Document: NUREG-0800
Document ID: ac43f632-9db1-4857-9f56-bfba45965456
Document Type: srp
Title: * These are modifications to a plant’s design, operations, or other activities that require NRC approval. These modifica
Source: NUREG-0800
Source URL: https://www.nrc.gov/docs/ML0232/ML023250195.pdf
Revision Date: 2023-06
Chapter: 19
Section ID: 19
CFR Part: 
CFR Title: 

Content:
structures, systems, or components that are risk significant but are not required by regulations, for example, amendment requests that as an unintended consequence compromise the effectiveness of the Mark I hardened wetwell vent system in protecting against containment overpressure failures in accidents beyond the design basis, or the diversity of the turbine-driven auxiliary feedwater pumps provided in response to NUREG-0737, Section II.E.1.1.  Involve changes for which the synergistic or cumulative effects could significantly impact risk, for example, power uprate requests that would increase operating power well beyond the levels approved in previous uprates and would introduce or substantially increase the frequency of risk-significant core damage sequences. If, upon further consideration, it is believed that approval of the request would compromise the safety principles described in Regulatory Guide 1.174 and substantially increase risk relative to the risk acceptance guidelines contained in the regulatory guide, the reviewers should inform NRC management of the risk concerns and the need to further evaluate the risk associated with the request. In such instances, the reviewers, with management concurrence, should ask the licensee to address the safety principles and the numerical guidelines for acceptable risk increases contained in Regulatory Guide 1.174 in its submittal. The reviewers may alternatively ask the licensee to submit the information needed in order for the NRC staff to make an independent risk assessment. The appropriate level of management involvement would depend on the nature and significance of the issue. In general, the decision regarding whether a license amendment request creates a special circumstance should, at a minimum, be supported by the division directors responsible for probabilistic safety assessment, the technical issue and the regulatory requirements in question, and licensing project management, as well as the Office of the