ML20056F565
| ML20056F565 | |
| Person / Time | |
|---|---|
| Site: | Zion File:ZionSolutions icon.png |
| Issue date: | 08/23/1993 |
| From: | Simpkin T COMMONWEALTH EDISON CO. |
| To: | Murley T NRC OFFICE OF INFORMATION RESOURCES MANAGEMENT (IRM), Office of Nuclear Reactor Regulation |
| References | |
| NUDOCS 9308300081 | |
| Download: ML20056F565 (6) | |
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a Commonwoalth Ed! son 1400 Opus Place g
Downers Grove, lilinois 6051S August 23,1993 i
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Dr. Thomas E. Murley, Director Office of Nuclear Reactor Regulation f
U.S. Nuclear Regulatory Commission Washington, D.C. 20555 Attn: Document Control Desk
Subject:
Zion Nuclear Power Station Unit 2 Request for Schedular Exemption from 10 CFR 50, l
Appendix J, Type A, Test Frequency l
NRC Docket No. 50-304 I
Dear Dr. Murley:
Commonwealth Edison Company (CECO), pursuant to 10 CFR 50.12(a), requests an exemption for Zion Unit 2 from the requirements of Title 10 of the Code of Federal Regulations, Part 50, Appendix J, " Primary Reactor Containment Leakage Testing for Water-Cooled Power Reactors". 10 CFR 50, Appendix J, Section III.D.1.(a) specifies that a set of three containment overall integrated leakage rate tests (ILRTs), also called Type A tests, be performed at approximately equal intervals during each 10-year
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service period. In addition is specifies that the third test of each set shall be conducted r
when the plant is shutdown for the 10-year plant inservice inspections. This e :emption is requested in order to decouple the Type A test from the 10-year service i
period and the third Type A test from the 10-year inservice inspections.
Zion Unit 2 completed its second Type A test of the second 10-year service period on November 12,1992. The next scheduled refueling outage for Unit 2 is the cycle 13 j
outage, which is also the 10-year inservice inspection outage. The cycle 13 outage is I
scheduled to begin January 2,1995. Since this would make the interval between successive tests only 26 months, the station proposes to move the next scheduled Type A test to the cycle 14 refueling outage, currently scheduled to commence in September 1996. The interval between the two successive Type A tests on the unit would then be 46 months. An exemption is required to allow the next scheduled Type A test to be decoupled from the inservice inspections and the 10-year inservice inspection period.
V%1n This relief from the schedular requirements for the Type A testing is appropriate i
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in that performing two Type A tests in 26 months and performing the Type A test and the inservice inspections at the same time is not necessary to achieve the underlying purpose of the rule. Attachment A to this letter contains detailed justification for the pg exemption in accordance with the guidelines established in 10 CFR 50.12(a).
@g As noted above, the cycle 13 refueling outage is scheduled to begin January 2, gg 1995. To ensure sufficient time for outage planning activities, Commonwealth Edison Q
Company requests that the proposed exen.ption request be approved no later than l
gg March 1,1994.
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Dr. Murley August 23,1993 i
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This request has been reviewed and approved by the Zion Station On-Site i
Review Committee in accordance with company procedure.
To the best of my knowledge and belief, the statements contained herein are true and correct. In some respects these statements are not based on my personal knowledge but upon obtained information received from other CECO and contractor employees. Such information has been reviewed in accordance with company practice and I believe it to be reliable.
Please direct any questions you may have regarding this exemption request to this ofIice.
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i Respectfully, f
674 MO T.W. Simpkin Nuclear Licensing Administrator l
Attachment:
A) Justification for Exemption ec:
J.B. Martin, Regional Administrator - RIII C.Y. Shiraki, Project Manager - NRR d
J.D. Smith, Senior Resident Inspector - Zion l
4 OfUce of Nuclear Facility Safety - IDNS 4
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JUSTIFICATION FOR EXEMPTION FROM 10 CFR 50, APPENDIX J TYPE A TEST FREQUENCY EXEMPTION:
f Commonwealth Edison Company (CECO) requests an exemption for Zion Unit 2 j
from the Type A testing schedule of 10 CFR 50, Appendix J, Section III.D.1(a).
i This section of Appendix J requi es a set of three containment overall integrated leakage rate tests (Type A tests).'e performed at approximately equal intervals during each 10-year service period with the third test of each set being
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conducted when the plant is shutdown for' the 10-year plant inservice inspections.
i DISCUSSION:
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The second 10-year service period for Zion Unit 2 extends from September 19, 1984 to September 18,1994. The first Type A test of the second 10-year service period was conducted in October of 1988. The second Type A test of the period was not conducted until 49 months later due to the extended lengths of the cycle 11 refueling outage and cycle 12 operating cycle. The second test was conducted during the cycle 12 refueling outaga in November of 1992. The as-left leakage rate was.05956 weight percent per day calculated with a 95 percent upper confidence level. This is well within the acceptance criteria of.075 weight percent per day. The unit shutdown for the 10-year inservice inspections is the cycle 13 refueling outage scheduled for January 1995. In order to meet the Appendix J,Section III.D.I.(a), test schedule requirements, the third Type A test would also have to be scheduled during the cycle 13 refueling outage. This would result in the performance of two Type A tests in a 26 month period.
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In order to preclude performing successive Type A tests in such a short interval, j
CECO is proposing that the next Type A test be performed in the cycle 14 refueling outage scheduled for September 1996. The interval between the successive tests would be 46 months. This interval between successive tests more closely the approximates 40 month separation which is the intent of the current rule, and is consistent with the general interval Zion Station Unit 2 has l
maintained to this point. In addition, since refueling outage.a do not necessarily l
occur coincident with a 40 month interval, a permissible variation of 25 percent i
or 10 months has generally been accepted by the NRC to permit flexibility in scheduling the Type A tests. We therefore request an exemption to allow the third test of the second 10-year service period to be performed approximately 21 months beyond the 10-year service period.
The purpose of the Type A test, to provide periodic verification by tests of the leak-tight integrity of the primary reactor containment, systems and components which penetrate containment, will not be adversely impacted by this deviation from the schedular requirement. The Type A tests are being and will continue to k:\\nla\\lt2-nrc M f/20
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JUSTIFICATION FOR EXEMPTION FROM 10 CFR 50, APPENDIX J TYPE A TEST FREQUENCY be performed on a regular periodicity. In addition, since the most suspect l
leakage paths are through valves and penetrations, and the Type B and Type C testing is not being affected, assurance that containment integrity is maintained can also be obtained by the performance of these tests.
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General Design Criteria (GDC) 52 of Appendix A to 10 CFR 50 requires that l
cach reactor containment be designed so that periodic integrated leakage rate j
testing can be conducted to assure containment isolation integrity. Type A test i
are required by Appendix J to assure that the containment leakage following the limiting design basis accident is less than the maximum allowable leak rate l
assumed in the accident analysis. Appendix J also requires local leakage rate tests (Type B and Type C tests) be conducted ofleakage through containment 1
penetrations and isolation valves to assure containment integrity during an accident.
j The ASME Boiler and Pressure Vessel Code for mechanical systems and components establishes the 10-year inservice inspection period. The purpose of j
the inspection program is to ensure that the structural integrity of Class 1,2, and 3 components is maintained in accordance with the requirements of ASME j
Code Section XI.
Compliance with 10 CFR 50, Appendix J, Section III.D.I.(a), to perform a Type A test and the 10-year inservice inspections during the same outage does not l
appear to serve the underlying purpose of Appendix J. Conducting the third Type A test during the same outage as the shutdown for the 10-year plant
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inservice inspections does not enhance the purpose, or provide further assurance of containment integrity above that which has already been demonstrated.
i Therefore, an exemption is requested to allow the third Type A test of the second l
10-year inservice inspections. This decoupling o he two programs has no safety I
r consequences because the requirements on contahiment integrity in' Appendix J l
and the structural integrity of Class 1,2, and 3 components in the ASME Code are not being changed by this proposed exemption.
As discussed in the following sections, the requested exemption meets the three necessary criteria of 10 CFR 50.12 (a)(1). In addition, there are special I
circumstances present which qualify for consideration for an exemption per the criteria established in 10 CFR 50.12(a)(2).
The criteria for granting an exemption are met per 10 CFR Part 50.12(a)(1):
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The requested exemptions and the activity which would be allowed thereunder are authorized by law.
The criteria established in 10CFR50.12(a) are satisfied in this case and there is no other prohibition oflaw which precludes the activities which would be authorized by the requested exemption. Therefore the NRC is authorized by law to approve these exemptions.
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JUSTIFICATION FOR EXEMPTION FROM 10 CFR 50, APPENDIX J TYPE A TEST FREQUENCY The requested exemption will not present undue risk to the public.
As stated in 10 CFR 50, Appendix J, the purpose of primary containment leak rate testing is to ensure that the leakage through primary containment shall not exceed the leakage allowed by the Technical Specifications or associated bases and to ensure that proper maintenance and repair is 4
performed throughout the service life of the containment boundary components. Performing two Type A tests in 26 months, and the Type A test concurrent with the inservice inspections is not necessary to achieve this purpose. Past Unit 2 Type A test data has demonstrated the leak-tight integrity of the containment and the proposed separation between the successive Type A tests is within the accepted 40 10 month interval. In addition, since the most suspect leakage paths are through containment penetrations and valves, and the Type B and C testing is not being affected, 3
assurance that containment integrity is maintained can be obtained by the performance of these tests.
The two programs, the containment Type A tests and the 10-year inservice l
inspections, are unrelated to one another because the 10-year inservice inspections are not conducted to assure containment integrity. Therefore, the two programs could be performed irrespective of one another.
s The containment will continue to be demonstrated to maintain its c.esign function, i.e. to limit leakage rates to within the values specified '.n the Technical Specifications. The manner in which the Type A test is performed is not being altered nor the acceptance criteria of the test.
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Based on the above discussions, this exemption will not "present an undue j
risk to the public health and safety".
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The requested exemption v-ill not endanger the common defense and j
security.
I The common defense and security are in no way compromised by this exemption request since it does not alter the physical plant in any physical j
manner.
At least one of the special circumstances are present per 10 CFR 50.12(a)(2):
1.
Application of the regulation in the particular circumstances is not necessary to achieve the underlying purpose of the rule.
The underlying purpose of the Appendix J is to ensure that l') the leakage 3
l rate through the containment does not exceed the allowable leakage rate values of the Technical Specifications and 2) periodic surveillance is performed so that proper maintenance and repairs are made during the k : \\nla\\hr-nrcz.wpf /22
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i JUSTIFICATION FOR EXEMPTION FROM 10 CFR 50, APPENDIX J TYPE A TEST FREQUENCY i
service life of the containment.Section III.D.I.(a) requires the performance of three Type A tests at approximately equal intervals during each 10-year service period, with the third test of the set being conducted at the same time as the 10-year inservice inspection. The completion of these three tests at approximately equal intervals over the 10-year period provides the i
assurance of primary containment integrity to meet the intent of the rule.
However, coupling the Type A test schedule to the 10-year inservice inspection schedule is not necessary to meet the underlying purpose of the rule. The 10-year inservice inspection is not related to the integrity of the containment pressure boundary. Linkage of the inservice inspection period j
and schedule to that of the Type A test schedule for no apparent safety-related purpose would require Zion Unit 2 to perform Type A tests during consecutive refueling outages and only 26 months apart. Given the above i
4 discussion, application of the regulation in this circumstance is not j
necessary to achieve the underlying purpose of Appendix J as the Type A tests will continue to be performed at approximately equal intervals to l
provide assurance of containment integrity.
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