ML19345C334

Deficiency Rept Re Improper Loads Used for Support/Restraint Design (Loca,Valve Discharge,Mismatch).Comprehensive Program Initiated to Identify Support/Restraints Affected,Revise Design Sketches & Perform Hardware Changes

ML19345C334
Person / Time
Site:	Mcguire, McGuire
Issue date:	11/26/1980
From:	Parker W DUKE POWER CO.
To:	James O'Reilly NRC OFFICE OF INSPECTION & ENFORCEMENT (IE REGION II)
References
10CFR-050.55E, 10CFR-50.55E, NUDOCS 8012040408
Download: ML19345C334 (4)

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DtJxe POWER COMPANY Powna Dutwixo 422 Sourn Cuuncu Srneur. CILAHI.OTTz, N. C. 3ft242 wiww o, manca.an. -

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- tbverter 26, 1980 .

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Mr.-James P. O'Reilly, Director v' 7 U. S. Nuclear Regulatory Cornission Region II 101 Marietta Street, Suite 3100 Atlanta, Georgia 30303 4

Re: McGuire Nuclear Station Units 1 and 2 Docket Nos. 50-369 and 50-370

Dear Mr. O'Reilly:

Pursuant to 100'R 50.55e,please find attached Significant Deficiency Report SD 369/80-20, 370-80-15.

Very truly yours,

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W.i111am O. Parker, Jr. /Y G7C:vr Attachnent cc: Director T. J. Donat Office of Inspection a Enforcenent NRC Resident Inspector U. S. Nuclear Regulatory Ccmnission otGuire hix: lear Station .

Washington, D. C. 20555 .'

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KGUIRE NUCLFAR STATION LNITS 1 & 2 REPORT NO: SD-369/80-20, 370/80-15 i REPORT DATE: tbvertber 26, 1980 INITIAL NCrf1FICATION DATE: October 28, 1980 FACILITY: ftGuire Nuclear Station, Units 1 & 2 IDENTIFICATICN OF DEFICIENCY: Improper Ioads Used for SuTport/ Restraint Design (ILCA, Valve Discharge, Mismatch)

DESCRIPfION OF DEFICIENCY:

This report describes a deficiency in use of design loacings for design of pipe support / restraints. Three separate problerrs contribute to the total deficiency as follows:

1) IOCA (Inss of Coolant Accident) piping analysis methods were not sufficiently defined to permit accurate definition of support / restraint loads at the time of initial design. After loadings became available, a review of the adequacy of affected support / restraints was performed and any inadecuacies dis-oovered in that review were corrected. Original support /

restraint design and this later review / resolution procedure were carried out by EDS Nuclear, Inc under contract to Duke Power prior to turnover of design responsibility to Duke in mid 1979. Recent revision activity on this scope of support /

restraints by Duke engineers at the site led to question the r adequacy of the support / restraints for ICCA loads. A sub-sequent detailed review of the procedure used by FDS Nuclear, Inc to review for IOCA adequacy revealed that the review pro-cedure was not sufficiently ccmprehensive to ensure adequacy of all parts of a suoport/ restraint. Hence the review was not /

ccrnplete, and sorte of the affected support / restraints may not be adequate for IOCA loads as required for consideration in design.

2) The above described problcrn concerning IOCA loads led to a review of methods used to include special dynamic and static loads in capport/ restraint design. Results of this review shovxi that an inadequacy existed in use of EDS Nuclear-supplied design loadings for sug: ort / restraints on the Pressurizer Safety / Relief piping due to valve discharge. Due to misccmtunication, valve discharge loads given for Faulted Condition were factomd downward for the Upset condition, as is acceptable for earthquake loadings for btGuire due to the 8/15 ratio that exists for CBE/SSE earthauakes. Since vzlve discharge loads do not factor and are the same for Upset and

for Faulted ^onditions, Upset allcwable loadings ard stresses

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November 26, 1980 Page 2 for support / restraints may be exceeded when 100-percent of valve discharge' loads are considered. Generally this deficiency is limited to those support / restraints which have ecmponents which are load or stress rated for the Lyset condition.

3) - During initial stages of review to correct IOCA and valve dis-charge load deficiencies, reference to current piping analysis results on file revealed that support / restraint loads shown on design drawings (sketches) did not match the on-file results, regardless of IOCA or valve discharge consideration. Investiga-tion through EDS Nuclear, Inc (who produced both the sketches and the piping analysis under centract to Duke Power) showed that increases in sugort/ restraint design loads recuired by recent revised piping analyses were not placed on design sketches unless the sketch recuired revision to show a structural change to the design. It was recuired that all such increases in load be con-sidered in support / restraint desian calculations and that adequacy of the support / restraints be proven for load increases. The problen occurredafter future update responsibility for these sketches was transferred from EDS Nuclear to Duke Power in mid 1979. Duke engineers at the site have performed revisions to designs or made engineering judgenents on installations based on sketch loads. Since sketch loadsmaynot represent current (higher) requireTents, revised and/cr installed configurations in this scope may not be adequate. This scope is limited to support /

restraint designs initially developed and maintained by EDS Nuclear and for which piping analyses have not been revised since sketch responsibility turnover in mid 1979.

The total number of support / restraints requiring analytical review and possible revision is 1591. The estimated nunber that may require some hardware change is 450. A majority of this scope of support / restraints is located in the Reactor Building.

ANALYSIS OF SAFTIY IMPLICATIONS:

Nbrst case safety consequence is that certain pipe support /rescraints may not be capable of withstanding loads as large as predicted by as-built piping analysis.

Although failure of these support / restraints is considered to be a renote possibility, absence of failure cannot be confirmed without further. review. In the event of excessive deformations or failure of these support / restraints, loadings en adjacent support / restraints would change such that adeauate support of the piping systen and loadings on cmponents to which it connects can not be confirmed as adequate. This, in turn, means that ability of the piping system to perform design functions cannot be assured.

CORRECTIVE ACTION:

A ccmprehensive program has been initiated to ccuplete the following: -

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tbverber 26, 1980 Page 3 (1) Identif,f all support / restraints affected in a nonconservative manner by each of the three cited problems.

(2) Perfom engineering review of designs identified in (1) and, if necessary, revise the designs to show required structural changes.

(3) Pavise all affected design sketches to show any higher loads 4

required by current piping analyses.

-(4) Make hah changes to affected support / restraints as required by revised designs.

(5) Paview piping analysis aM support / restraint interface methods and procedures and take actions necessary to prevent future problems in this area.

Schedules for conpletion of the above corrective action iters for Units 1 and 2 are as follcws:

Ccapletion Date Corrective ;ction Item Unit 1 Unit 2 (1) Identification Ccmplete 6/1/81 (2) Engr. Paview 12/19/80 Per Unit 2 Construction Schedule -

(3) Sketch Revision 12/19/80 Per Unit 2 Construction Schedule.

(4) Hardware Cunges 1/28/81 Per Unit 2 Construction Schedule (5) Procedure Confirmation -

3/1/81 All of the above iters are well underway for Unit 1 and results to date confim the expected minimum nunber and type of structural changes.

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