ML19306H415
| ML19306H415 | |
| Person / Time | |
|---|---|
| Site: | Millstone  |
| Issue date: | 04/07/1988 |
| From: | Office of Nuclear Reactor Regulation |
| To: | |
| Shared Package | |
| ML19306H414 | List: |
| References | |
| NUDOCS 8804200238 | |
| Download: ML19306H415 (2) | |
Text
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UNITED STATES
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j NUCLEAR REGULATORY COMMISSION E
WASHINGTON, D. C. 20555 g
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SAFETY EVALUATION BY THE OFFICE OF NUCLEAR REACTOR REGULATION s
RELATED TO AMENDMENT N0.16 TO FACILITY OPERATING LICENSE NO. NPF 49 NCRTHEAST NUCLEAP ENERGY COMPANY, ET AL.
MILLSTONE NUCLEAR POL'ER STATION, UNIT NO. 3 DOCKET NO. 50-423 I
INTRODUCTION l
l By letter dated July 31, 1987, the Northeast Nuclear Energy Company (licensee) preposed changes to surveillance requirements in the Millstone Unit 3 Technical I
Requirement 3/4.7.10 snubbers. This section allows the licensee to choose from three sample plans. Sample plan 2, as described in Section 4.7.10.e.2),
would he changed to remove the threshold criteria that requires all snubbers of one type be tested if the number of failures exceed about 10% of the sample.
In addition, the plotting of the test results would se changed to be by assigned order in the random sample rather than by the order of testing.
EVALUATION 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 Functional l
Test" will delete the " reject" line on Figure 4.7-1.
Figure 4.7-1 provides l
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 accompany-ing Figure 4.7-1 are being changed to delete the "rej2ct" region on Figure 4.7-1, to substitute an ex;:anded " continue testing *. qion, and to clarify the manner in which test results should be plotted sequentially in order of sample assignments; fi.e., each snubber should be plotted by its assigned order in the random sample, not by the order of testing). References tc the " reject" region in the test of Technical Specification Section 4.7.10.e.2) and Bases 3/4.7.10 are also being deleted.
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0 The acceptance criteria frepresented by Figure a.7-1 in the Technical Specifications) were developed using "Wald's Sequential Prebability Ration Plan". Statistical studies using Wald's sequential sampling plan indicate that a major change in the reject line caused an insignificant change in the accept lire or in cther words acceptarce is independent of rejection. These studies also demcnstrate that while the prcbability of false ecceptance of a l
tad snubber pcpulation under the proposed amendnent still exists it is negligible. As long as the " reject" line remains in the sample plan there is sore pessibility of rejecting a gcod snubber population and consequently requiring an unnecessary 1001 functional testing of snubbers with ettendant ALARA and safety concerns, manpower utilization and outage extension. The proposed technical specification change will alleviate these problems and j
still ensure continued or additional testing if snubber quality of failed s
i snubbers is equal to or greater than 5%.
f The changes proposed by the licensee have been reviewed by the staff and have been found to be acceptable because they will eliminate unnecessary testing of
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snubbers resulting in reduced man-rem exposure without undermining the effectiveness of the overall surveillance program.
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. ENVIRONMENT /.L CONSIDERATION 1
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1 This amendment changes surveillance requirements. The staff has determined thit the amendment involves no significant increase in the amounts, and no 1
significant change in the types, of any effluents that may be released l
offsite, and that there is no significant increase in individual or cumulative i
occupational radiation exposure. The Comission has previously published a l
proposed fir ~ing that the amendment involves no significant hazards j
consideration and there has been no public coment on such finding.
Accordingly, the amendment meets the eligibility criteria for categorical exclusion set forth in 10 CFR 51.22(c)(9). Pursuant to 10 CFR 51.2?fb), no J
environmental impact statetent or environnental assessment need be prepared 1
in connection with the issuance of the amendnent.
i CONCLllSION i
We have concluded, based on the considerations discussed above, that (1) i there is reasonable assurance that the health and safety of the public i
will not be endangered by operation in the proposed manner, and (2) such 1
activities will be conducted in compliance with the Comission's i
i regulations, and the issuance of the amendment will not be inimical to j
the comen defense and security or to the health and safety of the public.
3 Dated:
April 7,1988 Principal Contributor:
I R. Ferguson J
J. Rajan i
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