ML20095G931
| ML20095G931 | |
| Person / Time | |
|---|---|
| Site: | Diablo Canyon  |
| Issue date: | 04/17/1992 |
| From: | Office of Nuclear Reactor Regulation |
| To: | |
| Shared Package | |
| ML20095G898 | List: |
| References | |
| NUDOCS 9204290177 | |
| Download: ML20095G931 (3) | |
Text
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UNITED STATES l'
7, NUCLEAR REGU! ATORY COMMISSION
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W ASHINGTON. D. C. 20555 SAFETY EVALUATION BY THE C3FICE OF NUCLEAR REACTOR REGULATION RELATED TO AMENDMENT 00.
69 TO FACILITY OPERATING LICENSE NO. DPR-80 AND AMENDMEN1 n0. 68 TO FACILITY OPERATING LICENSE NO. DPR.82 PACIFIC GAS AND ELECTRIC COMPANY DIABLO CANYON NUCLEAR POWER PLANT, UNIT N05.1 AND 2 DOCKET NOS. 50-275 AND 50-323
1.0 INTRODUCTION
By letter dated March IB,1991, as supplemented by letters dated May 3 and Noven.ber 22, 1991, Pacific Gas and Elect. lc Company (PG&E or the licensee) requesteo ar.cndments to Facility Operating License Nos. DPR-80 Lnd DPR-82 for Diablo Canyon Units 1 and 2, respectively.
The anendment application is designated License Anenonent Request LAR 91-01. The Anwndnents change the ccabined Diabic Canyon technical specifications (TS) to delete the requirement to verify that the containment fan cooler unit (CFCU) dampers transfer frota the normal to the accident position. Specifically, 1
Surveillance Requiren.ent 4.6.2.3.a.(3) of TS 3/4.6.2.3, " Containment Cooling System," will be modified to delete the requiren.ent to verify that the contaira.ent f an cooler unit (CFCU) dampers transf er to the accident position.
The requiremert to verify damper position will not be necessary af ter a planned CFCU t.u,cification is made because the dampers will then be secured in the accident positior..
The CFCU nodification will be made curing the 5th ref ueling outage for each unit. Therefore, the revised TS 4.6.3.2.a.(3) is l
cycle dependent, and verification of CFCU camper posii.ior..dll wt he required starting with Cycle 6.
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2.0 EVALUATION The containment f an cooler system et Diab 4 Canyon consists of five containment fan cooler units (CFCUsi, each including moisture separators, high efficiency particulate air (HEPA) filters, cooling coils, direct drive fans, normal and accident air flow dampers, backdraf t and pressure relief dampers, distribution ductwork and the associated controls. During normal operatiori, air is orawn through the CFCU cooling coils anct is discharged through the ductwork to the contair. ment atmosphere. During post-accident l
operation, the normally-open dampers are closed and the post-accident dampers are opened. These changes in damper position add the moisture separators and l
HEFA filters to the flow path.
To assure operability of the system, TS
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4.6.2.3 requires periodic verification that each CFCU starts in its low speed (occicent) mode and that the dampers transfer to the accident position.
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The licensee plans to simplify the system by pernarently securing the CFCU rcrral-mode and accident-mode campers in positions such that both the normal and accident-mode functions can be perforned without changing the damper positier.s.
Af ter the chenge, the unit air flow rates will be in accordance with design air flow rates for both normal and accident nodes of operation.
This desigr. cnange will make it unnecessary to verify that the dampers transfer tc the accident position.
The design simplification is based on a safety analysis that did not take any crecit for the contairment air cleaning function of the accident flow path, i.e., no credit was taken for charcoal or HEFA filters.
This analysis showed that with sprays alone and without particulate retention, the postulated post-accident conditions satisfy the dose requirements of 10 CFR Part 100.
The hEFA 111ters ano n.oisture separators were originally inst lleo as a radiotodine removal systen, during the postulated post-accicent conditions to support tha existing analysis.
Subsequently, a revised analysis showed that the containment spray alone with no additional clearup system was sufficient.
The hEFA 111ters and moisture separators had already been installed when the revised analyticel results becone known, but the charcoal filters had not yet been itstalled. Based on the reruits of the revised anelysis, the licensee decided riot to install charcoal f liters.
Although the revised analysis showed that the HEFA filters and moisture separatois were not needed, they have been n.aintained ir. an operating concition sir.ce plant startup.
The safety analysis upon which the ebove conclusion is based has been documented by the licensee in Chapter 15 of the l'pooted FaAR.
Eased on this analysis, the licensee concludes that the.
is reasonable assurance that the health and safety of the cubiic will
,t be adversely Lffected by the prcpcsec CFCU simplification and TS cht ;cs.
The staff concurs with this conclusicn.
In sur.c. cry, the Staff has revieweo the iiter,see's request and concludes that the proposed changes will naintein adeouate safety margins and therefore will not si nificantly affect the public health and safety. On the basis of its t
review cf this natter as described above, the NRC staff finds that the proposed thonges to the Diablo Canyon TS are acceptable.
3.0 STATE CONSULTATION
Ir accordance with the Commissicr 's regulations, the Califorr.ia State official was notified of the proposed issuance of these amendments. The State official had no corinnts.
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4.0 ENVIRONMENTAL CONSIDERATION
These amendments involve changes with respect to the installation or use of a facility component'locateo within the restricted area as defined in 10 CFR Part 20 and change surveillarce requirements. The staff has determined that the amendments involve no significant increase in the aniounts, and no significant change in the types, of any. effluents that niay be released offsite end that there is no significant increase in -indiviaual or cumulative occupational radiation exposure. The Consission has previously issued (56 FR 24214) a proposed finding that the amenanents involve no significant hazards consideration anc 'there has been no public comment on.such finding.
Accordingly, these anendments meet the eligibility criteria for categorical-exclusion set forth in 10 CFR 51.22(c)(9).
Pursuantto10CFR51.22(b),no environmental in. pact statement ur environmental assessnient need be prepared in connection with the issuance of these anendments, 5.0 CONCLUSICH The NRC staff has 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 compilance with the Coen,1ssion's regulations, and (3) the issuance of these ar,endments will not-be inimical to the commoc.
def ense ano security or to the health and saf ety-of the public.
Principal Contributors:
A. Drozd i
H. Rooo Deted:
April 17, 1992 d
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