ML20216D645
| ML20216D645 | |
| Person / Time | |
|---|---|
| Site: | Brunswick  |
| Issue date: | 08/28/1997 |
| From: | NRC (Affiliation Not Assigned) |
| To: | |
| Shared Package | |
| ML20216D616 | List: |
| References | |
| NUDOCS 9709090378 | |
| Download: ML20216D645 (3) | |
Text
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aM:g ye UNITE 3 STATES a
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,1 NUCLEAR REGULATORY COMMISSION WASHINGTON, D.C. aceeHmot g
SAFETY EVALUATION BY THE OFFICE OF NUCLEAR REACTOR REGULATION RELATED TO AHENDMENT NO.186 TO FACILITY OPERATING LICENSE NO. DPR 71 AND AMENDMENT NO. 21't TO FACILITY OPERATING LICENSE NO. DPR 62 CAROLINA POWER & LIGHT COMPANY BRUNSWICK STEAM ELECTRIC PLANT. UNITS 1 AND 2 DOCKET NOS. 50 325 AND 50-324
1.0 INTRODUCTION
By letter dated January 15. 1997. Carolina Power and Light Company (CP&L), the licensee for Brunswick Steam Electric Plant (BSEP), Units 1 and 2, proposed to chan e Technical Specification (TS) 3.6.2.1.a.1 and corresponding Bases 3/4.
2 to revise the minimum and maximum values,of the pressgre suppression 001 water volumes from 87.600 ft3 and 89.600 ft to 86,545 ft and 89,843 ft,
3 letter dated Au it 1 TS 3/4.6.2, gust 22, 1997. CP&L requested a correction to the Bases for Depressurization and Cooling Systems, reflectin the fact that the recently approved 5 percent uprate in authorized power le el (Amendment No.183 for Unit 1 dated November 1,1996) increased the primary system operating pressure from the 1020 psig value currently described in the TS Bases to 1045 ps g.
That amendment was implemented at the conclusion of the fall 1996 Unit refueling outage.
The power uprate amendment has not yet been implemented on Unit 2: therefore the correspondin Bases TS will retain the 1020 psig value for primary operating pressure.
T e information provided in CP&L's August 22, 1997, letter does not affect the conclusions stated in the notice of " Proposed No Significant Hazards Consideration Determination" published in the Federal Reaister on March 26, 1997 (62 FR 14458),
2.0 DISCUSSION AND EVALUATION The licensee stated that on October 19, 1996. CP&L completed calculations which indicated that the su pression pool water level operating r, @ of -27" to -31" required b S 3.6.
1 was et equivalent to the correspc vjin watei volumes of 89,600 t and 87,600 ft del 1neated in the current BStr S.
Administrative controls on suppression chamber water level were implemented to ensure the minimum and maximum volumes specified in TS 3.6.2.1.a,1 were maintained.
The specific actions taken were reported in Licensee Event Report 19615 and included reanalysis of suppression chamber water volumes, The suppression pool water volume values in the revised calculations were analytically derived based upon a review of plant drawings associated with the suppression chamber and submerged structures. These calculations establish thatthe-27"and-31"1Slimitsofsuphressionpoolwaterlevelcorrespondto sup>ression chamber water volumes of 8,843 ft and 86,545 ft, respectively.
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CP&
has evaluated the impact of the revised suppression pool water as w,amarized below.
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Evaluations of the impact of the proposed change to the sup3ression pool volume limits for postulated (1) loss of-coolant accident (.0CA), (2) safety relief valve (SRV) blowdown, and (3) anticipated transient without scram
-(ATWS) events concluded that no adverse impact on containment parameters results from the proposed change to the maximum value of the pressure suppression pool volume. The proposed change to the minimum value does increase the suppression pool water temperature but the increase is not significant and the resulting tem)erature remains below acceptable limits.
Specifically, analyses indicate tlat the reduction-in the minimum suppression pool volume on the pool temperature following the postulated LOCA could result in a peak suppression pool water temperature of 199.5'F, and remains below the design limit of 200'F as specified in TS 5.2.2.b.
The slight increase in the sup ression pool water temperature associated with LOCA would also result in a sli ht reduction in the available net positive suction head (NPSH) for the res dual heat removal.(RHR) and core spray pumps.
However, adequate NPSH would be maintained throughout the postulated design basis LOCA.
The evaluation indicated that the impact of the proposed water volume limit reduction on ATWS events is a small increase in the suppression pool water temperature to 167'F which remains well below the specified limit of 190'F for ATWS events.
Reduced water volume also results in a slight increase in the peak bulk and local pool temperature for SRV blowdown events to 187.1'F and 198.1*F. which remains within acceptable limits of 200'F and 203*F.
respectively.
The analyses evaluated the potential impact of the proposed change to the suppression 2001 water volume limits on the SRV line loads. SRV discharge line reflood heig1t, wetwell pressurization, suppress %n pool swell loads, vent thrust loads, and condensation oscillation and chugging loads; The evaluation concluded that the change in suppression pool water volume limits has no adverse impact on these parameters because the bounding suppression pool-levels remain unchanged.
The analyses also concluded that the reduction in the minimum suppression pool water volume could slightly increase the peak su)pression pool temperature (less than 0.4'F) when an alternate to the RHR slutdown cooling function is used to reach shutdown conditions.
The potential increase in )eak suppression pool temperature has a negligible impact on the time required )y BSEP TS to reach cold shutdown.
The licensee stated that the BSEP analyses related to an Appendix R (10 CFR Part 50) fire event were reviewed to determine the impact of the suppression pool water volume limit change. These analyses indicate that the peak suppression pool water temperature would increase slightly as a result of the proposed change; however, the peak suppression pool water temperature of 186.4'F remains below the suppression pool design limit of 200'F.
Also, the resulting peak temperature for the station blackout (SBO) event, using assumptions and methodology consistent with the SBO Safety Evaluation for BSEP, is 198,8*F. This value is below the 200*F acceptance criterion stated in an NRC Safety Evaluation (SE) for 5B0. " Station Blackout Evaluation -
Brunswick Steam Electric Plant. Units 1 and 2,* dated October 4. 1990. A more in depth discussion-of the revised SB0 analysis including the assumptions used
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was provided in a CP&L letter to NRC dated December 23, 1996, and was found acceptable in an NRC letter to CP&L dated March 18. 1997.
In summary, the staff has reviewed the licensee's submittal as discussed above and finds the proposed TS change acceptable because the impact of the proposed change to the minimum and maximum suppression pool volume limits on suppression pool temperature and pressure following design basis LOCA, SRV blowdown ATdS. Appendix R fire, and SB0 events does not cause accident parameters to exceed acceptable values. The increase in the suppression pool temperature that could result from the proposed change is not significant.
Based on the above evaluation, the staff finds the proposed change to TS 3.6.2.1.a.1andthecorrespondingBases3/4.6.2torevisetheminimymand maximum vplues of the s 89,600 f t to 86.545 ft,uppression poo} acceptable.
water volumes from 87.600 ft and and 89.843 ft
3.0 STATE CONSULTATION
In accordance with the Commission's re official was notified of the proposed gulations, the State of North Carolina issuance of the amendments. The State official had no comments.
4.0 ENVIRONMENTAL CONSIDERATION
This amendment involves a change in the installation or use of a facility component located within the restricted area, as defined in 10 CFR Part 20.
The NRC staff has determined that the amendments involve 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 cumulative occupational radiation exposure.
The Commission has previously issued a proposed finding that the amendments involve no significant hazards consideration, and there has been no public comment on'such finding (62 FR 14458)
Accordingly, the amendments meet the eli 51.gibility criteria for categorical exclusion set forth in 10 CFR 22(c)(9).
Pursuant to 10 CFR 51.22(b) no environmental impact statement or environmental assessment need be prepared in connection with the issuance of =
the amendments.
5.0 CONCLUSION
The Commission 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 compliance with the Commission's regulations.
-and (3) the issuance of the amendments will not be inimical to the common defense and security or to the health and safety of the public.
Principal Contributor:- R. Goel Date: -August 28, 1997 l