ML20207E296

Summary of 880714 Meeting W/B&W Owners Group Re Industry & NRC Actions to Resolve Issues Raised in Generic Ltr 87-12. List of Attendees,Viewgraphs & B&W Design Differences Encl

ML20207E296
Person / Time
Site:	Davis Besse, Oconee, Arkansas Nuclear, Three Mile Island, Crystal River, Rancho Seco, 05000000
Issue date:	07/28/1988
From:	Trammell C Office of Nuclear Reactor Regulation
To:	Office of Nuclear Reactor Regulation
References
GL-87-12, NUDOCS 8808170324
Download: ML20207E296 (47)

Text

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' NUCLE AR PEGULATORY COMMISSION ie t lC WASHING TON, D. C. 20555 July 28,1988 k.*....f l Docket Nos. 50-312, 346, 269, 270, 287, 313, 289 and 302 FAL:L; TIES: RANCHO SECO OCONEE ARKANSAS NUCLEAR ONE, UNIT 1 ThREE 111LE ISLAND, UNIT 1 CRYSTAL RIVER 3 DAVIS-BESSE LICENSEES: SACRAMENTO MUNICIPAL UTILITY DISTRICT DUKE POWER ARKANSAS POWER & LIGHT GPU NUCLEAR FLORIDA POWER CORPORATION TOLEDO EDISON

SUMMARY

OF MEETING HELD WI1H B&W OWNERS GROUP ON JULY 14, 1988 RE: GL 87-12. "LOSS OF RHR WHILE THE REACTOR COOLANT SYSTEM IS PARTIALLY FILLED" On July 14, 1988, the NRC staff met with representatives of the B&W Owners Group to discuss industry and NRC actions to resolve the issues raised in Generic Letter 87-12. Persons attending the reeting are identified in Enclosure 1. Viewgraphs presented at U.e ,ntreting by the NRC staff are contained in Enclosure 2.

The purpose of the meeting was to emphasize the importance of the issues raised in GL 87-12 and to discuss both short-term and longer-term actions that the NRC staff is considering. The meeting provided an opportunity for the B&W Owners Group to cossnent on the various actions that are being considered. The NRC staff belietas that inadequate attention has been given by licensees to this mode of operation, that responses to GL 87-12 were generally inadequate, and prompt action is needed to reduce the probability of losses of decay heat removal in this mode of operation.

The short-ters actions being considered are containment closure prior to the time core damage could occur, providing RCS temperature instrumentation, improved level instrumentation, holding off on any maintenance that could potentially perturb RCS mater inventory, assuring that backup cooling equipment '

is available, controlling hot leg and cold leg closure such that rapid RCS levelchangescannotoccur(steampressurization),andcrewbriefingswith operating staffs of the Diablo Canyon event of April 10,1987(NUREG-1269)and ,

other evants.

8808170324 e50728 hDR ADOCH 05000269 PNU hi

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, 4 i s l Prograrred enhsncements for the longer term include permanent improved instrumentation, analyses, and technical specification changes where impacts dre identified with respect to the recomrended enhancerents.

E&W plants are less vulnerable to core uncovery while drained dcwn because the core flood check valves prevent differential pressure from developing across the internals and therefore prevent early core uncovery due to steam pressuri-zation. Also, B&W plants do not drain down to the mid-loop level often. Other differences ,are shown on Enclosure 3.

The B&W Owners Group felt that, because of these differences and the fact that only momentary losses of DHR flow have occurred at B&W plants, B&W plants should either be excluded from the letter NRC is considering or the more fore-giving design appropriately noted.

The Group also recommended that the usual Technical Specification definition of containment closure (for fuel movement) should be adequate for a definition of containment closure in the event of a total loss of decay heat removal ability.

CbdwM.__/r Charles M. Trammell, Senior Project Manager Project Directorate V Division of Reactor Projects - I:1, IV, V and Special Projects

Enclosure:

1. Attendees

2. Staff Viewgraphs

3. B&W Design Differences cc: w/ enclosures See next page I

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4 Mr. Kenneth P. Baskin San Onofre Nuclear Generatirg Southern California Edison Company Station, Unit No. 1 Cc Charles R. Kocher, Assistant Mr. Jack McGurk, Acting Chief General Ccunsel Radiological health Branch James Beolette, Esquire State Department of Health Seuthern California Edison Company Services Post Office Box 800 714 P Street, Office Bldg. 8

?oseread, California 91770 Sacramento, California 95814 Cavid R. Pigott Mr. Hans Kaspar, Executive Director Orrick, Herrington & Sutcliffe Marine Review Committee, Inc.

600 Montgomery Street 531 Encinitas Boulevard, Suite 105 San francisco, California 94111 Encinitas, California 92024 Mr. Robert G. Lacy Mr. Dennis M. Smith, Chief Manager, Nuclear Radiological Programs Division San Diego Gas & Electric Company Governor's Office of Emergency Sycs.

P. O. Box 1831 State of California San Diego, California 92112 2800 Headowv!ew Road Sacramento, California 95832 Resident Inspector / San Onofre NPS U.S. NRC P. O. Box 4329 San Clemente, California 92672 Mayor City of San Clemente San Clemente, California 92672 Chairman Board of Supervisors County of San Diego 1600 Pacific Highway Room 335 San Diego, California 92101 Director Energy Facilities Siting Division Energy Resources Conservation &

Development Commission 1516 - 9th Street Sacramento, California 95814 Regional Administrator, Region V U.S. Nuclear Regulatory Commission 1450 Maria Lane, Suite 210 Walnut Creek, California 94596 .

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ISSUE WE ARE SERIOUSLY CONCERNED THAT PWR

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OPERATION DURING DECAY H EAT REMOVAL SYSTEM COOLING IS A SIGNIFICANT CONTRIBUTOR TO THE LIKELlHOOD OF A ,

RELEASE DUE TO A CORE DAMAGE ACCIDENT O

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OVERVIEW BACKGROUND

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11. CORRECTIVE ACTIONS Ill. FUTUFtE STAFF ACTION l

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1. BACKGROUND A. EXPERIENCE B. PHENOMENA C. PROBABILISTIC RISK ANALYSIS (PRA)

D. GENERIC L t- I I E R (GL) 87 12 E. SERIOUS DEFICIENCIES F. REDUCED RCS INVENTORY OPERATION

1 A. EXPERIENCE d

ACCIDENTS CONTINUE TO INITIATE AT AN i

UNACCEPTABLY HIGH RATE. TWO REPORTED IN MAY. NUMEROUS PUBLICATIONS AND MEETINGS HAVE NOT LED TO SOLUTION.

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B. PHENOMENA PHENOMENA IDENTIFIED WHICH POTENTIALLY LEAD TO SEVERE CORE DAMAGE IN SHORTER TIME THAN PREVIOUSLY PELiEVED. OTHER "NEW" PHENOMENA AFFECT THE REACTOR COOLANT SYSTEM (RCS), DECAY HEAT REMOVAL (DHR) SYSTEM, INSTRUMENTATION AND OTHER EQUIPM ENT.

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D. GL 87-12

c. NO RESPONSES FULLY SATISFACTORY.

SOME LICENSEES UNSATISFACTORY IN EVERY ONE OF 12 CATEGORIES EVALUATED. SERIOUS LACK OF UNDERSTANDING AND INADEQUATE PREPARATION FOR OPERATION ID ENTIF!ED.

SOME LICENSEES NOT TAKING CORRECTIVE ACTION OF ANY KIND.

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D. GL 87 12 -

cont

b. INDIVIDUAL LICENSEES HAVE SHOWN EXCELLENT INSIGHT INTO SELECTED

. AREAS SUCH AS RCS D RAIN IN G, CONTAINMENT CLOSURE, INSTRU M ENTATION, DHR SYSTEM OPERATION, OTHERS. IN FORMATION IS NOT EFFECTIVELY SHARED.

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O D. GL 87-12 -

cont FOR EXAMPLE, DIABLO CANYON HAS RESPONDED I

TO CONCERNS AND ADDRESSED SUCH ITEMS AS:

1. CONTAINMENT CLOSURE l

l 2. LEVEL INDICATION IN CONTROL ROOM

3. RCS TEMPERATURE INDICATION

4. PREVENTION OF RCS PERTURBATIONS

5. RHR PROCEDURES

.6. BACKUP EQUIPMENT

7. ANALYSES

8. QUALITY CONTROL AND FOLLOWU P

9. PROCEDURES 1 O. OTHERS O

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5 E. SERIOUS DEFICIENCIES i 1. EVENTS CONTINUE TO ' INITIATE WHICH l HAVE POTENTIAL TO BECOME SERIOUS i

2. MITIGATION PLANNING TO PREVENT CORE DAMAGE IS OFTEN POOR l- -

3. PLANNING TO PREVENT A RELEASE i

SHOULD CORE DAMAGE OCCUR IS OFTEN i NONEXISTENT i  ;

i 4. ANALYSES OFFEN NON EXISTENT. PLANTS .

OPERATED IN UNANALYZED AREAS WHERE ,

IMPLICATIONS NOT UNDERSTOOD.

5. MANY MORE ....

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2 i F. REDUCED RCS INVENTORY OPERATION

! 1. LOSS OF DHR A FREQUENT OCCURRENCE

2. ONE THIRD (40). HAVE OCCURRED DURING  ;

REDUCED INVENTORY OPERATION <

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i F. REDUCFD RCS INVENTORY OKRATION-mrrr f

3. THIS IS OF SERIGIS 00NCERN KCAI!SE:

i A. TW) FISSION PRntllET PAPRIERS TtPICALLY M.KAIN BREAOG i

(RCS PRESSl*E BOIN)ARY #0 I GMAINEND 1

B. LOSS OF DlR OlALLENGES TIE 1

THIRI) BARRIER i

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11. CORRECTIVE ACTIONS A. APPROACH B. EXPEDITIOUS ACTIONS C. PROGRAMMED EN HANCEM ENTS 9

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A. APPROACH

1. SOME REDUCTION IN CORE DAMAGE LIKELlHOOD -

"EXPEDITIOUS ACTIONS" ACCOMPLISH IM M EDIATE, EFFECTIVE REDUCTION IN LIKELlHOOD OF RELEASE IF CORE DAMAGE ACCIDENT OCCURS

2. SIMULTANEOUSLY INITIATE ACTIONS WHICH TAKE A LONGER TIME TO DEVELOP "PROGRAMMED ENHANCEMENTS"

3. MODIFY EXPEDITIOUS ACTIONS AS '

APPROPRIATE AS PROGRAMMED ENHANCEMENTS BECOME AVAILABLE

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11. CORRECTIVE ACTIONS l

A. APPROACH B. EXPEDITIOUS ACTIONS

1. ASSURE CONTAINMENT CLOSURE

2. PROVIDE RCS TEMPERATURE

3. PROVIDE LEVEL INFORMATION

4. DO NOT PERTURB RCS

5. ASSURE BACKUP COOLING EQUIPMENT

6. CONTROL HOT AND COLD LEG

CLOSURE

7. DISCUSS DIABLO CANYON IM PLICATIONS WITH OPERATION STAFF C. PROGRAMMED ENHANCEMENTS

1. ASSURE CONTAINMENT CLOSURE

a. DEVELOP PROCEDURES TO REASONABLY ASSURE CONTAINMENT CLOSURE PRIOR TO THE TIME A CORE DAMAGE ACCIDENT CAN OCC'UR FOLLOWING LOSS OF DECAY HEAT REMOVAL.

b. IMPLEMENT PROCEDURES WHEN DRAINING RCS WHILE LEVEL IS BELOW TOP OF REACTOR VESSEL OR WHILE OPERATING IN A REDUCED INVENTORY CONDITION.

c. IF CONTAINMENT CANNOT BE CLOSED PRIOR TO REACHING CORE DAMAGE, THEN PENETRATIONS CAUSING CLOSURE FAILURE SHOULD NOT BE OPENED.

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4. DO NOT PERTURB RCS DO NOT ALLOW PERTURBATION OF THE RCS AND/OR SYSTEMS USED TO MAINTAIN THE RCS IN A STABLE AND CONTROLLED CONDITION WHILE DRAINING RCS OR AT REDUCED RCS INVENTORY.

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5. ASSURE BACKUP COOLING EQUIPMENT

a. IN ADDITION TO NORMAL DHR SYSTEM, PROVIDE SEVERAL INDEPENDENT MEANS OF ADDING INVENTORY TO THE RCS DURING REDUCED INVENTORY OPERATION.

b. WATER ADDITION RATE OF EACH MEANS TO BE SUFFICIENT TO MAINTAIN CORE IN A COVERED CONDITION.

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l 6. CONTROL HOT AND COLD LEG CLOSURE l ESSENTIALL.Y DO NOT SIMULTANEOUSLY BLOCK ALL HOT LEGS UNLESS A VENT iMTH iS PROVIDED TO THE REACTOR VESSEL UPPER PLENUM THAT IS LARGE ENOUGH TO PREVENT RCS PRESSURIZATION.

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7. DISCUSS DIAB LO CANYON EVENT WITH OPERATIO NS STAFF 3

a EVENT

b. LESSONS LEARNED IM PLICATIO NS FOR LICENSEE

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PLANT l

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l C. PROGRAMMED ENHANCEMENTS

1. INSTRU M ENTATION

2. PROCEDURES l

3. EQUIPMENT

4. ANALYSES

5. TECHNICAL SPECIFICATIONS

PROCEDURES ARE CONSIDERED TO REPRESENT '

THE LARGEST EFFORT, FOLLOWED BY ANALYSES. WE HAVE MINIMlZED INSTRU MENTATION RECOMMENDATIONS TO THE MINIMUM BELIEVED NECESSARY, AND WE ANTICIPATE EXISTING EQUIPMENT IS SU FFICIENT .TO MEET RECOMMENDATIONS.

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i B. EXPEDITIOUS ACTIONS

1. CONTAINMENT CLOSURE ,

2. RCS TEMPERATURE

3. RCS LEVEL t

4. DO NOT PERTUR8 RCS a

5. BACKUP EQUIPMENT

6. HOT AND COLD LEG CLOSURE

7. DISCUSS DIABLO CANYON IMPLICAT!ONS WITH OPERATIONS STAFF

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I C. PROGRAMMED ENHANCEMENTS l

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1. INSTRUMENTATION

2. PROCEDURES

3. EQUIPMENT

4. ANALYSES

5. TECHNICAL SPECIFICATIONS l

C. PROGRAMMED ENHANCEMENTS

1. INSTRU M ENTATION

a. RCS LEVEL

b. RCS TEMPERATURE

c. DHR SYSTEM M O NITORING

d. ABNORMAL CONDITION IN DICATIO NS O

1. INSTRU M ENTATION -

GENERAL 4

RELIABLE INDICATIONS TO BE PROVIDED IN THE CONTROL ROOM UNDER NORMAL AND ACCIDENT CONDITIONS WHENEVER 1RRADIATED

, FUELIS IN REACTOR VESSEL.

RELIABLE MEANS THE ITEM CAN BE I REASONABLY EXPEOTED TO PERFORM ITS INTENDED FU N CTIO N. CONTROL GRADE WILL l

GENERALLY MEET THIS REQUIREMENT. UNDER SOME CIRCUMSTANCES, A LESSER QUALITY IS SU FFICIENT.

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) 1. INSTRU M ENTATION -

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l a. RCS LEVEL L

PROVIDE TWO INDEPENDENT RCS LEVEL INDICATIONS ~ !N FHE CONTROL ROOM.

! b. RCS TEMPERATURE CONTINUOUSLY DISPLAY TWO TEMPERATURE

INDICATIONS WHENEVER REACTOR VESSEL HEAD 4

IS LOCATED ON TOP OF THE REACTOR VESSEL.

1. INSTRU M ENTATION -

cont

c. DHR MONITORING PROVIDE THE CAPABILITY OF MONITORING DHR SYSTEM PERFORMANCE WHENEVER A DHR SYSTEM IS IN USE FOR COOLING THE RCS.

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d. ABNORMAL CONDITION IN DICATIONS PROVIDE VISUAL AND AUDIBLE INDICATIONS OF ABNORMAL CONDITIONS IN TEMPERATURE, LEVEL, AND DHR SYSTEM PERFORMANCE.

2. PROCEDURES

a. DEVELOP AND IMPLEMENT PROCEDURES i THAT COVER NORMAL OPERATION OF NSSS, CONTAINMENT AND SUPPORTING i

SYSTEMS UNDER CONDITIONS WHERE l

COOLING NORMALLY PROVIDED BY DHR SYSTEMS.

b. PROVIDE EMERGENCY PROCEDURES THAT COVER ABOVE IDENTIFIED AREAS IF AN OFF-NORMAL CONDITION DEVELOPS.

c. PROVIDE ADMINISTRATIVE CONTROLS TO SUPPORT PROCEDURES AND ALL RECOMMENDED ACTIONS.

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3. EQUIPMENT

! a. PROVIDE ADEQUATE, RELIABLE EQUIPMENT FOR RCS COOLING AND FOR AVOIDING A LOSS OF RCS COOLING.

j b. PROVIDE PERSONNEL COMMUNICATIONS.

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c. PROVIDE ADDITIONAL EQUIPMENT TO MITIGATE A LOSS CF DHR OR A LOSS OF RCS INVENTORY SHOULD THESE OCCUR.

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4. ANALYSES f

a. PROVIDE BASIS FOR PROCEDURES, INSTRU M ENTATIO N, EQUIPMENT OPERATION, AND CO NTAI N M ENT.

b. ENCOMPASS THERMODYNAMIC AND CON FIGU RATION CON DITIO NS WHICH CAN BE REASONABLY ENCOUNTERED.

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c. EMPHASIZE DEVELOPMENT OF COMPLETE LINDERSTANDING OF NSSS BEHAVIOR t

DURING NONPOWER O PERATIN G REGIONS OF INTEREST.

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l 3 5. TECHNICAL SPECIFICATIONS

IDENTIFY TECHNICAL SPECIFICATIONS IM PACTED: BY ABOVE RECOMMENDED ACTIONS AND SUBMIT APPROPRIATE CHANGES.

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Ill. FUTURE STAFF ACTION J

STAFF IS STU DYING OPTIONS TO IMPLEMENT RECOMMENDATIONS IN BEST MANNER. THESE i

RANGE FROM VOLUNTARY LICENSEE RESPONSE TO ORDERS.

, CONCLUSIONS i

WE'VE C VERED THE ISSUE, THE BACKGROUND

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AS WE SEE IT, RECOMMENDED CORRECTIVE ACTIONS, AND THE OPTIONS WE ARE CONSIDERING.

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WE WELCOME INDUSTRY REPRESENTATIVE RESPONSE TO MOST RAPIDLY ACHIEVE THE DUAL OBJECTIVES OF:

1. SHORT TERM PROTECTION FROM A RELEASE DUE TO A CORE DAMAGE ACCIDENT AND i

2. LONG TERM RESOLUTION OF THE PROBLEMS ASSOCIATED WITH OPERATIO N '

DURING CONDITIONS WHERE COOLING BY DHR ,

SYSTEMS IS DESIRED. .

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B&W NSS LESS SUSCEPTIBLE TO LOSS OF

_ DER'DUE TO MID LOOP OPERATIONS o MINIMUM LEVEL REQUIRED FOR MAINTENANCE IS APPR0XIMATELY

, 30 INCHES AB0VE DMR St0P LINE .pg.f A .-

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o OT$G DESIGN PROVINS P95ITIVE p.si l MEANS OF VENTING RCS THUS PROVIDING A STABLE LEVEL INDICATION HAING BRAIN DOWN  !

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'N0ZKLES(WNICEAttNIGEER ELEVATIONS TRAN BST LIG N0ZZLES)

DIRECTLY INTS 15 LIT PLENUM THUS .

ELIMINATING LEVEL CAMGES DUE T0 -

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B&W.$$TiSSSUSCEPTIBLETOLOSSOF DHR DUE TO MID LOOP OPERATIONS (CONT'D) o INCORE THERMOC0UPLES EXIT THROUGH BOTTOM 0F RV THUS INCREASING PROBABILITY THAT C@tt EXIT .f ',

THERMOC0UPLES ndO5LS K AVAILABI,E l DURING DRAINED DOW OPERATIONS -

l o REACTOR L INTERAAL VENT l VALVES E5 CONCERN ABOUT UPPER 555tIZATION -

FORCING L D0tNI l

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s July 28, 1988 Progranted enhancements for the longer term include permanent improved instrumentation, analyses, and technical specification changes where impacts are identified with respect to the recommended enhancements.

B&W plants are less vulnerable to core uncovery while drained down because the core flood check valves prevent differential pressure from developing across the internals and therefore prevent early core uncovery due to steam pressuri-

zation. Also, B&W plants do not drain down to the mid-loop level often. Other differences are shown on Enclosure 3.

The B&W Owners Group felt that, because of these differences and the fact that only momentary losses of DHR flow have occurred at B&W plants, B&W plants should either be excluded from the letter NRC is considering or the more fore-giving design appropriately noted.

The Group also recommended that the usual Technical Specification definition of containment closure (for fuel movement) should be adequate for a definition of containment closure in the event of a total loss of decay heat removal ability.

original signed by Charles M. Traunell, Senior Project Manager ,

Project Directorate V Division of Reactor Projects - III, IV, Y and Special Projects

Enclosure:

1. Attendees '

2. Staff Viewgraphs

3. B&W Design Differences cc: w/ enclosures See next page DISTRIBUTION p conet Tue " d BGrimes

PDR - " NRC Participants LPDR ACRS (10)

PDV Reading MRJohnson GKnighton DKirsch Project Hanager PlantServiceList(Seenextpage)

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