ML20039G369

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Tech Specs for Redundant Decay Heat Removal Capability,Ar Nuclear One,Unit 2.
ML20039G369
Person / Time
Site: Arkansas Nuclear Entergy icon.png
Issue date: 11/30/1981
From: Decker Q
EG&G, INC.
To: Donohew J
Office of Nuclear Reactor Regulation
References
CON-FIN-A-6429 EGG-EA-5516, NUDOCS 8201180112
Download: ML20039G369 (14)
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WC fgSeae6lt nad 6/~ ; } 3pg7hact Wdf EGG-EA-5516, Rev. 1 NOVEMBER 1981 ffk TECHNICAL SPECIFICATIONS FOR REDUNDANT DECAY HEAT REMOVAL CAPABILITY, ARKANSAS NUCLEAR ONE, A/ SIC N 1/S UNIT NO. 2 e e 2F s

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. ~~ $3 . 5 I N !E & ~ Okh ?l&L This is an informal report intended for use as a preliminary or working document Prepared for the U.S. Nuclear Regulatory Conunission Under DOE Contract No. DE-AC07-76ID01570 Q FIN No. A6429 pg E 6 E 6 ldano kajgI12011130 l

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INTERIM REPORT Accession No . - . . _

Heport No EGG-EA-5516. Rev. I Contract Program or Project title:

Selected Operating Reactor Issues Program (III)

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Subject of this Document:

Technical Specifications for Redundant Decay Heat Removal Capability.

- Arkansas Nuclear One, Unit No. 2 Type of Document.

Technical Evaluation Report Author (s):

Q. R. Decker Date of Document:

November 1981 Responsible NRC Individual and NHC Office or Division:

J. N, Donohew, Division of Licensing T his doci e rItwa:.prepar 1 prunarily for prefninnary or internal use It has not receiwd f 01. tes een .ent appr oval. Since there nuty be substantive changes. this docurnent shoul:1 not be tonsidi red final F.G&G Idaho. Inc hf aho Falls. Idaho 83415 Prepared for the ll S. Nuclear Regulatorv Commission Washmgton, D.C.

Undei DOE Contract No. DE-AC07-761 D01570 NHC FIN No. __A6329 INTERIM REPORT L_

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i TECHNICAL SPECIFICATIONS FOR REDUNDANT DECAY HEAT REMOVAL CAPABILITY l ARKANSAS NUCLEAR ONE, UNIT NO. 2 h i

Docket No. 50-368 >

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pavember 1981 i

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Q. R. Decker l Reliability and Statistics Branch Enoineering Analysis Division EG&G Idaho, Inc.

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ABSTRACT -

This report reviews the Arkansas Nuclear One, Unit No. 2 technical specification requirements for redundancy in decay heat removal capability in all modes of operation.

FOREWORD ibis report is supplied as part of the " Selected Operating Reactor Issues Program (III)" being conducted for the U.S. Nuclear Regulatory Commission, Office of Nuclear Reactor Regulation, Division of Licensir:g, by EG&G Idahe. Inc., Reliability and Statistics Branch.

The U.S. Nuclear Regulatory Commission funded the work under the authorization, B&R 20 19 01 06, FIN No. A6429.

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i CONTENTS

1.0 INTRODUCTION

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1 2.0 REVIEW CRITERIA ................................................... l 3.0 DISCUSSIONS AND EVALUATION ........................................ 7 l 1

L 3.1 Startup and Power Operations ................................. 2 l 3.2 Hot Standby .................................................. 2 ,

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3.3 Shutdown .....................................................

I 3.4 Refueling .................................................... 3

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4.0 CONCLUSION

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5.0 REFERENCES

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I APPENDIX A--NRC MODEL TECilNICAL SPECIFICATIONS ......................... 5 l

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i TECHNICAL EVALUATION REPORT

_TECIINICAL SPECIFICATIONS FOR REDbNDANT DECAY HEAT REMOVAL CAPABILITY ARKANSAS NUCLEAR ONE, UNIT NO. 2 1.0 INTRODUC110N A number of events have occurred at operating Pressurized Water Peactor (PWR) facilities where decay heat removal capability has been seriously degradedJuetoinadequateadministrativecontrolsdoangshutdownmodeso{

operation. One of these events, described in IE Inf ormatien Notice 80-20, occurred at,the Davis-Besse, Unit No. I plant on April 19, 1980. In IE Bul-letin 80-12' dated May 9,1980, licensees were requested to inmediately

- implement administrative 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 eff 9ct inmediate action with regard to this problem, the NRC considered it necessary that an amendment of each license he made to provide for permanent long term assurance that redundancy in decayheatremgvalcapabilitywillbemaintained. By the letter dated June 11, 19S0, all P'aR licensees were requested to propose Technical Specification (TS) cnanges that provide for redundancy in decay heat removal capability in all modes of operation; use the NRC model TS which provide an acceptable sclution of the concern and include an appropriate safety analysis as a casis; and submit the proposed TS with the basis by October 11, 1980.

Arkansis Power & Light Co. (AP&L) submitted proposed revisions for l decay heat removal to their TS for Arkansas Nuclear One, Unit 2 (ANO-2), on October 31, 1980.4 2.0 REVIEW CRITERIA The re/iew criteria for this task are contained in the June 11, 1980 I

letter from the NRC to all PWR licensees. The NRC provided the model tech- l

! nical specifications (MTS) which identify the normal required redundant coolant system and the required actions when redundant systems are not '

dvailable fnr a typical two loop plant (Appendix A). This review will determine if toe licens*es existing and/or proposed p: ant TS are in agreement with the hRC MTS. l

!- The specific sections of the Combustion Engineering Standard Technical v f 5

Specifications that aoply to this task are as follow:

Reactor Coolant System I

!' 3/4.4 3/4.4.1 Reactor Coolant System and Coolant Circulation Startup and Power Operation (modes 1 & 2)  ;

t 3 .4 .1.1 Limiting Conditions for Operation  ;

4.4.1.1 Surveillance Requirement ,

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liot 5tandby (mode 3) 3.4.1.2 Limitinq Conditions for Operation 4.4.1.2.1 Surveillance 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 Refuelino Goerations (mode 6) 3.9.8.1 Limiting Condition for Operation 3.9.8.2 Limitinn Condition for Operation 4.9.8.1 Surveillance Requirement 4.9.8.2 Surveillance Requirement 3.0 DISCUSSION AND EVALUATION Arkansas Nuclear One, Unit 2 is a two coolant loop Combustion Engineer-ing (CE) PWR plant. The following discussion presents an evaluation of the proposed technical specifications submitted by AP&L for redundant decay heat removal as requested by the NRC.

3.1 5tartup and Power Operation--Modes 1 and 2 The proposed TS require that both reactor coolant loops and coolant pumps are to be operati onal. If these conditions are not met, the reactor is to be in Hot Standby (Mcde 3) within 1 hour1.157407e-5 days <br />2.777778e-4 hours <br />1.653439e-6 weeks <br />3.805e-7 months <br />. The proposed TS require verification that the required reactor coolant loops are in operation at least once per 12 hours1.388889e-4 days <br />0.00333 hours <br />1.984127e-5 weeks <br />4.566e-6 months <br />.

The above described proposed TS are in agreement with the MTS since two coolant loops are required and the periodic surveillance assures the operability cf the systoms.

3.2 Hot Standby--Mode T .

The proposed TS require two coolant loops and at least one associated coolant pump for each loop shall be operable and at least one of the coolant ,

loops shall be in operation during this operating mode.d The proposed TS require the plant to be in Hot Shutdown (Mode 4 & 5) in 12 hours1.388889e-4 days <br />0.00333 hours <br />1.984127e-5 weeks <br />4.566e-6 months <br /> if the two coolant loops are not operable and cannot be restored to operable status

a. All reactor coolant pumps may be de-energized for up to 1 hour1.157407e-5 days <br />2.777778e-4 hours <br />1.653439e-6 weeks <br />3.805e-7 months <br /> provided (1) no operations are permitted that would cause dilution of the reactor coolant system boron concentration, and (2) core outiet temperature is maintained at least 100F below saturation temperature.

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in 72 hours8.333333e-4 days <br />0.02 hours <br />1.190476e-4 weeks <br />2.7396e-5 months <br />, suspend all operations involving a reduction in baron concen-l tration in the coolant system and initiate corrective action to return the coolant loop to operation. Proposed TS require verification that at least one coolant pump is operable once per 7 days and at least one cooling loop is n- operation at least once per 12 hours1.388889e-4 days <br />0.00333 hours <br />1.984127e-5 weeks <br />4.566e-6 months <br />.

The proposed TS and surveillance regt.irements are in agreement with the MTS by requiring two coolant loops operable and one coolant loop in operation and periodic surveillance to assure conformance to these requirements.

. 3.3 Shutdown--Modec. 4&5 The proposed TS satisfy the requirements for the shutdown modes bv having at least two coolant loops operable; either the two reactcr coolant loops (including at least one of their associated coolant pumps and theie associated steam generators) or the two shutdown coolin The TS alsorequireoneoftheaboveloopstobeinoperation.glocos.a If this criteria is not met and innediate corrective action does not restore the loop (s) to operable or operational status, the reactor is to 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 /> and 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 to be operable with one of the two oper-ating. Operation and operability of the loops is required to be verified periodically.

3.4 Refueling--Mode 6 AP&L did not propose new technical specifications for all water levels (per MTS 3.9.8.1 and 4.9.8.1) as existing approved TS 6 meet the require-ments of the MTS. liowever they did provide proposed TS for the low water level.

In the low water level mode, (<23 feet water above the reactor pres-sure vessel itange) if either of the shutdown cooling loops are determined inoperable, the proposed T5 require that immediate corrective action be initiated to return the required cooling loop (s) to operable status.

The proposed TS for the low water level agree with the MTS; requiring at least two cooling loops be operable and surveillance to assure their operability.

c. The normal or emergency power source may be inoperable in MODE 5, ,

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b. All reactor coolant pumps and shutdown cooling pumps may be ife-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.

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Section 3.8 of Arkansas Nuclear One, Unit 2, TS 6 include provisions requiring redundant heat removal capability for all water levels. This satisfies the requirements of the NCR.

4.0 CONCLUSI0t!

An evaluation of the existing and proposed TS for Arkansas Nuclear One, Unit 2 indicates that they are in conformance with the MTS for redundant decay heat removal capability.

5.0 REFERENCES

1. NRC IE Information Notice 80-20, May 8, 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 11, 1980.
4. AP&L Letter, W. Cavanaugh to NRC, D. G. Eisenhut, dated October 31, 1980.
5. Standard Technical Specifications for Combustion Engineering Pressur-ized Water Reactors, NUREG-0212, Rev. 1, Fall 1980.
6. Arkansas Nuclear One, Unit 2, License Application, FSAR, Volume VIII, (Arkansas Power & Light Co., Little Rock, Arkansas) 1974.

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APPENDIX A MODf t TECin!C AL SPECIFIC ATIONS FOR REDUNDANT ()EC AY HE AT REMOVAL FOR COMBUSTION NGINEERING PRESSURIZED WATER RE AC TORS (PWR 's) 4

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. 3/4.4 REACTOR COOLANT SYSTEM

_3 / 4 .4 .1 RE ACTOR COOLANT LOOPS AND COOLANT CIRCULATION STARTUP AND POWER OPERATION i

LIMITING CONDITION FOR OPERATION 3.4.1.1 30th reactor coolant loops ano both reactor coolant pumps in each

  • oop shall be in operation.

APPLICABILITY: I and 2.*

ACTION:

With less than the above required reactor coolant pumps in operation, be in at least HOT STANDBY within I hour.

SfVEILLANCEREQUIREMENT 4.4.1.1 The above required reactor coolant loops 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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  • See Special Test Exceotion 3.10.3. I 7

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PEACTOR COOLANT SYSTEM HOT STANDBY LIMITING CONDIIION FOR OPERATION 3.4.1.2 a. The reactor coolant loops listed below shall be OPERABLE:

1. Reactor Coolant loop (A) and at least onu associated reactor coolant pump,  ;
2. Reactor Coolant Loop (B) and at least one associated -

reactor coolant pump,

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S. At least one of the above Reactor Coolant Loops shall be in ,

operation.*

APPLICABILITY: MODE 3 ACTION:

a. With less than the above required reactor coolant loops OPERABLE, restore the required loops to OPERABLE status within 72 hours8.333333e-4 days <br />0.02 hours <br />1.190476e-4 weeks <br />2.7396e-5 months <br /> or be in HOT $HUTD0'nN within the next 12 hours1.388889e-4 days <br />0.00333 hours <br />1.984127e-5 weeks <br />4.566e-6 months <br />.
b. With no reactor coolant loop in operation, suspend all operations involving a reduction in boron concentration of the Reactor Coolant System and immediately initiate corrective action to return the required loop to operation.

SURVEILLANCE REQUIREMENT 4.4.1.2.1 At least the above required reactor coolant pumps, if not in operation, shall be determined to be OPERABLE once per 7 days by verifying correct breaker alignments and indicated power availability.

4.4.1.2.2 At least one coolinq 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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  • All reactor coolant pumps nay be de-energized for up to I hour provided (i) 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.

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RE AC TOR COOLANT SYS11.M SHUTDOWN LIMI TING CONDI!!0N FOR uPERAT10N 3.4.1.3 a. At least two of the coolant loops listed below shall be OPERABLE:

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1. Reactor Coolant Loop (A) and its associated steam gen-orator and at least one associated reactor coolant pump,
2. Reactor Coolant Loop (B) and its associated steam gen-i
3. Shutdown Cooling Loop (A)#
4. Shutdown Cooling Loop (B)#
b. At least one of the above coolant loops shall be in operation.*

AP PL IC ABI L I TY :. i40 DES 4** and S**

q ACTION:

a. With less than the above required loops OPERABLE, immediately initiate corrective action to return the required coolant loops to OPERABLE status as soon as 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, suspend all operations involving a reduction in boron concentrat ion of the Reactor Coolant System and inmediately initiate corrective action to return the required coolant loop to operation.

temperature.

    • 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 i l

pressurizer water volume is less than 9UO cubic feet or (2) the secondary water temperature of each steam gt.nerator is less than 46 0F above each of the RCS cold leg temperatures.

  1. The normal or emergency power source may be inoperable in MODE 5.

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REACTOR COOLANT SYSTEM SURVE ILLANCE REQUIREMENT _

4.4.1.3.1 The required residual heat removal loop (s) shall be determined GPERAP,LE par Specificatinn 4.0.5.

4.4.1.3.2 The required reactor coolant pump (s), if not ia operation, si a!'

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 sid' water level to be greater than or equai 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 />. .

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 GPERATIONS 3/4.9.8 RESIDUAL HEAT REMOVAL AND COOLANT CIRCULATION ALL WATER LEVELS LIMITING CONDITION FOR OPERATION 3.9.8.1 At least one shutdown loop shall be in operation.

APPLICABILITY: MODE 6 ACTION: i

a. With less than one shutdown cooling loop in operation, except as provided in b. belon, suspend all operations involving an increase in the reactor decay heat load or a reduction in baron concentration of the Reactor Coolant System. Close all contain-ment penetrations providirig direct access from the containment 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 />,
b. The shutdown cooling 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. ,

c. The provisions of Specification 3.0.3 are not applicable.

SURVEILLANCE REQUIREMENT 4.9.8.1 At least one shutdown cooling loop shall be verified to be in  !

operation and circulating reactor coolant at a flow rate of greater than or equal to (3000) 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 LOW WATER LEVEL LIMIIING CONDI T!UN FOR OPERAT10N _

3.9.8.2 Two independrot shucdcwn cooling loops shall be OPERABLE.*

APPLICABILITY: MODE 6 when the water level above the top of the irradiated fuel assemblies seated within the reactor pressure vessel is less than 23 feet.

ACTION: ,

d. With less than the required shutdown cooling leops OPERABLE, irmediately initiate corrective action to return loops to OPERABLE status as soon as possible.
b. The provisions of Specification 3.0.3 are not applicable.

l SURVE ILLANCE REQUIREMENT 4.9.8.2 The required shutdown cooling loops shall be determined OPERABLE per Specification 4.0.5.

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i 3/4.4 REACTOR COOLANT SYSTEM i

i BASES 3/4.4.1 REACTOR COOLANT LOOPS AND COOLANT CIRCULATION i

lhe plant is designed to operate with both reactor coolant loops and associated reactor conlant pumps in operation, and maintain DNBR above 1.30 l during all normal operations and anticipated transients.

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j in MODE 3, a single reactor coolant loop provides suf ficient heat removal capability for removing decay heat; however, single f ailure con-siderations require that two loops be OPERABLE.

J In MODES 4 and 5, a single reactor coolant loop or shutdown cooling t 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 loops are not OPERABLE, this s specification requires two shutdown cooling loops to be OPERABLE.

The operation of one Reactor Coolant Pump or one shutdown cooling pump prosides adequate flow to ensure mixing, prevent stratification and produce gradual reactivity changes during boron concentration reductions in the Reactor Coolant System. The reactivity change rate associated with boron reductions will, therefore, be within the capability of operator  ;

j recognition and control.

The restrictions on starting a Reactor Coolant Pump during MODES 4 and 5 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 from the seccndary system, which could exceed the limits of Appendix G to 10 CFR Part 50. The RCS will be protected against overpressure transients and will rot exceed the limits of Appendix G by either (1) restricting the water volume in the pressurizer and thereby providing a volume for the l

primary coolant to expand into, or (2) by restricting starting of the RCPs to when the secondary water temperature of each steam generator is less i

! than (46)0F above each of the RCS cold leg temperatures.

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REFilFLING OPERATIONS BASE S 3/4.9.8 COOLANT CIRCULATION The requirement that at least one shutdowa cooling loop be in operation ensures that (1) sufficient cooling capacity is available to remove deca / heat and maintain the water in the reactor pressure vessel below 1400 F as required during the REFUELING MODE, and (2) sufficient

  • coolant circulation is maintained through the reactor core to minimize the effect of a boron dilution incident and prevent boron stratification.

The requirement to nave two shutdown cooling loops OPERABLE when there is less than 23 feet of water above the core, ensures that a single failure of the operating shutdown cooling loop will not result in a complete loss of decay heat removal capability. With one reactor vessel head removed and 23 feet of water above the core, a large heat sink is available fcr core cooling, thus, in the event of a failure of the operating shutdown cooling loop, adecuate time is provided to initiate emergency procedures to cool the core.

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