ML20082R387

Supplemental Info Revising Justification for Proposed Tech Specs,Per 831024 Request for Amend to Licenses DPR-77 & DPR-79.Amend Requested Rev to Allowable Value for Diesel Generator Start & Load Shed Timer

ML20082R387
Person / Time
Site:	Sequoyah
Issue date:	12/07/1983
From:	Mills L TENNESSEE VALLEY AUTHORITY
To:	Adensam E Office of Nuclear Reactor Regulation
References
TVA-SQN-TS-50, NUDOCS 8312130147
Download: ML20082R387 (2)

Text

y s TENNESSEE VALLEY AUTHORITY CH ATTANOOGA. TENNESSEE 374ot 400 Chestnut Street Tower II December 7,1983 TVA-SQN-TS-50 Director of Nuclear Reactor Regulation Attention: Ms. E. Adensam, Chief Licensing Branch No. 4 Division of Licensing U.S. ' Nuolear Regulatory Commission Wshington, D.C. 20555

Dear Ms. Adensam:

In the Matter of ) Docket No. 50-327 Tennessee Valley Authority ) 50-328 On October 24, 1983, TVA submitted a request (TVA-SQN-TS-50) to amend the Sequoyah unit 1 and unit 2 operating licenses, DPR-77 and DPR-79. The proposed amendment requested a change in the technical specifications to revise the allowable value for the diesel generator start and load shed

-timer listed in Table 3 3-4. Enclosed is a revised justification for the proposed technical specification.

If you have any questions concerning this matter, please get in touch with J. E. Wills at FTS 858-2683 Very truly yours, 8312130147 831207 PDR ADOCK 05000327 P PDR f g

L. M. Mills, tinager Nuclear Licensing Sworn to nd subscrib before me this 7 day of ,. 1983

$ b Notary'Public ~~ gy My Commission Expires /"U Enclosure ,

cc: U.S. Nuclear Regulatory Commission (Enclosure)

Region II Attn: Mr. James P. O'Reilly Administrator 101 Marietta Street, NW, Suite 2900 Atlanta, Georgia 30303 Mr. Michael H. Mobley, Director (Enclosure)

Division of Radiological Health T.E.R.R.A. Building 150 9th Avenue North Odl Nashville, Tennessee 37203 1983-TVA SOTH ANNIVERS ARY An Equal Opportunity Employer T

ENCLOSURE s . 4

, REVISED JUSTIFICATION FOR PROPOSED TECHNICAL SPECIFICATION CHANGE TVA-SQN-TS-50 -

SEQUOYAH NUCLEAR PLANT UNITS 1 AND 2 The NRC recently approved our proposed changes (TVA-SQN-TS-36 Enclosure No. 5) to the Sequoyah unit 1 and unit 2 technical specifications (T/S) to reflect the installation of undervoltage protection for Class 1E buses.

This approval was received on May 5,1983 by Amendment 29 to Facility Operating License DPR-77 for unit 1 and by Amendment 18 to Facility Operating License DPR-79 for unit 2.

The purpose of this T/S change is to increase the tolerance in the allowable value, specified in Table 3 3-4, for the diesel generator start and load shed timer. As stated in the additional information provided to the NRC by my December 1,1982 letter, the " error associated with the timers is 3; 10 percent for timers with settings greater than or equal to 200 seconds. . . " The manufacturer can only certify a setting of + 10 percent which yields a + 30 second value for a setpoint of 300 seconds.

However, in order to achieve maximum flexibility for operations, an allowable value of 3; 60 seconds is being requested.

As previously stated by TVA in the December 1, 1982 letter, the third time delay of 300 seconds for initiation of the transfer, for the case of a long duration of undervoltage, is long enough to allow operator action, but not allow damage to connected safety-related equipment. During previous telephone discussions related to the undervoltage technical specifications, the NRC agreed that an acceptable range of time delay for operator action would be within 3 minutes (180 seconds) to 8 minutes (480 seconds). The presently requested allowable value (240 seconds to 360 seconds) is within this range. A time delay smaller than 270 seconds, the shorter allowable value certified by the manufacturer, would ensure early action of load shedding and early transfer of the shutdown board to the diesel generator, if the degraded voltage has not been corrected. The above information was the basis for NRC approval of the T/S changes for the undervoltage modifi-cations. Attachment 1 provides the significant hazards consideration

- determina tion. The proposed change was evaluated pursuant to 10 CFR 50.92 and no significant hazards considerations are involved.