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March 13, 2003 The Honorable Richard A. Meserve
Dear Chairman Meserve: The Advisory Committee on Reactor Safeguards (ACRS) and its Plant Operations Subcommittee have had a number of interactions with the U.S. Nuclear Regulatory Commission (NRC) staff on the Reactor Oversight Process (ROP). In reports dated October 12, 2001, and February 13, 2002, the ACRS raised several issues that included:
The ACRS met with the staff at its 500th meeting on March 6, 2003, to discuss these issues. At the conclusion of this meeting, it was evident that there are still significant disagreements between the staff and the Committee. This report, then, is intended to clarify the ACRS views on this matter and to serve as a basis for further discussion. The ACRS views on the ROP are as follows:
DISCUSSION Our
view is that the purpose of the ROP is to assess changes in performance, not changes
in risk. We believe that the ROP is risk-informed because it focuses attention
on performance areas that are known to be cornerstones of safety. As we have noted
previously, however, it is misleading to assess the importance of changes even
in a risk-informed PI in terms of Clearly, degraded performance can translate into an increase in the risk
posed by a given plant. However, a realistic estimate of The SDP process should continue to evaluate the risk significance of events and findings. This information complements the performance assessment findings from the PIs. The two sets of information are complementary, and it is appropriate that both be addressed in the Action Matrix. We continue to doubt the validity of the assumption that degraded performance in the cross-cutting areas will be revealed by the current PIs and inspections. Efforts to develop new PIs should be focused on licensees' corrective action programs, human performance, and safety conscious work environment. The staff and the Committee agree that the significance of the thresholds for the various PIs should be examined. In addition to improving the coherence of the Action Matrix, parity in significance will yield another benefit. NRC and licensee resources are naturally biased toward performance areas that are rated other than green. If the thresholds are chosen inappropriately, then resources may be misallocated.
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