ST-HL-AE-2992, Forwards Propprietary Rev 1 to Supp 1 to WCAP-12067 & Nonproprietary Rev 1 to Supp 1 to WCAP-12087, Addl Info in Support of Evaluations for Thermal..., Per 890112 Request. Proprietary Rept Withheld (Ref 10CFR2.790)

Forwards Propprietary Rev 1 to Supp 1 to WCAP-12067 & Nonproprietary Rev 1 to Supp 1 to WCAP-12087, Addl Info in Support of Evaluations for Thermal..., Per 890112 Request. Proprietary Rept Withheld (Ref 10CFR2.790)

ML20235G626
Person / Time
Site:	South Texas
Issue date:	02/15/1989
From:	Mcburnett M HOUSTON LIGHTING & POWER CO.
To:	NRC OFFICE OF INFORMATION RESOURCES MANAGEMENT (IRM)
Shared Package
ML20011C537	List: ML20235G632 ML20235G677 ST-HL-AE-2992, Forwards Propprietary Rev 1 to Supp 1 to WCAP-12067 & Nonproprietary Rev 1 to Supp 1 to WCAP-12087, Addl Info in Support of Evaluations for Thermal..., Per 890112 Request. Proprietary Rept Withheld (Ref 10CFR2.790)
References
ST-HL-AE-2992, NUDOCS 8902230315
Download: ML20235G626 (4)

Text

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The Light L . co mpa nyS uth Texas Project Electric GeneratingP. Station O. Box 289 Wadsworth, Texas 77483 Ilouston Lighting & Power l-February 15, 1989 ST-HL-AE-2992 File No.: G09.17 10CFR2.790 10CFR50 U. S. Nuclear Regulatory Commission Attention: Document Control Desk Washington, DC 20555 South Texas Project Electric Generating Station Units 1 and 2 Docket Nos. STN 50-498, STN S0-499 Additional Information in Support of the Evaluation for Thermal Stratification of the Pressurizer Surge Lines

Reference:

1) ST-HL-AE-2973 dated February 1, 1989.

2) NRC Request for Additional Information dated January 12, 1989.

3) ST-HL-AE-2900 dated December 9, 1988

4) ST-HL-AE-2949 dated January 17, 1989 Enclosed is the PROPRIETARY report entitled " Additional Information in Support of the Evaluations for Thermal Stratification of the Pressurizer Surge Lines of the South Texas Project Units 1 and 2 Nuclear Power Plants" which is Supplement 1 to WCAP 12067, Revision 1. Also enclosed is the non-proprietary version of the report. Five (5) additional copies of each version were delivered to Mr. George Dick on February 15, 1989. This supplement provides additional information requested by the staff in Reference 2 and discussed in meetings on January 30 through February 2,1989. Specifically, this supplement gives clarification of leak rate calculations in the evaluation of leak-before-break (LBB) and justifies the maximum differential top-to-bottom pipe temperature, during a cooldown following a leak in the reactor coolant system (RCS),

Supplement 1 to WCAP 12067, Revision 1 demonstrates that the PICEP code yf. elds substantially more conservative results for the cases discussed than the Westinghouse computer codes used in the LBB analysis. The Westinghouse codes produce conservative best estimate results. This is shown by comparing PICEP and Westinghouse computer code predictions with measured plant data (Duane Arnold) and experimental results. HI.&P beleves that the difference in j computer code predictions is attributable to the difference in crack opening area models, leak rate calculation models and crack surface roughness. We believe that the model used by Westinghouse for STP analyses is appropriate. ,,

8902230315 890216 T PDR P

ADOCK 05000498 M/N PDC g/ $4 / /k ,~

L4\NRC\ed A Subsidiary of Houston Industries Incorporated IfI 88f l I Aan

1 ST-HL-AE-2992 Houston Lighting & Power Company South Texas Project Electric Generating Station F le No.: G09.17 p

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l The supplement also justifies the use of 250 F as the maximum surge line pipe 6 T during a forced cooldown with a postulated crack in the surge line.

The 250 AT is based on expeditious depressurization of the RCS in such an event Technical Specifications require shutdown for unidentified RCS leakage exceeding 1 gpm. STP procedures for unidentified leakage from the RCS dering ,

coeration would result in identification of a postulated surge line crack l nile the plant is in mode 3 when there is minima 14 T on the surge line pipe. '

Upon discovery that the source is a nonisolable RCS pressure boundary leak, depressurization of the RCS would be paramount, and the operators would be expected to initiate depressurization expeditiously. To provide further i assurance, plant operating procedures are being revised to reinforce the need l for prompt depressurization in the event of a nonisolable leak in the RCS.

The attached report together with WCAP 12067, Rev. 1 provides the basis for the 40 year qualification of the STP surge line. The development and conclusion of the WCAP are briefly described below.

WCAP 12067, Rev. 0 (Ref. 3) provided analyses of the effects of thermal stratification on the pressurizer surge line and residual heat removal (RHR) line as presented to the staff on November 30, 1988. (The RHR line analysis was later resubmitted separately as WCAP 12108.) The supplement (Ref. 4) to WCAP 12067, Rev. 0 was submitteu in response to NRC comments in Supplement 6 to the STP SER, and the WCAP was revised to include the supplement and other ,

explanatory information (Ref. 1). Meetings in Pittsburgh and at STP January  !

30-February 2, 1989 concerning the staff review of the WCAP have culminated in the submittal of the attached supplement to WCAP 12067, Rev. 1. ,

The work presented in the WCAP and its supplement leads to the following conclusions:

(a) Based on plant monitoring results from Westinghouse PWR's (including South Texas Unit 1) and flow stratification test data, the thermal design transients for the surge line have been updated to incorporate the effects of stratification.

(b) The global structural and local stresses and loads in the surge line piping and support system meet ASME III code allowables. The max 1muir cumulative fatigue usage factor for 40 year design life is bss than the allowable of 1.0.

( c ', 'latigue crack growth (FCO) analyses show that a postulated 10%

initial crack will not propagate beyond 60% of the pipe wall in 40 years design life.

(d) LBE is confirmed for all loading combinations, including maximum postulated stratification, using the methods of SRP 3.6.3 and NUREG 1061, consistent with previously submitted reports WCAP--10489 and WCAP-11256.

HI4P wf il continue t o scnitor the Unit 1 pressurizer surge line until the ffrst refueling outsge. A final report will then be prepared which will make use of STP and othcr available industry data, and is expected to confirm the L4\NRC\ed l

Houston Lighting & Power Company ST-HL-AE-2992 .

le No.: G09.17 South Texas Project Electric Generating Station conservatism of the analyses. Also, both the Units 1 and Unit 2 surge lines have been visually examined (ASME Section XI VT-3) and no apparent distress or structural damage was found.

As Attachment 1 contains information proprietary to Westinghouse Electric Corporation, it is supported by an affidavit signed by Westinghouse, the owner of the information. The affidavit sets forth the basis on which the information may be withheld from public disclosure by the Commission and addresses with specificity the considerations listed in paragraph (b) (4) of j Section 2.790 of the Commission's regulations. ]

Correspondence with respect to the proprietary aspects of the Application for Withholding or the supporting Westinghouse Affidavit should reference CAW-89-031 and should be addressed to R. A. Wiesemann, Manager of Regulatory and Legislative Affairs, Westinghouse Electric Corporation, P. O. Box 355, Pittsburgh, Pennsylvania, 15230-0355.

i The Application for Withholding and accompanying affidavit is included as Attachment 3.

If you should have any questions on this matter, please contact Mr.

A. W. Harrison at (512) 972-7298.

b M WW M. A. McBurnett I

Manager, Operations Support Licensing MAM/ RAH /hg Attachments: 1. Supplement 1 to WCAP 12067, Revision 1 (Proprietary). j

2. Supplemenc 1 to WCAP 12087, Revision 1 (non-proprietary).  !

3. Westinghouse Application for withholding, CAW-89-031.

l l

4 4

l l L4\NRC\ed i

3

_ Houston Lighting & Power Company ST-HL-AE-2992

- South Texas Project Electric Generating Station .

' File No.:-G09.17

3. ,

p 3

cc:

Regional Administrator,; Region IV Rufus S. Scott

' Nuclear Regulatory Commission ~ ' Associate General Counsel i 611 Ryan Plaza Drive, Suite 1000 . Houston Lighting & Power Company Arlington,_TX 76011 P. O. Box 1700 Houston, TX .77001 George Dick, Project Manager ,.

U.S. Nuclear Regulatory Commission INPO f

,. Washington, DC 20555 Records Center ,l l 1100 Circle 75 Parkway Jack ~E. Bess Atlanta, CA '30339-3064 Senior Resident Inspector / Unit 1--

e e/o U.S. Nuclear negulatory Dr.. Joseph M. Hendrie. 'q

, Commission. 50 Be11 port Lane {

P. 0. Box 910' 3ellport, NY 11713 .{

Bay City,.TX 77414 J. I; Tapia .

. Senior Resident. Inspector / Unit 2

-c/o U.S. Nuclear Regulatory Commission-P. O. Box.910 Bay City, TX 77414 J. R. Newman, Esquire.

>Newman & Holtzinger, P.C.

1615 L Street, N.W.

Washington, DC. 20036-R. L.- Range /R. P. Verret Central Power & Light Company

'P. O. Box 2121 Corpus Christi, TX 78403 R. John Miner (2 copies)

Chief Operating Officer City of Austin Electric Utility 721 Barton Springs Road-Austin, TX 78704 j

R. J. Costello/M. T. Hardt City Public Service Board P..O. Box 1771 San Antonio, TX 78296 Revised 12/21/88 L4\NRC\ed

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