ML20107E359

Application for Amends to Licenses NPF-4 & NPF-7,revising Tech Specs to Allow Use of Improved Fuel Rod Bowing Evaluation Methodology to Reduce Rod Bow Penalty on Nuclear Enthalpy Hot Channel Factor.Fee Paid

ML20107E359
Person / Time
Site:	North Anna
Issue date:	02/14/1985
From:	Stewart W VIRGINIA POWER (VIRGINIA ELECTRIC & POWER CO.)
To:	Harold Denton, John Miller Office of Nuclear Reactor Regulation
Shared Package
ML20107E361	List: ML20107E359 ML20107E374
References
731, NUDOCS 8502250542
Download: ML20107E359 (8)

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VIRGINIA ELECTRIC AND PowsR COMPANY RIcuxoxu, VIRGINIA 23261 W.L.SrawAmr yd*,"d7[,7,1, February 14, 1985 Mr. Harold R. Denton, Director Serial No. 731 Office of Nuclear Reactor Regulation PSE/RCA/mjp/2002N Attn:

Mr. James R. Miller, Chief Docket Nos.:

50-338 Operating Reactors Branch No. 3 50-339 Division of Licensing License Nos.: NPF-4 U. S. Nuclear Regulatory Commission NPF-7 Washington, D.C.

20555 Gentlemen:

AMENDMENT TO OPERATING LICENSES NPF-4 AND NPF-7 NORTH ANNA POWER STATION UNIT NOS. 1 AND 2 PROPOSED TECHNICAL SPECIFICATION CHANGE Pursuant to 10CFR50.90, the Virginia Electric and Power Company requests an amendment, in the form of changes to the Technical Specifications, to Operating License Nos. NPF-4 and NPF-7 for the North Anna Power Station Units 1 and 2.

Through the use of an improved fuel rod bowing evaluation methodology, Westinghouse has successfully demonstrated to the NRC that the existing rod bow penalty on 17x17 R-grid fuel can be reduced. Vepco proposes to employ this N.iminate the Rod Bow Penalty on the nuclear enthalpy hot channel el benefit t 4H is the safety evaluation for the proposed change, factor, F which permits a simplification of the plant Technical Specifications. The proposed Technical Specifications are presented in Enclosure 2.

This request has been reviewed and approved by the Station Nuclear Safety and 0perating Committee and the Safety Evaluation and Control Staff.

It has been determined that this request does not involve any unreviewed safety questions as defined in 10CFR50.59 or a significant hazards consideration as defined in 10CFR50.92.

We have evaluated this request in accordance with the criteria in 10CFR170.12. A voucher check in the amount of $150.00 is enclosed as an application fee.

V t

yours, L&

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W. L.

tewart f

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r1 ErwiA Er.scrate Axn POwra COMPANY TO V

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- Enclosures (1). Safety Evaluation for Proposed Rod Bow Penalty Changes

. (2) Proposed Technical Specifications Changes (3) Voucher Check for $150.00 cc: Mr. James P. O'Reilly

. Regional Administrator Region II Mr. Leon B. Engle NRC - Project Manager - North Anna Operating Reactors Branch No. 3 Division of Licensing Mr. M. W. Branch NRC Resident Inspector North Anna Power Station Mr. Charles Price

Department of Health 109 Governor Street

' Richmond, Virginia -23219 E

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CG000NWEALTH OF VIRGINIA )

)

CITY OF RICHMOND

)

The foregoing document was acknowledged before me, in and for the City and Commonwealth aforesaid, today by W.

L.

Stewart who is Vice President Nuclear Operations, of the Virginia Electric and Power Company.

He is duly authorized to execute and file the foregoing document in behalf of that Company, and the statements in the document are true to the best of his knowledge and belief.

W Acknowledged before se this /Y day of M

, 19 A - 7 /-

19 Y,

My Commission expires:

L 6. 7h cM Notary Public (SEAL) s/ col

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J ENCLOSURE 1 1

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F PAGE 1

Safety Evaluation An improved Westinghouse methodology to analyze the effect of fuel rod bowing was presented in References 1,

2 and 3 and approved by the NRC in Reference 4.

VEPC0 intends to apply the results of these methods to determine the departure from nucleate boiling ratio (DNBR) effects of rod bou for the North Anna power Station Units 1 and 2,

which are fueled-with Westinghouse standard 17x17 fuel assemblies.

VEPCO will continue to use a

conservative design uncertainty (FSU) value of 1.0815 (1,05 x 1.03) for evaluation and measurement of the total overall peaking factor FS, even though a smaller value can be justified based on the information presented in Figure 3 (Response to Suestion 33) of Reference 3.

This. Figure is the replacement for Figure 6-1 of Reference 1.

The total retained DNBR Margin for 17 x 17 fuel has been quantified to be 9.1%

(Ref. 3 and 5). The component parts of this margin are identified in the attached Table 1,

taken from Reference 5.

The new R-grid-rod how DNBR penalties shown in Figure 2 (Response to Suestion 33) of Reference 3

are substantially less than the

. retained 9.1X margin.

Therefore, the removal of the Fdh rod bou penalty -currently being applied in the North Anna Units 1 and 2 Technical Specifications is justifiable based on the

" adequate

(

additional. margin available.

This Fdh reduction had been used to r.

I partially offset the previous (Ref 6) DNBR rod bou penalties of 11.4X i

(full; flow) and 14X (low flow) associated with 85X gay closure data.

Attached are the revised North Anna Unit 1

and 2

Technical i'

r s

PAGE 2

Specifications which incorporate this change.

As a

result of our evaluation, we have determined that the implementation of the updated rod bow penalty and the removal of the Technical Specification Fdh rod bow penalty for North Anna does not result in an unreviewed safety question as defined in 10CTR50.59.

In

addition, the change does not involve a

"significant hazards consideration".

There is a reduction of the retained DNBR margin due to the removal of the Fdh rod how penalty from the Technical Specifications; however, this is compensated for by implementation of the NRC-approved rod bow penalties, which enable a commensurate level of safety to be maintained.

E

PAGE 3

Table 1: Retained DNBR Margin W Standard 17 x 17 Fuel 1.28 DNBR vs. 1.30 DNBR 1.6X DNB correlation multiplier 1.7X 0.865 vs. 0.88 TDC.038 vs..051 1.2%

Pitch Reduction 1.7%

Extra Grid 2.9%

Total Retained Margin 9.1%

O

PAGE 4

References 1.

J.

Skaritka, et al.,

" Fuel Rod Bow Evaluation", WCAP-8691 Rev 1,

(Proprietary) and WCAP-8692 Rev. 1 (Non-Proprietary), July 1979.

2.

Letter, E.

P.

Rahe, Jr.

(W) to de R.

Miller (HRC), " Partial

Response

to Request Number 1

for Additional Information on WCAP-8691 Rev.

1,"

NS-EPR-2515, dated October 9,

1981, 3.

Letter, E.

P.

Rahe, Jr. (W) to J.

R.

Miller (NRC), " Remaining

Response

to Request Number 1

for Additional Information on WCAP-8691 Rev.

1,"

NS-EPR-2572, dated March 16, 1982.

4.

Letter, C.

O.

Thomas (NRC) to E.

P.

Rahe, Jr. (W), " Acceptance for Referencing of Licensing Topical Report WCAP-8691(P)./

WCAP-8692(NP)," dated December 29,1982.

5.

Letter,-

C.

Eicheldingar (W) to V.

Stello, Jr. (NRC), MS-CE-1161, August 13, 1976.

6.

Letter, T.

M.

Anderson (W) to J.

F.

Stolz (NRC), MS-TMA-2053, dated March 16, 1979.

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