ML20003C300

Application to Amend License DPR-28,incorporating Proposed Stability & Recirculation Pump Trip Tests.Forwards Proposed Tech Specs & NEDO-24279, VT Yankee Nuclear Power Station Proposed Stability & Recirculation Pump Trip Tests.

ML20003C300
Person / Time
Site:	Vermont Yankee
Issue date:	02/12/1981
From:	Heider L VERMONT YANKEE NUCLEAR POWER CORP.
To:	Office of Nuclear Reactor Regulation
Shared Package
ML20003C301	List: ML20003C300 ML20003C302 ML20003C303
References
FVY-81-28, NUDOCS 8102270608
Download: ML20003C300 (3)

Text

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Proposed Change 92 V ICit 510NT Y A N l{ ICIC N lTCIslCA IR I'OW EIR ('t )liI'014 ATI()N SEVENTY SEVEN GROVE STREET 2.C.15.1 l(UTI. AND. VEIO10NT 03701 FVY 81-28

,y ,, c , y o ENGINEERING OFFICE T URNPIKE RO AD W EST DO RO. M ASS AC HUSET TS 015 81 T ,' L , PH O N S 6 9 F 3 6 6 9 0 ft 1,

4 February 12, 1981 >

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United States Nuclear Regulatory Commission ,

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Washington, D.C. 20555 u i, Attention: Office of Nuclear Reactor Regulation 2

References:

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

(2) Ceneral Electric Company, Vermont Yankee Nuclear Power Station Proposed Stability and Recirculation Pump Trip Test, NEDO-24279, 80 NED 283, January 1981

Subject:

Proposed Stability and Recirculation Pump Trip Test

Dear Sir:

Pursuant to Section 50.59 of the Commission's Rules and Regulations, Vermont Yankee hereby proposes the following changes to Appendix A of the Operating License.

s PROPOSED CHANGE: The changes are described on Attachment 1. Revised Technical Specification pages are included.

REASON FOR CHANCE: The above changes are required to perform the proposed stability and recirculation pump trip tests described in Reference 2. The stability tests are being performed to provide data for support of Vermont f Yankee stability performance and for qualification of stability models.

The proposed test includes points at natural circulation high power conditions where data is currently lacking. The objective of the recirculation pump trip is to provide data for qualification of Vermont Yankee's operational transient model. The results of these tests will be used for licensing support. Specific reasons for each change are described on Attachment 1.

BASIS FOR CHANGE: The basis for the changes is provided in Reference 2.

SAFETY CONSIDERATION: None of the changes are deemed to involve unreviewed safety questions.

All changes are related to the performance of the proposed stability and recirculation pump trip test. Strict test procedures will assura safe plant operation during the proposed test. Although the actual time at natural 810227O A e

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i U.S. Nuclear Regulatory Cormission February 12, 1981 Attn: Office of Nuclear Reactor Regulation Page 2 circulation is expected to be less than 48 hours5.555556e-4 days <br />0.0133 hours <br />7.936508e-5 weeks <br />1.8264e-5 months <br />, the entire test may take up to 7 days due to utility system electrical load requirements.

The change to allow intentional operation in the natural circulation mode

~

is a prerequisite to performing the pump trip test and three of the four stability test points. The pump trip test is to be performed under operating i limits which are based on postulated transients having a more severe effect on fuel thermal limits than the proposed test. Stability test points VPT2 and VPT3 (Figure 2-1, Reference 2) lie within the bounds of previous stability' analysis and have a decay ratio less than 1.0. Test point VPT4 is expected to be just below or at the threshold of instability. Special precaution will be taken to limit the magnitude of any APRM oscillation to +15% and to avoid a resonant response in the reactor control system.

i (Section 2.2, Reference 2).

The changes to the RBM rod block, the APRM rod block and APRM flux scram trip settings while in the run mode at natural circulation conditions are

, Reference 2) may be

. necessary to assure that test point VPT4 (Figure 2 1 reached and to avoid an inadvertent scram during testing. Special LOCA and MCPR limits' consistent with the most limiting condition of operation for the natural circulation stability test points have been defined.

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'The removal of the standard MCPR multiplier, .Kf , for stability testing at natural circulation conditions is justified. The purpose of the Kg factor is to ' provide required thermal margin to protect against a slow flow increase

! transient (where a flux' scram does not occur). Special test procedures will address pump starting at natural circulation conditions and thus provide protection'against a flow increase transient without the Kf factor. The MCPR limits for the special stability testing at natural circulation are based on limiting transients from VPI4, Lthe highest power stability test

-  ; point. These limits include an arbitrary additional margin of 0.05 in delta CPR to the delta CPR results of the analysis (Reference 2).

The flow biased APRM Rod Block normally provides the LOCA margin required for operation at reduced flow. This assurance will be diminished when the APRM rod block trip is increased, therefore special restrictions 4

on MAPLHGR's are required for operations in that mode. After adjustment 2

of the APRM . Rod Block ' setting, the MAPLHGR's shall be 80% of the limits

, specified in Tables 3.11-1A through G.

To minimize the risk of inadvertently tripping the plant during the conduct of these tests, Vermont Yankee requests relief similar ' to that -

provided to perform various Surveillance Tests under Technical j- Specifications. Specifically, relief must be granted to permit bypassing l of any effected trip function for those moments when.the test instrumentation is installed or removed at the station. The required trip functions shall be.otherwise operable during the test.

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U.S. Nuclear Regulatory Commission February 12, 1981 Attn: Office of Nuclear Reactor Regulation Page 3 An evaluation of this change has been made and it has been concluded that the change does not present significant hazards not described or implicit in the safety analysis report and does not involve an unreviewed safety question as described in 10CFR50.59.

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

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 is enclosed.

SCHEDULE OF CHANGES: This proposed change should be approved no later than February 27, 1981. Upon approval of the above, it is our intent to perform the proposed test (Reference 2) during the first rod pattern exchange in Cycle 8.

We trust you will find this submittal acceptable; hcwever, should

-you have any questions, please contact us.

Very truly yours, VERMONT YANKEE NUCLEAR POWER CORPORATION NY L. H. Heider Vice President COMMONWEALTH OF MASSACHUSETTS)-

)ss COUNTY OF WORCESTER )

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.

-'ej, .p

',c sNh Robert H. Groce Notary Public

' f * (?q, i. f" My Commission Expires September 14, 1984

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