ML20011E528
| ML20011E528 | |
| Person / Time | |
|---|---|
| Site: | Davis Besse  |
| Issue date: | 01/31/1990 |
| From: | Office of Nuclear Reactor Regulation |
| To: | |
| Shared Package | |
| ML20011E527 | List: |
| References | |
| NUDOCS 9002160008 | |
| Download: ML20011E528 (3) | |
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l SAFETY EVALUATION BY THE OFFICE OF NUCLEAR REACTOR REGULATION RELATED TO AMENDMENT NO. 146 TO FACILITY OPERATING LICENSE NO. NPF-3 TOLEDO EDISON COMPANY AND THE CLEVELAND ELECTRIC ILLUMINATING COMPANY DAVIS-BESSE NUCLEAR POWER STATION, UNIT NO. 1 DOCKET NO. 50-346 l
1.0 1HTRODUCTION InitsletterdatedMarch7,1988,theToledoEdisonCompany(thelicensee) requested an amendment to the operating license for the Davis-Besse Nuclear Power Station, Unit No. 1, to remove from Specification 4.6.1.2.a of Appendix A.
Technical Specifications, a specific surveillance requirement. This requirement presently states that certain primary containment leakage rate tests be conducted during the same shutdown when the 10-year plant intervice inspection is being conducted. The licensee also requested that the Bases in the Davis-Besse Technical Specifications (TSs) be revised to reflect the uncoupling of these two types of tests.
2.0 DISCUSSION Section Ill D.1(a) of Appendix J to 10 CFR Part 50 states in part that "... a set of three Type A tests shall be performed, at approximately coual intervals during each 10-year service period. The third test of each set shall be conducted when the plant is shutdown for the 10-year plant inservice inspections."
Appendix J defines Type A tests as those "... intended to measure the primary reactor containment overall integrated leakage rate..."
These tests are also identified as integrated leakage rate tests (ILRTs). This Appendix J requirement has been incorporated into the surveillance requirements in Specification 4.6.1.2.a of the Davis-Besse TSs. The 10-year inservice inspection (ISI) is composed of the series of inspections performed every 10 years in accordance with Section XI of the ASME Boiler and Pressure Vessel Code and Addenda as recuired by 10 CFR 50.55a.
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The length of time required to perform the Type A tests (i.e., the ILRTs) necessitatu that they be performed during refueling outages. The Appendix J requirement to conduct these ILRTs at approximately equal intervals requires an interval of about 40 months. However, this schedule may not coincide with the plant's refueling outages. Accordingly, the TSs issued with the Davis-Besse operating license allow a variation of 10 months in this interval; i.e., the ILRT test interval can range from 30 to 50 months.
The 10-year 151 is presently scheduled to be performed during the forthcoming refueling outage (i.e., the sixth) r, tarting in February 1990.
The licensee had previously requested, in its letter dated November 20, 1987, an exemption from the Appendix J requirement to couple the third ILRT of the set of three Type A tests every 10 years from the 10-year 151. This Exemption was issued in the staff's letter dated January
, 1990. The intent of the subject amendment request is to revise the Davis-Besse TSs to introduce flexibility in the scheduling of the ILRTs now permitted by the Exemption cited above.
Specifically, the requested amendment would permit the next ILRT to be conducted during the seventh refueling outage starting in January 1992 since the last ILRT for the Davis-Besse facility was successfully completed in September 1988 during the fifth refueling outage. The next ILRT could be conducted no later than November 1992.
However, the present coupling requirement in the Davis-Besse TSs requires that the next ILRT be conducted during the forthcoming sixth refueling outage starting in February 1990. As discussed in the Exemption cited above, the NRC staff found that this requirement is not necessary to achieve the underlying purpose of the subject rule.
3.0 EVALUATION The purpose of the periodic ILRTs is to demonstrate that the leakage rate from the primary containment and systems and components penetrating primary containment do not exceed the allowable leakage rate specified in TS 3.6.1.2.a of the Davis-Besse TSs. This demonstration in turn is required to ensure that the calculated offsite radiological doses using the ptimary containment design basis leakage rate of 0.5 percent by weight of the containment ateosphere under the conditions associated with the design basis accident (DBA) remain valid.
These offsite radiological doses for the DBA were originally calculated in accordance with 10 CFR Part 100 and compared to the reference guidelines for determining the suitability of the Davis-Besse site.
In summary, the periodic ILRTS are required to support the original site suitability determinationfortheDavis-Besseplantinaccordancewith10CFR100.11(a) which requires a "... demonstrable leak rate from the containment..."
(Emphasis supplied.) The licensee has successfully performed this required demonstration for the Davis-Besse facility in the three ILRTs performed to date. Additionally, the licensee will continue to perform these Type A tests throughout the plant's lifetime on a schedule consistent with the requirements of Appendix J to 10 CFR Part 50.
Furthermore, the licensee's compliance with
. SectionIII.D.1(a)ofAppendixJwhichrequiresthatasetofthreeILRTsbe performed during each 10-year service period will ensure that the permissible 10-month variation in the surveillance interval will not accumulate indefinitely.
On this basis, the NRC staff concludes that the pro)osed uncoupling of the Type A tests from the 10-year ISI will not offect tie required continuing demonstration of the validity of the original calculations performed in compliance with 10 CFR Part 100.
The purpose of the 10-year ISI is to provide assurance of the structural integrity of the Davis-Besse safety-related structures systems and components in compliance with 10 CFR 50.558. Thelicenseewillalsocontinuetoperform the 10-year inservice inspections in compliance with 10 CFR 50.55a.
On this basis,from the 10-year ISI will not affect the required continuingthe NRC staff con tests demonstration of the structural integrity of the Davis-Besse safety-related structures, systems and components.
Inasmuch as the purposes of the Type A tests and the 10-year ISI are independent of each other and the performance of one does not directly affect the other, there is no safety-related concern associated with the present requirement that they be coupled in the same refueling outage.
Furthermore, both tests will continue to be conducted on a schedule consistent with the Commission's regulations. On this basis, the NRC staff finds that the proposed uncoupling of the Type A test from the 10-year ISI is acceptable.
4.0 ENVIRONMENTAL CONSIDERATION
This emendment involves a change to a requirement with respect to the installation or use of a facility component located within the restricted crea as defined in 10 CFR Part 70 or a change to a surveillance requirement. The staff has determined 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 commulative occupational radiation exposure. The Commission has previously issued a pr.sposed 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 10CFR51.?2(c)(9). Pursuant to 10 CFR 51.22(b), no environmental impact statement nor environmental assessment need be prepared in connection with the issuance of this amendment.
5.0 CONCLUSION
The staff hes 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, and (2) such activities will be conducted in compliance with the Commission's regulations, and the issuance of this amendment will oct be inimical to the connon defense and security or to the health and safety of the public.
Principal Contributor: H.D.tynch Dated:
January 31, 1990
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