Risk-based technical specifications: Development and application of an approach to the generation of a plant specific real-time risk model

Technical Report · Thu Oct 01 04:00:00 EDT 1992

OSTI ID:6908758

Puglia, B; Gallagher, D; Amico, P; Atefi, B ^[1]

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1. Science Applications International Corp., Reston, VA (United States)

This report describes a process developed to convert an existing PRA into a model amenable to real time, risk-based technical specification calculations. In earlier studies (culminating in NUREG/CR-5742), several risk-based approaches to technical specification were evaluated. A real-time approach using a plant specific PRA capable of modeling plant configurations as they change was identified as the most comprehensive approach to control plant risk. A master fault tree logic model representative of-all of the core damage sequences was developed. Portions of the system fault trees were modularized and supercomponents comprised of component failures with similar effects were developed to reduce the size of the model and, quantification times. Modifications to the master fault tree logic were made to properly model the effect of maintenance and recovery actions. Fault trees representing several actuation systems not modeled in detail in the existing PRA were added to the master fault tree logic. This process was applied to the Surry NUREG-1150 Level 1 PRA. The master logic mode was confirmed. The model was then used to evaluate frequency associated with several plant configurations using the IRRAS code. For all cases analyzed computational time was less than three minutes. This document Volume 2, contains appendices A, B, and C. These provide, respectively: Surry Technical Specifications Model Database, Surry Technical Specifications Model, and a list of supercomponents used in the Surry Technical Specifications Model.

• Research Organization: Nuclear Regulatory Commission, Washington, DC (United States). Div. of Operational Events Assessment; Science Applications International Corp., Reston, VA (United States)
• Sponsoring Organization: NRC; Nuclear Regulatory Commission, Washington, DC (United States)
• OSTI ID: 6908758
• Report Number(s): NUREG/CR-5925-Vol.2; SAIC--92/6668-R1-Vol.2; ON: TI93002316
• Country of Publication: United States
• Language: English

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