ML20215N246
| ML20215N246 | |
| Person / Time | |
|---|---|
| Site: | Hatch  |
| Issue date: | 10/30/1986 |
| From: | Bernero R Office of Nuclear Reactor Regulation |
| To: | GEORGIA POWER CO. |
| Shared Package | |
| ML20215N226 | List: |
| References | |
| TAC-10710, TAC-64785, NUDOCS 8611050099 | |
| Download: ML20215N246 (6) | |
Text
i 7590-01 UNITED STATES OF AMERICA NUCLEAR REGULA'ITiRY COMMISSION In the Matter of GEORGIA POWER COMPANY, ET AL Docket No. 50-321 (Edwin I. Hatch Nuclear Plant,
)
Unit No. 1)
)
EXEMPTION I.
The Georgia Power Company (GPC or the licensee) and three other co-owners are the holders of Facility Operating License No. DPR-57 which authorizes operation of the Edwin I. Hatch Nuclear Plant, Unit 1 (Hatch 1 or the facility) at steady state reactor power levels not in excess of 2436 megawatts thermal.
The facility is a boiling water reactor located at the licensee's site in Appling County, Georgia. The license is subject to all rules and regulations and orders of the Nuclear Regulatory Connission (the Commission) now or tereafter in effect.
II.
Section 50.54(b) of 10 CFR 50 requires that primary reactor containments for water cooled power reactors be subject to the requirements of Appendix J to 10 CFR Part 50. Appendix J contains the leakage test requirements, schedules, and acceptance criteria for tests of the leak-tight integrity of the primary reactor containment and systems and components which penetrate the containment.
Appendix J was published on February 14, 1973, and by letter dated August 7, 1975, the Commission requested GPC to review the containment leakage testing program for the facility and to provide a plan for achieving full compliance where necessary.
GPC responded on August 28, 1975, by stating that the containment leak rate test program for Hatch I had been reviewed and the program was in full 8611050099 861030 PDR ADOCK 05000321 P
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l compliance with Appendix J.
However, in a letter dated November 16, 1977, GPC reported that in formulating a test program for the Edwin I. Hatch Nuclear Plant, Unit 2 (Hatch 2) it discovered that'the Hatch 1 program needed to be updated. Consequently, proposed changes to the Hatch 1 Technical Specifications were also submitted in the November 16, 1977 letter.
In response to GPC's proposed changes, the Commission issued Amendment No. 53 to Facility Operating License No. DPR-57 for Hatch 1 on April 12, 1978.
In its letter of April 12, 1978, the Commission indicated that Amendment No. 53 did r.ot resolve all of GPC's proposed changes but that they would be reviewed as part of the review of the Hatch 2 program.
Subsequently, on March 5, 1979, GPC submitted an updated containment leak rate test program which was developed utilizing the recently-approved test program for Hatch 2.
In addition to providing the updated program, the March 5,1979, letter also provided proposed changes to the Technical Specifications for Hatch 1 and proposed piping modifications, both of which were necessary for the full implementation of the updated program.
Since GPC developed this updated test program by comparing each penetration at Hatch I with its similar penetration at Hatch 2 and applying the same guidelines used to develop the Hatch 2 program, the updated test program at Hatch 1 should meet all the requirements of 10 CFR 50, Appendix J..
5; ensure that the guidelines utilized in the development of the Hatch 2 program were properly carried over and applied to Hatch 1, the updated Hatch 1 program was independently reviewed in detail by our contractor, the Franklin Research Center (FRC).
FRC prepared a Technical Evaluation Report (TER) " Containment Leakage Rate-Testing - Edwin I Hatch Nuclear Plant Unit 1" dated April 22, 1982, documenting the results of its review of GPC's March 5,1979 submittal.
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. The TER identified six proposed test items as exceptions to the requirements of Appendix J and determined that exemptions to the requirements cf Appendix J were required as to these six items. These items concern:
- 1) isolation valves ' tested with water 2) main steam isolation valves (MSIVs)
- 3) airlocks 4) closed systems outside containment 5) transversing incore probe system and 6) control rod drive lines. However, additional staff review, documented in the Safety Evaluation Report (SER), has shown that only the MSIV test item is an exception to the Appendix J requirements and that the other five items are in compliance with Appendix J.
This additional staff review ir.cluded consideration of additional information concerning items 4 and 5 above that was provided by the licensee in a May 14, 1986 submittal.
III Appendix J to 10 CFR 50 requires leak rate testing of BWR main steam isolation valves (MSIVs) (Paragraph II.H.4) at Pa, the peak calculated containment pressure.related to the design-basis accident (Paragraph III.C.2).
Further, Appendix J requires that the measured leak rates be included in the summation of the leak rates for the local leak rate tests of all penetrations and valves subject to Type B and C tests (Paragraph III.C.3).
The licensee proposes to leak test the MSIVs at a reduced pressure and exclude the measured leakage from the combined local leak rate test results.
l Each main steam line is provided with two MSIVs that are oriented to seal
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in the direction of post-accident containment atmosphere out-leakage.
The design of the MSIVs is such that testing in the reverse direction tends to unseat the valve. Simultaneous testing of the two valves, at design pressure,
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. by pressurizing between the valves, would lift the disc of the inboard valve and result in a meaningless test. The prcposed test calls for a test pressure i
of 28 psig (one-half of Pa) to avoid lifting the disc of the inboard valve. The total observed leakage through both valves (inboard and outboard) is then conservatively assigned to the penetration. The staff concludes that this procedure is acceptable based on the conservative test direction for the inboard valve. Furthermore, excluding-the leakage from the summation for the local leak rate tests is acceptable because a separate leakage rate acceptance criterion of 11.5 standard cubic feet per hour is used for the MSIVs. The separate limit of 11.5 scfh was also included in the original facility Technical Specifications. This separate limit was found acceptable during the operating license review for Hatch 1, as discussed in Section 5.4.4 of the SER, dated May 11, 1973, and Supplement No.1 to the SER, dated December 10, 1973.
The radiological consequence of this separate leakage was considered generically as described by Regulatory Guide 1.96, " Design of Main Steam Isolation Valve Leakage Control Systems for Boiling Water Reactor Nuclear Power Plants," Rev.1, i
dated June 1976, which recommended the installation of a supplemental. control system for plants with construction permits issued after March 1,1970, but concluded that the Hatch 1 plant and other plants for which construction permits were issued prior to March 1,1970 did not need to add such a leakage control system.
Pursuant to Final Rule 10 CFR 50.12 (50 FR 50764) published on December 12, 1985, the special circumstances for granting this exemption have been identified, as follows. The purpose of the requirements to leak test the MSIVs at Pa is to assure that pressure conditions during testing represent pressure conditions that could be experienced in a design-basis accident
. so that potential leakage during a design-basis accident will be identified adequately during testing. However, as noted above, application of this requirement to valves with configurations similar to these MSIVs tends to unseat the valves and give meaningless results and would not serve the underlying purpose of the rule. The proposed alternate test, while at a somewhat reduced pressure, conservatively treats the resulting leakage indication and provides a more meaningful indication of potential leakage across the valves. Accordingly, with respect to the exemption from the requirement for full pressure testing, application of the rule in this instance would not serve the underlying purpose of the rule.
The purpose of the requirement-to include the measured leak rates of the MSIVs in the summation of the local leak rate tests for all of the penetrations and valves subject to Type B and C tests is to assure that there is adequate margin between the detected combined valve leakage and the leakage limit.
Experience has demonstrated that adequate margin can be maintained even if leakage from MSIVs is considered separately and subject to a separate specific leakage restriction of 11.5 standard cubic feet per hour.
Accordingly, with respect to the exemption from the requirement to combine the result of all valve leakage tests, application of the rule in this instance is not necessary to achieve the underlying purpose of the rule. Consequently, special circumstances described by 10 CFR 50.12(a)(2)(ii) exist in that application of the regulation in the particular circumstances is not necessary to achieve the underlying purpose of the rule in that the licensee has proposed an acceptable alternative test method that accomplishes the intent of the regulation.
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. The staff concludes that leak testing the MSIVs in the way described above is an acceptable alternative to the requirements of Appendix J, and that an exemption to Appendix J is justified and acceptable.
Accordingly, the Comission has determined that, pursuant to 10 CFR 50.12, the exemption is authorized by law, will not present an undue risk to the public health and safety, and is consistent with the comon defense and security; furthermore, in accordance with 10 CFR 50.12(a)(ii) special circumstances, as discussed above, are present. Therefore, the Comission hereby grants the exemption identified above.
Pursuant to 10 CFR 51.32, the Comission has determined that the issuance of the exemption will have,no significant impact on the environment (51 FR 36762).
A copy of the Comission's concurrently issued Safety Evaluation related
~ to this action is available for public inspection at the Comission's Public Document Room,1717 H Street, N.W., Washington, D.C., and at the Appling County Public Library, 301 City Hall Drive, Baxley, Georgia.
This Exemption is effective upon issuance.
FOR-THE NUCLEAR REGULATORY COMMISSION Robert M. Bernero, Director Division of BWR Licensing Office of Nuclear Reactor Regulation Dated at Bethesda, Maryland ~
this 30th day of October 1986