ML20056G986
| ML20056G986 | |
| Person / Time | |
|---|---|
| Site: | Millstone  |
| Issue date: | 09/01/1993 |
| From: | Opeka J NORTHEAST NUCLEAR ENERGY CO., NORTHEAST UTILITIES |
| To: | NRC OFFICE OF INFORMATION RESOURCES MANAGEMENT (IRM) |
| Shared Package | |
| ML20056G987 | List: |
| References | |
| B14558, NUDOCS 9309080035 | |
| Download: ML20056G986 (5) | |
Text
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NORTHEAST UTILITIES senerei On.co.. seicen sueet. Bernn. Connecticui l
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P.O. BOX 270 e,w una n
.ee" HARTFORD. CONNECTICUT 06141-o270 J [*j C1 (203) 665-5000 k
L September 1, 1993 i
i Docket No. 50-245 l
B14558 Re:
10CFR50.90 l
I U.S. Nuclear Regulatory Commission Attention: Document Control Desk Washington, DC 20555 Gentlemen:
Millstone Nuclear Power Station, Unit No.1 Proposed Revision to Technical Specifications Appendix J Local Leak Rate Testina Pursuant to 10CFR50.90, Northeast Nuclear Energy Company (NNECO) hereby proposes to amend Operating License No. DPR-21 by incorporating the changes identified herein into the Technical Specifications of Millstone Unit No.1.
BACKGROUND / DISCUSSION Millstone Unit No.1 Technical Specifications currently contain a requirement that any one penetration (except main steam isolation valves) not exceed a leakage of 5% L,, (18.8 SCFH).
L,, is the allowable operational leak rate and is derived from the maximum allowable test leak rate, L,.
Leakage from containment occurs through multiple paths; most notably through containment penetrations, air locks, and through the systems which penetrate the containment boundary.
10CFR50 Appendix J and Technical Specification Surveillance Requirement 4.7.A.3.e.(1)(a) establish an acceptance limit for all i
the leakage through these penetrations and valves of less than 0.60L,. Appendix J does not establish acceptance limits for individual penetrations.
l Each type of penetration has a unique configuration and could leak at different rates. For example, assigning the same allowable leak rate (5% L,,) to a Gibbs l
manway which has a double 0-ring seal and a penetration such as X-25/202D where six valves varying in size from 2 inches to 18 inches are simultaneously tested, results in unrealistic requirements for both penetrations.
At Millstone Unit No.1, individual penetration leakage will be addressed as necessary to ensure overall leakage limits are not exceeded.
This will allow NNECO to focus resources where they can be most beneficial.
Eliminating the Technical Specification requirement that each penetration not exceed 5% L, could also preclude costly shutdowns or startup delays which may be initiated in order to do maintenance which does not affect plant performance nor provide any I
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i U.S'. Nuclear Regulatory Commission B14558/Page 2 l
September 1, 1993 I
substantial benefit to public health and safety.
In addition, deletion of the 5%
L,, requirement could eliminate the expenditure of resources involved in preparation of License Event Reports for a situation which is not safety significant should any one individual penetration leak rate exceed 18.8 SCFH.
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Finally, eliminating the overly restrictive criterion on leakage could reduce operational radiation doses by preventing unwarranted maintenance. This proposed change will remove a requirement which has a potentially high cost with limited safety significance.
DESCRIPTION OF THE PROPOSED CHANGES The proposed changes will revise the surveillance requirements for local leak rate testing which are included in Technical Specification Section 4.7.A, i
Containment Systems, to remove the 5% L,, limit.
Removing the 5% L,, limit will allow Millstone Unit No. I to address individual penetration leakage while maintaining the overall leakage rate for Type B and C tests below the Appendix J acceptance criterion of 0.60 L,.
1 In addition, Section 4.7.A.3.e.(1) contains several symbols which are inconsistent with 10CFR50 Appendix J and ANSI 45.4 and 56.8.
Correcting these will bring our technical specifications into agreement with the terminology of Appendix J.
Finally, the Millstore Unit No. I specifications allow the exclusion of main steam isolation valves (MSIVs) from the combined leakage of 0.60 L,.
That exclusion is not recognized in Appendix J and is being deleted from the Millstone Unit No.1 Technical Specifications.
Specifically, the changes are as follows:
Reword Section 4.7. A.3.e.(1)(a) to read "A combined leakage rate of l
less than 0.60 L, for all penetrations and valves subject to Type B and C tests.
Remove Section 4.7.A.3.e.(1)(b) in its entirety.
l Renumber Section 4.7.A.3.e.(1)(c) as 4.7.A.3.e.(1)(b)
Bases Section 4.7 is being revised to state that the combined leakage rate for all penetrations and valves subject to Type B and C tests is limited to less than
- 0. 60 L,. provides a markup of the proposed changes, whereas Attachment 2 provides retyped pages of the Millstone Unit No.1 Technical Specifications.
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i U.S' Nuclear Regulatory Commission B14558/Page 3 September 1, 1993 SAFETY ASSESSMENT Allowable leakage is established to ensure that radiation doses to the general public, in the event of an accident, stay within the limits of 10CFR100.
To ensure that requirement is met, an acceptable overall leakage value L, was established based upon accident pressure, containment volume, fission product inventory and conservatism. The total contribution to leakage from penetrations is 60 percent or 0.60 L,.
This contribution is independent of the number of penetrations, their location, or their individual contribution to leakage and is established as the acceptance criterion in 10CFR50 Appendix J.
The 5% L, acceptance limit does not ensure that the 0.60 L, limit is achieved. If all the penetrations at Millstone Unit No.1 just met the 5% L,, requirement, the overall leakage would exceed both the 0.60L, limit and the maximum allowable test leak j
rate.
Removing the 5%
L,,
limit for individual penetrations would not affect the allowable leakage limit for Millstone Unit No. I and therefore, cannot decrease the safety of the general public.
SIGNIFICANT HAZARDS CONSIDERATION In accordance with 10CFR50.92, NNEC0 has reviewed the proposed changes and has concluded that they do not involve a significant hazards consideration (SHC).
The basis for this conclusion is that the three criteria of 10CFR50.92(c) are not compromised.
The proposed changes do not involve an SHC because the changes would not:
1.
Involve a significant increase in the probability or consequences of an accident previously evaluated.
The proposed change only modifies the wording of 4.7.A.3.e.(1)(a) and I
i deletes the individual penetration limit of 5% L,.
The proposed change l
l does not modify the quantity of the release assumed in the existing i
accident analysis.
The wording changes to 4.7.A.3.e.(1)(a) align the Millstone Unit No.1 l
Technical Specifications with 10CFR50 Appendix J.
In addition to revised nomenclature, the exclusion of the MSIVs from the 0.60 L, total leakage limit is removed.
The wording change does not affect any of the procedures or practices currently in place at Millstone Unit No.1.
The leakage limit for MSIVs contained in 4.7.A.3.e.(1)(c) has not been modified.
The individual penetration leakage criterion of 5% L,, is functionally an
" administrative limit" for monitoring penetration leakage and its deletion as a surveillance requirement will have no affect on the requirement I
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i U.S'. Nuclear Regulatory Commission B14558/Page 4 September 1, 1993 j
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governing the combined Type B and C leakage rates (0.60L ) defined in l
Therefore, the change does not affect the probability or consequences of an accident previously evaluated.
j 2.
Create the possibility of a new or different kind of accident from any j
previously evaluated.
The proposed changes do not change the way the plant is operated, nor do f
they affect the release limits or leakage paths assumed in any accident analysis.
There is no change to the function or design of any penetration.
The proposed change does not create the possibility of an accident of a different type' since the change only modifies the surveillance requirements to agree with 10CFR50 Appendix J.
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3.
Involve a significant reductic.1 in a margin of safety.
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The accident analyses do not consider any specific leakage path. Rather, i
they assume maximum allowable leakage. The margin of safety demonstrated t
by the Millstone Unit I accident analyses is based upon this de:ign leakage.
The combined Type B and C leakage limit of less than 0.60 L, l
defined in 10CFR50 Aopendix J provides assurance that design' leakage is not exceeded. The proposed changes do not affect either of these' values.
i Therefore, the margin of safety is not reduced by the proposed change.
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I The Commission has provided guidance concerning the application of the standards of 10CFR50.92 by providing certain examples (51 FR 7751, March 6, 1986) of l
amendments that are not considered likely to involve an SHC.
The changes i
proposed herein are not enveloped by an example, however, this does not diminish the conclusion that the proposed changes do not constitute an SHC.
j The changes align the Millstone Unit No.1 Technical Specifications with the f
nomenclature and acceptance criteria established by 10CFR50 Appendix J.
ENVIRONMENTAL CONSIDERATIONS i
i NNEC0 has reviewed the proposed licensed amendment against the criteria of 10CFR51.22 for environmental considerations.
The proposed change. does not i
significantly increase the types and amounts of effluents-that may be released l
l offsite, nor significantly increase individual or cumulative occupational l
radiation exposures. Based on the foregoing, NNECO concludes that the proposed j
change meets the criteria delineated in 10CFR51.22(c)(9)- for a categorical exclusion from the requirements for an environmental impact statement.-
i The Millstone Unit No.1 Nuclear Review Board has reviewed and approved the proposed changes and concurs with the above determinations.
i In accordance with 10CFR50.91(b), we are providing the State of_ Connecticut with -
a copy of this amendment.
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U.S'. Nuclear Regulatory Commission i
B14558/Page 5 September 1, 1993 local leak rate testing will be performed during the Cycle 14 refueling outage.
Therefore, we respectfully request that the Staff process and issue this proposed license amendment by January 15, 1994, to be effective upon issuance.
If you have any questions, please contact us.
Very truly yours, NORTHEAST NUCLEAR ENERGY COMPANY i
FOR:
J. F. Opeka Executive Vice President BY:
W. D. Romberg &
Vice President I
cc:
T. T. Martin, Region I Administrator J. W. Andersen, NRC Acting Project Manager, Millstone Unit No. 1 P. D. Swetland, Senior Resident Inspector, Millstone Unit Nos. 1, 2, and 3 Mr. Kevin T. A. McCarthy, Director Monitoring and Radiation Division Department of Environmental Protection 79 Elm Street P.O. Box 2066 Hartford, CT 06102-5066 l
Subscribed and sworn to before me j
this / d day of S o b uffA, 1993 W11rA d. OnhEL
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Notary Public Date Commission Expires: s /al,/qK i
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