ML19344F091

Application for Suppl 1 to Proposed Change 81 Amending App a Tech Specs of License DPR-28 Concerning Reactor Vessel Pressure/Temp Limitations.Class III Fee Encl

ML19344F091
Person / Time
Site:	Vermont Yankee
Issue date:	09/05/1980
From:	Heider L VERMONT YANKEE NUCLEAR POWER CORP.
To:
Shared Package
ML19344F092	List: ML19344F091 ML19344F095
References
WVY-80-128, NUDOCS 8009120401
Download: ML19344F091 (3)

Text

. Propor:d Ch:ngs 81 Supplement No, 1 e

, VERMONT Y AN KME NUCLEAR POWER CORPOR ATION SEVENTY SEVEN GROVE STREET RUTI.AND, VERMONT 05701 '

8hfl28 REPLY TO:

ENGINEERING OFFICE TURNPIKE RO AD WESTDORO. M ASSACHUSETTS 0158 8 T ELEPHONE 6 t ? 366-90 t l September 5, 1980 United States Nuclear Regulatory Commission Washington, D.C. 20555 Attention: Office of Nuclear Reactor Regulation

References:

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

(b) Proposed Change No. 81, WVY 79-94, PC-81-1, " Reactor Vessel Pressure / Temperature Limitations", August 27, 1979 (c) General Electric Licensing Topical Report NED0-21778-A;

" Transient Pressure Rises Affecting Fracture Toughness Requirements for Boiling Water Reactors", December, 1978 (d) SIL No. 14, Supplement 1, " Reactor Pressure Vessel Surveillance Program", General Electric, June 9,1980 (e) Figure 4.2-3, " Change in NDTT Versus Neutron Exposure", Vermont Yankee Nuclear Power Station Final Safety Analysis Report

Subject:

Reactor Vessel Pressure / Temperature Limitations

Dear Sir:

Pursuant to Section 50 59 of the Commission's Rules and Regulations, Vermont Yankee Nuclear Power Corporation hereby proposes the following modifications to Appendix A of the Operating License.

Proposed Change:

A change is proposed to Figure 3 6.1 (Reactor Vessel Pressure Temperature Limitations for Operation through 8.0E7 MWH(t) of the Vermont Yankee Technical Specification. This supplement supercedes in its entirety the change proposed by Reference (b). The change, included as an attachment to this letter, depicts the revised allowable heat up curves for reactor operation through a power output of 1.15E8 MWH(t). Because 10CFR50, Appendix G is currently undergoing revision and approval is anticipated in the-near future, a second version of Figure 3 6.1 is attached. This figure incorporates the requirements of the revised Appendix G and is labeled accordingly. This change deletes Figures 3 6.2 and 3 6 3 because they no longer apply. Revised bases pages 117 and 118 are provided which reflect this change.

80091204 /0/

Unit d St:t;s Nucl:2r R gulttory Commis2 ion Sept:mb:r 5, 1980 Att:ntion: Offics of Nuclocr Rccctor R;gulction Pega 2 L

Reason for Change:

NRC approval of this change will permit the continued operation of Vermont Yankee to a power output of 1.15E8 MWH(t)* Upon issuance of the next revision to 10CFR50, Appendix G, approval of the curves marked " Adjusted Per Revised 10CFR50, Appendix G" will allow the use of nuclear heat at lower temperatures. The lowar criticality temperature will decrease both vessel heat up time during start up and heat up time to reach the temperature needed for operational hydrostatic leak tests, thereby improving plant availability.

Basis for Change:

This supplement to Proposed Change 81 adjusts the curves of the attached Figure 3 6.1 to compensate for the effects of increased neutron exposure to permit operation to a power output of 1.15E8 MWH(t). This adjustment is necessary because the Change 81 curves are limited to a power output of 8.0E7 MWH(t); a value which will be reached in December, 1980.

Neutron fluence calculations for determination of RTNDT shift are based on a "K value" from Reference (d). This value is:

2 8.0E13n/CM

• 1000 MWD ( )

The RTNDT shift numbers utilized are based on FSAR curves, Reference (e).

The fSAR curves are more conservative than those curves included in Regulatory Guide 199 as the Regulatory Guide 199 curves are not applicable for the low fluences ( < 3 0E17n/cm 2 ) whien will be seen by the Vermont Yankee reactor vessel.

The second Figure 3 6.1, clearly marked as " Adjusted Per Revised 10CFR50, Appendix G", depicts lower criticality limits to allow heat up with nuclear heat. Approval of this Figure is requested upon issuance of the 10CFR50, Appendix G Revision. Based on Reference (c), the Appendix G Revision is the result of a conclusion which states that the probability of a reactor solid pressure transient concurrent with a control rod drop accident is sufficiently low such that current vessel pressure / temperature criticality limits may be lowered to allow heat up with nuclear heat.

Sa fety Considerations:

The curve shifts to accommodate a higher power output limit are based on a neutron fluence determination factor contained in Reference (d). This value is more conservative (higher) than previously calculated valves for Vermont Yankee by a factor of 4 3 Additionally, the ultimate RTNDT shift values l were derived from FSAR curves which are more conservative than those curves l contained in Regulatory Guide 1 99 Regulatory Guide 1 99 is not applicable for neutron fluer.ces less than 3 0E17niCd2 ; fluence values seen by the reactor vessel at a power output of 1.15E8 MWH(t)*

The lowered criticality temperature limit (second Figure) is based on the information contained in NED0-21778-A, Reference (d), which states that this change is acceptable based on the low probability of a water solid pressure transient and the negligible effect of lowering the criticality limits.

c-Unit:d Stctsc Nuclesr R2gulstery Commiccion Septcmbar 5, 1980

. Attsntien Offica of Nuclear R :ctor Rigulation Pigs 3 One positive aspect of the ptoposed lowering of the criticality limits is the reduction in time spent at temperatures where fracture is of concern. Such a reduction of time spent in this region would imply less chance of occurrence of a maintenance or testing operation that might inadvertently flood up and oressurize the vessel.

This submittal has been reviewed by the Vermont Yankee Nuclear Safety Audit and Review Committeet 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 has already been provided by Reference (b).

4 Schedule of Change:

This proposed change, indicated by the first version of Figure 3 6.1 attached to this letter, must be approved no later than December 1, 1980 in

order to assure continued operation within the bounds of the technical specifications. Vermont Yankee also requests that the version of Figure 3 6.1 marked " Adjusted per Revised 10CFR50, Appendix G" be reviewed and approved as soon as the proposed revision to Appendix G becomes effective.

Very truly yours, VERMONT YANKEE NUCLEAR POWER CORPORATION L. H. Heider Vice President RLS/kab COMMONWFALTH OF MASSACHUSETTS)

)ss COUNTY OF WORCESTER )

i Then personally appeared before me, L. H. Hsider, who, being duly sworn,

did state that he is a Vice President of Verm ei Yankee Nuclear Power Corporation, that he is duly authorized to exc. t3 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.

i.,_

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. [.1 * **-t [a Robert H. Groce Notary Public My Commission Expires September 14, 1984 1

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