Resolution of Generic Safety Issues: Item B-4: ECCS Reliability ( NUREG-0933, Main Report with Supplements 1–34 )
Numerical reliability goals and methods of analysis have not been established by the NRC. The current basis for plant licensing continues to be NRC regulations which require, among other things, that the consequences of a LOCA be suitably mitigated despite the postulated subsequent occurrence of a series of independent malfunctions, including the loss of offsite power and postulated single failures in mitigating safety features. As the state of the art on probabilistic evaluation techniques becomes more widely accepted, increasing concern has been expressed regarding the adequacy of the current licensing basis. This NUREG-04713 item will address these concerns by assessing the reliability of current U.S. and foreign emergency core cooling system designs.
This item is covered412 under TMI Action Plan Item II.E.3.2, "System Reliability," in Section 3 of this report.