ML20205M961

Application for Amend to License DPR-36,consisting of Proposed Change 133,modifying Specified Surveillance Interval for Control Element Assembly Partial Movement Test from Once Every 2 Wks to Monthly.Fee Paid

ML20205M961
Person / Time
Site:	Maine Yankee
Issue date:	10/18/1988
From:	Randazza J Maine Yankee
To:	NRC OFFICE OF ADMINISTRATION & RESOURCES MANAGEMENT (ARM)
Shared Package
ML20205M965	List: ML20205M961 ML20205M975
References
MN-88-29, NUDOCS 8811030374
Download: ML20205M961 (4)

Text

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[. MaineYankee RELIABLE I.ECTRCTY FOR MA NE S'NCE 1972 t' EDISON DRIVE e AUGUSTA, MAINE 04330. (207) 622-4868 October 18, 1988 Proposed Change #133 HN-88-29 United States Nuclear Regulatory Commission Attention: Document Control Desk Hashington, D. C. 20555

Reference:

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

Subject:

Proposed Change #133 - Control Element Assembly (CEA) Test Frequency Gentlemen:

The proposed change would modify Technical Specification 4.2, "Equipment and Sampling Tests", which provides testing requirements for selected plant equipment. The proposed change modifies the specified survelliance interval for the Control Element Assembly (CEA) partial movement test in Table 4.2-2 from performance once every two weeks to monthly to agree with the Combustion Engineering standard technical specifications.

Technical Specification requirements for CEA partial movement tests are provided to ensure that mechanical binding does not develop among the CEA's and go undetected.

During the time from 1972 to 1988, Maine Yankee has conducted more than 300 CEA partial movement tests. He have never found a CEA that would not have tripped on demand during any of these tests. However, we have had many instances of a dropped CEA during these tests. Changing the test frequency from every two weeks to monthly will reduce the frequency of dropped CEA induced plant transients. This will increase plant reliability while still providing adequate assurance that any CEA mechanical binding 'muld be detected in a timely fashion.

An evaluation of the safety impact of the proposed change has been conducted and is enclosed as Attachment 1. The evaluation demonstrates that less frequent testing will cause fewer plant transients and challenges to plant systems due to dropped rods while having an insignificant effect on the probability of the CEA's failure to insert on demand. Also, the evaluation shows that the proposed change has an insignificant effect on plant safety.

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MaineYankee linited' States Nuclear i<egulatory Commission Page Two 1 Attention: Document Control Desk HN-88-29 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 2.

This proposed change has beeri 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 Haine is being informed of this request by a copy of this letter. ,

He request that this proposed change be made effective immediately upon issuance.

An application fee of $150.00 is enclosed.  !

Very truly yours, 4

HAINE YANKEE John B. Randazza 1

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Presider.t JBR/bjp Attachment

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cc: Mr. Richard H. Hessman Mr. William T. Russell i i Hr. Cornelius F. Holden t Mr. Pat Sears Mr. Clough Toppan STATE OF HAINE i

1 Then personally appeared before me, John B. Randazza, who being duly sworn  !

did state that he is President of Maine Yankee Atomic Power Company, that he  !'

is duly authorized to execute and file the foregoing request in the name and '

on behalf of Haine Yankee Atomic Power Company, and that the statements therein are true to the best of his knowledge and belief.

0'8 AY,b Y s Notary Public ,

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MaineYankee ATTACHMENT 1 SAFETY IMPACT OF CHANGING CEA PARTIAL HOVEHF.NT TEST FREQUENCY The purpose of conducting the CEA movement tests is to detect mechanical binding of the CEA's. By roving the CEA's we ensure that they are free to move and free to insert on demand.

The NRC has previously approved Control Element Assembly (CEA) partial '

movement testing on a monthly interval by acceptance of the CE standard Technical Specifications (NUREG-0212, Rev. 2). Thirteen operating CE NSSS plants utilize magnetic jack drive mechanisms for CEA motion control. Of  ;

these thirteen plants, only Maine Yankee conducts CEA partial movement tests every two weeks. The other twelve plants conduct monthly tests.

The few instances of stuck or sluggish CEA's that have occurred at CE plants in the past were limited to a single mechanism and occurred predominantly at nearly the full in position. Changing to a monthly test interval will not change this. Therefore, the probability that enough CEA's (sufficient to effect subcriticality) fail to insert on demand is not affected.

Prior to reactor startup after refueling shutdowns, we are required to 7 conduct a startup test program. As a part of this test, control rod drop  :

times are measured. Any mechanical binding or misalignment resulting from shutdown maintenance would be detected at this time. Thus, at the time of l

! startup, we are assured that all CEA's are free to insart.

On the other hand, less frequent testing results in fewer dropped CEA induced transients. Dropped CEA's require operator actions and often cause power reductions which generate radioactive waste. Although none of these issues are safety problems, it is beneficial to maintain steady state operations from a plant safety point of view. Thus the change to a monthly CEA test interval will result in an improvement in plant safety.

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MaineYankee ATTACHMENT 2 NO SIGNIFICANT HAZARDS EVALUATION The proposed change does not involve a significant hazards consideration because operation of Maine Yankee per this change would not:

1. Involve a significant increase in the probability or consequences of an accident previously evaluated. As stated in the evaluation of Attachment 1, the proposed change is expected to have an insignificant impact on plant and public safety. After 15 years of operation, ano more than 300 Control Element Assembly (CEA) partial movement tests, we have never found a CEA that would not have tripped c.) demand.

Further, it is expected than any potential failure mechanism would develop slowly over time. Therefore, a change from a two week to a monthly test interval is expected to have little or no impact on the [

orobability of finding a significant number of mechanically stuck CEA's during a test. Also, changing the frequency at which CEAs are tested has no impact on the consequences of a fail to scram accident.

No safety systems or functions relied on to mitigate the consequences of such an event will be affected by this change. Therefore, we believe that the proposed amendment to increase the Control Element Assembly partial movement test interval does not involve a significant 4

increase in the probability or consequences of an accident previously evaluated.

2. Create the possibility of a new or different kind of accident from any accident previously evaluated. The proposed amendment changes the frequency at which CEA's are tested. Changing the frequency of CEA testing does not result in a chang 9 in the failure modes of the CEA's. Therefore, the proposed amendment does not create the possibility of a new or different kind of accident from any accident previously evaluated, i

3. Involve a significant reduction in a margin to safety. The change, in the margin to safety is expected to be so small that it is '

insignificant. Relaxation of the existing CEA partial movement test i interval can be obtained without increasing CEA failure to scram probabilities above those previously accepted by the NRC. The NRC has approved operation of other CE plants in accordance with CE standard  ;

Technical Specifications and this change is in accordance with the CE standard Technical Specifications. Therefore, the proposed amendment does not involve a significant reduction in a margin to safety. In fact, a reduction in the number of dropped rod transients may enhance ,

overall safety.

Based upon the above considerations, Maine Yankee has determined that this change does not involve a significant hazards consideration.

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