NRC regulatory practices in reactor physics code reviews

摘要

This paper discusses the process taken by the U.S. Nuclear Regulatory Commission (NRC) in reviewing physics codes and methods. In recent years, because of increased computing storage capability, enhanced computation times, and general progress in analytical techniques and methods, applicants (licensee and vendors), have sought to take advantage of these improvements by asking the NRC staff to review these analytical physics codes and methods. These requests reflect a desire to exploit better methods to provide enhanced computational accuracy and reduce uncertainties, leading to overall improved fuel management core designs and, usually, increased safety margin. This paper describes the review process and gives examples of typical requests for reviews of code improvements and new codes by nuclear power plant licensees and vendors. In addition, it provides examples of the NRC staff technical requirements in evaluating and approving these enhanced codes and methods. Finally, this paper also includes a brief overview of the review process for non-light-water reactors.