ML20127D403

Forwards Clarification of Statement Made in Individual Plant Exam Rept,Transmitted Via ,Consisting of Changes to Pages 2-13,2-14 & Updated List of Effective Pages

ML20127D403
Person / Time
Site:	Callaway
Issue date:	01/08/1993
From:	Schnell D UNION ELECTRIC CO.
To:	NRC OFFICE OF INFORMATION RESOURCES MANAGEMENT (IRM)
References
ULNRC-2745, NUDOCS 9301150208
Download: ML20127D403 (5)

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, b7lONy ano, Om rres et ILLECTitiC uw qgJanuary8,1993 U.S. Nuclear Regulatory Commission Attn: Document Control Desk Mail Station P1-137 Washington, D.C. 20555 ULNRC- 2745 Gentlemen:

DOCKET NUMBER.50-483 CALLAWAY PLANT JNnTVTonAT, pr. A NT RYAMTNATION

Reference:

ULNRC-2703 dated September 29, 1992 The referenced letter transmitted the Callaway Individual Plant Examination (IPE)' report. The purpose of this letter is to clarify a statement made in that report.

Section 2.4.4 of the IPE report states that

"....for each reference used in the IPE, Union Electric reviewed the current revision of each record against the revision _ documented in the IPE calculation packages to determine if the subsequent revisions would change the modeling or results of the IPE." Union Electric did not-perform a review of all packages at the time of the-submittal but did review the latest record revisions for each package at the time it was prepared.- The intent of the statement was to describe the process of maintaining the Callaway PRA as a living document. As part of our periodic update process, it is our' intention to perform a Level 1 IPE reference review after Refuel 6,_ scheduled for this fall. The objective of this review will be to identify any plant changes, made after our performance of the IPE, which will require changes in_the Level 1 PRA models. This reference review, along with reviews of design change packages, will be the basis for our first update of the Callaway Level 1 PRA. The PRA update should be completed by the middle of 1994.

Attached are changes to pages 2-13, 2-14 and an updated List of Effective Pages for the IPE report. Should you have any questions on this matter, please contact us.

Very truly yours, 5b0000 /l '

9301150208~930108 6INI PDR ADOCK 05000483 Donald F. Schnell p PDR GGY/WBB/dls d/f Attachment III.

cc: T. A. Baxter,-Esq.

Shaw,.Pittman, Potts & Trowbridge 2300 N. Street,-N.W.

Washington, D.C. 20037 Dr. J. O. Cermak CFA,-Inc.  ;

18225-A Flower Hill Way Gaithersburg, MD 20879-5334 L. Robert Greger Chief, _ Reactor Project Branch 1 U.S. Nuclear Regulatory Commission Region III 799 Roosevelt Road Glen Ellyn, lilinoin 60137 Bruce Bartlett Callaway Resident Office U.S. Nuclear Regulatory Commission RR#1 Steedman, Missouri 65077 L. R. Wharton (2)

Office of Nuclear Reactor Regulation U.S._ Nuclear Regulatory Commission 1 White Flint, North, Mail Stop 13E21 11555 Rockville Pike Rockville, MD 20852 Manager, Electric Department Missouri Public Service Commission P.O. Box 360 Jefferson City, _MO 65102 l

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LIST OF EEEECTIVE PAGES TABLE OF CONTENTS Rev. Tables Rev.

i 2.5-6 il 2.5-7 lii 2.5-8 iv 2.5-9 v 2.5-10 vi 2.5-11 vii 2.5-12 viii 2.5-13 List of Acronyms (ix-xii) 2.5-14 2.5-15 CliAPTER 1. 0 _

Text CHAPTER 3.0 1-1 1-2 SECTION 3.1.1 1-3 Text 1-4 3.1-1 1-5 3.1-2 1-6 3.1-3 1-7 3.1-4 1-8 3.1-5 Eiqures 3.1-6 1.2-1 3.1-7 ,

1.4-1 3.1-8 1.4-2 3.1-9 1.4-3 3.1-10 3.1-11 CHAPTER 2.0 3.1-12 Text 3.1-13 2-1 3.1-14 2-2 3.1-15 -

2-3 3.1-16 2-4 3.1-17 2-5 3.1-18 2-6 3.1-19 2-7 3.1-20 2-8 3.1-21 2-9 Tables 2-10 3.1.1-1 (1) 2-11 3.1.1-1 (2) 2-12 3.1.1-1 (3) 2-13 1/93 3.1.1-1 (4) 2-14 1/93 3.1.1-2 (1) 2-15 3.1.1-2 (2)

IAhles 3.1.1-2 (3) 2.5-1 3.1.1-2 (4) 2.5-2 3.1.1-2 (5) 2.5-3 3.1.1-2 (6)

.2.5-4 3.1.1-2 (7) 2.5-5 3.1.1-2 (8)

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s 2.4.2 PRAs of Other-Plants _ Reviewed by Union Electric-  ;

During performance of che_Callaway IPE, Union-Electric _ referred ~

to other plant PRAE for information on methodologies used and to  ;

. comparc Callaway results to results from other, similar studies. i The PRAs referred to are' listed below: "

1. Surry (NUREG-1150 and NSAC-152)

2. Sequoyah (NUREG-1150 and NSAC-152)

3. Seabrook (Seabrook Station PSA)

4. Zion (NUREG-1150 and NSAC-152)

5. Turkey Point (IPE submittal)

6. Oconee tNSAC-60)

The reports on the Surry, Sequoyah and Zion PRAs were referred to

from time-to-time, throughout the Callaway study, for-insights.on methods and intermediate and final results. In addition, the list of initiating events for Callaway was compared to initiators 1 used in the Surry, Sequoyah and Seabrook studies. The Turkey Point IPE submittal was reviewed primarily for guidance'during d

_ preparation of this submittal. Regarding the Oconee PRA', Union  :

Electric employed the methodology used therein to determine large  ;

pipe break flooding frequencies. -

2.4.3 Plant Documentation Used Almost all categories.of.the controlled-documentation available for Callaway were used to complete the IPE program. This documentation included the FSAR, Technical Specifications, plant ,

- procedures, piping 1and instrumentation diagrams, piping isometric drawings, one-line and elementary wiring diagrams, electrical schematics,-mechanical and electrical system descriptions, LERs, irs, maintenance work orders, operator logs, and various-calculations.

g; 2.4.4 ~ Process Used to Confirm *thLt the IDE Represents the As-Built, As-Operated Plant Section 2.1.2, item 3 of NUREG-1335 states _that "The.intentnof such a confirmation ... (is) to account for1the impact of _ _

previous plant modifications or modifications. conducted within-

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the.IPE framework."

O As' stated in'ULNRC-2099 dated 10-33-89 (60-day response to GL 88-20 Supplement 1), our extensive design control, configuration

control,-and-document control programs ensure that drawings and procedures used in the IPE reflect the current design and

{ operating philosophy of the plant. For future updates of the ]

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• Level I PRA1models, the Union Electric-IPE team will maintain-cognizance of changes made to pertinent references used in the IPE in order to reflect these changes, as required, in the Level-1 PRA models and results.

2.4.5 IPE Walkdowns The_walkdowns conducted as part of the IPE program are described [

-briefly hereinafter.

Two walkdowns were conducted in support of the front-end portion of the IPE. The team for both walkdowns was comprised of Messrs.

Connelly and Davidson (both of Union Electric) and Mr. Quilici (of NUS). Most of the rooms containing safety-related plant equipment were visited during these walkdowns. Photographs'were taken and information was obtained and recorded with respect to .

room cooling, room access, component labeling, emergency lighting, and component layout within the rooms. Information .

obtained during these walkdowns was used primarily to supplement" s plant documentation used for fault' tree modeling and for identification of potential recovery actions.

Two walkdowns were conducted in support of the containment performance portion of the IPE.

The first was conducted by Ms. Anselm (of UE)_and Mr. Vanover (of GKA). - The_ purposes of this walkdown- were to obtain information

• to support auxiliary _ building modeling (nodalization) in_the Callaway MAAP model, to determine if there were any submerged break-locations, and-to obtain information on fire suppression sprays.

The second walkdown in this category was conducted by Mr. Carlson (of UE), Mr. Vanover (of GKA), and Mr. Fulford-(of NUS). This walkdown was conducted in the containment building andfaddressed various MAAP modeling and containment performance' issues.

Three walkdowns were conducted in. support; of the internal:

flooding analysis. These walkdowns were conducted by Ms. Walker and Mr._Stecko (of UE) and Mr. Jorgenson (of NUS). During these walkdowns, information was obtained as to equipment potentially -

.. .- impacted ~by-internal flooding and the associated flooding sources.

2.5 SYSTEM DEPENDENCIES

, -It was recognized early in the Callaway'IPE program that L

dependent failures would be important contributors to core damage'. Therefore, a principal focus of-the Callaway_ program 1was to thoroughly address system dependencies and_ dependent failures.

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