-05)," dated September 28, 1995. This report questions the extent of
augmented reactor vessel inspection required in 10 CFR Part 50,
50.55a(g)(6)(ii)(A)(2). In accordance with guidance provided by the
Commission following that meeting, in Staff Requirements Memorandum (SRM)
M970512B, dated May 30, 1997, the staff has initiated a broader, risk-informed
review of the BWRVIP-05 proposal. Further, the final safety evaluation report
(SER) will need to be reviewed by the Advisory Committee on Reactor Safeguards
(ACRS) prior to issuance. Based on the NRC staff's review of the BWRVIP-05
report, the staff has concluded that the industry's assessment does not
sufficiently address risk, and additional work is necessary to provide a
complete risk-informed evaluation. Therefore, the NRC staff's current
estimate is that completion of this effort, including industry input and ACRS
review, will take approximately six months.
One result of the additional review performed to date was the identification
of a transient at a foreign BWR of U.S. design in which the reactor pressure
vessel (RPV) was subjected to high pressure at a low temperature. This cold
over-pressure transient was not included as a design-basis event for BWRs nor
was it considered from a risk perspective in the BWRVIP-05 report. However,
the recognition of this transient has led the staff to determine that cold
over-pressure transients are of sufficient safety significance that they need
to be addressed
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August 7, 1997
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as part of the BWRVIP-05 review. Therefore, the staff intends to request an
industry evaluation of the potential for, and consequences of, nondesign-basis
events which were not addressed in the BWRVIP-05 submittal.
In order for the additional analysis requested by the Commission to be
completed and reviewed, the staff will consider technically-justified requests
for reliefs from the augmented examination in accordance with 10 CFR
50.55a(a)(3)(i), 10 CFR 50.55a(a)(3)(ii), and 50.55a(g)(6)(ii)A(5) from BWR
licensees who are scheduled to perform inspections of the BWR RPV
circumferential shell welds during the Fall 1997 or Spring 1998 outage
seasons. Acceptably-justified reliefs would be considered for inspection
delays of up to two operating cycles for BWR RPV circumferential shell welds
only. Licensees will still need to perform their required inspections of
"essentially 100 percent" of all axial welds.
Granting reliefs for 40-months or two operating cycles is based on the
consideration of the availability of inspection equipment and the need for
licensees to reschedule inspections if they should be deemed necessary upon
completion of the risk-informed evaluation.
Licensees should be aware that if the NRC staff determines at the conclusion
of its review of the BWRVIP-05 proposal that inspections of the BWR RPV
circumferential shell welds are necessary, any licensee who seeks and receives
schedular relief will be required to perform the inspections at the first
reasonable opportunity.
This information notice requires no specific action or written response. If
you have any questions about the information in this notice, please contact
the person listed below or the appropriate NRC Regional Office.
signed by S.H. Weiss for
Marylee M. Slosson, Acting Director
Division of Reactor Program Management
Office of Nuclear Reactor Regulation
Technical contact: C. E. Carpenter, NRR
301-415-2169
E-mail: cec@nrc.gov
