ML20205R756

Application for Amend to License NPF-68,revising Tech Spec 3.1.1.2 to Specify Min Shutdown Requirement During Operation in Modes 3,4 & 5.Tech Specs Encl.Fee Paid

ML20205R756
Person / Time
Site:	Vogtle
Issue date:	03/30/1987
From:	James O'Reilly GEORGIA POWER CO.
To:	NRC OFFICE OF INFORMATION RESOURCES MANAGEMENT (IRM)
Shared Package
ML20205R759	List: ML20205R756 ML20205R825
References
SL-2136, NUDOCS 8704060432
Download: ML20205R756 (7)

Text

_ . . ~ ~

Georgia Fbw!r Company '

18 333 Piedmont Avenue

. Atlanta, Georgia 30308 -

< Telephone 404 526-7351 ,

s f x 545 .\

Atlanta, evrgla Ym2

.A cre ,

o Nv1ce I[sYde'nt March 30,1987 U. S. Nuclear Regulatory Commission SL-2136 Attention: Document Control Desk 0135m -

Washington, D.C. 20555 NRC DOCKET 50-424 OPERATING LICENSE NPF-68 .

V0GTLE ELECTRIC GENERATING PLANT - UNIT 1 REQUEST TO REVISE TECHNICAL SPECIFICATION 3.1.1.2 SHUTDOWN MARGIN - MODES 3, 4 AND 5 -

Gentlemen:

In accordance with the provisions of.10 CFR 50.90 as required.by 10 CFR 50.59(c), Georgia Power Company (GPC) hereby proposes a change to the Technical Specifications, Appendix A to Operating License NPF-68.

Technical Specification (TS) 3.1.1.2 specifies the minimum shutdown requirement during operation in Modes 3, 4, and 5. Figure 3.1-2 of this specification depicts the required shutdown margin for Mode 4 when no reactor coolant pumps are in operation, and for Mode 5 at all times. The basis for this specification is the boron dilution accident. Recently, Westinghouse revised their analysis methodology for analyzing boron dilution accidents.

Following this, Westinghouse reanalyzed the VEGP boron dilution accident, resulting in a need to increase the shutdown margin requirements shown in TS Figure 3.1-2.

Enclosure 1 provides a detailed description of the p.roposed change and '

circumstances necessitating the change request.

Enclosure 2 details the basis for our determination.that the proposed  :

change does not involve significant hazards considerations.

Enclosure 3 provides page change instructions for incorporating the proposed change into the VEGP Unit 1 Technical Specifications. .The proposed changed VEGP Unit 1 Technical Specifications pages follow Enclosure 3.-

Payment of filing fee is enclosed.

i We request that the proposed amendment,,once approved by the NRC, be issued with an allowable implementation period of 60 days. ,

se\

p \g 8704060432 870330 44 DR ADOCK O Q ,

& /** #smo  !

D U. S. Nuclear Regulatory Comission March 30,1987 Page 2 Pursuant to the requirements of 10 CFR 50.91, Mr. J. L. Ledbetter of the Environmental Protection Division of the Georgia Department of Natural Resources will be sent a copy of this letter and all applicable attachments.

Hr. James P. O'Reilly, states that he is Senior Vice President of Georgia Power Company and is authorized to execute this oath on behalf of Georgia Power Company, and that to the best of his knowledge and belief the facts set forth in this letter are true.

GEORGIA POWER COMPANY By: we s h(9 ' ke k Q Ja P. O'Reilly j

r Vice President Sworn to and subscribed before me this 4 t day of March,1967.

. f/ / ....ay rum, cw sia, we at targe y, ff, gj My Commission Expwes Sept.18,1987

/ '

Notary Public EMB/im Enclosures i

j 01315m

'.~,

r , ,.

8 U. S. Nuclear' Regulatory Commission March 30.1987 Page Three c: Georgia Power Company i Mr. R. E. Conway Mr. L.' T. Gucwa Mr. G. Bockhold, Jr.

i - Mr. J. F. D' Amico GO-NORMS Southern Company Services j Mr. J. A. Bailey 1

Shaw, Pittman,- Potts & Trowbridge '

l Mr. B. W. Churchill, Attorney-at-Law j Troutman, Sanders, Lockerman & Ashmore Mr. J. E. Joiner, Attorney-at-Law

! U. S. Nuclear Regulatory Commission Dr. J. N. Grace, Regional laministrator Mr. H. H. Livermore, Senior Resident Inspector-Construction, .Vogtle Ms. M. A. Miller, Licensing Project Manager, NRR (2 copies) '

Mr. J. F. Rogge, Senior Resident Inspector-0perations, Vogtle l Georgians Against Nuclear Energy Mr. D. Feig i i Ms. C. Stangler l

2 1

J I

i l

i 1

! 0135m <

I i .

ENCLOSURE 1 TO SL-2136 NRC DOCKET 50-424 OPERATING LICENSE NPF-68 V0GTLE ELECTRIC GENERATING PLANT - UNIT 1 REQUEST TO REVISE TECHNICAL SPECIFICATION 3.1.1.2 SHUTDOWN MARGIN - MODES 3,.4 AND 5 BASIS FOR CHANGE REQUEST Technical Specification (TS) 3.1.1.2. specifies the minimum shutdown .

requirement during operation in Modes 3, 4, and 5. -Two figures, 3.1-1 and 3.1-2, are included with this specification. Figure _3.1-1 depicts the required shutdown margin for Mode 3, and for Mode 4 when at least one reactor .

coolant pump is in operation. Figure 3.1-2 depicts the required shutdown margin for Mode 4 when no reactor coolant pumps are in operation, and for Mode 5 at all ' times.

During its review of the Diablo Canyon natural circulation test results,'the NRC staff asked several questions relative to the amount of mixing of the water _ contained within the reactor vessel . upper head and the rest of the reactor coolant system. The NRC staff took the position that under low flow, .

natural circulation conditions, the water in the upper head could become stagnant and not actively mix with the remainder of the reactor coolant.

Dissolved boron in the water within the_ upper head would, therefore, not be -

available to mitigate the consequences of a boron dilution accident. This is not a concern during operation with one or more reactor coolant pumps running i as the reactor coolant flow is sufficient to ensure adequate mixing.  ;

Credit for the boron contained in the water within the vessel upper head was H taken in conducting the FSAR boron dilution accident analysis. Due to the new NRC Staff position Westinghouse has reanalyzed the VEGP boron dilution -

accident for Modes 4 and 5 when no reactor coolant pumps are in operation._ In the reanalysis, credit for the boron contained in the water within the vessel upper head was eliminated.

The safety design bases ~ for the boron dilution accident are discussed in FSAR Section 15.4.6. For dilution events during hot standby, hot shutdown, and cold shutdown (Modes 3, 4, and 5), TS 3.1.1.2 specifies the required shutdown margin as a function of RCS boron concentration. The specified shutdown margin ensures that the operator has a minimum of 15 minutes from the time of the high flux at shutdown alarm to the total loss of shutdown margin. A reduced active mixing volume results in a reduction of this time available to the operator. By increasing the boron requirement, the time between the high flux at shutdown alarm and total loss of shutdown margin.is increased and the safety design bases are met.

The boron dilution accident for Vogtle has been reanalyzed to exclude the 1 water within the vessel upper head for the condition when no reactor coolant pumps are in operation. This reanalysis has resulted in a slightly increased boron requirement as shown in revised TS Figure 3.1-2. The title for TS Figure 3.1-2 has also been revised to be consistent with the reanalysis and with TS 3.4.1.3.

0135m El-1 3/30/87

ENCLOSURE 2 TO SL-2136 NRC DOCKET 50-424 OPERATING LICENSE NPF-68 V0GTLE ELECTRIC GENERATING PLANT - UNIT 1 REQUEST TO REVISE TECHNICAL SPECIFICATION 3.1.1.2 SHUTDOWN MARGIN - MODES 3, 4 AND 5 10 CFR 50.92 EVALUATION Pursuant to 10 CFR 50.92, Georgia Power Company has evaluated the attached proposed amendment to the VEGP Unit 1 Technical Specifications and has determined that its adoption would not involve significant hazards considerations. The basis for the determination is as follows:

Proposed Change:

This change increases the required shutdown margin under low reactor coolant flow conditions, e.g. Mode 4 when no reactor coolant pumps are in operation, and Mode 5.

Basis:

The proposed change does not involve a significant hazards consideration because operation of VEGP Unit 1 in accordance with this change would not:

(1 ) involve a significant increase in the probability or consequences of an accident previously evaluated. This change merely increases the required shutdown margin during periods of low reactor coolant flow. The increase in shutdown margin counteracts a decrease in the assumed active mixing volume available to mitigate the consequences of a boron dilution event from that previously analyzed.

(2) create the possibility of a new or different kind of accident from any accident previously evaluated. This increase in shutdown margin requirement does not create the possibility of a new or different kind of accident.

. (3) involve a significant reduction in a margin of safety. The change in shutdown margin does not reduce a margin of safety as the previous safety design bases are shown to be met.

The previous VEGP boron dilution accident analysis was reviewed by the NRC and found to be acceptable as discussed in Section 15.4.6 of the Safety Evaluation Report (NUREG-1137). The analysis methodology used by Westinghouse included credit for the boron within the reactor vessel upper head. In response to NRC questions on recently acquired natural circulation test results, Westinghouse revised their analysis methodology to eliminate this boron credit.

0135m E2-1 3/30/87-

\~ .

ENCLOSURE 2 TO SL-2136 NRC DOCKET 50-424 OPERATING LICENSE NPF-68 V0GTLE ELECTRIC GENERATING PLANT - UNIT 1 REQUEST TO REVISE TECHNICAL SPECIFICATION 3.1.1.2 SHUTDOWN MARGIN - MODE 3 4 AND 5 10 CFR 50.92 EVALUATION The change in the analysis methodology involves only the deletion of the reactor vessel upper head volume from the active mixing volume available for mitigation of the boron dilution event. Deletion of this credit is a conservative change to the analysis. With reduced mixing volume, the time available to the operator to preclude the event is reduced. By increasing the boron requirement, the time between the high flux at shutdown alarm and total loss of shutdown margin is increased and the safety design bases are met.

l Therefore, based on the above considerations, Georgia Power Company has determined that this change does not involve a significant hazards consideration.

i l

l 0135m E2-2 3/30/87

ENCLOSURE 3 TO SL-2136 NRC DOCKET 50-424 OPERATING LICENSE NPF-68 V0GTLE ELECTRIC GENERATING PLANT - UNIT 1 REQUEST TO REVISE TECHNICAL SPECIFICATION 3.1.1.2 SHUTDOWN MARGIN - MODES 3, 4 AND 5 INSTRUCTIONS FOR INCORPORATION Q

The proposed change to the Technical Specifications (Appendix A to Operating License NPF-68) would be incorporated as follows:

Remove Page Insert Page

! IV IV 3/41-3b 3/4 1-3b i

i

)

i 1

l i

l i i Ol35m E3-1 3/30/87 l

- . _ . _ ~ - . .. . . _ _ ~ . _ . . _ _ - . . _ _ _ _ . - _ - - - _ . , _ _- . .