ML19347B524

Application for Suppl 1 to Proposed Change 89 to License DPR-28,changing Tech Specs 2.1,3.1 & 4.1 Re Min Critical Heat Flux Ratio

ML19347B524
Person / Time
Site:	Vermont Yankee
Issue date:	10/07/1980
From:	Heider L VERMONT YANKEE NUCLEAR POWER CORP.
To:	Office of Nuclear Reactor Regulation
Shared Package
ML19347B525	List: ML19347B524 ML19347B526
References
WVY-80-140, NUDOCS 8010150267
Download: ML19347B524 (4)

Text

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v Proposed Changs No. 89 Supplement'1 VERMONT YAN KME NUCLEAR POWER CORPORATION SEVENTY SCVEN GROVE STREET I{tJTI.AND. VElt>10NT 05701 WVY 80-140 REPLY TO:

ENGINEERING OFFICE TURNPIKE RO AD WESTDoRO. M ASS ACHUSETTS 015 81 TELEPHONE 617-366-9011 October 7, 1980 United States Nuclear Regulatory Commission Washington, D. C. 20555 Attention: Office of Nuclear Reactor Regulatior

References:

(1) License No. DPR-28 (Docket No. 50-271)

(2) Vermont Yankee Proposed Change No. 89 (WVY-80-ll?), dated August - 19, 1980 (3) Letter, C. M. Richards (GE) to J. W. Heard (VYNPC) dated September 12, 1980

Subject:

Reload 7 Licensing Submittal, Additional Information.

Dear Sir:

Pursuant to Section 50 59 of the Commission's Rules and Regulations, Veruont Yankee Nuclear Power Corporation hereby proposes the following changes to Appendix A of the operating' license.

Proposed Change:

The changes are described on Attachment.89-S-1. Revised pages are attached.

Reason and Basis for Change:

The reasons for the. changes are described on Attachment 89-S-1. The following paragraphs,' taken from a General Electric letter (Reference (3)),

provide additional reasons.and basis.

Basis for Change:

~

The majority of General Electric .BWR's currently operating in the U.S.

were originally designed and licensed on a basis of Minimum Critical Heat Flux C010 15 02W f

United States Nuclear Regulatory Commission-Washington, D. C.~ 20555 October 7,~ 1980 Page Two 4

. Ratio (MCHFR). The MCHFR is a local phenomenon and so long as the Limiting Condition of- Operation (LCO) was defined in terms of a local phenomenon it was believed necessary to provide adjustments in' trip _ setpoints to account ' for

, power distribution effects. 'This adjustment was made by setting down the APRM ,

F scram and rod block by the ratio of Maximum Total Peaking Factor (MTPF) to Design Total Peaking Factor. (DTPF). _ In 1974 GEXL was accepted as the license basis.- GEXL. protects against departure from nucleate boiling by establishing limits on bundle power, rather than limits on local heat flux. This change effectively removed the technical need for this adjustment; however, the requirement was not deleted from the plant technical specifications.

As long as all bundles in a given core possess the same number of active fuel rods, have the same active fuel length and identical cladding heat flux  !

and bypass energy deposition fractions, administration of the set down

requirement on a peaking factor basis is relatively simple. 'With the '

j introduction of improved fuel designs (different active fuel length and number

, of active rods) the administration of' this requirement has become complex and 4

tedious.

~

Further, the different active fuel lengths also complicate the

, interpretation of the Technical Specifications. A strict interpretation of the wording in most plant technical specifications would require that APRM scram and rod block trips be set on the basis of th'e maximum total peaking factor; properly the trips should be set based on the maximum ratio of peaking factor to~ peaking factor " limit". While we believe all BWR Owners are i interpreting and administering this section properly, it is ambiguous and should be modified to remove the ambiguity.

General Electric recommends that all BWR Owners who have not already done

! so, make the following changes to their plant technical specifications:

1 Replace 'the set down factor, A/MTPF# (which is based only on the 144" fuel),

, with an equivalent factor, FRP/MFLPD## (which incorporates the effect of different fuel lengths in a slightly conservative fashion). This change will correct both of the aforementioned problems.

Safety Considerations:

l

. None of the changes' are deemed to involve significant unreviewed safety questions. Th; changes,1 in fact,, remove ambiguity from the existing sections.

This submittal has;been reviewed. by the Vermont Yankee Nuclear Safety 1 Audit and Review Committee.

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• Anis the. design peaking factor and MTPF is the maximum total

. peaking factor. Specific symbols ma/ vary in individual technical ~ specifications.

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United States Nuclear Ragulatory Commission Washington, D. C. 20555 October 7, 1980-Page Three

• • FRP is fraction of rated power and MFLPD is maximum fraction of limiting power density.

Fee Determination:

This proposed change requires an approval that involves a single safety issue and is deemed not to involve a significant hazards consideration. For these reasons, Vermont Yankee Nuclear Power Corporation proposes this change as a Class III Amendment. A payment of

$4,000.00 was forwarded with Reference (2).

Schedule of Change:

This proposed change should be approved no later than November 14, a

1980, which is the currently planned startup date for Cycle 8.

We trust you will find this submittal acceptable; however, should you have any questions, please contact us.

Very truly yours, VERMONT YANKEE NUCLEAR POWER CORPORATION WY /

L. H. Heider Vice President COMMONWEALTH OF MASSACHUSETT3)

)ss COUNTY OF WORCESTER )

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Then personally appeared before me, L. H. Heider, who, being duly sworn, did state that he is a Vice President of Vermont Yankee-Nuclear Power Corporation, that he is duly authorized to execute and file .the foregoing request in the name and on the behalf of Vermont Yankee Nuclear Power Corporation, and that the statements therein are true to the best of his

, knowledge and belief.

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. Robert H. Groce Notary Public f' *

". My Commission Expires September 14, 1984

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ATTACHMEPT 89-S-1 Description of Proposed Changes to Technical Specifications ,

e Section Location Change ,

-Reason 2.1 P.5a, Item A.l.a Replace the current A.l.a To correct a slight non-with the enclosed. conservatism in the scram settings.

2.1- 'P.6, Item B Replace the current B with To correct a slight- non-the enclosed. conservatism in the rod block settings.

2.1' 'P.14a,' Item A.l.a Replace MTPF in bases with To assure bases reflect actual MFLPD. scram settings.

2.1. P.1.4b, Item B Replace'" maximum total peaking To assure bases reflect actual factor" with " ratio of maximum rod block settings.

1 fraction of. limiting power density to fraction of rated power".

! -31 P.18, Item 3 1.B.b Replace the current 3 1.B.b with the To reflect the new limiting enclosed. safety system setting in the limiting conditions for operation.

4.1 P.18, Item 4.1.B Repla'ce the current 4.1.B with the To reflect the new limiting enclosed. condition for. operation in the ,

surveillance requirements.

4.1 P.31, Item 4.1.B Replace " peak heat flux and total To assure bases reflect actual peaking factor" with " ratio of surveillance requirements.

maximum fraction of limiting power I density to fraction of rated power".

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