ML20203Q303

Application for Amend to License DPR-36,incorporating Proposed Change 122,revising Tech Specs Turbine Valve Test Frequencies.Supporting Documentation Encl.Fee Paid

ML20203Q303
Person / Time
Site:	Maine Yankee
Issue date:	05/05/1986
From:	Randazza J Maine Yankee
To:	NRC OFFICE OF ADMINISTRATION (ADM)
Shared Package
ML20203Q304	List: ML20203Q303 ML20203Q318
References
6997L-FWS, MN-86-55, NUDOCS 8605090225
Download: ML20203Q303 (5)

Text

-

MAIRE HARHEE ATOMICPOWERCOMPARSe ,uous,aj,?, gT,%

g (207) 623-3521 e

May 5, 1986 HN-86-55 Proposed Change #122 Director of Nuclear Reactor Regulation United States Nuclear Regulatory Commission Washington, D. C. 20555 Attention: Document Control Desk

References:

(a) License No. DPR-36 (Docket No. 50-309)

Subj ect: Proposed Technical Specification Concerning Turbine Valve Test Frequencies Gentlemen:

In accordance with the Rules of the Commission, Maine Yankee proposes to modify our Technical Specifications concerning Turbine Valve test frequencies.

He request that the enclosed Table 4.2-2 replace the existing Table. This change will bring surveillance frequencies for the Turbine Valves in line with the requirements for Excess Flow Check Valve testing set forth in Specification 4.6. .

This request is consistent with the Commission's interest in improving Technical Specifications, by reducing the number of unnecessary or duplicative requirements, while retaining those which are necessary for the protection of the public health and safety. NUREG-1024 (Technical Specification - Enhancing the Safety Impact) makes a strong case that testing beyond that necessary to assure proper operation may be adverse to safety. The NUREG identifies turbine valve testing frequency as one example which should be considered as a candidate for relaxation. He believe the relaxation requested is prudent and will result (as the NUREG-1024 Task Force puts it) in "an overall positive benefit to plant safety in that the risk of a test-induced plant transient would be reduced".

In over 13 years of commercial operation, we have experienced only one failure of a turbine valve to pass its required surveillance test. Since the valves are redundant, such a single failure would not have had any adverse consequences. During the same period, we have experienced at least four trips clearly associated with turbine valve testing (See Attachment 1). As noted in the NUREG, plant trips are often precursors to events of more significant safety consequences.

6997L-FHS g m" N Manr P

% 4$904

M AINE YANKEE AVOMIC POWER COMPONY (Jnited States Nuclear Regulatory Commission Page Tao Attention: Document Control Desk HN-86-55 Hith regard to the matter of significant hazards considerations, we have evaluated this proposed change as required by 10 CFR 50.92. He concluded that no significant hazards consideration exists. Our analysis is attached to this letter as Attachment 1.

This Proposed Change has been reviewed and approved by the Plant Operation and Review Committee. The Nuclear Safety Audit and Review Committee has also reviewed this submittal. A representative of the State of Maine is being informed of this request by a copy of this letter.

He request that this proposed change be made effective thirty days after issuance.

An application fee of $150.00 is enclosed.

Very truly yours, MAINE YANKEE ATOMIC P0HER COMPANY

- N -

John B. Randazza Executive Vice President FHS/bjp Attachments cc: Mr. Ashok C. Thadani Dr. Thomas E. Hurley Mr. Cornelius F. Holden Mr. Clough Toppan, State of Maine STATE OF MAINE Then personally appeared before me, John B. Randazza, who being duly sworn did state that he is Executive Vice President of Haine Yankee Atomic Power Company, that he is duly authorized to execute and file the foregoing request in the name and on behalf of Maine Yankee Atomic Power Company, and that the statements therein are true to the best of his knowledge and belief.

/ *

/' / Notary Public EENeucE.

MY C0em4ssl04 EXPmES DCTOBER 3.1992-6997L-FHS

MAINE YANKEE ATOMIC POWER COMPANY ATTACHMENT 1 Significant Hazards Consideration Evaluation Summary

1. Hill this change significantly increase the probability or consequences of a previously analyzed accident?

No. A decrease in the frequency of turbine valve testing will not significantly increase the probability of any previously analyzed accident, and should improve plant safety by decreasing the probability of a test-induced plant trip.

Turbine valve failures can result in an uncontrolled cooldown or a turbine overspeed. Each steam supply line contains two valves in series (e.g., a governor valve and a stop valve). Maine Yankee has never experienced the concurrent failure of two valves. Under the monthly testing frequency, we have observed only one instance of a valve failing to pass a surveillance test in over thirteen years of comercial generation.

Maine Yankee's Emergency Operating Procedures (both present and the revision being prepared) directs operators to assure that all turbine "

valves are closed following a trip. If not closed, the operator is to close the excess flow check valves, thus terminating any possibility of excessive cooling. In addition, the valves close automatically on steam low pressure if the cooldown were allowed to progress to approximately 460*F.

Plant trips can be precursors to events of more significant safety consequences. During the thirteen years of commercial operation, Maine Yankee has experienced at least four trips clearly associated with turbine valve testing.

2. Hill this change create the possibility of a new or different kind of accident from any accident previcusly analyzed?

No. Since only the frequency of testing will be altered under this proposed change, no new potential accident sequences are created.

3. Hill this change significantly decrease any margin of safety?

No. Since only the frequency of testing and not the nature of the tests

will be altered, this change will have no adverse affect on any margin of

! safety.

A brief review of plant trips identified at least four which were readily attributable to actions associated with turbine valve testing. Therefore, we conclude that this change will likely result in an overall improvement in plant safety by decreasing the number of times the plant is at risk of a spurious trip induced by the test procedure.

l l

l 6997L-FHS i

o

M AINE YANKEE QTOMIC POWEft COMPONY ATTACHMENT 2 Page Change List Remove Existing Page 4.2-4 and replace with the enclosed page 4.2-4.

6997L-FHS

MAINE YANKEE ATOMIC POWER COMPANY ATTACHMENT 3 Proposed Technical Specifications 6997L-FHS

..