ML20236G934

Application for Amend to License NPF-49,changing Tech Spec Section 4.7.10.e.(2), Functional Tests & Figure 4.7-1, Sample Plan 2 for Snubber Functional Test, by Deleting Reject Line on Sample Plan 2.Fee Paid

ML20236G934
Person / Time
Site:	Millstone
Issue date:	07/31/1987
From:	Mroczka E NORTHEAST NUCLEAR ENERGY CO., NORTHEAST UTILITIES
To:	NRC OFFICE OF ADMINISTRATION & RESOURCES MANAGEMENT (ARM)
Shared Package
ML20236G937	List: B12616, Proposed Tech Specs,Deleting Reject Line on Sample Plan 2 from Section 4.7.10.e.(2) Re Functional Tests & Figure 4.7-1 Re Sample Plan 2 for Snubber Functional Test ML20236G934
References
B12616, NUDOCS 8708050004
Download: ML20236G934 (4)

Text

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July 31,1987 Docket No. 50-423 B12616 Re: 10CFR50.90 U.S. Nuclear Regulatory Commission l Attn: Document Control Desk Washington, D.C. 20555

Reference:

(1) Examination and Performance Testing of Nuclear Power Plant Dynamic Restraints (Snubbers), OM4, Rev. 2, Draf t 2, March 1987. )

l Gentlemen:

s Millstone Nuclear Power Station, Unit No. 3 Proposed Revision to Technical Specifications - Snubbers i

Pursuant to 10CFR50.90, Northeast Nuclear Energy Company (NNECO) hereby proposes to amend its Operating License NPF-49 by incorporating the attached proposed changes into the Technical Specifications of Millstone Unit No. 3.

Specifically, the proposed changes to Technical Specification Section 4.7.10.e.(2)

(Functional Tests) and Figure 4.7-1 (Sample Plan No. 2 for Snubber Furictional Test) will delete the " reject" line on Sample Plan No. 2, commonly called the "37-Plan." The second sampling plan is defined by Technical Specification Section 4.7.10.e(2) and requires that a representative sample of snubbers be tested each refueling in accordance with Figure 4.7-1. Figure 4.7-1 provides the acceptance criteria method for the functional test results and denotes a " reject" region and a " continue testing" region. If at any time the plotted test results fall within this " reject" region, then all snubbers are to be functionally tested.

Surveillance Requirement 4.7.10.e(2) and its accompanying Figure 4.7-1 are being changed to delete the " reject" region on Figure 4.7-1, to substitute an expanded

" continue testin6" region, and to clarify the manner in which test results should be plotted sequentially in order of sample assignments; (i.e., each snubber should be plotted by its assigned order in the random sample, not by the order of testing).

References to the " reject" region in the text of Technical Specification Section 4.7.10.e(2) and bases 3/4.7.10 are being deleted.

Discussion Inclusion of the reject line on the 37-Plan does nothing to increase the level of n confidence in the snubber population. Its only function, when used with this plan, is to identify a " bad" snubber population early in the testing phase. Alternately, I the line could be detrimental to a good snubber population; there is a slight h4 hg

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July 31,1987 )

chance (2 percent) that the first sample of a good population could cross the reject line. This would force testing 100 percent of that population, unnecessarily.

Deletion of the line will neither decrease nor increase the level of confidence in the snubber population. The level of confidence will remain constant as good i populations (45.5 percent f ailed snubbers) will fall within the " accept" region of l the plan and bad populations (>5.5 percent failed snubbers) will continue to be I tested to 100 percent.

i Safety Evaluation NNECO has reviewed the attached proposed changes pursuant to 10CFR50.59 and has determined that they do not represent an unreviewed safety question.

Effect on Design Basis Accident Analysis The proposed changes basically redefine Surveillance Requirements 4.7.10.e(2),

Snubber Functional Test Sample Plan No. 2, to alleviate any possibility of unnecessary 100 percent testing of the Millstone Unit No. 3 snubber populations during future refueling outages.

The " reject" region only serves to identify a bad snubber population early in the test program. Deleting the " reject" region does not reduce the confidence level in l the snubber population because that is set by the " accept" region. In addition, a recent revision to the industry standard for testing snubbers (Reference (1)) was used as the guide in determining the proposed changes. This industry standard ,

does not include a " reject" region. The 37-Plan " reject" region is overly l conservative when it is applied to relatively small test populations; i.e., f 1000.

Therefore, it is appropriate to delete such a region from the snubber test programs where population size is typically in the order of hundreds, not ,

thousands. In summary, the level of confidence will remain constant a' ,thus, f the proposed changes will not increase the probability of occurrence or the consequences of an accident previously evaluated in the safety analysis.

Potential for Creation of an Unanalyzed Accident i

l There are no failure modes associated with the proposed changes. The acceptance criteria for a population of snubbers has not changed, if the population is bad, the failures versus number tested plotted in Figure 4.7-1 will remain in the " continue testing" region until all the snubbers have been tested. Based on no change in the acceptance criteria, the proposed changes will not create the possibility of an accident of a different type than any evaluated previously in the safety analysis report. 4 Effect on the Margin of Safety There are no changes to the safety limits and there is no impact on the basis of the Technical Specifications. Therefore, the proposed changes do not reduce the margin of safety as specified in the basis of any Technical Specification.

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U.S. Nuclear Regulatory Commission B12616/Page 3 July 31,1987 i Summary and Conclusions  !

Based on the foregoing assessment, the changes proposed herein are considered safe and do not represent an unreviewed safety question as defined in 10CFR50.59 since they do not:

1. Increase the frequency of occurrence or the consequences of an accident or 3 malfunction of equipment important to safety previously evaluated in the ]

safety analysis report.

2. Create the possibility of an accident or malfunction of a different type than j any evaluated previously in the safety analysis report.

3. Reduce the margin of safety as defined in the basis for any Technical j Specification. j l

Significant Hazards Consideration l

l In accordance with 10CFR50.92, NNECO has reviewed the attached proposed changes and has concluded that they do not involve a significant hazards I

consideration. The basis for this conclusion which is supported by our determinations made pursuant to 10CFR50.59. The proposed changes do not i involve a significant hazards consideration because the changes do not:

l l 1. Involve a significant increase in the probability or consequences of an accident previously evaluated. The proposed changes basically redefine Surveillance Requirements 4.7.10.e(2), Snubber Functional Test Plan No. 2, to alleviate any possibility of unnecessary 100 percent testing of the Millstone Unit No. 3 snubber populations during future refueling outages.

Deletion of the " reject" region does not reduce the confidence level in the j snubber population because that is set by " accept" region.

l 2. Create the possibility of a new or different kind of accident from any previously evaluated. There are no new failure modes associated with the proposed changes as no design changes have been made. The acceptance criteria for a population of snubbers has not changed. Therefore, the proposed changes will not increase the possibility of an accident or malfunction of a different type than any evaluated previously in the safety analysis report.

3. Involve a significant reduction in a margin of safety. Since, there are no changes to the safety 'imits and there is no impact on the basis of the Technical Specification.

Moreover, the Commission has provided guidance concerning the application of standards in 10CFR50.92 by providing certain examples (March 6,1986, FR7751) R of amendments that are considered not likely to involve significant hazards consideration. Although the proposed changes herein are not enveloped by a specific example, the proposed changes would not involve a significant increase in the probability or consequences of an accident previously analyzed. The results of safety evaluation show that deletion of the " reject" region does not reduce the confidence level in the snubber population because that is set by " accept" region, t

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. U.S. Nuclear Regulatory Commission

. B12616/Page 4 i July 31,1987 Based upon the information contained in this submittal and the environmental assessment for Millstone Unit No. 3, there are no significant radiological or nontadiological impacts associated with the proposed action and that the proposed q license amendment will not have a significant effect on the quality of the human i environment. i i

The Millstone Unit No. 3 Nuclear Review Board has reviewed and approved the f attached proposed revision and concurs with the above determinations. j In accordance with 10CFR50.91(6), NNECO is providing the State of Connecticut l with a copy of this proposed amendment.

Pursuant to the requirements of 10CFR170.12(c), enclosed with this amendment i request is the application fee of $150.

I 1 NNECO intends to select and use the Sample Plan No. 2 for the snubber functional l tests during the upcoming refueling outage scheduled in November 1987 and q future refueling outages. Therefore, NNECO requests that this proposed >

amendment be reviewed and approved by the Staff on a schedule in accordance with the start of the upcoming refueling outage. If there are any questions j regarding this submittal, please contact our licensing representative directly. j i

Very truly yours, j l NORTHEAST NUCLEAR ENERGY COMPANY l

. &t E. 3.Qczka Senior Vice Presid(/

ent cc: W. T. Russell, Regico 1 Administrator -l R. L. Ferguson, NRC Project Manager, Millstone Unit No. 3 l W. 3. Raymond, Resident Inspector, Millstone Unit No. 3 STATE OF CONNECTICUT)

) ss. Berlin COUNTY OF HARTFORD )

l Then personally appeared before me, E. 3. Mroczka, who being duly sworn, did state that he is Senior Vice President of Northeast Nuclear Energy Company, a Licensee herein, that he is authorized to execute and file the foregoing information in the name and on behalf of the Licensees herein, and that the statements contained in said information are true and correct to the best of his knowledge and belief.

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{ My ~ on Expires March 31,1988

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