Develop Seismic Equipment List (Task 2)

Task Overview

Objective

The objective is to develop of a list of the equipment and systems required to provide protection for all seismically induced initiating events (including seismically induced fires and floods) and the structures that house them.

Purpose

This section describes a process for developing an SPRA seismic equipment list (SEL). The SEL is important for demonstrating completeness of the seismically initiated sequences considered in the SPRA. The initial list forms the basis for the seismic fragility and systems analysis tasks. The identification of SSCs for fragility screening and evaluation for use in an SPRA is an iterative process involving interaction between risk assessment and structural or fragility personnel. The SEL is typically developed by risk assessment personnel based on accident sequence and system fault tree logic models in the SPRA and consideration of other SPRA studies that may be available. Risk assessment personnel and structural and fragility personnel subsequently interact to refine and screen the SEL.

Guidance

The development of the initial SEL may be implemented with the following six steps:

1. Identify SSCs that are important to safe shutdown from full-power PRA models. Additional SSCs may be identified based on other plant-specific PRA models (e.g., Fire PRA model) as necessary.
2. Identify SSCs from review of seismic evaluation performed for previous plant seismic evaluations such as an Individual Plant Examination of External Events (IPEEE) or stress test.
3. Identify structures and passive components that are important to seismic response.
4. Identify additional SSCs from plant walkdown.
5. Review the SEL initial draft (for example, compare with piping and instrumentation diagrams).
6. Document the SEL.

Supplemental Guidance

Related Element of ASME/PRA Standard

Part 5, Seismic Plant Response (SPR)

EPRI Guidance

Seismic Probabilistic Risk Assessment Implementation Guide (3002000709) provides recommendations regarding development of an SEL. Appendix E provides a sample SEL.

Seismic Fragility and Seismic Margin Guidance for Seismic Probabilistic Risk Assessments (3002012994) provides in-depth guidelines for performing fragility analysis as part of an SPRA to develop practical methods for assessing nuclear plant seismic margins

Methodology for Assessment of Nuclear Power Plant Seismic Margin (NP-6041-SLR1) provides guidance for identifying equipment and component lists in support of performing an SMA and refers utilization of an existing PRA model.

Seismic Evaluation Guidance: Screening, Prioritization and Implementation Details (SPID) for the Resolution of Fukushima Near-Term Task Force Recommendation 2.1: Seismic (1025287) compares the SPID guidance to the ASME/ANS PRA Standard supporting requirements.

Updated Equipment Seismic for Capacities from Experience Data for use in the Fragility Calculations (3002011627)

Updated Equipment Seismic for Capacities from Experience Data for use in the Fragility Calculations, Phase II (3002013017)

Generic Implementation Procedure (GIP) for Seismic Verification of Nuclear Power Plant Equipment, Seismic Qualification Utility Group (SQUG) provides a detailed technical approach, generic procedures, and documentation guidance that can be used by USI A-46 licensees to verify the seismic adequacy of mechanical and electrical equipment used for safe shutdown.

Other Guidance

NUREG/CR-2300, "PRA Procedures Guide, A Guide to the Performance of Probabilistic Risk Assessments for Nuclear Power Plants" (Vol 1 and 2)

IAEA Safety Guide SSG-3, “Development and Application of Level 1 Probabilistic Safety Assessment for Nuclear Power Plants” (Section 8.62 provides generic guidance for SEL development.

IAEA Safety Guide NS-G-2.13, “Evaluation of Seismic Safety for Existing Nuclear Installations” Section 5.28 provides general guidance on SEL creation and screening.