ML20085D965
| ML20085D965 | |
| Person / Time | |
|---|---|
| Site: | Brunswick  |
| Issue date: | 10/07/1991 |
| From: | Office of Nuclear Reactor Regulation |
| To: | |
| Shared Package | |
| ML20085D962 | List: |
| References | |
| NUDOCS 9110170299 | |
| Download: ML20085D965 (6) | |
Text
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'o UNITED STATES
$" i m i
NUCLE AR REGULATORY COMMISSION
,C WASHINGTON, D. C. 20$55 k.%
ENCLOSURE SAFETY EVALUATICH BY THE OFFICE OF NUCLEAR REACTOR REGULATION, RELATED TO AMENDMENT NO. 155 TO FACILITY OPERATING LICENSE NO. OPR-71 CAROLINA POWER & LIGHT COMPANY BRUNSWICK STEAM ELECTRIC PLANT, UNIT 1 DOCKET NO. 50-325
1.0 INTRODUCTION
By letter dated August 22, 1991, as supplemented September 10, 1991, Carolina Power & Light Company (CP&L) submitted a request for changes to the Brunswick Steam Electric Plant (BSEP), Unit 1, Technical Specifications (TS) 3.8.1.1 Actions b.3, c.3, and e.3.
The proposed license amendment allows a one-time-only extension of the 7-day allowed out-of-service time (A0T) for one inoperable emergency diesel generator (EDG) for each of the EDG Nos. 3 and 4 to a 14-day A0T during the BSEP, Unit 2, refueling outage No. 9.
This A0T is needed to perform the EDG manufacturer's 18-month inspection and to support planned mair.tenance work while each of the EDGs (Nos. 3 and 4) is torn down.
The outage began on September 12, 1991. The four EDGs at BSEP, Unit 1 (EDG Nos. I and 2), and Unit 2 (EDG Nos. 3 and 4) are designed and operated with a shared configuration where power supply to some engineered safety features (ESF) loads (i.e., two residual heat removal and one service water) of each unit are provided by the opposite unit's EDGs. TS 3.8.1.1 requires that all four EDGs be operable whenever either unit is in operation or Action statements b.3, c.3, and e.3 of the TS require an inoperable EDG to be restored to an operable status within seven days. The September 10, 1991, letter provided additional information that was reque 'ed by the staff during a conference call with CP&L conducted on August 30, 1991. This letter did not change the action noticed in the Federal Register on September 4,1991, and did not affect the initial i
proposed no significant hazards consideration determination.
1.1 BACKGROUND
Unlike a dedicated EDG configuration between two units, BSEP's shared EDG configuratior, does not provide sufficient time for regular maintenance of its EDGs during a unit refueling outage with one unit in operable status.
Surveillance Requirement (SR) 4.8.1.1.2.d.1 of the TS requires that each EDG be subjected to the manufacturer's required inspection at least once every 18-months during shutdown. This requires a partial tear down of the EDG l
accoroing to procedure OMST-DG500, "Erergency Diesel Generators Inspection."
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i in the past, CP&L has been performing the required regular EDC maintenance when both units were shutdown or during multiple 7-day ADTs with an inoperable EDG and one unit operating.
For this. outage, the licensee proposes to perform the above 18-month SR on EDG Nos. 3 and 4 during the requested 14-day A0T period -
along with other extensive maintenance work, rather than during multiple 7-day A0Ts as permitted by the above actions of TS 3.8.1.1.
The licensee finds that a 14-day period (12 day work window) will provide two-extended-days work window, as opposed to two 7-day A0Ts (10-days work window), which can be used to perform additional maintenance on each of EDGs by eliminating the following repetitive work evolutions:
- 1) Draining and filling system piping & heatup 2)Stagingandcleaninguptoolsandmaterials
- 3) Starting and loading of EDGs as required under the TS
- 4) Placing and removing clearance
- 5) Performing acceptance and surveillance testing 2.0 EVALUATION The licensee has provided a list of the maintenance activities that are currently scheduled based on the 7-day A0T. However, other maintenance items that are not scheduled could be accommodated due to the added efficiency and elimination of the above-mentioned repetitive work evolutions if the 14-day A0T were granted. _CP&L also provided the emergency core cooling system (ECCS) equipment and other safety-related equipment that would be available to safely shut down Unit I during a worst case design basis accident (DBA) coincident with the loss of any one of the remaining three EDGs. The licensee has stated that based on the General Electric (GE) Document EAS-40-0688, " Relaxation of Safety System Paraneter in the Brunswick Steam Electric Plant," they conclude that the remaining equipment car be used to safely shutdown BSEP, Unit 1, under each of the postulated conditions. The licensee further stated that the core damage ~ probability for a 14-day A0T is no greater than that which exists for two 7-day A0Ts. The licensee based-this on their probabilistic risk assessment (PRA) study which showed that an increase in overall core damage probability is less than SE-7 over the second 7-day ACT period.
The licensee contends that this small increase in overall core damage probability is deemed acceptable because the additional maintenance could effectively reduce EDG Nos. 3 and 4 outage frequencies, thereby increasing E00s availability. On this basis, CP&L has determined that a one-time extension of the 7-day A0T for one inoperable EDG for each of the EDG Nos. 3 and 4 to a 14-day A0T would not have unacceptable effects on the overall safety of the plant.
, To assure the operability and availability of the redundant safety equipment, CP&L will provide the following compensatory measures:
1.
CP&L will conduct simulator training for all five BSEP shift operating crews prior to entering into the first 14-day A0T to assure that operating personnel are cognizant of the appropriate measures.
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CP&L will avoid performing other testing or maintenance (e.g.,
transformer cad switchyard work) that would increase the likelihood of a plant transient during this period.
3.
Redundant equipment powered from the other emergency Nus on linit 2 will not be renoved from service for discretionary maintenance in order to assure that at least one train of necessary safety-related equipment is available, To ensure that BSEP, Unit 1, redundant equipment powered from the other emergency bus on linit 2 would remain operable, the staff reviewed in detail the list of surveillance tests to be conducted during the extended A0T for EDG Nos. 3 and 4 In a followup conference call with the licensee on September 23, 1991, the staff requested that certain surveillance tests listed on Attachments 2 and 3 to the September 10, 1991 letter be performed at another time than during the extended A0T window. The licensee has agreed to the staff's request and will reschedule the following tests:
(1) for EDG No. 3: OPT 08.2.4, IPT 24.1.1-1, OPT 07.1.8, and OPT 12.3.2.A, and (2) for EDG No. 4: OPT 08 P.4, APT 24.1-1, IMST - CS21tt, and OPT 07.1.8.
Based on the staff's review of the proposed amendment request and pertinent supporting documents, the staff finds that:
1.
The proposed maintenance activities indeed could take longer than 7-days, and the requested 14-day A0T could provide an extra two day working window, thus eliminating the need for two separate 7-day A0Ts.
2.
The extended A0T coeld provide an opportunity to perform a more comprehensive maintenance and inspection to look for any potential problems, thereby increasing long-term EDG reliability and safety margin.
3.
The licensee's compensatory actions and analysis of available safety equipment presented in GE's document EAS-40-0688 provide assurance that the plant can be safely shutdown with the three remaining EDGs.
4 By letter dated September 10, 1991, the licensee clarified that the remainder of the 18-month surveillance tests (TS 4.8.1.1.2.d.2 through 4.8.1.1.2.d.7) will be perforned to reset the surveillance cycle during this outage and thus will not need to be performed again until the next refueling outage.
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- 3_ 5.
With1n 24-hours prior to removal of an EDG from operable status and once per 72-hours thereafter, the operability of the three remaining EDGs will be verified under SR 4.8.1.1.2.a.4 and SR 4.8.1.1.2.a.5 (starting and running). SR 4.8.1.1.1.a (offsite power) will be performed within 2-hours of removal of any one EDG from operable status and once per 12-hours thereafter.
6.
With a loss of one EDG among the remaining three operable EDGs, the TS require restoration of at least three EDGs to operable status within 2-hours or be in at least hot-shutdown within the next 12 hours1.388889e-4 days <br />0.00333 hours <br />1.984127e-5 weeks <br />4.566e-6 months <br /> and in cold shutdown within the following 24 hours2.777778e-4 days <br />0.00667 hours <br />3.968254e-5 weeks <br />9.132e-6 months <br />.
Based on the review of compensatory mearures committed to by CP&L in the September 10, 1991, letter, rescheduling of certain surveillances mentioned previously, and current SRs, the staff concurs with CP&L's determination that a one-time extension of the 7-day A0T for an inoperable EDG to a 14-day A0T period would not_have an unacceptable effect on the overall safety of the plant. Also, it is the staff's judgement that an event requiring plant shutdown concurrent with a loss of offsite power and the loss of one additional EDG is a very unlikely event over the 14-day A0T period and, does not, therefore represent a significant risk to the health and safety of the public.
On this basis, the staff concludes that a one-time extension of the A0T from 7 days to 14 days for an inoperable EDG for each of EDG Nos. 3 and 4, during the upcoming BSEP, Unit 2, refueling outage from the requirement of TS 3.8.1.1,-
Actions b.3, c.3, and e.3, is acceptable.
3.0 STATE CONSULTATION
In accordance with the Commission's regulations, the State of North Carolina official was notified of the proposed i.ssuance of the amendment. The State official had no comments.
4.0 ENVIRONMENTAL CONSIDERATION
The amendment changes a requirement with respect to installation or use of a facility component locate' within the restricted area as defined in 10 CFR Part
- 20. The NRC 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 cumulatiu occupational radiation exposure.
The Commission has previously issued a proposed finding that the amendment involves i
no significant hazards consideration, and there has been no public comment on such finding (56 FR 43803 - September 4,1991).
Accordingly, the amendment meets the eligibility criteria for categorical exclusion set forth in 10 CFR l
51.22(c)(9).
Pursuant to 10 CFR 51.22(b) no environmental impact statement or I
environmental assessment need be prepared in connection with the issuance of the amendment.
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3 E.0 CONCLUSION The Conuits4cn has concluded, based on the consideratioris discussed above, that:
(1) there is reasonable assurance that the health and safety of the pblic will r.ct be endangered by operation in the proposed manner, (2) such activities will be ccnducted in ccr.ipliance with the Conriission's regulations, arc (3) the issuance of the cniend::ent will not be inimical to ? he common defense arid security cr to the health and safety of the pubiic, f>rircipal Cor.tributors:
P. Kang H. Le R. Gierdina Date: October 7, 1991
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x Af1ENDflENT FO. 155
'TO FACILITY OPERATillG LICENSE NO. DPR BRUNSWICK, UNIT 1
- Docket File NRC PnR Local'PDR PD11-1: Reading))
S. Varga (14E1 G. Lainas'(14E4 E. Adensam P. Anderson N. Le OGC D.-Hagan(MNBB3302)
E. Jordan (MNBB 3302)
G. Hill (4) (PI-37) 7E4))
C. Grimes 1103 F. Rosa R. Jones BE23)
P. Kang (7E4)
B. Giardina (11E22)
ACRS (10)
GPA/PA OC/LFliB
-Brunswick File L. Reyes, Ril cc:
Brunswick Service List
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