ML20195D455

Summary of Operating Reactors Events Briefing 98-07 Held on 981021.List of Attendees,Significant Elements of Discussed Events & Significant Events That Were Identified for Input Into NRC Performance Indicator Program Encl

ML20195D455
Person / Time
Site:	Davis Besse
Issue date:	11/10/1998
From:	Stolz J NRC (Affiliation Not Assigned)
To:	Roe J NRC (Affiliation Not Assigned)
References
OREM-98-007, OREM-98-7, NUDOCS 9811180051
Download: ML20195D455 (13)

Text

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,(. November 10, 1998 l

MEMORANDUM TO: Jack W. Roe, Acting Director Division of Reactor Program Management FROM: John F. Stolz, Chief [ Origin al aign e d b y ]

Events Assessment and Generic Communications Branch Division of Reactor Program Management

SUBJECT:

OPERATING REACTORS EVENTS BRIEFING OCTOBER 21,1998 - BRIEFING 98-07 I On October 21,1998, we conducted an Operating Reactors Events Briefing (98-07) to inform

)

senior managers from the Offices of the EDO, NRR and regional offices of selected events that  ;

occurred since our last briefing on July 8,1998. -Attachment i lists the attendees.  !

Attachment 2 presents the significant elements of the discussed event.

Three significant events were identified for input into the NRC Performance Indicator Program (Attachment 3).

. The statements contained in the attached briefing slides represent the best information currently available to the NRC Future followup could produce new information that may alter the NRC's current view of the event discussed.

' Attachments: As stated (3) .

cc w/atts:

See next page CONTACT: Kathy Gray, NRR (301) 415-1166-DISTRIBUTION '(w/atts) ,

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' MemeH4esN PUBLIC LKilgore, SECY i w PECB R/F Kathy Gray WBurton  :

DOCUMENT NAME: G:\KAG\ORTRANS To receive a copy of this document, indicate in the box: "C" = Copy without attachment / enclosure "E" =

Copy with attachment / enclosure "N" = No cospr/ A OFFICE PECB lE PEC Q l PFMI f l C(PhCB jN NAME KGray Ma% EGoodv' vin R($nnU JSbc j DATE 10/JLA/98 0 1$/ /0/98 1(/ /(l' /98 f(/ /9 /98 /

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)i November 10, 1998 MEMORANDUM TO: Jack W. Roe, Acting Director Division of Reactor Program Management FROM: John F. Stolz, Chief Events Assessment and Generic

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Communications Branch Division of Reactor Program Mana ement

SUBJECT:

OPERATING REACTORS EVENTS BRIEFING OCTOBER 21,1998 - BRIEFING 98-07 On October 21,1998, we conducted an Operating Reactors Events Briefing (98-07) to inform  ;

senior managers from the Offices of the EDO, NRR and regional offices of selected events that occurred since our last briefing on July 8,1998. Attachment 1 lists the attendees.

Attachment 2 presents the significant elements of the discussed event.

Three significant events were identified for input into the NRC Performance Indicator Program (Attachment 3).

The statements contained in the attached briefing slides represent the best information currently available to the NRC. Future followup could produce new information that may alter the NRC's current view of the event discussed.

Attachments: As stated (3) cc w/atts:

See next page CONTACT: Kathy Gray, NRR (301) 415-1166 l

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l l

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l l

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cc:

S. Collins, NRR (O-5E7) S. Richards (0-13D1)

F. Miraglia, NRR (O-5E7) A. Hansen (0-13E21)

F, Gillespie, NRR (0-5E7)

8. Boger, NRR (0-14E4)

B. Sheron, NRR (0-5E7)

J. Zwolinski, NRR (0-14E4)

E. Adensam, NRR (0-13E4)

G. Lainas, NRR (O-7D26)

G. Holahan, NRR (0-8E2)

D. O'Neal, NRR (0-8D1)

L. Spessard, NRR (0-9E4)

M. Markley, ACRS (T-2E26)

T. Martin, AEOD (T-4D18)

C. Rossi, AEOD (T-4A9)

F. Congel, AEOD (T-4D28)

S. Rubin, AEOD (T-4D28)

M. Harper, AEOD (T-4A9)

W. Leschek, AEOD (T-4A9)

G. Tracy, EDO (0-16E15)

J. Gilliland, PA (0-2A13)

A. Thadani, RES (T-10F12)

M. Federline, RES (T-10F12)

W. Hill, SECY (0-16C1)

H. Miller, Region I C. Hehl, Region I L. Reyes, Region 11 L. Plisco, Region ll S. Vias, Region ll J. Dyer, Region lil G. Grant, Region ill E. Merschoff, Region IV P. Gwynn, Region IV G. Fader, INPO J. Zimmer, DOE i

l l

9 LIST OF ATTENDEES OPERATING REACTORS EVENTS FULL BRIEFING (98-07)--

October 21,1998 l NAME OFFICE NAME OFFICE W. Burton - NRR D. O'Neal NRR K. Gray NRR P. Wilson NRR' J. Stolz NRR E. Goodwin NRR 1

. T. Koshy NRR D. Collins NRR-R. Dennig NRR R. Ennis NRR

'D. Skeen NRR S. Newberry NRR ,

-S. Richards NRR M. Tschiltz OEOD  !

J. Hannon NRR A. Hansen NRR i W. Lyons NRR K. Naidu NRR j C. Goodman NRR S. Wong NRR  !

TELEPHONE ATTENDANCE (AT ROLL CALL)

BegiDDR Resident insoectors Region I Davis Besse Site Region ll1 Region IV M!SA Technical Training Center f

4 ATTACHMENT 1 t

OPERATING REACTORS EVENTS BRIEFI'NG 98-07 l 1

l LOCATION: 0-12 B4, WHITE FLINT WEDNESDAY, OCTOBER 21,1998,11:00 A.M.

I DAVIS BESSE, UNIT 1 SCRAM WITH COMPLICATIONS 1

i I

l l PRESENTED BY:

4 EVENTS ASSESSMENT AND GENERIC COMMUNICATIONS BRANCH DIVISION OF REACTOR PROGRAM MANAGEMENT, NRR ATTACilMENT 2

i 98-07 DAVIS BESSE, UNIT 1 SCRAM WITH COMPLICATIONS OCTOBER 14,1998 PROBLEM-SIMULTANEOUS MAINTENANCE AT POWER ON MULTIPLE i l SYSTEMS AND TRAINS LEADS TO SCRAM WITH NATURAL CIRCULATION AND COMPLICATIONS.

l CAUSFJ INADEQUATE PLANNING OF MAINTENANCE ACTIVITIES.

SAFETY SIGNIFICANCE:

MULTIPLE SUPPORT SYSTEMS PLACED IN ABNORMAL CONDITIONS; POSSIBILITY EXISTED TO DISABLE SEVERAL SYSTEMS INCREASING RISK OF INADEQUATE CORE COOLING AFTER TRIP.

DISCUSSION

• INITIAL CONDITIONS OCTOBER 14, OPERATING AT 100%; PLANT DOING TRAIN 2 MAINTENANCE, TRAIN 1 " PROTECTED" MAINTENANCE BEING DONE ON FLOW ELEMENT ON CCW TRAIN 1 AND ON AUXILIARY BOILER MAINTENANCE ALSO DOING PM ON ALTERNATE BUS TIE CIRCUIT BREAKER TO 4160 VITAL BUS D1 FOR TRAIN 2 i

CONTACT: EDWARD GOODWIN, NRR/DRPM/PECB AIT: NO i

REFERENCE:

10 CFR 50.72 #34915 SIGEVENT:IBD

~

DAVIS BESSE, UNIT 1 98-07 i o SEQUENCE OF EVENTS AT 1356 PM, BUSES D1 AND D2 ARE DE-ENERGlZED AND LOCKED OUT WHILE RACKING IN BUS TIE CIRCUlT BREAKER AACD1; CCW PUMP 2 STOPS, CCW PUMP 1 STARTS FROM STANDBY MODE EDG 2 STARTS WHEN BUS D1 IS DEENERGlZED; DOES NOT LOAD DUE TO LOCKOUT; SECURED 5 MINUTES LATER BECAUSE OF NO CCW FOR TRAIN 2 POWER REDUCED TO 86% TO MATCH AVAILABLE CONDENSATE FLOW AT 1415, SMALL LEAK IN CCW SYSTEM IDENTIFIED BY SURGE TANK LOW LEVEL DURING BUS RECOVERY

! PROCESS l

l -

AT 1511, POWER RECOVERED TO VITAL BUS D1 AT 1522, CCW PUMP 2 RESTARTED AT 1523, LARGE CCW LEAK NOTED BY CCW TANK LOW LEVEL AND CONTAINMENT SUMP HIGH LEVEL; CCW CONTAINMENT ISOLATION VALVES AUTOCLOSE ON LOW / LOW CCW TANK LEVEL; THIS ISOLATES COOLING TO RCP MOTORS AND SEAL COOLERS AT 1523, IAW PROCEDURE, OPERATORS SCRAM PLANT AND TRIP RCP'S i

1 L

DAVIS BESSE, UNIT 1 98-07 MSSV'S LIFT ON REACTOR TRIP / TURBINE TRIP; ONE FAILS TO RESEAT; STEAM PRESSURE LOWERED FROM 955 TO 920 PSIG TO RESEAT l

AT 1623, OPERATORS CLOSE MAIN STEAM ISOLATION l VALVES TO TERMINATE COOLDOWN; COOLDOWN EXACERBATED BY NO RCP'S AND NO AUXILIARY BOILER o COMPONENT COOLING WATER PERFORMANCE INITIAL CONDITIONS: CCW PUMP 2 RUNNING, CCWP 1 IN STANDBY; FLOW SWITCH FE 1822 OUT OF SERVICE FOR MAINTENANCE l -

LOSS OF BUS D1 DEENERGlZES CCW PUMP 2, LOW FLOW SENSED STARTING CCWP 1 AFTER 30 SECOND TIMER DELAY, CCWV 5095 AND 5097 OPEN, REESTABLISHING NONVITAL CCW FLOW INTERRUPTION OF NONVITAL CCW FLOW HAS ALLOWED STEAM TO FORM IN OPERATING LETDOWN HEAT EXCHANGER l

l -

WHEN CCWP1 REESTABLISHES FLOW, A PRESUMED PRESSURE TRANSIENT CAUSES PARTIAL OPENING OF RUPTURE DISK WHICH IS DETECTED BY MAKEUP REQUIREMENTS TO CCW SURGE TANK l -

WHEN PUMP 2 RESTARTS CAUSES ANOTHER TOTAL FAILURE OF RUPTURE DISK i ..

DAVIS BESSE, UNIT 1 98-07 l

RAPID LOSS OF CCW SURGE TANK LEVEL CAUSES CLOSURE OF CCW CONTAINMENT ISOLATION VALVES WHICH ISOLATES LEAK.

CCW CONTAINMENT ISOLATION INTERRUPTS CCW TO RCP SEAL AND BEARING COOLERS AND TO MOTOR HX o SYSTEMS / COMPONENTS POTENTIALLY IMPACTED EDG 2 l -

MSSV'S i -

MAKE UP PUMP 2 AFW l

AUXILIARY BOILER l

MANUAL MOTORDRIVEN AUXILIARY FEEDPUMP l -

RCS l

LETDOWN EMERGENCY AC POWER o ROLE OF MAINTENANCE ACTIVITIES-PROTECTED TRAIN MAINTENANCE PROCESS RISK MATRIX INFLUENCE ON TRANSIENTS o UNRELATED ONGOING ISSUES PRESSURIZER SPRAY VALVE

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4 i

DAVIS BESSE, UNIT 1 98-07 L e RISK IMPLICATIONS CCW SYSTEM FAILURES REPRESENT 22% OF CDF FOR PLANT ACCORDING TO IPE l

l AVAILABLE MODELS DO NOT TREAT CCW NOR DEAL l SPECIFICALLY WITH NATURAL CIRCULATION SCRAM l

l NO STAFF CALCULATION AVAILABLE YET BUT PROBABLY j NOT THAT LARGE A CCDP GIVEN THE DURATIONS  ;

INVOLVED AND THAT VITAL CCW NOT LOST DURING

! EVENT i

j -

NO LICENSEE STUDY DONE l

l o RECENT OPERATIONAL HISTORY FOLLOWUP -

o IMMEDIATE AND WEEKEND FOLLOW BY RESIDENT STAFF l AUGMENTED BY A REGIONAL SPECIALIST INSPECTOR.

l l o LICENSEE CONVENED A ROOT CAUSE ASSESSMENT TEAM. ,

l 0 LICENSEE EXECUTIVE MANAGEMENT HAS INITIATED AN EXAMINATION OF RECENT OPERATIONAL PERFORMANCE AND HAS ASKED INPO AND OTHER UTILITIES TO PARTICIPATE.

l o LICENSEE IS INSTITUTING SHORT AND LONG TERM CREW TRAINING ON CCW TRANSIENTS; NIGHT ORDERS PUBLISHED o TIME DELAY ON CCW NON-VITAL SUPPLY / RETURN VALVES l ' CHANGED

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A8.T. spew.ADER DAVIS BESSE 1 bd. O9} D h f' Briefing 18-07 '

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I 3.10 4 12/91

6. .,,.

OPERATING REACTOR PLANTS SIGNIFICANT EVENTS -

SORT > Event Date QUERY > Event Type SIG & Close out Date >= 01/30/96 & Event Type = "SIG" DATE OF 50.72 .

OR CLOSEQUT PLANT & UNIT EVENT NUMBER DESCRIPTION OF EVENT SIGNIFICANCE BRIEFING PRESENTER RECCW COOK 1,2 03/12/9633889 Total weight and distribution of ice in ice BENEDICT R. MIGMLIGNT condenser may not have met license requirements.

• Physical condition of ice baskets scy not have been adequete to support design Loeds. Trash collected from melted ice might have interfered with post-accident recirculation from containment simp.

tiASHINGTON NUCLEAR 206/17/9834408 Licensee declared an unusual event due to a fire Reactor Protection System- 96-05 ~PETRONE C. MR/ INFORMAL header Line break which flooded two ECCS pump i rooms, residual heat removal C and low pressure [

core spray. The region sent an AIT to investigate. ,

SUSQUEHANNA 2 07/02/9834466 An automatic reactor scram on intermediate range- Reactor Protection System . SKEEN D. MR/ INFORMAL (

monitor upscale occurred during start up with reactor at 1 percent power, ,

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t ATTACHMENT 3 ETS-11 Page:1 10/22/96 .

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