ML20087G253

Informs NRC of Status of Standby Nuclear Svc Water Pond Design Calculations Being Revised.Util Plans to Extend Date for Rev Completion to 950801

ML20087G253
Person / Time
Site:	Catawba
Issue date:	03/27/1995
From:	Rehn D DUKE POWER CO.
To:	NRC OFFICE OF INFORMATION RESOURCES MANAGEMENT (IRM)
References
NUDOCS 9504040050
Download: ML20087G253 (6)

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A. Catawbg NudeurGenemnon Department Ha knident

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. March 27,1995 U.S. Nuclear Regulatory Commission o ATTN:- Document Control Desk Washington; D.C. 20555  !

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Subject:

Catawba Nuclear Statiori, Units 1 and 2 Docket Nos. 50-413 and 50-414 '

Request for Extension of Commitments .

Inspection Report Nos. 50-413/94-17 and 50-414/94-17 l

Reference:

Letter from D.L. Rehn, DPCo to NRC, dated November 8,1994  ;

f Gentlemen: -

In the reference letter, specifically, in the response to Violation 50-413,414/94-17-02 (Example Al), it was indicated that design calculations associated with the Standby Nuclear Service Water Pond (SNSWP) analysis were being revised. The purpose of this ,

letter is to inform the NRC concerning the status of this effort and to advise the s' taffof our plans to extend the date for the completion of this commitment.

Calculation CNC-1223.24-00 0006 " Nuclear Service Water System HX Outlet Terriperature Calculation and Heat Load Rejected to SNSWP", has been revised.

I Additional heat load to account for pump work was added to this calculation. This included a more accurate accounting for the LOCA unit heat rejection and the shutdown unit core decay and containment cooldown heat load. The result was that the total heat rejection to the SNSWP was reduced by approximately 10% Also, this calculation was

. revised to. account for inventory losses related to ser ice water makeup to safety-related systems Therefore, Calculation CNC-1223.24-00-0013. " Nuclear Senice Water System Design Verification" -will not have to be revised a; a result of this violation example, contrary to what was originally indicated in the reference letter. Both of these calculations are considered revised as committed to in the reference letter.

' In the reference letter, it was indicated that calculation CNC-1150.01-00-0001, " Standby Nuclear Senice Water Pond - Thermal Analysis During One Unit LOCA and One Unit 9504040050 950327 PDR ADOCK 05000413-P mm m unaw PDR [by %\ h

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. l Document Control Desk Page 2  ;

March 27,1995 l Shutdown", was to be revised based on the inputs from the heat load and inventory calculations. In addition to changes based on these inputs, as committed to in the reference letter, Catawba plans to incorporate other changes into the SNSWP thermal model Specifically,1993 meteorological data has proven to be more restrictive than previously modeled meteorological conditions. The SNSWP thermal model is being updated to account for this more recent data. In addition, a SNSWP survey performed in December 1994 resulted in a smaller SNSWP inventory than was originally believed.

These new conditions are being incorporated into the SNSWP thermal model. The combination of utilization of the 1993 meteorological data as worst-case conditions and reduced SNSWP inventory has resulted in an increased workscope as compared to what was originally anticipated to fully resolve the long-term SNSWP issues. This necessitates a change in Catawba's committed due date for resolution. As a result, the final revision to calculation CNC-1150.01-00-0001 will not be complete by April 1,1995. It should be noted however, that Catawba has determined that in spite of the 1993 meteorological data and reduced SNSWP inventory, the SNSWP continues to remain operable.

Catawba is pursuing a plan for the long-term resolution of all SNSWP issues. This plan will result in raising the minimum surface elevation of the SNSWP. This will require a change to Technical Specification 3.7.5a from 570 feet to 571 feet Mean Sea Level. Final resolution and documentation of the issues contained in this violation example (with the exception of raising the SNSWP minimum surface elevation) are scheduled for completion by August I,1995. Catawba is presently awaiting all necessary environmental approvals for raising the SNSWP minimum surface elevation.

If you have any questions pertaining to this information, please call L.J. Rudy at (803) 831-3084.

Very trul.v vours, Of J D.L I e m LJR/s

Document Control Desk Page 3 l March 27,1995  ;

l xc: S.D. Ebneter, Regional Administrator Region II R.J. Freudenberger, Senior Resident inspector R.E. Martin, Senior Project Manager ONRR

, il I Duke herCompany DLRws Catau ba Suclear Generanor Depanment nce President

, MOO ConcordRoad '50M313:03 0thce York;SC29745 (MbtHJC6Far DUKEPOWER March 27,1995 U S. Nuclear Regulatory Commission ATTN: Document Control Desk Washington, D.C. 20555

Subject:

Catawba Nuclear Station, Units I and 2 Docket Nos. 50-413 and 50-414 Request for Extension of Commitments Inspection Report Nos. 50-413/94-17 and 50-414/N-i7

Reference:

Letter from D L. Rehn, DPCo to NRC, dated November 8,1994 Gentlemen.

In the reference letter, specifically, in the response to Violation 50-413,414/94-17-02 (Example Ai), it was indicated that design calculations associated with the Standby Nuclear Service Water Pond (SNSWP) analysis were being revised. The purpose of this letter is to inform the NRC concerning the status of this effort and to advise the staff or our plans to extend the date for the completion of this commitment.

Calculation CNC-1223.24-00-0006, " Nuclear Service Water System HX Outlet Temperature Calculation and Heat Load Rejected to SNSWP", has been revised.

Additional heat load to account for pump work was added to this calculation. This included a more accurate accounting for the LOCA unit heat rejection and the shutdown unit core decay and containment cooldown heat load. The result was that the total heat rejection to the SNSWP was reduced by approximately 10%. Also, this calculation was revised to account for inventory losses related to senice water makeup to safety-related l

systems. Therefore, Calculation CNC-1223.24 00-0013 " Nuclear Senice Water System l

Design Verification", will not have to be revised as a result of this violation example, i contrary to what was originally indicated in the reference letter. Both of these calculations are considered revised as committed to in the reference letter.

In the reference letter, it was indicated that calculation CNC-1150.01-00-0001, " Standby Nuclear Service Water Pond - Thermal Analysis During One Unit LOCA and One Unit by W D4.t A ,* * .,4 W

1

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Document Control Desk -

Page 2

- March 27,1995 Shutdown", was to be revised based on the inputs from the heat load and inventory I. calculations. In addition to changes based on these inputs, as committed to in the  ;

reference letter, Catawba plans to inc.orporate other changes into the SNSWP thermal model. Specifically,1993 meteorological data has proven to be more restrictive than previously modeled meteorological conditions. The SNSWP thermal modelis being updated to account for this more recent data. In addition, a SNSWP swvey performed in December 1994 resulted in a smaller SNSWP inventory than was originally believed.

These new conditions are being incorporated into the SNSWP thermal model. The combination of utilization of the 1993 meteorological data as worst-case conditions and reduced SNSWP inventory has resulted in an increased workscope as compared to what -

was originally anticipated to fully resolve the long-term SNSWP issues. This necessitates l a change in Catawba's committed due date for resolution. As a result, the final revision to _I' calculation CNC-1150.01-00-0001 wil! not be complete by April 1,1995. It should be noted however, that Catawba has determined that in spite of the 1993 meteorological data ,

and reduced SNSWP inventory, the SNSWP continues to remain operable. l Catawba is pursuing a plan for the long-term resolution of all SNSWP issues. This plan will result in raising the minimum surface elevation of the SNSWP. This will require a change to Technical Specification 3.7.5a from 570 feet to 571 feet Mean Sea Level. Final resolution and documentation of the issues contained in this violation example (with the exception of raising the SNSWP minimum surface elevation) are scheduled for completion by August 1,1995. Catawba is presently awaiting all necess'ary environmental approvals for raising the SNSWP minimum surface elevation.

If you have any questions pertaining to this information, please call LJ. Rudy at (803) 831-3084.

Very truly yours, en

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LJR/s

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Document Control Desk l Page 3 March 27,1995 xc- S.D. Ebneter, Regional Administrator Region 11 R.J. Freudenberger, Senior Resident Inspector R E. Martin, Senior Project Manager ONRR i

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