ML18141A157
| ML18141A157 | |
| Person / Time | |
|---|---|
| Site: | Surry  |
| Issue date: | 09/29/1983 |
| From: | Neighbors J Office of Nuclear Reactor Regulation |
| To: | Office of Nuclear Reactor Regulation |
| References | |
| NUDOCS 8310120003 | |
| Download: ML18141A157 (31) | |
Text
Docket Nos. 50-280 and 50-281 Licensee:
Virginia Electric and Power Company (VEPCO)
Facility: Surry Power Station, Unit Nos. 1 and 2
Subject:
SUMMARY
OF MEETING HELD ON SEPTEMBER 21, 1983 WITH VEPCO TO DISCUSS BORON REDUCTION The subject meeting was held in Bethesda, Maryland between NRC and VEPCO representatives, a list of attendees is attached.
The purpose of the meeting was to discuss the VEPCO proposal to reduce the boron concentration in the Surry Boron Injection Tanks and the Boric Acid System.
VEPC0 1s application for amendment was submitted on September 13, 1983.
A presentation was made by VEPCO and is attached.
VEPCO plans to provide, as a result of the meeting, information on radiological dose savings and a clarification of VEPC0 1s use of Westinghouse data.
ORB#l:(t,~
DNeighq rs 09/,i_~I.
r-1.
10-i20003 830929 - --
DR ADOCK 05000280 I
PDR D. Neighbors, Project Manager Operating Reactors Branch #1 Division of Licensing
Mr. W. L. Stewar:
Virginia Electric.and Power Company cc:
Mr. Michael W. Maupin Hunton and Williams Post Office Box 1535 Richmond, Virginia 23213 Mr. J. L. Wilson, Manager P. O. Box 315 Surry, Virginia 23883 Donald J. Burke, Resident Inspector Surry Power Station U. S. Nuclear Regulatory Commission Post Office Box 166 Route 1 Surry, Virginia 23883 Mr. J. H. Ferguson Executive Vice President - Power Virginia Electric and Power Company Post Office Box 26666 Richmond, Virginia 23261 James P. 0 1Reilly Regional Administrator - Region I~
U. S. Nuclear Regulatory Commission 101 Marietta Street, Suite 3100 Atlanta, Georgia 30303
- ~ MEETING
SUMMARY
DISTRIBUTI~
Docket File NRC PDR Loca*l PDR ORB#l Reading S. Varga, Chief D. Neighbors OElff*--- *---------
E. Jorda ACRS ( 1 0)
L. Engle J. Guo J. Guttmann
NRC D. Neighbors L. Engle J. Guo J. Guttmann VEPCO R. Cartwright E. Smith J. Wilson W. Craft R. Bilyeu R. Cross M. Bowling W. Rodi 11 N. Smith e
LIST OF ATTENDEES September 21, 1983 e
AGENDA FOR 9/21/83 NRC/VEPCO MEETING BORON CONCENTRATION REDUCTION SURRY POWER STATION I.
Introduct~on I I.
De~cription of Effected Systems A.
Boron Injection Tank (BIT)
B.
Concentrated Boric Acid System III.
Discussion of Maintenance & Exposure Concerns IV.
T. S. Changes Requested V.
Impact on Operations VI.
Discussion of Accident Analysis Performed, Applicable Assumptions and Results VI I.
VI I I.
A.
BIT
- l. Main Steam Line Break Analyses
- 2.
Inadvertant Safety Injection (SI)
B.
Concentrated Boric Acid System
- l. Volume Required for Cold Shutdown
- 2.
Time to Borate To Cold Shutdown Conclusions Questions and Answers Bob Cartwright
- ~
Ben Rodi 11 Ben Rodill Ben Rodill Ben Rodill Noval Smith Jack Wilson NRC/VEPCO
e e
IMPLEMENTATION
- Design Change Package - Cap recirc
- Set Point Changes
- Heat tracing controls
- BAST level alarms
- Procedure Update
- Eliminate old requirements
- Add new requirements
- Change blender nomographs
jdm/09478/1 PRESENTATION TO NRC BY W. B. RODILL SEPTEMBER 21, 1~83 e
SUBJECT:
VEPC0 1S T.S. CHANGE REQUEST FOR REDUCING BORON CONCENTRATION REQUIREMENTS SURRY POWER STATION, UNITS l AND 2
e AREAS COVERED BY ~RESENTATION
- 1.
Systems involvea in the Tech. Spec. Change Request.
. a.
Concentratea Boric Acia System
- o.
Boron Injection Tank SLIDE l L.
Concerns relevant to the high boric acia concentration in these
~
systems.
- 3.
Review of the Tech. Spec. changes requestea.
- 4.
Im~act on operations.
jdm/0947B/2
e
- 1.
Is a part of CVCS.
~.
Snared System.
- 3.
Consists of
- 3 7~00 Gallon Tanks BORIC ACID SYSTEM
- 4 Boric Acid Transfer ~umps*
- Batcn Tank
- Boric Acid ~il.ters
- and associated piping, valves, neat tracing, controls and instrumentation
- 4.
Simplified sketcn snown on SLIDE 3 jdm/09478/3 SLIDE 2
YDLUN(
COIITIIOl TAllll lCV 1111 C ltv lllll CHIIIIGIIII PUMP IUCTIOII
,cv IIIJI
,cv 1114 I MOY IJH IICI llTDO'IIII IUIID
- tu.
,---r------
I I
ro IIT IORIC ACID
- FllllR HtV 111' FIIOM IIT IOIIIC ACID TAIIKI
'HCV IIDI IOIIIC ACID TIIAIISHA PUMl'I e-
9 SLIDE 4
. PURPOSE OF CONCENTRATED ~ORIC ACID SYSTEM (i.e. BORIC ACID TANKS)
- 1.
Provide a inventory of concentrated Boric Acid (11.5 - llOttr,_,
weignt) for
- cnemical snim reactivity control..
- providing makeup to tne RCS, RWST, spent fuel pit and refueling cavities as necessary.
- 2.
Provide for recirculation of Boric Acid tnru tne BIT.
J.
Tne tnree BAT 1s are sized Jo provide sufficJent Boric Acid to bring reactors to cold snutdown assuming a stuck rod.
Required 4200 gallons per unit..
jdrn/09476/4
e SLIDE 5 NORMAL REPLENISHMENT FOR BORIC ACID TANKS
- 1.
Batching by way of the-Batch Tank and Boric Acid Transfer Pumps.
- 2.
Concentrating and recycling of reactor coolant letdown via the Boron Recovery System.
- ~
jdm/09476/5
- Tnis has led to tne concentrated boric acid system and tne Boron Injection Tank becoming nignly radioactive.
e SLIDE 6 BORON INJECTION TANK
- 1.
~00 gallon tank containing concentrated ooric acid at 11.5% - 13.0%
oy wei gnt.
- 2.
Provides for inje~tion of nignly concentrated ooric acid to mitigate tne reactivity addition from tne cooldown caused by a steam line break.
- j.
Normally isolated from RCS and cnarging system by two sets of parallel isolation valves.
- 4.
Is kept full oy recirculation from tne boric acid tanks.
- 5.
Operation of BIT takes place upon actuation of a Safety Injection signal.
Recir. lines to and from BAT are isolated
- Parallel Isolation valves open establisning a flow path from discnarge of cnarging pumps, tnru tne BIT to tne cold legs of tne RCS.
. o.
Simplified sketcn snown on SLIDE 1.
jdm/09478/6
SLIDE. 7
\\-'5\\
~OV-lfl61C
) C.OLD LEG45 Q~....-.\\-. __,
EAC.TOrz C.OOLA.~,
YSiE.M MD\\l *\\~~1 D I - '5\\
i I
......... ~,,,....12EC112CULATIOI-J TO 80'2.IC. AC1 D TA,.._iiL.c::;
e
-+-t-+w-QE!c.112cu LAT I OtJ TO VD.~ME C[j.ffm-TAi,.J~
1-cs, I le!\\(
I~.lEC.1'10 "TA~\\L
\\-S\\-""TK-'2 C\\OO~Q\\\\<<>~S.
I -'51 Tv- \\BB4C
~IMPL\\ F\\ED D'2AW\\i-...\\q BOl20\\J \\~j EC""f\\Ot-J 'T At'J~
SLH<!\\2y POWEK' SiAilOJ-4 U~\\i
\\
MDV-\\B6tB
' i a--~,- FJ20M Di6CJ-1At2.Q E Or SAFEiY lt-JJECTIO~
CHAgGl~C:i PUf.t\\P'5*
__, __ -~s ___, --
MCN- \\BG,A i---+-1-t-v-l2EC 112(ULA110~ r8oM B0r21C ACJD TA~ll5 t-..10TE5 r\\J - ~EA, 1"12AC ltJC'l M~ - MOT012. OPE.'2.ATED VALV\\
C><]-~012.MALL'( OPE~ VALVE
~-~D'lt-MLLY CLOSED VAL.VE
e SLIDE 8 CONCERNS
- l.
The BIT and boric acid system are highly radioactive and contaminated.
- i.
The concentrated boric acid is a {orrosive fluid which must be heated to 145°F to maintain solution solubility. Leakage has led to:
t(
a; Spread of fad1oactive material.
- b.
Degradation of carbon steel components and supports.
- c.
Failure of heat tracing which in turn can lead to Boron plateout and line plugging.
- 3.
These mai*ntenance problems in turn have resulted in excessive radiation exposures to station personnel.
jdm/09478/7
A.
B.
BIT
- l.
- l.
- 3.
- 4.
e e
PROPOSED T.S. C~ANGES TO REDUCE MAINTENANCE AND PERSONNEL RADIATION EXPOSURES SLIDE 9 Reduce minimum Borit acid concentration from 11.5 wt% to O wt%.
at Eliminate requirement for continuous recirculation between the
- BIT and Boric acid tank.
Eliminate the requirement to maintain BIT and isolated portion of inlet and outlet piping at 145°F.
Eliminate the periodii check of BIT level and,oncentration.
Boric Acid System
- l.
Reduce minimum Boric acid concentration from 11.5 wt% to 7 wt%.
- 2.
Reduce minimum temperature requirement from 145°F to 112°F.
- 3.
Increase minimum stored gallons of boric acid from 4200 to 6000 per unit. Is required to ensure enough boric acid is available to bring the reactor to cold shutdown assuming a stuck rod.
jdm/09478/8
e SLIDE l 0 IMPACT ON OPERATIONS A.
BIT Reduction of O wt%
- 1.
Eliminates need to maintain line heat tracing and tank heaters.
- 2.
Eliminates need to*maintain the recirculation line triQ valves which assure isolation on an SI signal.
- j.
Eliminates need to verify BIT level and concentration.
- 4.
Reduces the potential for degradation of caroon steel components due to leakage.
- 5.
Operation of BIT inlet and outlet valves in SI flow path will remain unchanged.
- o.
Minor changes required:
E Cut recirculation lines and weld ends closed to assure concentrated boric acid will not leak from the boric acid tanks to the BIT.
Remove power to BIT tank heaters, line heat tracing ~nd the trip valves on the recir. lines.
Revisfon required to station procedures and documents.
- 7.
Reduces the RCS dilution required for a return to power following an inadvertant SI.
- 8.
Benefits -- reduced maintenance.
reduced radiation exposure.
e SLIDE 11 IMPACT ON OPERATIONS (continued)
B.
BAT Reduction to 7 wt%
- -* --:::-~~:~==----
- 1.
Reduces the minimum solution temperature (from 145°F to 112°F) which*must be maintained to prevent boron plateout.
2 I
Reduces duty on heat tracing thereby increasing the life expectency of heat tracing.
- 3.
Reduces the potential for boron plateout upon loss on heat tracing due to the lower heat losses at the lower temperatures.
- 4.
No hardware changes required.
~.
Minor changes:
- adjust.heat tracing settings.
Reset boric acid tank level alarm instrumentation. Note
- 6000 gallons per unit is now required to ensure cold _
shutdown can be reached.
Revision required to station procedures and documents.
Station curve book nomographs for boron addition will be revised.
- 6.
Increases time to borate under normal and emergency conditions.
All times found to be *satisfactory.
7 I
Beoefits - reduced maintenance
- reduced radiation exposures.
\\
CON CL US IONS BASED ON THE ACCIDENT ANALYSES PERFORMED, VEPCO HAS CONCLUDED THAT THE PROPOSED REDUCTIONS IN BORON CONCENTRATION WILL NOT:
o INCREASE THE PROBABILITY OF OCCURRENCE OR CONSEQUENCES OF ANY OF THE ACCIDENTS EVALUATED IN THE FSAR o
INTRODUCE THE POSSIBILITY OF AN ACCIDENT OF A TYPE DIFFERENT FROM THOSE PREVIOUSLY EVALUATED AND DOCUMENTED rn THE FSAR
\\
o RESULT IN THE VIOLATION OF ANY SAFETY ANl\\LYSIS CRITERION ESTABLISHED TO PRESERVE SAFETY MARGIN AS A RESULT, NO UNREVIEWED SAFETY QUESTION AS DEFINED IN 10CFR 50.59 RESULTS FROM THE PROPOSED CHANGES.
e ACCIDENT ANALYSES TO SUPPORT BORIC ACID CONCENTRATION REDUCTION SURRY POvJER STATION N. A. SMITH PRESENTED TO THE NRC SEPTEMBER 21, 1983
e ACCIDENTS INVOLVING SAFETY INJECTION AND POTENTIALLY IMPACT.ED BY BORON INJECTION TANK CONCENTRATION REDUCTION o CREDIBLE/HYPOTHETICAL STEAMLINE BREAK o
INADVERTENT SAFETY INJECTION
ANALYSIS OF CREDIBLE/HYPOTHETICAL STEAMLINE BREAK o ANALYSIS SIMILAR IN SCOPE TO THOSE PRESENTED BY
- *FLORIDA POWER & LIGHT (TURKEY POINT)
- DUKE POWER (McGUIRE) o METHODLOGY/ASSUMPTIONS CONSISTENT WITH UFSAR EXCEPT:
- PRESENCE OF INTEGRAL FLOW REST RI CTORS IN STEAM GENERATOR NOZZLES
- ZERO BORON IN BIT AND ASSOCIATED SAFETY INJECTION PIPING
ANALYSIS OF CREDIBLE/HYPOTHETICAL STEAMLINE BREAK o CASES CONSIDERED
- DOUBLE-ENDED MAIN STEAM PIPE RUPTURE AT NO-LOAD CONDITIONS WI TH OUTS I DE POWER AVAILABLE
- DOUBLE ENDED MAIN STEAM PIPE RUPTURE AT NO-LOAD CONDITIONS WITH LOSS OF OUTSIDE POWER SIMULTANEOUS WITH THE STEAM BREAK
- BREAK EQUIVALENT TO STEAM FLOW OF 247 LBS/SEC AT 1100 PSIA FROM ONE STEAM GENERATOR*WITH OUTSIDE POWER AVAILABLE (BOUNDS ANY SINGLE STEAM DUMP OR SAFETY VALVE).
o PRESENCE OF INTEGRAL FLOW RESTRICTORS ELIMINATES FSAR DISTINCTION BETWEEN BREAKS INSIDE/OUTSIDE CONTAINMENT.
STEAM LI NE BREAK METHODS OF ANALYSIS SYSTEM TRANSIENT ANALYSIS o ANALYSIS PERFORMED WITH RETRAN (REFERENCE VEPCO'S TOPICAL REPORT TRANSMITTED BY VEPCO LETTER NO. 215, APRIL 14, 1981) o USES A 40 VOLUME, 51 JUNCTION TWO-LOOP MODEL WHICH ACCOUNTS FOR:
- PLANT NEUTRON KINETICS
- PRESSURIZER
- FEEDWATER SYSTEM (MAIN AND AUXILIARY FEEm~ATER)
- TRANSPORT & MI XI NG OF BORON
STEAMLINE BREAK ANALYSIS ASSUMPTIONS (SYSTEM TRANSIENT ANALYSIS)*
o DESIGN SHUTDOWN MARGIN.
o END OF LIFE (MOST NEGATIVE) MODERATOR TEMPERATURE COEFFICIENT o
MOST REACTIVE CONTROL ASSEMBLY FULLY WITHDRAWN o
INTEGRAL FLOW RESTRICTORS
STEAMLINE BREAK ANALYSIS ASSUMPTIONS (SYSTEM TRANSIENT ANALYSIS) o DESIGN SHUTDOWN MARGIN o END OF LIFE (MOST NEGATIVE) MODERATOR TE~DERATURE COEFFICIENT o MOST REACTIVE CONTROL ASSEMBLY FULLY WITHDRAWN o INTEGRJ!L FLOW REST RI CTORS
e
- o * --M-I-fHMUM-S-A-F-E-T+-HME-8-T-lON EAPAB I UTY (OtlE HHSI PUMP) o INITIAL BORON CONCENTRATION IN BORON INJECTION TANK AND ASSOCIATED SAFETY INJECTION PIPING ASSUMED. TO BE ZERO o
CONSERVATIVELY HIGH STEAM GENERATOR HEAT TRANSFER COEFFICIENT (NUCLEATE BOILING IN SECONDARY SIDE THROUGHOUT THE TRANSIENT).
o FULL MAIN FEEDWATER (PRIOR TO FEEDLINE ISOLATION) AND FULL AUXILIARY FEEm~ATER FLO\\~.
e
. STEAMLINE BREAK METHOD OF ANALYSIS - CORE THERMAL HYDRAULIC ANALYSIS o USES VEPCO VERSION OF COBRA III C/MIT
/*!
i (REFERENCE VEP'd:0 1S TOPICAL REPOHT TRANSMITTED
\\
BY VEPCO LETTER 795, SEPTEMBER 28, 1979, AND APPROVED BY NRC LETTER OF AUGUST 26, 1983.
o HOT CHANNEL FACTORS ASSOCIATED \\*/ ITH MOST REACTIVE CONTROL ASSEMBLY FULL WITHDRAWN FROM THE CORE o \\~-3 CORRELATION o EXAMINED CAREFULLY CHOSEN STATEPOINTS FROM EACH TRANSIENT RESULTS o MINIMUM DNBR>l.30 FO~ ALL THREE CASES
e e
EVALUATION OF INADVERTENT SAFETY INJECTION o
METHOD OF ANALYSIS HAND CALCULATIONS usrrm FSAR BORON DILUTION METHODOLOGY o
RESULTS OF ANALYSIS MAXIMUM REACTIVITY INSERTION RATES BOUNDED BY FSAR ANALYSES __ OF ROD WITHDRAWALS FROM POWER AND FROM A SUBCRITICAL CONDITION
- TOTAL VOLUME OF CLEAN vJATER POTENTIALLY INJECTED BOUNDED BY FSAR BORON DILUTION SCENARIOS AND 1981 BORON DILUTION REVIEW (SERIAL NO. 266, J UN E 1, 19 81 )
- TOTAL VOLUt1E OF BIT AND ASSOCIATED SI PIPING rs NOT LARGE ENOUGH TO CAUSE A LOSS OF DESIGN SHUTDOWN MARGIN FOR ANY OPERATIONAL MODE OR INADVERTENT CRITICAL ITV DURING COLD SHUTDOWN/
REFUELING SHUTDOvJN CONDITIONS AT ANY TIME IN LIFE
- UFSAR CONCLUSIONS REt1AIN VALID
e COLD SHUTDOWN CAPABILITY ANALYSIS o
METHOD OF ANALYSIS -
HAND CALCULATIONS USING DESIGN DATA FOR.SEVERAL RECENT CORE RELOADS o
ASSUMPTIONS
- PEAK XENON INITIAL CONDITIONS NO XENON FINAL CONDITION
- DESIGN (TECH SPEC LIMIT) SHUTDOl'JN MARGIN END OF LIFE (MAX. ABSOLUTE VALUE) MODERATOR DEFECT
- 20% UNCERTAINTY FACTOR ON REACTIVITY REQUIREMENTS TO COVER-CALCULATIONAL UNCERTAINTY AND CYCLE-TO-CYCLE VARIATIONS
- VOLUMETRIC MIXING MODEL CONSERVATIVELY NEGLECTS HIGH BORIC ACID DENSITIES WITH RESPECT TO THE RCS
I_
COLD SHUTDOWN CAPABILITY ANALYSIS RESULTS o
FOR CONSERVATIVE, WORST CASE CONDITIONS, THE BORIC ACID VOLUME ( AT 7*. 0 vJT /0) REQUIRED TO REACH COLD SHUTDOWN CONDITIONS WILL BE< 6000 GALLONS o THE ASSOCIATED BORATI ONS TIME IS < 100 MINUTES, WHICH IS WELL WITHIN THE MOST RESTRICTIVE ACTION STATEMENT IN THE TECHNICAL SPECIFICATIONS