ML20151B435
| ML20151B435 | |
| Person / Time | |
|---|---|
| Site: | Waterford  |
| Issue date: | 04/01/1988 |
| From: | Office of Nuclear Reactor Regulation |
| To: | |
| Shared Package | |
| ML20151B418 | List: |
| References | |
| NUDOCS 8804080229 | |
| Download: ML20151B435 (3) | |
Text
.
' r at
[
UNITED STATES
{
g, NUCLEAR REGULATORY COMMISSION t,
9y WASHINO YON, D. C. 20555
%...../
, SAFETY EVALUATION BY THE OFFICE 0F_ NUCLEAR REACTOR REGULATION RELATED TO AMENDMENT NO. 35 TO F,ACIL!TY OPERATING LICENSE NO. hPF-38 LOUIS _!_ANA POWER AND LIGHT COMPANY WATERF000 STEAM ELECTRIC STATION, UNI 1 3 DOCKET NO. 50-382 1.0 _ INTRODUCTION application dated January 28, 1988 Louisiana Power and Light Company By &L or the licensee) requested charges to The Technical Specifications (2P (Appendix A to Faciitty Operating License No. NPF-38) for Waterford Steam Electric Station, Unit 3.
The 3ropos?d changes addressed by this anendment would add provisions to allow t'le shutdown cooling flow to be reduced to 2000 ppm at 375 hours0.00434 days <br />0.104 hours <br />6.200397e-4 weeks <br />1.426875e-4 months <br /> after the reactor is shut down.
1 2.0 DISCUSSION On July 9,1987, the NRC issued Generic Letter 87-12 "Loss of Residual Heat R eoval (RHR) While the Reactor Coolant System (RSC) is Partialiy Fi!!ad" which, with other NRC and industry publications, noted the effect of shutdowr cooling (SDC) flow rate up]n the 1)otential for vortexing at the connection of the SDC suction line to the RLS when the RCS is partially drained. The Generic Letter requested licenstes to investigate the poten-tial loss of residual heat renoval (RHR) and the effects of such a loss on operations. As a part of the review, licensees have further requested technical specificatio's changes to allow for reduced SDC flow to around 2000 ypm when decay heat and other considerations are appropriate. For the proposed amendment, LP8L has addressed decay heat and boron strati-fication ecncerns.
3.0 EVALUATION The licensee h s perfomed analyses to detemine SDC flow rates required to remove decay heat during b de 6 (refueling) a' several differ 3nt times i
following reactor shutdown. The heat renova'i rate of the SDC heat exchanger was detemined at steady state RCS and SOC system conditions for several SDC flow rates. The decay heat curves were then used to detemine the times after reactor shutdown when the decay heat rate equaled the heat exchanger i
power for the selected SDC flow rates. The licensee has chosan the flow rate of 2000 gpm at 375 hours0.00434 days <br />0.104 hours <br />6.200397e-4 weeks <br />1.426875e-4 months <br /> after reactor shutdown as the next appro-1 priate level for RHR operation; the Technical Specifications c1 ready address 3000 gpr after the rLactor has been shutdown for at least 17C hours.
8804300229 080401 PDR ADOCK CSOOO302 4
P PDR i
.n,____--_______________..
, The licensees analysis included conservatisms in the overall heat transfer coefficients and decGy heat concerns, which c;ntain a 10% conservatism, from NUREG-0800, Branch Technical Position ASE 9-2, Revision 2.
No credit was taken for h at los u s fron the RCS and SDC system piping. The re-sulting analysis of ?000 spm at 375 hours0.00434 days <br />0.104 hours <br />6.200397e-4 weeks <br />1.426875e-4 months <br /> after reactor shutdown is, therefore, acceptable.
The liceasee further analyzed the effects of reduced SDC system flow on the potential for baron stratification, i.e., inadequate boron mixing.
Also of concern in the boron dilution event is the loop transit time or time to criticality with the most limiting fisw. At 2000 gpm, the flow is stiil well within the turbulent flow regime and the lo0p transit time is less than half the ninimum time to criticality for the most limitinc dilution event. Therefore, the SDC flow rates at 2000 ppm and greater are acceptable.
The licensee has proposed to revise the Technical Specificatien to incor-porate the additior,a1 SDC system flow of 2004 gpm at 375 hours0.00434 days <br />0.104 hours <br />6.200397e-4 weeks <br />1.426875e-4 months <br /> tfter reactor shutdown and we find the proposed changes acceptable.
4.0 CONTACT W!TH STATE OFFICIAL The NRC staff has advised the Administrator, Nuclear Energy Division, Office of Environuntal Affairs, State of Louisiana of the proposed detemination of no significant hazards censideration. No coments were received.
5.0 FNVIRONPINTAL CONSIDERATION The amendment relates to changes in installation or use of a facility cceponent l vated within the restricted area as defined in 10 CFR Part 20.
i 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 indivf dual or cumulative occupational radiation exposure. The i
Comission has previously issued a proposed finding that this amendment involves no significant hazards consideration and there has been no public coment on such finding. Accordingly, the amendment meets the eli criteria fer categorical exclusion set forth in 10 CFR 51.72fc)(9)gibility Pursuant to 10 CFR 51.22(b), r.o environmental impact statcrent or environ-mental assessr,cnt need be prepared in connection with the issuance of this amendment.
6.0 CONCLUSION
t 1
Based upon its evaluation of the proposed changes to the Waterford 3 Tec5nical Specificattens, the staff aas concluded that:
there is reason-abh assurance that the health and safety of the public will not be endangered by operation in the proposed manner, and such activities will be conducted in ecmpliance with the Commission's regulstions ar.d the t
. issuance of the amendment will not be inimical to the comon defense End security or to the health and safety of the public. The staff, therefore, concludes that the proposed changes are acceptable, and are hereby incorporated inte the Waterford 3 Technical Specifications.
Dated: April 1,19tB Principal Contributer:
David L. Wigginton b
I 4
1 i
i e
d
-