ML17320B097

Forwards Results of Exxon Nuclear Co Review of Safety Analyses.Util Concurs W/Vendor That Analyses in Compliance W/Nrc Requirements for Development & Application of Computer Codes Used in Performing Safety Analyses

ML17320B097
Person / Time
Site:	Cook
Issue date:	06/04/1984
From:	Hering R INDIANA MICHIGAN POWER CO. (FORMERLY INDIANA & MICHIG
To:	Harold Denton Office of Nuclear Reactor Regulation
References
AEP:NRC:0860P, AEP:NRC:860P, NUDOCS 8406080228
Download: ML17320B097 (18)

Text

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ACCESSION NBR:8006080228.

DOC'ATE: 84/06/00 NOTARIZED; NO

DOCKET FACIL:50 316-Donald C'.

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05000316 AUTH',NA

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DENTONr H,'R ~

Officed of Nucl ear Reactor Regul ationi Director SUBJECT ~ O',Forwar ds;-nesul.ts of Exxon Nuclear <<Co.review. of.-safety.

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INDIANA 8 NICHIGAN ELECTRIC COMPANY P.O. BOX 16631 COLUMBUS, OHIO 43216 June 4, 1984 AEP:NRC:0860P Donald C. Cook Nuclear Plant Unit No.

2 Dooket No. 50-316 License No. DPR-74 SAFETY ANALYSES PERFORMED BY EXXON NUCLEAR COMPANY Mr. Harold R. Denton, Director Office of Nuclear Reactor Regulation U.S. Nuclear Regulatory Commission Washington, D.C. 20555

Dear Mr. Denton:

During an audit performed from April 3-5, 1984 at Exxon Nuclear Company's facility in Richland, the NRC identified a number of items of apparent non-compliance with NRC requirements for the development and application of computer codes used in performing safety analysis.

The Exxon response to this audit was submitted to your Mr. Uldis Potapous on May 24, 1984.

Exxon has also reviewed the analyses that they made in support of our license amendment application to the Donald C.

Cook Nuclear Plant Unit No.

2 Appendix A Technical Specifications which was initially submitted on March 1, 1984, reference AEP:NRC:0860.

The results of this review are included as an attachment.

Corporate QA and technical personnel have reviewed the attachment and discussed its contents with Exxon personnel.

On the basis of the attached letter, we concur with Exxon's conclusion that their analyses were in compliance with NRC requirements.

This document has been prepared following corporate procedures which incorporate a reasonable set of controls to ensure its accuracy and completeness prior to signature by the undersigned.

Very truly yours,

~

~

R.F. Hering

'g~iI+

Vice President 84php8p228 p4pgp~

PDR ADOCK 050003i6 Attachment cc: John E. Dolan W.G. Smith, Jr. - Bridgman R.C. Callen G. Charnoff E.R.

Swanson, NRC Resident Inspector - Bridgman oo'

f w

I o

~

0 K)$$Ã4 NUCLEAR COMPANY,Inc.

600 -108h Avenue N.E., C-00777, Bellevue. Washington 98009. Y'eteohone (206! 453-4300 May 31, 1904 ENC-AEP-0357 Hr. George

John, Sr.

Engineer Indiana E Michigan Electric Company c/o American Power Electric Power Service Corp.

One Riverside Plaza

Columbus, Ohio 43215

Dear George:

As a result of an audit on April 3-5, 1984, the NRC identified a number of items of apparent non-conformance with the NRC requirements regarding Exxon Nuclear's development and application of computer codes used for safety analyses.

As you requested during our phone conversation on May 29,

1984, we have reviewed the safety analyses performed by Exxon Nuclear fo..

D.C. Cook Unit 2 Cycle 5 in respect to each of the items listed in the audit report.

Our conclusion is that the analysis is in compliance with the NRC requirements.

The results of our review for each of the items of apparent non-conformance are given in the Attachment to this letter.

Please contact me if you have further questions regarding this matter, Contract Administrator RAPIFAX PAGE ATTN.

No f09 i<<IS

JCC: 084:84

~Findin:

A.

Criteri on V

of Appendix 8

to M

CFR Part 50

states, in

part, "Activities affecting quality

~.. shall be accomplished in accordance with... instructions, procedures, or drawings..."

Section 5 of the Exxon Nuclear Company (ENC )

Topical Report Ho.

XH-NF-IA (Rev.

6) states that the quality assurance program and associated quality-related design and procurement activities are prescribed by documented instruction, procedures, and

drawings, as appropriate, to assure adequate definition of the instruction for satisfactory completion of activities.

In addition, Item 4 of Appendix I

commits to compliance with Regulatory Guide 1.64 and ANSI N45.2. 11-1974.

Contrary to the above, ENC failed to prescribe adequate definition of the instruction for satisfactory completion of Safety-related compute code acti vities as follows:

I, The main document gov ming the development and use of computer codes is

ÃN-NF-608, "Guide for Use and Control of Computer Codes'ithin Exxon Nuclear Company for Engineering and Design Calculations,"

which identifies "guidelines" to be used that have an optional connotation versus mandatory.

ENC Res onse The analyses performed in support of Cycle 5

operation of O.C.

Cook Unit 2 were in compliance with the guidelines and requirements of XN-NF-608,

~hich is interpreted as mandatory for ENC design analyses.

\\

RAPIFAX NO.

F'AGE

~ OF (Q ATTN.

JCC:084:84

~F3ndin 2,

There is no procedure or "guideline" which requires code input data to be independently verified.

ENC Res onse Procedures which are required for design cal ulations are contained in XN-NF-P00,002, which has been in effect at ENC for several years.

This document identifies a

number of acceptable methods fcr assuring that design calculations have been performed using correct i~put and appropriate methods.

Checking of calculations by a second qual1fiec 1ndividual is one of these acceptable alternatives, The other allowable methods are independent (audit ) calculations and design testing.

As a

part of ENC 's approved equality Assurance

program, comp)iance with XH-HF-P00,002 1s mandatory.

'ghen the independent checking of calculations is used as the means of assur1ng analytical

accuracy, verificat1on may involve internal

checks, comparison with experimental

data, comparison with results of other fuel and NSSS supp I i er s, compa rison w1th pre vi ous perf ormance test

results, or comparison with results from a similar analysis.

These options are, allowed to provide flexibility 1n determining the most effective method of verification.

Secause the emphas1s is placed on 'an overall review of the analysis and the results thereof, it is not always appropriate to require 1ndependent checking of computer code input.

NO, <<>

aq'E g oF (3

JCC:084:84 The analyses performed in support of Cycle 5 operation of D.C. Cook Unit 2 conform to the requirements of XN-NF-P00,002.

In complying with this procedure, the ENC technical staff performed and documented

detailed, independent oval.rchecks of the calculations supporting the license amendment request.

Input parameters employed for the O.C.

Cook Unit 2 lOCA/ECCS and plant transient analyses are reported in XH-NF-81-60, Revision 1, "O.C.

Cook Unit 2 Prima y Design Parameters for ECCS and PTS Analysis," dated December 1981.

These data were reviewed and confirmed by American Electric Power prior to the cycle 4 analyses.

Ninor changes to the data to reflect steam generator plugging were made for the cycle 5 calculations, These changes have been independently reviewed as to appropriateness and accuracy by ENC technical staff.

Reviewers notes appear in the appropriate calculational workbooks, NRC Staff auditors had the plant transient analysis workbook in hand 'during the NRC's April 3-5 computer code audit; whether a review was performed by the NRC auditor is not known.

No discrepancies were cited concerning the

workbook, RAPIFAx m.

~ t O7 PASS,t Qf ATrM.

. ~

JCC:084:B4

~Fin din:

3.

.Neither procedures nor "guidelines "

address Section 9,

"Corrective Action," of ANSI N45.2.11-1974 concerning actions to be taken, ENC~Res ense Corrective action requirements for computer code development activities and design calculations are defined in Quality Assurance procedure No.

16 pf XN-NF-1, which covers review and verification of product design.

Beyond these requirements,

however, it has been fNC's practice to evaluate corrective action independently for each occurrence to assure that the unique nature of each individual problem is taken into account in determining the cor recti ve action.

The design analyses performed by fxxon Nuclear in support of Cycle 5

operation of D.C.

Cook Unit 2 are in compliance with XN-NF-1, which includes OA Procedure 16.

. ~

JCC:084 84

~Fi ndi n The definitions contained in Sections 1.2.2, "Use Codes,"

and" 1.2,3, "Special Codes."

of XN-NF-608 are not specific with respect to testing requirements.

ENC Res onse All computer codes used in ENC design analyses are verified under the requirements of Section 3.1,l.c of XN-NF-608, as described in the response to Finding A.5, below.

All of the analyses performed by Exxon Nuclear in support of Q.C.

Cook Unit 2, Cycle 5 operation utilized computer codes which were verified in accordance with XN-NF-608.

l II 4 RAPIFAX NG, (OVAL PAGE q

GP (g

ATTg,

. ~

JCC:084:84

~Fin din:

5.

Section 3.1.l.c, "Test Cases,"

of XN-NF-608, does not require "that a

test procedure be established prior to performing verification tests nor does it require user notification of any options that have not been tested.

ENC Res onse Section

3. 1. 1.c currently requires that all test cases for code verification execute each major code path at least once.

This requirement assures that there are no significant options which have not been

tested, Because these procedures require that all major paths be exercised during the code verification

process, a

requirement that potential users be apprised of any options which have not been tested during code verification would rarely be exercised.

For the D.C.

Cook Unit 2 Cycle 5 analysis, all of the major code paths were exercised and the results documented during the verification of the code versions which were used for the analysis.

RAPiPAX PAGE 7 I (g ATTN-

JCC: 084:84

~Finds n:

e.

Section 3.1.1.e, "Miscellaneous Requirements,"

of XN-NF-608, does not require identification of the computer type used in an analyris

~

ENC Res onse Design calculations are prefaced with an information block which includes the

date, the code version, and the computer version used for the analysis.

This information block is required by XN-NF-P00,002, which is a

part of the EHC guality Assurance Program.

All of the calculations performed by ENC in support of Cycle 6

operation of D.C.

Cook Unit 2 include an identification of the computer used in the analysis.

JCC: 084:84

~Findin:

7, Sectfons

3. 1. 1.f and

3. 1.2.d of XM-NF-608 do not require that the Computer Code Council document the reasons for any disapproval votes.

ENC Res onse In the development and approval of computer

codes, sufficfent coordination is scheduled that dissenting votes are not likely to occur.

If a code council member has difficulty ~ith some aspect of a computer code which is under evaluation, the developer endeavors to resolve his concern prior to the code council vote.

No dissenting votes ~ere recorded during the revfew of the computer codes used in the analyses supporting Cycle 5 operation of O.C.

Cook Unit 2.

.(opz PAGE ATTN.

XC 684 84

~Find tn ':

8.

Sections 3.4 and 3.5 of XN-NF-608 do not specifically require reporting of errors in EPICS evaluation models.

An ECCS evaluation model that is/remains acceptable to the staff fs one that does not contain a

significantly known error.

(Reference 10 CFR Part 50.46 and 10 CFR 50, Appendix K).

~ENC Res ense XN-NF-608 currently requires that error's in fCCS evaluation models be reported in conformance with 10 CFR Part 21.

No errors have been discovered in the ENC analyses supporting O.C.

Cook Unit 2.

In the event that errors which adversely impact the D;C.

Cook Unit 2 analysis were to be discovered, they would be reported as required by 10 CFR 50.46 and Appendix K or 10 CFR Part 21, as appropriate.

10

~Fi ndi n B.

ENC Quality Assurance Procedure XN-NF-P00,002, Revision 13, Sect fon 3.5,3.2,

states, in

part, "Documentation providing a sugary of the basis of the checks and comparisons performed shall be indicated on the engineering calculations sheet,..., plus the signature and date of the checker."

Contrary to the above, no su+nary nor any signature or date of checker was included in the backup calculation NO. E-T122-969-1.

Further, benchmark comparisons of calculated primary and system performances against available data were requested by NRC.

This was submitted to NRC on December 16, 1983.

The backup calculations were dated December 1,

1983 for this submfttal,

~EII I The subject cal cul ation (E-T122-969-1) was a

preliminary benchmark calculation using PTSPQR2 to predict measured phenomena associated with a tube rupture event at the Prairie Island nuclear plant.

As a

preliminary

analysis, E-T122-969-1 had not been reviewed for cmplfance with XN-NF<<P00,002.

This review will be performed as requfr ed prior to fssuance of the report.

The D.C. Cook Unit 2 Cycle 5 analyses have been checked in compliance with XN-NF-P00,002.

RAPIPAX NQ'(O~+

PAGE

(( Of/g

. ~

JCC;084:84 Findin~:

C.

Secti on 1.2.7, "Software Devel opment Record,"

(SDR) of N-NF-608 (Revi si on 3),

states that the SDR shall contain such things as:

listings of the various versions of the

code, sunearies of modifications, verification and qualification records compiled to date, and approvals made to date for use of the code, and records of the review by an independent party of verification and qualification.

Contrary to the above, the SDRs for the REFLEX and TOODEE-2 computer codes were not complete with all versions of the codes, and contained updated SetS that did nOt identify the preparer,

purpOSe, Or that they had been independently checked.

ENC Res onse Both REFLEX and TOODEE2 were developed prior to the adoption of XN-NF-608 as the procedure for computer code development and are in compliance with computer code quality assurance procedures which were in effect at the time of their development, These programs provide equivalent assurance to that provided by compliance with XN-NF-608.

Use of these two codes, REFLEX and TDOOEE2, for analysis of O.C.

Cook Unit 2,

Cycle 5

operation is supported by code verification and qualification in compliance with an ear lier quality assurance

program, which was acceptable for computer.

code applications when it was applied to REFLEX and.TOODEEZ.

eaaiwx m ICZ-waar

/Z.% Q ATA4.

12 t

C

'CC ON 84

~Findin:

0.

Criteri on

XV11, "qua 1 1 ty Assurance Records,"

of 10 CFR Part 50, Appendix B, states that sufficient records shall be maintained to furnish evidence of activities affecting quality and that the records shal 1 include at least the results of reviews and tests and that the records shall be identifiable and retrievable.

Contrary to the above, ENC failed to provide the documentation of verification and qual ificat1on of the REFLEX and TOODEE-2 coaputer codes.

The calculation notebooks, or cop1es thereof, that documented the original calculations and their independent checking could not be retrieved during the inspection.

ENC Res onse The records of the verification and qualification of.

these two codes were not available during the audit because the code custodian was not available to retrieve them, The records have been subsequently retrieved and are available for future aud1t.

Both of these codes have been in use at ENC for many

years, and the records are not fully in compliance with the Software Development Record procedures in XN-NF-608, The available records

are, however, in compliance with the programs which were in effect at the time their respective development programs were completed.

These prograas were judged to be in compliance with 10 CFR 50, Appendix B.

Although compliance with ÃN-NF-608 will not be atta1ned for some

t1me,

<<1\\

of the development, qualification, and verification records required for SN compliance are present in the records package.

The development and qualification recor ds for REFLEX and TOOOEE2 cover the versions of these codes used for the analysis of Cycle 5 operation of D.C.

Cook Unit 2.

RAF iF'AX m/bPZ-FtAGE ty 9F.~ g ATTN.