A large energy provider is pursuing risk-informed regulatory changes for operational efficiency and flexibility at all its nuclear power plants (NPP). Among other requirements, all natural and man-made hazards to the NPP are required to be evaluated as part of the regulatory submittal. Any hazards determined to be risk significant must be included in the risk evaluations supporting the change in regulatory requirements. This ongoing multi-year project supports the regulatory submittals by: (1) evaluating external hazards to each NPP; (2) screening hazards that are not risk significant; and (3) developing efficient and cost-effective solutions to characterize and quantify the risk from hazards that cannot be screened.
Seismic and extreme wind hazards (e.g., tornados) typically do not screen and require further risk assessment. However, a detailed probabilistic risk assessment (PRA) requires significant cost and time to complete and maintain. Additionally, each NPP must be evaluated separately for plant-specific hazards based on their location and plant design. A cost-effective and efficient solution was needed to adequately assess the risks from these hazards at the various NPPs. The methods and results must be accepted by the energy provider and regulator (i.e., Nuclear Regulatory Commission).
A team of Jensen Hughes risk engineers from multiple offices collaborated with the energy provider’s staff to evaluate the external hazards, develop solutions for risk significant hazards that could not be screened and justify the approach to the regulator. Our team developed and refined cost-effective methods for performing seismic and extreme winds risk assessments to support these regulatory submittals. Innovative and pragmatic approaches were developed while ensuring regulatory acceptance of the methods. Jensen Hughes engineers responded to technical challenges posed by the regulators and represented the energy provider during regulatory audits.
These analyses supported a larger effort by Jensen Hughes Risk Informed Power Solutions (RIPS) to develop License Amendment Requests (LAR) for the NPPs. The energy provider has implemented risk-informed regulatory changes at many of their NPPs and are continuing to pursue these changes at the remaining sites in their fleet. As a direct result of the regulatory changes, one plant saved over $2 million and helped to maintain grid reliability by avoiding a plant shutdown. Additional operational flexibility and cost savings have been achieved at other nuclear power plants.