ML17212B492
| ML17212B492 | |
| Person / Time | |
|---|---|
| Site: | Saint Lucie  |
| Issue date: | 03/29/1982 |
| From: | Nelson C Office of Nuclear Reactor Regulation |
| To: | Robert E. Uhrig FLORIDA POWER & LIGHT CO. |
| References | |
| NUDOCS 8204080325 | |
| Download: ML17212B492 (7) | |
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8"'l"END OELD Dr, Robert E. Uhrig IRE Vice President ACRS-10 Advanced Systems 8 Technology RAClark Florida Power 8 Light Company PHKrqutzer-3 P. 0. Box 529100 CNel son Niami, Florida 33152 Gray Fi1e Cg P
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Dear Or. Uhrig:
~. SgakoQ We have reviewed your letters of February 1, 1978 (L-78-36) and August 2, 1978 (L-78-250) regarding post-LOCA boron concentration control.
We have determined, based on the enclosed evaluation, that your response to the concerns expressed in our letter of September 27, 19?7 is acceptable.
Enclosure:
As stated cc:
See next page QFigiI;a) Signed by:
Christian C, Nelson, Prophet tianager Operating Reactors Branch
~3 Division of Licensing ORB¹3 C
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Florida Power 8 Light Company CC:
Harold F. Reis, Esquire Lowenstein,
- Newman, Reis 8 Alexrad 1025 Connecticut Avenue, N.W.
Washington, D. C.
20036 Norman A. Co'll, Esquire McCarthy, Steel, Hector 8 Davis 14th Floor, First National Bank Building Miami Florida 33131-Indian River Junior College Library 3209 Yirginia Avenue Fort Pierce, Florida
. 33450
.'dministrator Department of Environmental Regulation Power Plant Siting Section State of Florida 2600 Blair Stone Road Tallahassee, Florida 32301 Mr. Weldon B. Lewis County Administrator St. Lucie County 2300 Yirginia Avenue, Room 104 Fort Pierce; Florida 33450 U.S. Environmental Protection'Agency Region IY Office.
. ATTJl:
Regional Radiation Representative 345 Courtland Street, N.E, Atlanta, Georgia 30308 Mr. Charles B. Brinkman Manager - Washington Nuclear Operations C-E Power Systems Combustion Engineering, Inc.
4853 Cordell Avenue, Suite A-1 Bethesda,'aryland 20014 Mr. Jack Schreve Office of the Public Counsel Room 4, Holland Building Tallahassee, Florida 32304 Resident Inspector/St.
Lucie Nuclear Power Station c/o. U.S.N.R.C.
P. 0.
Box 400 Jensen Beach,'lorida 33457 Bureau of Intergovernmental Relations
'60 Apalachee Parkway Tallahassee, Florida'2304 Regional Administrator Nuclear Regulatory Commission, Region II Office of Executive Director for Operations 101 Marietta Street; Suite 3100 Atlanta, Georgia 30303
4
~
p ENCLOSURE 1
St. Lucie Unit 1
.Post-LOCA Boron Concentration Control l.
INTRODUCTION During long-term cooling following a LOCA, residual, heat removal is accomplished by contisiuous boil-off of fluid in the reactor vessel.
As borated water is de-livered to the core region via safety injection and virtually pure w'ater escapes.
as
- steam, the boric acid concentration of the-remaining coolan't is increased.
If the solubility limit is exceeded, precipitation of boric acid will occur which could result in blockage of the coolant passages and a degradation.in cooling capability.
This report 'documents the result of a review performed by the Reactor Systems Branch (RSB) on the licensee's proposed procedures and equipment for post-LOCA boron concentration control at St. Lucie Unit l.
2.
EVALUATION 2.1 Guidelines for Review The guidelines for this review are. contained in Reference 1, which is a
0 memorandum describing the methods used to review boric acid buildup during post-LOCA long-term cooling.
There is no Spp section specifically covering this toyic.
'2.2 Licensee's Analysis
"'he submitted analysis of the post-LOCA boron concentration control for St.
Lucie 1 (References 2, 3, and 4) predicts that the minimum time to reach A
boron saturation is about 20 hours2.314815e-4 days <br />0.00556 hours <br />3.306878e-5 weeks <br />7.61e-6 months <br /> following*a.large cold-leg break without diluting flow, which is considered'as the worst case since low RCS pressure
yields lowest boric acid solubility..A reactor'oolant system pressure of 20 psia.is assumed for this size break.
The. analysis predicts that a minimum flushing flow of 20 gallons per minute is required within 10 hours1.157407e-4 days <br />0.00278 hours <br />1.653439e-5 weeks <br />3.805e-6 months <br /> post-LOCA to assure that boron does not precipitate.
To. prevent the buildup of boron in the core during the long-term recirculation mode, the.licensee proposes to inject-a minimum of 250 gpm of-recirculation flow into the reactor coolant.system hot'.eg.within 10 hours1.157407e-4 days <br />0.00278 hours <br />1.653439e-5 weeks <br />3.805e-6 months <br />. after a
- LOCA, to assure the required 20 gpm flow.
2.3 Realig'nment Procedures an'd Equipment The primary procedur'e described by the. l.ic'ensee (hot-leg injection via the shutdown cooling suction line) in Reference 2; promotes 'flow through the cord'y prov'iding injection flow to the hot leg.
Hot-leg injection,-in conjunction with existing cold-leg injection, will establish core flushing. flow for both hot-leg and cold-leg breaks.
The ECCS realignment.flow path establisbes flow
.from. the containment sump and low pressure safety 'in'jection pump (LPSI pump)'o the shutdown cooling bypass (recirculation) line,,into the shutdown cooling suction line'nd the hot leg.
This procedure in'sures a minimum of 250 gpm
'I flow, which is available for core flushing during post-LOCA long-term cooling.
A flow transmitter'nd its two backups,.all located ia the reactor au'xiliary building, are used to monitor this flow to the hot leg.
In the event that the primary procedure,to achieve core flushing is inopera-tive, an alternative procedure (hot-leg injection via the pressurizer aux-iliary spray) has 'been des'cribed by'the licensee in Reference 2.
Core flush-ing can be provided by diverting a portion of the high pressure safety h
injection 'flow through the pressurizer auxiliary spray and into the hot leg; This procedure can provide a minimum flow of 200 gpm.
A flow transmitter, located in the reactor auxiliary building, is used for monitoring this flow rate.
The motor operated
- valves, used in the primary procedure, which are required to be qualified as safety grade equipment, are so 'qualified by the licensee.
These. valves are not submerged post-LOCA.
The solenoid valves used in the alternate procedure that may become submerged in the post-L'OCA environment, are so qualified by the licensee.
2.4 Singl e Failure The licensee has conducted a single-failure analysis for St. Lucie Unit 1
in accordance with the criteria set forth in Branch Technical Position ICSB,18 to demonstrate that the boron dilution function is not vulnerable to a single
. failure.of, electric. systems...
Me have r'eviewed the, pi.ping. and instrumentation diagrams for St. Lucie 1, and have verified that 'the two independent hot leg injection subsystems described by the licensee do meet the single-failure criteria.
2.5 On-Site Verification.
Ouring his harch 1982 site visit, the HRR Project Yianager for St. Lucie 1 p]ant.,
Hr.. Chris Nelson, ha's reviewed the licensee's curre'nt Emergency Procedure-Loss of Reactor Coolant (Ref. 5).and the related P&I diagrams.
The review has confirmed the implementation of the post-LOCA boron concentration control
~
procedures described in the licensee's FSAR and.other submitted documents.
4 3.
CONCLUSION In summary, on the basis'f the above evaluation, we conclude that the St. Lucie 1
I design and technical specifications for post-LOCA boron concentration control are acceptable.
4.
REFERENCES b
(1)
Hemorandum for T.. H. Novak, Chief, Reactor Systems
- Branch, from K..I.
Parczerski, Reactor Safety Branch, Jan.
21, 1976.
I (2)
Appendix 6C of the FSAR, St..Lucie 1, Rev. 48; August 20, 197'5.
(3)
Letter from Robert E. Uhrig, Florida Power 8 Light Co., to Don K. Davis,
\\
USNRC, dated. Feb. 1, 1978, Long Term Cooling (ECCS).
(4)
Letter from Robert E. Uhrig, Florida. power 8 Light Co., to R. M. Reid, USNRC,-dated August 2, 1978, Post-LOCA Boron Concentration'ontrol.
(5)
Emergency Procedure
- 0120042, Rev. 19, "Loss of Reactor Coolant,",
, Page ll of 21, "Appendix A '- Hot Leg Injection," St. Lucie 1 Plant.
5; PRINCIPAL CONTRIBUTOR; P.. Ting