ML20202F257

Submits Rept Per 10CFR50.46 Re Errors in Changes to ECCS Evaluation Model.Rept Supersedes Info Provided in Licensee

ML20202F257
Person / Time
Site:	Catawba
Issue date:	02/05/1998
From:	Gordon Peterson DUKE POWER CO.
To:	NRC OFFICE OF INFORMATION RESOURCES MANAGEMENT (IRM)
References
NUDOCS 9802190163
Download: ML20202F257 (4)

Text

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Catasha Nudeer Surion

• 4800 Concord Road York, SC 29745

. Gary R. hereoa (803) 831-4,51 omcr YuePrnident (803) 831-3426 fax February 5, 1998 U. S. Nuclear Regu?a ory Commission Attention:- DocumtSt m. trol Desk J Washington, DC 2 W S-f 01

SUBJECT:

Dul'e Ent:Ny Corporation Catawba Nuclear Station Docket Nos- 50-413, 50-414 Report Pursuant to 10 CFR 50.46 Errors in or Changes to an ECCS Evaluation Model In a letter dated December 19, 1997 Duke Energy Corporation submitted a report pursuant to 10 CFR 50.46 titled " Errors in-or Changes to ECCS Evaluation Model". (erroneously labeled as 10CFR40.46 in the title) This report covered both the McGuire and Catawba Nuclear Stations. Upon review of-this letter, the NRC's Project Manager for-Catawba raised-some questions ac-to differences between the December 19, 1997 letter and the values of Peak Clad Temperature (PCT) as listed in the Catawba Updated Final Safety Analysis Report (UFSAR).

Upon review of these differences it was determined that both

-the UFSAR (for Catawba Unit 2 small break LOCA PCT value only) and the December 19, 1997 letter contained errors with respect to the Peak Clad Temperatures for Catawba.

Therefore, this letter supersedes the information provided in the. December 19, 1997 letter for Catawba Nuclear Staticn.

(McGuire Nuclear Station had previously submitted a-report pursuant to'10 CFR 50.46 in a letter to the NRC dated October 2, 1997) 10 CFR 50.4 6 (a) (3) (ii) requires reporting of changes to or errors in the ECCS avaluation model (E.), M or in the application c# the EM, which affect the LOCA peak clad temperature (PCT). For Catawba, the large break LOCA is analyzed with the Framatome Technolcgies, Inc. (FTI) large

~ break LOCA EM. For small break LOCA analyses, the Framatome Technologies Inc. (FTI) small break LOCA EM is used for the i

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9 U ., S . NRC, Document Control Desk February 5, 1998 Page 2-Unit 1 analysis with BWI replacement steam generators. The results of the Westinghouse small break LOCA EM are used by FTI as the basis for the Unit 2 Westinghouse Model D steati.

generator analysis. This report covers-changes to the evaluation models for Catawba for the year ending August 31, 1997.

Large Break LOCA By letter dated July 25, 1997, Duke Energy notified the NRC-of an error in the FTI LOCA EM in which the decay heat was underpredicted. This error resulted in a PCT change that was greater than 50 *F. FTI reanalyzed the large break LOCA analyses of record for Catawba and determined an increase in PCT of 77 F for Unit 1 and 9' F for Unit 2 making the PCT

- values 2152 *F and 2174 F respectively for Catawba Unit 1 and 2. These values are correct]y stated in the UFSAR.

Unit 1 Small Break LOCA FTI performed a-reanalysis of the small break LOCA replacement steam generator analysis for Catawba Unit 1 in order to assure compliance with the recently approved SBLOCA evaluation model, BAW-10168, Revision 2. The result of this i analysis are a maximum PCT of 1254 F, a maximum local

- cladding oxidation fraction of 0.284%, and a total core metal-water reaction of less than 0.03%. The Unit 1 small break LOCA reanalyces with the decay heat error correction resulted in a limiting PCT of 1342 *F (an increase of 89

• F). LOCA analyses for Catawba with the FTI EM decay heat error correction are now in place which meet the acceptance criteria of 10 CFR 50.46. The core power distribution monitoring is being performed consistent with Technical l Specifications to ensure the core power peaking assumed in the LOCA analyses d9 not exceeded. Therefore the PCT for Catawba Unit 1 is-1343 F. This value is correctly stated in the UFSAR.

Unit 2 Small Break LOCA Westinghouse has provided Duke with a list and description of the ECCS small break LOCA EM changes and errors that affect the PCT result for McGuire and Catawba. The Evaluation Model changes.and errors were reported to the NRC via Westinghouse letter NSD-NRC-97-4983. The revised Westinghouse maximum PCT for Catawba Unit 2 is 1426 F (an increase of 10 F) . FTI further~ adds a 24% tube plugging h

a f . U. S. NRC, Document Control Desk February 5, 1998 Page 3 penalty and accounts for other calculated penalties and the res"It is a PCT of 1595 *F.

In August of 1996, Westinghouse obtained NRC approval for an improved condensation model in the NOTRUMP code. This results in a PCT decrease of 150 "F that was not previously credited. In addition, an increase in PCT of 30 'F was also included due to previous Westinghouse penalties for c net PCT change of -120 *F from the FTI Catawba Unit 2 SBLOCA PCT UFSAR repor*ed value of 1715 F. The FTI Catawba Unit 2 SBLOCA analysis is the analysis of record. It is based on the original Westinghouse analysis and penalties plus an FTI evaluation for 24% tube plugging. No FTI errors have been reported in the past year that would affect the CNS-2 SBLOCA analysis. Therefore the PCT for the FTI Catawba Unit 2 SBLOCA analysis is 1595 *F which can be arrived at by either subtracting 120 F from 1715 F or adding the 24% tube plugging and other calculated penalties to 1426 *F. The value in the UFSAR of 1715 F is incorrect and will be revised.

Please direct any questions or comments on this letter to M.S. Kitlan, Jr. at (803) 831-3205.

Very truly yo s,

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. M- -

G. R. Peterson i

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. U< S. NRC, Document Control Desk-February:5,.1998 Page 4 f

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L.-A._Reyes U. S. Nucle'ar Regulatory Commission Regional Administrator, Tegion II Atlanta Federal Center 61'Fcrsyth St., SW, Suite 23T85 Atlanta, GA 30303 P. S.-Tam

, NRC Senior Project-Manager (CNS)

U. S. Nuclear Regulatory Commission

. Mail Stop O-14H25 Washington,.DC 20555-0001-D. J. Roberts

~

. Senior Resident Inspector (CNS)

. U. S. Nuclear Regulatory Commission Catawba Nuclear Site 4

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