ML18152A519

Discusses 880916 Mgt Meeting to Discuss Corrective Actions Prior to Using Reactor Cavity Seal for Upcoming Unit 2 Refueling.List of Attendees Encl

ML18152A519
Person / Time
Site:	Surry
Issue date:	10/20/1988
From:	Ernst M NRC OFFICE OF INSPECTION & ENFORCEMENT (IE REGION II)
To:	Cartwright W VIRGINIA POWER (VIRGINIA ELECTRIC & POWER CO.)
References
NUDOCS 8811020109
Download: ML18152A519 (31)

Text

OCT 2 O 1988 Virginia Electric an~ower Company

~TTN:

Mr. W. R. Cartwright, Vice-President, Nuclear Operations P. 0. Box 26666 Richmond, VA 23261 Gentlemen:

SUBJECT:

MANAGEMENT MEETING

SUMMARY

This letter refers to the Management Meeting held at our request on September 16, 1988.

This meeting was in fulfillment of the requirements of a Confirmation of Action letter (CAL) issued by us on September 6, 1988.

This CAL required a meeting to discuss your corrective actions prior to using the reactor cavity seal for the upcoming Unit 2 refueling.

The issues discussed at this meeting related to items of concern involving the leakage past the Unit 1 reactor cavity seal which occurred on May 17, 1988.

A meeting summary, a list of attendees, and a copy of your handouts are enclosed.

Subsequent to our September 16, 1988 meeting, you shut down Surry Unit 1 for corrective modifications to the emergency power distribution system.

Following that shutdown, you determined that Unit 1 reactor will be defueled prior to Unit 2, to inspect fuel assemblies for suspected defects, and to replace fuel assemblies as necessary. On September 26, 1988, members of my staff contacted Surry Plant Management to discuss your planned corrective actions for the Unit 1 reactor cavity seal.

During that telephone conversation, we requested that you document your plans regarding corrective actions for the Unit 1 reactor cavity seal in a letter to us.

Your letter to us of October 3, 1988, docketed your plans for corrective action.

Should you have any questions concerning this matt"er, please contact us.

Enclosures:

1.

Management Meeting Summary

2.

List of Attendees

3.

Handout

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/'[}'" L. Benson, Station Manager

N. E. Hardwick, Manager - Nuclear Programs and Licensing

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/NRC Resident Inspector

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ENCLOSURE 1 MANAGEMENT MEETING

SUMMARY

A Management Meeting was held at the Region II office on September 16, 1988, to discuss issues of concern associated with the leakage past the Unit 1 reactor cavity seal on May 17, 1988.

The Regional Administrator began the meeting with opening remarks which identified our areas of concern.

Following an acknowledgement of the concerns by the licensee's Senior Vice President for Power Operations, and some introductory remarks by the new Vice President for Nuclear Operations, the Surry Station Manager presented a summary of the reactor cavity seal leakage event. The summary of the event identified several problems.

These problems were that the initial review of the event at the stations was inadequate; the management sensitivity to abnormal events, including this event, has been lacking; and the improper design or fit of the seal was not recognized as a potential problem during initial review by management.

The station manager also discussed the general reactor cavity seal design, the seal leak event on May 17, the station response to the event, lessons learned from the event, and corrective actions which were being implemented as a result of the event.

After the station manager's presentation, the licensee I s Manager of Nuclear Engineering presented the design conclusions including the design basis, possible seal failure mechanism, pressure supply modifications, long term design requirements, and design lessons learned.

NRC representatives asked some questions with regard to clarification of chronology during the presentation.. Also, specific questions were asked relating to why the NRC was not made aware of this event prior to August 26, 1988.

At the conclusion of the presentation by'the licensee's station manager, the Regional Administrator expressed serious concern with regard to licensee management's inappropriate sensitivity to significant abnormal events.

The meeting was closed by the Deputy Regional Administrator.

ENCLOSURE 2 MANAGEMENT MEETING ATTENDEES Virginia Electric and Power Company D. Benson, Station Manager, Surry R. Calder, Manager Nuclear Engineering W. Cartwright, Vice President, Nuclear Operations P. Doody, Project Engineer, Nuclear*

S. Eisenhart, Staff Engineer, IOER E. Grecheck, Assistant Station Manager, Surry F. Moore, Vice President, Power, Engineering Services G. Pannell, Director, SEC W. Stewart, Senior Vice President, Power Operations Nuclear Regulatory Commission H. Berkow, Director, Project Directorate II-2, NRR F. Cantrell, Section Chief, DRP, RII M. DeGraff, Reactor Engineer, DRS, RII M. Ernst, Acting Regional Administrator, RII A. Gibson, Director, Reactor Safety Division, RII C. Hehl, Deputy Director, DRP, RII W. Holland, Senior Resident Inspector, Surry, RII G. Jenkins, Director, EICS, RII C. Julian, Chief, Operations Branch, DRS, RII W. LeFave, AIT Member, NRR L. Nicholson, Resident Inspector, Surry, RII T. O'Connor, Reactor Engineer, DRS, RII C. Patel, Project Manager, NRR R. Schin, Reactor Engineer, DRS, RII L. Reyes, Director, DRP, RII C. Rossi, Director, Division of Operational Events Assessment, NRR M. Shymlock, Section Chief, Operational Programs Section, DRS, RII W. Troskoski, Region II Coordinator, Executive Director for Operations B. Uryc, Enforcement Coordinator, RII S. Varga, Director, Project Directorate I/II, NRR B. Wilson, Branch Chief, DRP, RII

ENCLOSURE 3 VIRGINIA POWER MANAGEMENT MEETING REACT.OR CAVITY SEAL LEAKAGE EVENT NRC BRIEFING September 16, 1988

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e VIRGIIIIIA POWER D. L. BENSON

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STATION MANAGER

AGENDA

• GENERAL OVERVIEW

• PROBLEMS -

ROOT CAUSE

• GENERAL.REVIEW OF SEAL DES 1.GN

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• SEAL LEAK EVENT DESCRIPTION/EVALUATION

• STATION :RESPONSE TO EVENT

• LESSONS LEARNED

• CORRECT l"VE ACTIONS

• DESIGN REVIEW

• DESIGN ISSUES

OVERVIEW

• ON MAY 17, 1966 WITHOUT.-FUEL IN THE VESSEL OR FUEL HANDLING ACTIVITIES IN PROGRESS A REFUELING CAVITY SEAL LEAK OCCURRED DUE TO OPERATOR ERROR.

• DURING THE EVENT, THE ~ESPONSE OF SUMP LEVEL AND RADIATION MONITORS INDICATED A HIGH PROBABILITY OF A DEGRADED BACK-UP SE:AL.

• IT APPEARS THAT THE BACK-UP SEAL WOULD HAVE ALLOWED A CAVITY DRAIN RATE OF APPROXIMATELY 3 INCHES PER MINUTE ALLOWING ADEQUATE TIME TO PLACE A FUEL ASSEMBLY IN A SAFE LOCATION.

OVERVIEW (cont.)

• DUE TO AN INADEQUATE.INITIAL REVIEW OF THIS EVENT, THE POSS I BIL ITV OF J-SEAL DAMAGE WAS NOT RECOGNIZED UNTIL A MORE RIGOROUS INDEPENDENT EVA[UAT I ON WAS COMPLETED BY CORPORATE SAFETY EVALUATION AND CONTROL STAFF.

• ACTIONS WILL BE TAKEN TO ENSURE THE PROPER FUNCTION OF BOTH UNITS CAVITY SEALS PRIOR TO USE

• ACTIONS WILL BE TAKEN TO ENSURE THAT ABNORMAL EVENTS WI LL RECEIVE MORE RESPONSIVE AND DETAILED REVIEW IN THE FUTURE..

• PROBLEM - ROOT CAUSE PROBLEMS

• INADEQUATE IN IT I AL: REVIEW OF EVENT

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• SEAL POTENTIALLY DEGRADED ROOT CAUSE

• MANAGEMENT SENS IT l*V ITV TO ABNORMAL EVENTS

• INADEQUATE STATION BASED EVENT REVIEW

• IMPROPER FIT OF SEAL

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GENERAL DES.IGN DESCRIPTION

• A PERMANENTLY INSTALLED STEEL DIAPHRAGM PLATE EXTENDS INWARD FROM THE REACTOR CAVITY LEAV°JNG A 6-1 /4 INCH ANNULAR OPENING AROUND THE REACTOR VESSEL FLANGE

• INFLATABLE SEALS AND PASSIVE J-SEALS ARE MECHANICALLY FASTENED TO THE INNER AND OUTER FACES OF THE REMOVEABLE,1-SHAPED, STEEL SEAL RING

• WHEN LOWERED INTO PLACE, THE VERTICAL POSITION OF THE SEAL RING IS DETERMINED BY 8 INNER AND OUTER SUPPORTS WHICH REST ON THE REACTOR FLANGE AND DIAPHRAM PLATE

• THE INFLATABLE SEALS ARE PR~SSURIZED BY INSTRUMENT AIR TO 20 PSI

• THE VERTICAL POSITION OF THE SEAL RING ESTABLISHES THE PRELOAD OF THE J-SEAL

• SEEPAGE PAST THE ASSEMBLY IS COLLECTED IN DR IP PANS AND DRAINED

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SEAL LEAKAGE EVENT DESCRIPTION INITIAL CONDITIONS

• NO FUEL IN REACTOR V~SSEL

• REACTOR CAVITY ISOLATED FROM SPENT FUEL POOL

• TYPE C TESTING OF INSTRUMENT A IR VALVES IN PROGRESS (TYPE C TESTING OF I.A VALVES INTENTIONALLY SCHEDULED FOR "FUEL OUT" PERIOD TO AV O ID MAN IP UL AT I ON O.F VALVES DUR I NG FUEL MOVEMENT)

• VALVE MANIPULATIONS. ASSOCIATED W 1TH TYPE C TESTING AND RELATED MAINTENANCE CAUSED LOSS OF AIR TO MAIN SEAL, N2 BACKUP SYSTEM SUPPORTS SEAL FOR SOME PERIOD OF Tl.ME THEN LEAKAGE BEGINS

EVALUATION RESULTS BASED ON SUMP LEVEL RESPONSE, RADIATION MONITOR RESPONSE AND INTERVIEWS REVIEW OF OPERATOR ACTION:

• VALYE MANIPULA~IONS ASSOCIATED WITH TYPE C TESTING OF INSTRUMENT AIR CONTAINMENT PENETRATION ISOLATION VALVES LED TO LOSS OF AIR TO MAIN SEAL INITIAL STATION CONCLUSIONS:

• VALVE 1-IA-838 MISALIGNED CLOSED, PROBABLY EVENING OF MAY 16th

• LEAKAGE OCCURRED AT A RATE OP APPROXIMATELY 35 GPM FOR 7 HOURS AND WAS CORRECTED BV OPERATOR AT APPROXIMATELY 0850

• BASED ON TRAINING AND KNOWLEDGE OF SEAL DESIGN WE DID NOT BELIEVE THAT LEAKAGE OBSERVED WAS AN INDICATION OF DEGRADED SEAL e

EVALUATION RESULTS (Cont)

INDEPENDENT REVIEW CONCLUSIONS:*

• VALVE 1-IA-838 WAS MISALIGNED IN A THROTTLED POSITION

• AT APPROXIMATELY 0830, A RAPID LEAK OCCURRED OVER A 4 TO 6 MINUTE PERIOD AND WAS INITIATED AND CORRECTED BV OPERATOR ACTIONS

• J-SEAL NOT FUNCTIONING AS DESIGNED CONSENSUS CONCLUSION:

• SOME LEAKAGE DID BEGIN 7HRS. PRIOR TO IDENTIFICATION

• A FINAL RAPID LEAK PROBABLY OCCURRED COINCIDENT W 1TH VALVE MANIPULATIONS

• • • • PROBABLE HIGHEST LEAK.AGE RATE ASSUMING LEAKAGE IN FINAL 4 MINUTES YIELDS 6450 GPM

• UNDER REFUELING CONDITIONS (POOL AND CAVITY CONNECTED) LEVEL DROP RATE WOULD BE APPROXIMATELY 3.2 INCHES PER MINUTE

• TIME NEEDED TO STORE FUEL ASSEMBLY IS LESS THAN S MINUTES e

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S~GNIFICANT EVENT: REVIEW MEETINGA2 WEEKS AFTER INSPECTED AND CLEANED INCORE SUMP ROOM SNSOC RECEIVED FORMAL PRESENT AT I ON OF INDEPENDENT REVIEW GROUP; B/25/BB

LESSONS LEARNED

• INADEQUATE REVIEW OF* EVENT SITE EVENT REVIEW FUNCTION WAS NOT EFFECTIVE MANAGEMENT ASSESSMENT LED TO HUMAN FACTORS EMPHASIS., INADEQUATE TECHNICAL REVIEW

• SENSITIVITY TO ISSUE

• SIGNIFICANCE NOT RECOGNIZED NO REVIEW TEAM ASSIGNED DISTRACTED BY *oTHER EVENTS

• UN IT 2 AU_X IL I ARY FEEDWATER BLOCKAGE e

LESSONS LEARNED (cont.)

• LOSS OF CONTROL OF VALVE.

- NEED TO REVIEW CONTROL OF* VALVES BV TVPE C TEST PERSONNEL

... - UNIQUE FEATURES OF** INSTRUMENT A IR DRAWi NGS AND CONTROLS PROCEDURAL ISSUES

- FUEL HANDLING ABNORMAL PROCEDURES ARE NOT WELL INTEGRATED* WITH **.INTERFACING PROCEDURES

- NEED PROCEDURES FOR. INSTALLATION AND OPERATION OF BACKUP N2 BOTTLES

-INADEQUATE TRACKING OF PROCEDURAL COMMITMENTS

LESSONS LEARNED (cont.)

• TRAINING

- ADDITIONAL TRAINING IS NEEDED ON SEAL DESIGN 1

CORRECTIVE ACTIONS.

• REVIEW AND UPGRADE STATION BASED EVENT REVIEW FUNCTION - ASAP I

• REVIEW EVENT W 1TH MANAGEMENT STAFF REGARD I NG NEED TO ENSURE BROAD BASED EVENT REVIEW AND SENSITIVITY TO ALL EVENTS -9/30/BB

• EVALUATE CONTROL OF VALVES BY TYPE C TEST SUPERVISORS AND PERSONNEL -

9/30/88

• EVALUATE INSTRUMENT A IR SYSTEM TO I DENT I FY OTHER COMPONENTS WHERE ADDITIONAL CONTROLS ARE NEEDED (IN CONJUNCTION WITH *GL BB-14) -

02/06/69 e)

• REVISE FUEL HANDLING.ABNORMAL PROCEDURES -

PRIOR TO FUEL MOVEMENT INSTITUTE PROCEDURAL COMMITMENT CONTROLS -

10/31/BB

CORRECTIVE ACTIONS

• DEVELOP PROCEDURES FOR INSTALLATION AND OPERATION OF N2 BOTTLES -

PRIOR TO USE OF CAVITY SEAL

• TRAIN OPERATIONS PERSONNEL ON THIS EVENT, SEAL DESIGN, SENSITIVITY. TO ABNORMAL EVENTS AND PROCEDURE CHANGES -

PRIOR TO USE OF CAVITY SEAL

VIRGINIA POWER e

R. W. CALDER -

MANGER NUCLEAR ENGINEERING j

REACTOR CAVITY SEAL ASSEMBLY

• DESIGN BASIS AND CRITERIA

• POSSIBLE SEAL ASSEMBLY FAILURE MECHANISMS

• PRESSURE SUPPLY MODIFICATIONS

• ACTIVITIES PRIOR TO U2 REFUELING

• LONGTERM DESIGN REQUIREMENTS

• DESIGN LESSONS LEARNED

DESIGN BASIS AND CRITERIA

• DESIGN FUN CT I ON UFSAR SECT I ON 9. 12.3. 1

- FILL CAVITY TO DEPTH TO LIMIT REFUELING RADIATION LEVELS

- PREVENT LEAKAGE

- PASSIVE SEAL PREVENTS FAILURE IF PNEUMATIC SEAL DEFLATES

• DESIGN REQUIREMENTS IN DRAWING AND FABRICATION SPECIFICATION

- TOLERANCES

- SHOP TESTS

• NO SPECIFIC CALCULATIONS

DESIGN BASIS AND CRITERIA (Cont)

• N O I N ST A L L AT I O N S P E C I F I C AT I O N

• NO SEAL ASSEMBLY PREOPERATIONAL TEST RESULTS

• RECONSTRUCTED DES I GN CRITERIA

-REDUNDANCY: PASS IVE AND ACT I VE

-NO SPECIFIC TESTING REQUIREMENTS

-DRAIN DESIGN ACCOMMODATES ALLOWABLE ASSEMBLY LEAKAGE

-J-SEAL PERFORMANCE MUST ALLOW SAFE TERMINATION OF REFUELING OPERATIONS

POSSIBLE SEAL ASSEMBL V FA I LURE MECHANISMS

• CAUSE OF LEAKAGE

- DEFLATION OF THE INFLATABLE SEALS ISOLATION OF INSTRUMENT AIR SUPPLY AND DEPLETION OF N2 SUPPLY

- PASSIVE J-SEAL NOT PROPERLY SEATED

• POTENTIAL CAUSES OF IMPROPER J-SEAL SEATING

- IMPROPER SUPPORT SETT ING

- SEAL RING OUT-OF-ROUND DUE TO REPEATED HANDLING

- WAVINESS OF SEATING SURFACES AND OF J-SEAL

- NON COPLANAR REACTOR FLANGE AND DIAPHRAM PLATE

- FLEXURE OF DI APHRAM PLATE UNDER HYDRO ST AT IC LOAD

- DAMAGED OR IMPROPERLY ASSEMBLED J-SEAL e

PRESSURE SUPPLY MODIFICATION

• ADDED BACKUP BOTTLED N2 SYSTEM TO IMPROVE RELIABILITY OF PRESSURE SUPPLY

• 'ADDED CHECK VALVES AND PRESSURE RELIEF

• UNIT 2 COMPLETED - UNIT 1 PARTIAL

• DRAW I NG DETAILS AND COMPONENT TAGG I NG NOT CONSISTENT WITH CURRENT INDUSTRY PRACTICE

UNIT 2 ACTIVITIES

• VER I FY ADEQUACY OF PRESSURE SUPPLY INSTRUMENT AIR -- NITROGEN SYSTEM WALKDOWN UPGRADE APPLICABLE SECTIONS OF INSTRUMENT AIR DRAWINGS

,

• INSPECT SEAL RINGS

- INSPECTION OF CRITICAL SEAL ASSEMBLY DIMENSIONS

( HORIZONTAL AND VERTICAL ALIGNMENT)

- INSPECT AND IF NECESSARY, REPLACE J-SEALS AND, INFLATABLE SEALS

• MODIFY SEAL RING

- RESET ASSEMBLY SUPPORT SETTING TO ACCOMMODATE ACTUAL DIMENSIONS AND ENSURE PRELOADING OF J-SEALS

- INSTALL BACKING RING TO INCREASE PRESSURE ON J-SEALS

• TEST J-SEAL LEAKAGE AFTER INSTALLATION AND PRIOR TO FUEL MOVEMENT

I LONG TERM MODIFICATION DESIGN CONSIDERATION

• UNIT 2 TEST RESULTS

• ALARA CONSIDERATIONS

• MAINTAIN REDUNDANCY

~ PASSIVE VERSUS ACTIVE COMPONENTS

• MAINTENANCE REQUIREMENTS

• INDUSTRY EXPERIENCE WITH ALTERNATIVE DESIGNS

• OUTAGE CRITICAL PATH - EASE OF MODIFICATION AND INSTALLATION e

• POTENTIAL FOR CATASTROPHIC FAILURE

• SENS IT IV ITV TO GAP WIDTH AND OFFSET HEIGHTS

• CAPABILITY TO WITHSTAND DYNAMIC IMPACT

DESIGN LESSONS LEARNED

• REEMPHASIZE NEED FOR BETTER DESIGN DOCUMENTATION

• MAINTENANCE, INSPECTION AND PERIODIC TEST CRITERIA SHOULD BE SPECIFIED IN DESIGN

- LACK OF BASIS FOR TEST ACCEPTANCE CRITERIA MAY ALLOW UN-

, SATISFACTORY CONDITIONS TO BE ACCEPTED BY EVALUATION

- CRITICAL TOLERANCES WERE NOT VERIFIED

- SEAL REPLACEMENT CRITERIA NOT ESTABLISHED

- PASSIVE SEAL PERFORMANCE NOT DEMONSTRATED

- SEAL ASSEMBLY PERFORMANCE CRITERIA NOT ESTABLISHED

• INSTRUMENT AIR DRAWING DETAILS NOT SUFFICIENT e