Level of evidence for reasonable assurance guides to prediction

Over the past years, the DOE Contractors have produced a great deal of work that has been extensively reviewed and criticized by the Nuclear Regulatory Commission (NRC), the Materials Review Board (MRB) of the DOE, the Advisory Committee on Reactor Safeguards (ACRS), and the technical support group at Brookhaven National Laboratory (BNL). Common aspects of the reviews and criticisms have provided information on the level of evidence required by the scientific community to defend performance claims. Important indicators of the type of evidence that the NRC will require for favorable decisions of reasonable assurance also can be obtained from 10 CFR 60 and its rationale, from NRC guides and Technical Position papers, from past reviews of the DOE programs by NRC Contractors, and from the use of reasonable assurance by the NRC in its 1984 Waste Confidence Decision. This report describes general concepts related to the acceptability and unacceptability of the level of evidence needed to defend claims with reasonable assurance. The concepts were formulated on the basis of analyses of the NRC position papers, and of common aspects of the reviews and criticisms dealing with compliance demonstration.