ML20244C239
| ML20244C239 | |
| Person / Time | |
|---|---|
| Site: | Palisades  |
| Issue date: | 06/01/1989 |
| From: | Office of Nuclear Reactor Regulation |
| To: | |
| Shared Package | |
| ML20244C233 | List: |
| References | |
| NUDOCS 8906140174 | |
| Download: ML20244C239 (4) | |
Text
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SAFETY EVALUATION BY THE OFFICE OF NUCLEAR REACTOR REGULATION RELATED TO AMENDMENT NO.126 TO PROVISIONAL OPERATING LICENSE NO. DPR-20 CONSUMERS POWER COMPANY PALISADES PLANT DOCKET NO. 50-255
1.0 INTRODUCTION
By letter dated March 3,1982 as supplemented by letters dated August 29, 1984, March 21, and April 20 and May 4, 1989, Consumers Power Company (the licensee) requested a change to the Palisades Technical Specifications, section 4.5.2.a-and d.
The proposed revision deals with the local leak rate testing of the containment air lock door seals to assure a leak-tight integrity of the reactor containment in order to meet the requirements of 10 CFR Part 50, Appendix J.
Specifically, technical specification (TS) Section 4.5.2.a would be revised to include local
-leak rate testing of air lock door seals of the reactor containment within 72
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hours of each door opening at a test pressure not less than 10 psig. TS Section 4.5.2.d (Test Frequency) would also be revised to require that the reduced pressure test would be performed within 72 hours8.333333e-4 days <br />0.02 hours <br />1.190476e-4 weeks <br />2.7396e-5 months <br /> after each door opening or the first of a series of openings.
By letters dated March 21, 1988, the licensee withdrew the proposed change dealing with the action statement associated with exceeding the allowable leak rate appearing in TS 4.5.2.c.(3).
The staff found the proposed action statement to be unacceptable.
Subsequently, by letter dated April 20, 1989, the licensee modified the amendment, request to include the j$6 acceptance criteria for the allowable leakage dur ng the air lock door seal i;f.I dH testing at 10 psig and proposed a revised action statement when the allowable leak rate appearing in TS 4.5.2.c.(3) is exceeded.
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f 2.0 EVALUATION b
In October 1980, the NRC revised ?;D CFR Part 50, Appendix J,Section III.D.2.
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regardire air lock door testing. The revision was initiated as a result of the C
recommudations by the door seal manufacturer who indicated that the door seals were not designed for repetitive testing at the calculated peak containment internal pressure related to the design basis accident (Pa). Basically, the revised rule allows:
1.
Testing of the entire air lock assembly at accident pressure'(pa) every 6 months or after the air lock has been opened during a' period when containment integrity is not required.
2.
Air lock testing within 72 hours8.333333e-4 days <br />0.02 hours <br />1.190476e-4 weeks <br />2.7396e-5 months <br /> of opening (or every 72 hours8.333333e-4 days <br />0.02 hours <br />1.190476e-4 weeks <br />2.7396e-5 months <br /> during periods of frequent opening) whenever containment 8906140174 890601
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This testing may be at Pa, at a reduced pressure, or may be conducted by pressurizing between double seals.
3.
Air lock door seal testing may not be substituted for the 6 months test at not less than Pa.
By letter dated August 29, 1984, the licensee proposed to test the air lock door seals within 72 hours8.333333e-4 days <br />0.02 hours <br />1.190476e-4 weeks <br />2.7396e-5 months <br /> of each door opening or the first series of openings at a reduced pressure not less than 10 psig.
The proposed time period (i.e., 72 hours8.333333e-4 days <br />0.02 hours <br />1.190476e-4 weeks <br />2.7396e-5 months <br />) in which the reduced pressure test would be performed after containment entry meets requirements of Appendix J, Paragraph III.D.2.(b) (iii) and, therefore, is acceptable.
Paragraph III.D.2.(b)(iii) of Appendix J also permits a lower test pressure for the air lock doors when testing seal integrity following entries into the containment.
The proposed 10 psig minimum test pressure is adequate to test the seals in order to assure sealing capability without damaging the door and the latching mechanisms.
This lower test pressure is recommended by the door manufacturer and will not require the use of a strong back or changes to secure the doors as would be the case when testing at a pressure Pa.
Furthermore, the 10 psig lower test pressure is, a common valt9 used by other licensees in the nuclear industry.
The staff requested the licensee to modify the proposed amendment request to include the maximum allowable leakage rate for the reduced pressure test of the door seals.
By letter dated April 20, 1989, the licensee proposed an allowable leakage criterion of 2500 cc/ minute (0.023 La) as specified in the proposed TS 4.5.2.b(2).
This criterion is based on recent past tests where the proposed leakage limit was administratively applied to the air lock door testing.
The purpose for specifying a leakage rate limit for the air lock door seals is to assure that failure of the air lock will not result in exceeding the acceptance criterion of 10 CFR Part 50, Appendix J, Paragraph III.C.3 (0.60 La) for the total containment penetrations.
The Ethyl-Propaline-Dione-Monomer (EPDM) rubber seals that meet the ASTM material specification are used as a sealant material for the air lock seals at Palisades.
This sealant material has a sealing capa-bility that can reasonably justify a leakage of 2500 cc/ min (STP).
This has been confirmed by other licensees' experience that have applied a similar leakage rate limit.
Over the years, there has been an improvement in the performance and reliability and a reduction in the leakage for the door seals at the Palisades plant.
The proposed criterion is well within the acceptable limits for the overall containment leakage including the sum leakage for all penetrations as applied by 10 CFR Part 50, Appendix J.
In addition, the leakage rate proposed by the licensee contains a comfortable margin since this is a small fraction of the total leakage rate allowed for types B and C tests of 10 l
CFR Part !G, Appendix J.
Based on this evaluation, the staff finds the proposed change dealing with the testing of the air lock door at the lower test pressure and the leakage rate criterion does meet the requirements of Paragraph III.D.2.(b)(iii) and 2.(b)(iv) of 10 CFR Part 50, Appendix J and is, therefore, acceptable.
The licensee has proposed action statemerr associated with exceeding the limit-ing conditions for operation (LCO) dealing with 0.60 La (TS 4.5.2.c.(1)) and La (TS 4.5.2.c.(2)).
The staff has reviewed these action statements and finds them
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. consistent with the guidance provided in the STS.
On this basis, the proposed action statements associated with TS 4.5.2.c.(1) and c.(2) are acceptable
.By letter dated March 21, 1988, the licensee withdrew the proposed change dealing with the action statement in TS 4.5.2.c.(3) that was rejected by the staff.
Specifically, the unacceptable action statement associated with TS 4.5.2.c.(3) would permit a full air lock door test to be performed or shutdown the reactor 1
if the total containment leak rate exceeds 0.60 La.
By letter dated April 20, 1989, the licensee modified the action statement associated with TS 4.5.2.c.(3) so that if the one air lock door seal leakage causes total containment leakage to exceed 0.60 La, the door must be declared inoperable and the remaining operable door shall be lock closed and tested within four (4) hours.
If the seal leakage of the remaining door causes total containment leakage to exceed i
0.60 La, in conformance with specification TS 4.5.2.b.(1) and the TS cannot be met within 48 hours5.555556e-4 days <br />0.0133 hours <br />7.936508e-5 weeks <br />1.8264e-5 months <br />, the licensee would be required to place the plant in cold shutdown within the following 36 hours4.166667e-4 days <br />0.01 hours <br />5.952381e-5 weeks <br />1.3698e-5 months <br />.
The staff does agree with the modified action statement since it is similar to the statement used in the TSs of other nuclear power plants and does meet the guidance provided in the Combustion Engineering Standard Technical Specifications.
On this basis, the staff finds the modified action statement for TS 4.5.2.c.(3) to be acceptable.
In our review of the licensee's submitted documentation regarding the containment air lock door surveillance program, one remaining issue dealing with requirements of Paragraph III.D.2.(b)(ii) needs to be resolved.
Paragraph III.D.2.(b)(ii) of Appendix J states:
" Air locks opened during periods when containment integrity is not required by the plant's Technical Specifications shall be tested at the end of such periods at not less than Pa."
l Whenever the plant is in cold shutdown or refueling, containment integrity is not required.
However, if an air lock door is open during this period, Paragraph III.D.2.(b)(ii) of Appendix J requires that an overall air leakage test at not less than Pa be conducted before plant heating and startup.
By letter dated August 29, 1984, the licensee conservatively interpreted requirements of Paragraph III.D.2.(b)(ii).
However, the licensee's conservative interpretation notwithstanding, the proper vehicle available to gain relief from the Code of Federal Regulations is through the submittal of an exemption request.
Specifically, the staff has concluded that with proper justification a partial exemption may be granted allowing the substitution of the seal leakage test of l
Paragraph III.D.2.(b)(iii) for the full pressure test of Paragraph III.D.2.(b)(ii) of Appendix J when no maintenance or modification that could affect sealing capability has been performed on an air lock.
Whenever maintenance or modification that could affect the sealing capability has been performed on an air lock door, the requirement of Paragraph III.D.2.(b)(ii) of Appendix J must still be met by the licensee. The staff has granted such partial exemption to numerous plants and intends to revise Appendix J to alleviate the need for further exemptions in the future.
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3.0 ENVIRONMENTAL CONSIDERATION
This amendment involves a change in the installation or use of a facility component located within the restricted area as defined in 10 CFR Part 70 and a i
change to the surveillance requirements. The staff has detemined that the amendment. involves no significant increase in the amounts, and no significant change in the types, of any effluents that may be released offsite, and that there is no significant increase in individual or cumulative occupational radiation exposure. The Commission has previously issued a proposed finding that this amendment involves no significant hazards consideration and there has been no public comment on such finding. Accordingly, this amendment meets the eligibility criteria for categorical exclusion set forth in 10 CFR 51.22(c)(9).
Pursuant to 10 CFR 51.22(b), no environmental impact statement or environmental assessment need be prepared in connection with the issuance of this amendment.
4.0 CONCLUSION
l We have concluded, based on the considerations discussed above, that (1) there is reasonable assurance that the health and safety of the public will not be endangered by operation in the proposed manner, (2) such activities will be conducted in compliance with the Commission's regulations, and (3) the issuance of the amendment will not be inimical to the common defense and security or to the health and safety of the public.
Date: June 1,1989 Principal Contributor: Dominic C. Dilanni
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