ML20031F382
| ML20031F382 | |
| Person / Time | |
|---|---|
| Site: | Zion File:ZionSolutions icon.png |
| Issue date: | 08/31/1981 |
| From: | Decker Q EG&G, INC. |
| To: | Shemanski P Office of Nuclear Reactor Regulation |
| References | |
| CON-FIN-A-6429 EGG-EA-5519, NUDOCS 8110190690 | |
| Download: ML20031F382 (20) | |
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- ((fg EGG-EA-5519 AUGUST 1981 TECHNICAL SPECIFICATIONS FOR REDUNDANT DECAY HEAT REMOVAL CAPABILITY, ZION STATION UNITS 1 AND 2
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NRC Researc1 anc "ecinical 0 S?'2 8 sex l
ASSIS:8nce lep00: /
D' Q. R. Decker
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l PHLBMSNARY U.S. Department of Energy Idaho Operations Office a Idaho National Engineering Laboratory v
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Prepared for the 4
U.S. Nuclear Regulatory Commission Under DOE Contract No. DE-AC07-76ID01570 FIN No. A6429 EGnS,o,n.
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'NTERIM REPORT Accession No.
Report No. EGG-EA__5519 e
Centract Program or Project
Title:
Selected Operating Reactor Issi-Proaram (III)
Subject of this Document:
Technical Specifications for Redundi-
.leat Removal Capability, Zion Station Units 1 and 2 Type of Document:
Technical Evaluation Report Authorg J:
Q. R. Decker DKte of Document:
F August 1981 Assistance Report Rssponsible NRC Individual and NRC Office or Division:
Paul C. Shemsnski, Division of Licensing his document was prepared primarily f ar preliminary or internal use. it has not received full review and approval. Since there may be substantive changes this document should not be considered final.
EG&G ! iano, Inc.
Idaho Falls, Idaho 83415 Pre >ared for the U.S Nuc!;ar Regulatory Commission Washington, D.C.
Under DOE Contract NG. EMC07-761D01570 NRC FIN No.
A6429 0
INTERIM REPORT i
0476J e
TECHNICAL SPECIFICATIONS FOR REDUNDANT DECAY HEAT REMOVAL CAPABILITY ZION STATION UNITS 1 AND 2 Docket Nos. 50-2 5 and 50-304 August 1981 i,
1 Q. R. Decker l
Reliability and Statistics' Branch Engineering Analysis Division l
EG&G Idaho, Inc.
NRC Researca anc Tec! nica 1
i Assistance Report t
l 1. 3 J
-TAC No. 42105 and 42106 l
ABSTRACT In response to D. G. Eisenhut letter dated June 11, 1980, Commonwealth Edison submitted " Proposed Revisions tc Technical Specifications" for the Zion Station Units 1 and 2.
These proposed revisions would provide for redundancy in decay heat removal capability in all modes of operation.
After review of the proposed revisions, it is concluded tnat existing and proposed technical specification assure redunJant decay heat remeval capability in all operating modes with the exception of refueling (mode 6).
FOREWORD This report is supplied as part of the " Selected Operating Reactor Issues Program (!!!)" being conducted for the U.S. Nuclear Regulatory Commission, Of f ice of Nuclear Reactor Regulation, Division of Licensing, by EG&G Idaho, Inc.
The U.S. Nuclear Regulatory Commission funded the work under the authorization, B&R 20 19 01 06, FIN ho. A6429.
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CONTENTS 1
1.0 INTRODUCTION
1 2.0 REVIEW CRITERIA...................................................
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3.0 DISCUSSIONS AND EVALUATION........................................
2 3.1 Power Operations and Hot Standby.............................
2 3.2 Hot Shutdown.................................................
2 3.3 Shutdown.....................................................
3 3.4 Refueling....................................................
3
4.0 CONCLUSION
S......................................................
4
5.0 REFERENCES
4 APPENDIX A--NRC MODEL TECHNICAL SPECIFICATIONS.........................
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TECHNICAL EVALUATION REPORT TECHNICAL SPECIF V.ATIONS FOR REDUNDANT DECAY HEAT REMOVAL CAPABILITY o
ZION STATION UNITS 1 AND 2 0
1.0 INTRODUCTION
A number of events have occurred at operating PWR facilities where decay heat removal capability has been seriously degraded due to inade-quateadministrativecontrolsduringshutdownmodesofgperation. One of these events, described in IE Information Notice 80-20, occurred at the Davis-Besse, Unit No. I plant on April 19, 1980.
In IE Bulletin 80-124 dated May 9, 1980 licensees were requested to immediately implement admin-istrative controls which would ensure that proper means are available to provide redundant methods of decay heat removal. While the function of the bulletin was to effect inmediate action with regard to this problem, the NRC considered it necessary that an amendment of each license be made to provideforpermanentlongtermassurancethatredundancyindecayheag removal capability will be maintained.
By letter cated June 11, 1980, all PWR licensees were requested to prof'se technical specification (TS) changes that provide for redundancy in cecay heat removal capability in all modes of operation; use the NRC model TS which provide an acceptable solu-tion of the concern and include an appropriate safety analysis as a basis; and submit the proposed TS with the basis by October 11, 1980.
Commonwealth Edison (CE), Chicago, Illinois, submitted proposed o
revisions for decay heat removal to their Technical Specifications (TS) for Zion Units 1 and 2,4 on November 7, 1980.
2.0 REVIEW CRITERIA The review criteria for this task are contained in the June 11, 1980 letter from the NRC to all PWR licensees. The NRC provided the model tech-nical specifications (MTS)5 which identify the normal required redundant coolant system and the required actions when redundant systems are not available for a typical four loep plant (Appendix A). The general review criteria are:
1.
Two independent methods for decay heat removal are required in the plant TS for each operating mode.
2.
Periodic surveillance requirements should insure the operability of the systems.
The specific sections of the Westinghouse Standard Technical Specifica-tionsb that apply to this task are as follows:
o 3/4.4 Reactor Coolant System 3/4.4.1 Reactor Coolant System and Coolant Circulation 4
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Startup and Power Operation (mod _es 1 & 2) 3.4.1.1 Limiting Conditions for Operation 4.4.1.1 Surveillance Requirement Hot S_tandby ("iode 3)
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3.4.1.2 Limiting Conditions for Operation 4.4.1.2.1 Surveiilance Requirement 4.4.1.2.2 Surveillance Requirement Shutdown (modes 4 & 5_)_
3.4.1.3 Limiting Conditions for Operation 4.4.1.3.1 Surveillance Requirement 4.4.1.3.2 Surveillance Requirement 4.4.1.3.3 Surveillance Requirement 4.4.1.3.4 Surveillance Requirement Refueling Operations (mode 6) 3.9.8.1 Limiting Condition for Operation 3.9.8.2 Limiting Condition for Operation 4.9.8.1 Surveillance Requirement 4.9.8.2 Surveillance Requirement 3.0 DI5 CUSS 10N AND EVALUATION s
lion Station Units 1 and 2, are four loop Westinghouse (West) Pn'R plants.
Zion's operating modes as described in the proposed TS differ from those of the Nuclear Regulatory Commission (NRC) MTS.
Zion includes startup and power operatior in Mode 1, hot standby in Mode 2, hot shutdown in Modes 3 and 4, cold shutdown in Mode 5, and refueling in Mode 6.
These different operating modes were determined to be satisfactory and provide redundant decay heat removal as required by the NRC.
The evaluations of the Commonwealth Edison proposed TS are as follows:
3.1 Power Operation and Hot Standby--Modes I and 2(T
).
g The proposed TS require that all reactor coolant loops shall be oper-ating.
af this condition is not met, the reactor is to be in Hot Shutdown (Mode 3; w thin I hour. The proposed TS require verification that the required reactor coolant loops are in operation at least once per shift.
lhe above described proposed TS provide redundant heat removal since f our coolant loops are required to be operating and the periodic surveil-Iance assures the operability of the systems.
3.2 Hot Shutdown--Mode 3 (350*F< T sToper*)
avg.
The proposed TS require at least two coolant loops (with their associ-o atea steam generators and coolant pumps) shall be operable and at least one 2
of the coolant loops shall be in operation during this operating mom.1 The proposeu TS require the plant to be in Hot Shutcown (favy <350"F)
(%de 4) in l? hours if the two coolant loops are not operable and cannot tw 0
restored to operable Status in 77 hours8.912037e-4 days <br />0.0214 hours <br />1.273148e-4 weeks <br />2.92985e-5 months <br />, suspend all operations involvirq d reduction in boron concentration in the coolant system and initiate cor:ec-tive action to return the coolant loop to operation.
Proposed TS require o
verification tnat at least one coolant pump is operable once per week and at least one coolir.g loop is in operation at least once per shif t.
The proposed TS meet the requirements of tne MTS for the hot shutdown mode, since they require two coolant loops to be operable including at least one assoclated coolant pump and steam generator ner loop; with assurance of operability through periodic surveillance.
3.3 Shutuown--Mode 4 (200 < T 5 350 F) and Mode 5 ( 200 F) 3yg The proposed TS satisfy the requirements for the shutdown modes by having at least two coolant loops operable; either two of the f our reactor coolant loops (including at least one of their associated coolant pumps and their associated steam generators) and/or two residual heat removal (RHR) loopsb to be in operable status, ana requiring that at least one of the six coolant loops be in operation.c if this criteria is not met and immediate corrective action does not restore the loop (s) to operable or coerational status, the reactor is to be in Cold Shutdown within 20 nours anc reduction of boron concentration operations are to be suspended.
The requirements for this mode of operation are met by requiring two coolant loops and associated pumps and steam generators to be operable with one of the two loops operating.
Operation and operability of the loops are required to be verified periodically.
3.4 Refueling--Mode 6 (5140 F)
The proposed TS for tnis mode states that tne limiting conditicn for operation is for all water levels and requires at least one residual heat rudoval (RHR) loop to be in operation.
If less than one snotdown cooling loop is in operation, except for the provision to alter the core cont igura-tion without the cooling loop in operation, all operations that would a.
All reacter coolant pumps may be de-energized for up to I hour provided (1) no operations are permitted that would cause dilution of the reactor coolant system boron concentration, and (2) core outlet temperature is maintained at least 100F below saturation temperature.
b.
The normal or emergency power source may be inoperable in MODF 5.
c.
All reactor coolant pumps and shutdown cooling pumps may be de-energized for up to I hour provideo:
(1) no operations are permittm' that would cause dilution of the reactor coolant system boron concentretion, and (2) core outlet temperature is maintained at least 100F below saturation temperature.
3
increase the decay heat load or boron reduction of the reactor coolont sys-tem are to be suspended. All containment penetrations that a' low direct inside to outside atmosphere accesses are to be closed in 4 hours4.62963e-5 days <br />0.00111 hours <br />6.613757e-6 weeks <br />1.522e-6 months <br />. At ledst one shutdown cooling loop shall be verified in operation at least Once per day.
The proposed TS require that in the refueling mode with the water level less than 22 feet above the irradiated fuel assemblies in the pressure ves-sel, two independent RHR loops shall be operable and, if either of the RHR loaps are determined inoperable, corrective action to return the required loop (s) to operable status be initiated immediately.
Zion's proposed TS for all water levels 00 nnt agree with the NRC MTS for this operating mode. The surveillence requirements of the MTS (4.9.8.1) require verification of at least one RHR loop operational and circulating coolant at a flow rate of >(2800) gpm at least once per 4 hours4.62963e-5 days <br />0.00111 hours <br />6.613757e-6 weeks <br />1.522e-6 months <br />.
Zion's proposed TS do not require the verification of the coolant flow rate.
In adJition, the propcsed TS only reauire verification that one loop is opera-tional once per day rather than once per 4 hours4.62963e-5 days <br />0.00111 hours <br />6.613757e-6 weeks <br />1.522e-6 months <br /> as required by the MTS.
For the low water level operating modc, Zion's proposed TS differ from the MTS by the amount of water above the fuel assemblies seated within the pressure vessel.
Zion requires two independent RHd loops to be operable when the water level is 22 feet above the fuel.
THe NRC MTS requires two indpenuent RHR loops to be operable when the water level is 23 feet above the fuel.
This does not conform to the MTS.
4.0 CONCLUSION
g An evaluation of the proposed TS for Zion, Units 1 and 2 indicate that they provide adequate decay heat ren' oval capability for operating modes 1 tnru 5.
The proposed TS for operating mode 6 (refueling) contains differ-ences from the MTS in that:
(1) there is no requirement for coolant flow rate verification for all water levels; (2) RHR loop operabiiity is only verified daily instead of every four hours; and (3) the low water levol begins at 22 f eet instead of 23 feet as required by the MTS.
With the above exceptions, the proposed TS changes provice assurance that there is adequate redundancy fc decay heat removal with the respect to single tailure considerations.
5.0 REFERENCES
1.
NRC IE Information Notice 80-20, May.
1980.
2.
NRC IE Bulletin 80-12, May 9, 1980.
3.
NRC Letter, D. G. Eisenhut, To All Operating Pressurized Water Reactors (PWR's), dated June ll, 1980.
4.
CE Letter, T. R. Tramm to NRC, Harold R. Denton, November 7, 1980.
5.
Standard Technical Specifications for Westinghouse Pressurized Water Reactors, NUREG-0452, Rev. 1, July 1979.
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APPEN0lx A MODEL TECHNICAL SPECIFI':iTIONS FOR REOUh0 ANT DECAY HEAT REMOVAL fnR ALL PRESSURIZED W ATER REACross (PWR's) l i
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3/4.4 RLALTUR Q )LAf41 SYSTEM J/4.4.1 del.LTUM C00LAf4T LOOPS Af.D C00LAf4T CIRCULATIjg bli.<l'JP At.0 POWER OPER ATIO*.
LIMliifiG C0r DITION FOR OPERAllut.
3.4.1.'
All reactor coolant loops shall be in op' ation.
APPLICAolLITY: MOULS I and 2.*
ACTIdii:
v.ith less than the above required re6; tor coolant loops in operation, he in at least WJT 5TAtiDisY within ? hour.
Soave IL_L A!.CL REQUlkEMEtiT 4.4.1.1 The above required r'f adtor coclant loops shall i>e verit ied to be in operation and circulating reactor coolant at least once per 12 hours1.388889e-4 days <br />0.00333 hours <br />1.984127e-5 weeks <br />4.566e-6 months <br />.
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REACTUR COULANT SYSTEN HOT STAhDBY LIMITlini Luf4DIT10N FOR OPERATIOM 3.4.1.2 a.
At least two of the reactor coolant loops listeo below shall l
be OPERABLE:
1.
Reactor Coolant Loop (A) and its associated steam generator and reactor coolant pump, 2.
Reactor Coolant Loop (B) and its associated steam generator and reactor coolant pump, 3.
Reactor Coolant Loop (C) and its associateo steam generator and reactor coolant pump, 4.
Reactor Coolant Loop (D) and its associated steam generator and reactor coolant pump.
b.
At least one of the above coolent loops shall be in operation.*
APPLICABitlTY: MODE 3 ACTION:
With less than the above required reactor coolant loops OPEKA6LE, a.
restore the required loops to OPERABLE status within 72 hcurs or be in HOT SHUTOOWN within the next 12 hours1.388889e-4 days <br />0.00333 hours <br />1.984127e-5 weeks <br />4.566e-6 months <br />.
I All reactor coolant pumps may be da-erergizen for up to I hour provided o
(1) no operations are permitted that woulu cause dilution of the reactor coolant system boron concentration, and (2) core outlet temperature is maintained at least 100F below saturation temperature.
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With no reactor coolant loop in operation, suspena all operations involving a reduction in boron concentration of the Reactor e
Coolant System and immediately initiate corrective action to return the required coolant loop to operation.
SUR'vEILLANCE REQUIREMENT 4.4.1.2.1 At least the above requireo reactor coolant pumps, if not in operation, shall be determined to be OPERABLE once per 7 days by verifying correct breaker aligr.nents and indicated power availability.
4.4.1.2.2 At least one cooling loop snall be verified to be in operation and circulating reactor coolant at least once per 12 hours1.388889e-4 days <br />0.00333 hours <br />1.984127e-5 weeks <br />4.566e-6 months <br /> t
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REACTOR C001. ANT SYSTEM SHUIDuWN LIMITIhG CONDITION FOR OPERATION e
At least two of the coolant loops listed below shall be 3.4.1.3 a.
OPERABLE:
r 1.
Reactor Coolant Loop (A) and its associated steam gen-erator and reactor coolant pump,"
2.
Reactor Coolant Loop (B) ana its associated steam gen-erator and reactor coolant pump,*
3.
Reactor Coolant Loop (C) and its associated steam gen-erator and reactor coolant pump,*
4.
Reactor Coolant Loop (D) and its associated steam gen-erator and reactor coolant pump,*
5.
Residual Heat Reiaoval Loop (A),**
6.
Residual Heat Removal Loop (8).**
b.
At least one of the above coolant loops shall be in operation. ***
t A reactor coolant pump shall not be started with one or more of the RCS cold leg temperatures less than or equal to (275)0F unless 1) the pressurizer water volume is less than cubic feet or 2) the secondary OF above each water temperature of each steam generator is less than of the RCS cold leg temperatures.
The normal or emergency power source may be inoperable in MODE 5.
All reactor coolant pumps and decay heat removal pumps may be de-energized for up to I hour provided 1) no operations are permitted that would cause dilution of the reactor coolant system boron concentration, and
- 2) core outlet temperature is maintained at least 100F below saturation t einperature.
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REACTOR COOLANT SYSTEM APPLICABILilY: MODES 4 and 5.
ACTION:
e With less than the above required loops OPERABLE, immediacely a.
initiate corrective action to return the required loops 1 OPERABLE status as soon is possible; be in COLD SHUTDOWN within 20 hours2.314815e-4 days <br />0.00556 hours <br />3.306878e-5 weeks <br />7.61e-6 months <br />.
b.
With no coolant loop in operation, suspeno all operations involving a reduction in boron concentration of the Reactor Coolant System ano immeoiately initiate corrective action to return the required coolant loop to operation.
SURVEILLANCE REQUIREMENT 4.4.1.3.1 The required residual heat removal loop (s) shall be determined OPERABLE per Specification 4.0.5.
4.4.1.3.2 Tne required reactor coolant pump (s), if not in operation, shall be determined to be OPERABLE once per 7 days by verifying correct breaker alignments and indicated power availability.
4.4.1.3.3 The required steam generator (s) shall be determined OPERABLE by verifying secondary side level to be greater than or equal to (
)% at least once per 12 hours1.388889e-4 days <br />0.00333 hours <br />1.984127e-5 weeks <br />4.566e-6 months <br />.
e 4.4.1.3.4 At least one coolant loop shall be verified to be in operation and circulating reactor coolant at least once per 12 hours1.388889e-4 days <br />0.00333 hours <br />1.984127e-5 weeks <br />4.566e-6 months <br />.
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REFUELING OPERATIONS 3/jl.9.8 RESIOUAL HEAT REMGVAL AND COOLANT CIRCULATION ALL WATER LEVELS LIMITILG CONDITION FOR UPERATION 3.9.d.1 At least one residual heat removal (RHR) loop shall be in operation.
APPLICABILITY: MODE 6 ACTION:
a.
With less than one residual heat removal loop in operation, except as provided in b. below, suspend all operations involving an increase in the reactor decay heat load or a reduction in boron concentration of the Reactor Coolant System. Close ali containment penetrations providing direct access f rom the con-tainment atmosphere to the outside atmosphere within 4 hours4.62963e-5 days <br />0.00111 hours <br />6.613757e-6 weeks <br />1.522e-6 months <br />.
o.
The residual heat removal loop may be removed from operation for up to I hour per 8 hour9.259259e-5 days <br />0.00222 hours <br />1.322751e-5 weeks <br />3.044e-6 months <br /> period during the performance of CORE ALTERATIONS in the vicinity of the reactor pressure vessel (hot) legs.
e c.
The provisions of Specification 3.0.3 are not applicable.
SURVEILLANCE REQUIREMENT 4.9.8.1 At least one residual heat removat loop shall be verified to be in operation and circulating reactor coolant at a flow rate of greater than or equal to (2800) gpm at least once per 4 hours4.62963e-5 days <br />0.00111 hours <br />6.613757e-6 weeks <br />1.522e-6 months <br />.
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REFUELING OPERATIONS LUW WALER LLVEL t
LIMITING CONDITION FOR OPERATION 3.9.8.2 Two independent Residual Heat Removal (RHR) loops shall be OPERABLE.*
APPLICABILITY: MODE 6 when the water level above the top of the irraaiated fuel assemblies seated within the reactor pressure vessel is less than 23 feet.
ACTION:
With less than the required RHR loops OPERABLE, immediately a.
initiate corrective action to return the required RHR loops to OPERABLE status as soon as possible.
b.
The provisions of Specification 3.0.3 are not applicable.
SURVEILLANCE REQUIREMENT 4.9.8.2 The required Residual Heat Removal loops shall be determinea OPERABLE per Specification 4.0.5.
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The normal or emergency power source may be inoperable for each RHR loop.
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3/4.4 REACTOR COOLANT SYSTEM BASES 3/4.4.1 REACTOR COOLANT LOOPS AND COOLANT CIRCULATION The plant is designed to operate with all reactor coolant loops in f
operation, and maintain DNBR above 1.30 during all normal operations and anticipated transients.
In MODES I and 2 with one reactor coolant loop not in operation this specification requires that the plant be in at least HOT STANDBY within 1 hour1.157407e-5 days <br />2.777778e-4 hours <br />1.653439e-6 weeks <br />3.805e-7 months <br />.
In MODE 3, a single reactor coolant loop provides sufficient heat removal capability for removing decay heat; however, single failure con-siderations require that two loops be OPERABLE.
In MODES 4 and 5, a single reactor coolant loop or P.HR loop provides sufficient heat removal capability for removing decay heat; but single failure considerations require that at least two loops be OPERABLE. Thus, if the reactor coolant locps are not OPERABLE, this specification requires two RHR loops to be OPERABLE.
The operation of one Reactor Coolant Pamp or one RHR pump provides adequate flow to ensure mixing, prevent stratification and produce gradual reactivity changes during bcron concentration reductions in the Reactor Coolant System. The reactivity change rate associated with boron reduction will, therefore, be within the capability of operator recognition and control.
The restrictions on starting a Reactor Coolant Pump with one or more RCS cold legs less than or equal to (275)0F are provided to prevent RCS pressure transients, caused by energy additions f rom the secondary system, which could exceed the limits of Appendix G to 10 CFR Part 50. The RCS will be protected against overpressure transients and will not exceed the limits of Appendix G by either (1) restricting the water volume in the pressurizer and thereby providing a volume for the primary coolant to expand into, or (2) by restricting starting of the RCPs to when the secon-dary water temperature of each steam generator is less than (
)0F above each of the RCS cold leg temperatures.
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REFUELING OPERATIONS BASES i
3/4.9.8 RESIDUAL HEAT REMOVAL AND COOLANT CIRC _U_LATION The requirement that at least one residual heat removal (RHR) loop be 3
in operation ensures that (1) sufficient cooling capacity is available to remove decay heat and maintain the water in the reactor pressure vessel below 140 F as required during the REFUELING MODE, and (2) sufficient cool-ant circulation is maintained through the reactor core to minimize the effect of a boron dilution incident and prevent boron stratification.
The requirement to have two RHR loops OPERABLE when there is less than 23 feet of water above the core ensures that a single failure of the oper-ating RHR loop will not result in a complete loss of residual heat removal capability. With the reactor vessel head removed and 23 feet of water above the core, a large heat sink is available for core cooling. Thus, in the event of a failure of the operating RHR loop, adequate time is provided to initiate emergency procedures to cool the core.
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