ML032390379

Enclosure 2: Slides to 07/25/03 Meeting with Southern Nuclear Co. to Discuss Elimination of Reliance on Kaowool for Service Water Intake Structure

ML032390379
Person / Time
Site:	Farley
Issue date:	08/22/2003
From:	Stinson M Southern Nuclear Operating Co
To:	Office of Nuclear Reactor Regulation
References
Download: ML032390379 (20)

Text

Joseph M. Farley Nuclear Plant Appendix R Status and Elimination of Reliance on Kaowool Fire Barriers for the Service Water Intake Structure (SWIS)

Mike Stinson General Manager Farley Nuclear Support July 25, 2003 SOUTHERN COMPANY Energy to Serve Your World Enclosure 2

Agenda

1. Introduction & Purpose

2. Appendix R Overview

• Current exemption for the SWIS

• Background information

3. Basis for the New SWIS Exemption

• Deterministic and risk-informed performance-based approaches

• Application of risk-informed performance-based methodology

• Change evaluation process

• Assessments

4. Summary 2

Introduction & Purpose

• Discuss status of Farley's Kaowool issues

• Discuss SNC's application of risk-informed performance-based methodology for the Farley SWIS Appendix R 10 CFR 50.12 exemption

• Receive feedback from the NRC on the proposed approach 3

Appendix R Overview Doug McKinney Farley Licensing Manager 4

Background Information

• Kaowool related Appendix R exemption requests for Plant Farley were approved by the NRC during 1985 and 1986

• The 1986 exemption for the SWIS relied on Kaowool for protection of several cables

• On August 26, 1999, the NRC informed Farley that qualification tests did not demonstrate that Kaowool met regulatory requirements 5

Background Information (cont.)

• SNC re-evaluated the Appendix R program

• SNC planned modifications to eliminate dependence on Kaowool

-5 modifications completed 27 modifications scheduled to be completed by the end of the spring 2006 outage

• SNC will change licensing documents 6

Background Information (cont.)

For the SWIS, three options were identified

1. Comply with the Current Licensing Basis

2. Install alternate seal injection pump and reroute cables

3. Determine whether a risk-informed performance-based evaluation would justify not relying on Kaowool 7

Background Information (cont.)

• A risk-informed performance-based pilot study was completed

• SNC discussed proposed risk-informed performance-based exemption approach in previous meeting with the NRC

• A confirming risk-informed performance-based analysis was completed

• SNC plans modifications and new SWIS exemption 8

SWIS Plan View- Existing t

N 72A Train B Racew ays Train A >

Racew ays Legend Strainer Pit Zone 72A - SW Purnp Deck and Strainer Pit Zone 72B - Sw itchgear Room - Train B Zone 72C - 5kV Disconnect Sw itch - Train B Zone 72D - 5kV Disconnect Sw itch - Train A Zone 72E- Sw itchgear Room - Train A Zone 73 - Battery Room - Train B Zone 74 - Battery Room - Train A Unit 2 SW Pumps Unit 1 SW Pumps Train A B B AB A 0

A A A AB 00 B B Train B 72B I 72C 72D I ~~72E Train B 7 Train A c )

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Current Exemption for the SWIS Five of eleven specific configurations rely in part on Kaowool for exemptions from Section III.G.2 requirements:

• U1 Train A cables for Strainer Pit MOVs U2 Train A cables for Strainer Pit MOVs

• U2 Train A raceways for certain lube and cooling water pump cables

• Power cables to pumps

• Train A / Train B raceways in northeast corner 10

Basis for the New SWIS Exemption Doug McKinney Farley Licensing Manager 11

Deterministic Approach

• Modifications

• Deterministic reanalysis, confirming no spurious operation

• Creation of new fire areas

• One SW pump for fire scenario 12

Risk-Informed Performance-Based Approach

• Evaluated power cables to SW pumps

• Evaluated cable raceways in NE corner 13

Application of Risk-Informed Performance-Based Methodology

• Support 10 CFR 50.12 exemption

• Based on RG 1.174 criteria

• Draft Section 8.3 of NEI Implementation Guide for NFPA 805 14

Change Evaluation Process The Change Evaluation Process consisted of four major parts:

• Change Definition

• Initial Assessment

• Detailed Analysis

• Documentation 15

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• NflmItIon usmeut Yee E mt~

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Preliminary Assessment - Initial Fire Modeling ~~~~~~~~..

Fire Scenario fr N 72A IE Train B Racew ays Train A Racew ays Legend Strainer Pit Zone 72A - SW Purrp Deck and Strainer Pit Zone 72B - Sw itchgear Room - Train B Zone 72C - 5kV Disconnect Sw itch - Train B Zone 72D - 5kV Disconnect Sw itch - Train A Zone 72E - Sw itchgear Room - Train A Fire Scenario Fire Scenariol Zone 73 - Battery Room - Train B Zone 74 - Battery Room - Train A Unit 2 SW Pumps Unit I SW Pumps Train A Train B B B AB A A A A AB B B I 72C 72D 72B 72E Train B 7 7 Train A 17

Preliminary Assessment - Initial Risk Assessment Determined that combined analysis was required for SW pumps 18

Combined Analysis

• Fire modeling

- One SW pump remains operable

• Fire risk analysis

- CDF determined for one SW pump

- RG 1.174 criteria met for SWIS

• Defense-In-Depth Elimination of dependence on Kaowool meets NFPA 805 criteria to

- Prevent fires from starting

- Detect fires quickly and suppressing those that occur

- Provide protection for systems and structures so that safe shutdown can be achieved

• Safety Margin

- NRC criteria met 19

Summary

• Continue modifications - complete in 2006

• SWIS Current licensing bases changes Exemption based on risk-informed performance-based methodology

• New exemption will be submitted to NRC

• NRC feedback 20