ML14191B085

Summarizes 890209 Enforcement Conference Re Unanalyzed Loss of safety-related Motor Control Ctrs,Environ Qualification Deficiencies & Introduction of Hydrogen Into Station & Instrument Air Sys

ML14191B085
Person / Time
Site:	Robinson
Issue date:	02/22/1989
From:	Ernst M NRC OFFICE OF INSPECTION & ENFORCEMENT (IE REGION II)
To:	Utley E CAROLINA POWER & LIGHT CO.
References
NUDOCS 8903090079
Download: ML14191B085 (62)

Text

ACCELERATED I)TR1BUTION DEMONSTRATION SYSVTEM REGULATORY INFORMATION DISTRIBUTION SYSTEM (RIDS)

CESSION NBR:8903090079 DOC.DATE: 89/02/22 NOTARIZED: NO DOCKET #

FACIL:50-261 H.B. Robinson Plant, Unit 2, Carolina Power & Light C 05000261 AUTH.NAME AUTHOR AFFILIATION ERNST,M.L.

Region 2, Ofc of the Director RECIP.NAME RECIPIENT AFFILIATION UTLEY,E.E.

Carolina Power & Light Co.

SUBJECT:

Summarizes 890209 enforcement conference re unanalyzed loss of safety-related motor control ctrs,per IR 50-261/88-36.

DISTRIBUTION CODE: IE01D COPIES RECEIVED:LTR ENCL SIZE: 6 I

TITLE: General (50 Dkt)-Insp Rept/Notice of Violation Response NOTES:

5 RECIPIENT COPIES RECIPIENT COPIES

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ID CODE/NAME LTTR ENCL ID CODE/NAME LTTR ENCL PD2-1 PD 1

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1 NRR/DREP/RPB 10 2

2 NRR/DRIS DIR 9A 1

1 NRR/PMAS/ILRB12 1

1 NUDOCS-ABSTRACT 1

1 OE LIEBERMAN,J 1

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1 RGN2 FILE 01 1

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D NOTE, TO ALL "RIDS" RECIPIENTS:

PLEASE HELP US TO REDUC wm!

CDoTACT THE DOCUMErT CONIROL DESK, ROOM P1-37 (EXT. 20079) TO ELIMINATE YOUR NAME FROM DISTRIBT7IN LIsTs FOR DOCUMErS YOU DON'T NEE!

TOTAL NIMBER Ov COPIES REQUIRED: LTTR 23 ENCL 23

License No. DPR-23 Carolina Power and Light Company ATTN:

Mr. E. E. Utley Senior Executive Vice President Power Supply and Engineering and Construction P. 0. Box 1551 Raleigh, NC 27602 Gentlemen:

SUBJECT:

ENFORCEMENT CONFERENCE

SUMMARY

(NRC INSPECTION REPORT NOS. 50-261/88-36 AND 50-261/88-38)

This letter refers to the Enforcement Conference held at our request on February 9, 1989.

This meeting concerned activities authorized for your H. B. Robinson facility. The issues discussed at this conference related to:

of Sfty-Related Motor Control Centers 5 and 6

2.

Fnvironmertal Qualification Deficiencies

a.

.Reactor Containment Fan Coolers

b. Reactor Head Vent System

3. Introduction of Hydrogen into Station and Instrument Air Systems CP&L discussed the specific details for each of the above issues as presented in the handouts enclosed.

There was little or no new information presented that would differ significantly from that presented in Inspection Report Nos. 50-261/88-30, 50-261/88-36, and 50-261/88-38.

With respect to the introduction of hydrogen into plant air systems, the licensee stated that hydrogen concentrations were such that no threats to equipment or facility occurred.

A list of attendees and a copy of your handouts are enclosed. We are continuing our review of these issues to determine the appropriate enforcement action.

In accordance with Section 2.790 of the NRC's "Rules of Practice," Part 2, Title 10, Code of Federal Regulations, a copy of this letter and its enclosures will be placed in the NRC Public Document Room.

7.......

Carolina Power and Light Company 2

Should you have any questions concerning this matter, please contact us.

Sincerely, original signed by Phil Stohr Malcolm L. Ernst Acting Regional Administrator

Enclosures:

1. List of Attendees

2. Handouts cc w/encls:

C. R. Dietz, Manager Robinson Nuclear Project Department R. E. Morgan, Plant General Manager State of South Carolina bcc w/encls:

J. Lieberman, DOE

.G.

Jenkins, EICS NRC Resident Inspector Document Control Desk 1C

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ENCLOSURE 1 List of Attendees Carolina Power and Light Company M. A. McDuffie, Senior Vice President, Nuclear Generation C. R. Dietz, Manager, Robinson Nuclear Project R. E. Morgan, Plant General Manager W. J. Flanagan, Manager, Modification Projects L. I. Loflin, Manager, Nuclear Licensing J. M. Curley, Director, Regulatory Compliance J. Deitrick, Senior Engineer M. Heath, Project Engineer Nuclear RegulatoryCommission M. Ernst, Acting.Regional Administrator C. Hehl, Deputy Director, Division of Reactor Projects (DRP)

E, Merschoff, Deputy Director, Division of Reactor Safety (DRS)_

D. Verrelli, Chief, Reactor Projects Branch 1, DRP G. Jenkins, Director, Enforcement and Investigation Coordination Staff

• ~j Lc r

.Scion (Pss), DRS N. Merriweather, Reactor Inspector, PS5, DRS IL.

Ga ri-r, SE!-i-1or Re,'- i dtit Ins pec tor, Rob inson C. Paulk, Reactor Inspector, PSS, DRS G. Wisemar, Reactor Inspector, P55, DRS R. Goddard, Regional Counsel H. Dance, Chief, Reactor Projects Section 1A (PS-lA), DRP R. Carroll, Jr., Project Engineer, PS-lA, DRP P. Lo, Project Manager, NRR

ENCLOSURE 2 HANDOUT ENFORCEMENT CONFERENCE USNRC REGION 11 BY ROBINSON NUCLEAR PROJECT CAROLINA POWER & LIGHT COMPANY FEBRUARY 9, 1989 AGENDA

1. INTRODUCTION C. R. DIETZ

2. ENFORCEMENT ISSUE

• MCC 5&6 OVERLOAD W. J. FLANAGAN

• EQ NONCOMPLIANCE M. P. HEATH

• HYDROGEN INCIDENT R. E. MORGAN

3. CLOSING REMARKS C. R. DIETZ

PRESENTATION TO NUCLEAR REGULATORY COMMISSION FEBRUARY 9, 1989 UNANALYZED LOSS OF SAFETY-RELATED MCC's 5 AND 6 AT H.B. ROBINSON

AGENDA

1. PREVIOUS EVENTS

• 8/11/74 LOSS OF MCC's ENFORCEMENT ACTION CORRECTIVE ACTION

• 5/2/75 LOSS OF MCC's CORRECTIVE ACTION RESULTS

11. CURRENT EVENTS DBD RECONSTITUTION CALCULATION CONCEPTS CALCULATED LOSS OF MCC's CALCULATED CABLE OVERLOAD CORRECTWE ACTION 111.

SUMMARY

• EARLY VS CURRENT EVENTS

• SAFETY SIGNIFICANCE

8/11/74 LOSS OF MCC'S INIT COND

- PLANT OPERATING AT 100% POWER T= 0 MIN

- MCC 6 TRIPPED ON START OF HVE-2B

- TURBINE RUNBACK

- REACTOR TRIP - HIGH PRESSURIZER PRESSURE

- SI - HIGH STEAM LINE FLOW/LOW Tave 1= 2 MIN

- MCC 6 RESET T= 15 MIN - MCC 5 TRIPPED ON OVERLOAD T=16 MIN - MCC 5 RESET T=17 MIN - MCC 6 DISCOVERED TRIPPED & RESET

INVESTIGATION OF 8/11/74 EVENT CAUSE

• HVE-2B DISCHARGE DAMPER WOULD NOT SEAL TIGHTLY CAUSING FAN TO ROTATE BACKWARDS BACKWARDS ROTATION RESULTED IN EXCEPTIONALLY HIGH STARTING CURRENT

• HVE-2B BREAKER INSTANTANEOUS TRIP MAY HAVE BEEN SET TOO HIGH CORRECTIVE ACTION

• ADJUSTED HVE-2B DISCHARGE DAMPER LINKAGE TO ELIMINATE BACKFLOW

2 0CURRENT IN AM PEPL E3§ l~

710 700 2006 sos 671.

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CHRONOLOGY CONTINUED 1/14/75 REGION 11 INSPECTION 2/21/75 INSPECTION REPORT - TWO INFRACTIONS FAILURE TO REPORT EVENT OF 8/11/74 FAIL.,E TO IDEN lFY AND CORRECT CAUSE; POTENTIAL FOR CAUSING OR CONTRIBUTING TO AN OCCURRENCE WITH SAFETY SIGNIFICANCE 2/25/75 MODIFICATION M-309 CHANGED HVE-2A/B BREAKER TRIP FROM 2115A TO 1125A ADDITIONAL CHANGES WERE TO BE MADE DURING THE NEXT REFUELING

6 q59 2

o*

20 CURRENT IN AM PER E3 30 40 50 so 7092

§§§?

900 S

6 8 9 1 4

9 6

~ 6 l 0 7 -3

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5/2/75 LOSS OF MCC'S INIT COND - PLANT IN COLD SHUTDOWN

- TURBINE ON TURNING GEAR T= 0 MIN - HVE-2B STARTED T= 6 MIN - MCC 6 TRIPPED T=10 MIN - MCC 6 RESET T=14 MIN - MCC 5 TRIPPED

CHRONOLOGY CONTINUED 5/8/75 INSPECTION OF MCC 5&6 FEEDER BREAKERS MCC 5 PHASE B LOW @ 560A MCC 6 PHASE A&B LOW @ 520A & 560A INSTANTANEOUS TRIP DEVICES ERRATIC 5/8/58 R'ECOGNZE MCC's COULD SEE >600A CORRECTIVE ACTION

• OVERCURRENT TRIPS REPLACED

• LONG TIME TRIP RAISED TO 720A 12/29/75 480 VAC DISTRIBUTION SYSTEM COORDINATED

Ici aq1 2

3 4

5467a91 CURRENT IN AM RE 7700 600 300X

_________40C

-~~----300 4.0 50306C

.267..1 CURRNT I

A.APtRE X 1 30 BASI FO DAT Stnds~.

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CURRENT IN AMPERES 9 6..8g1 2

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3003 CURRET IN M~tRE1X 1

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SUM MARY SIGNIFICANCE OF EVENT WAS NOT RECOGNIZED INFRACTION FOR OCCURRENCE DEEMED SAFETY SIGN!FICANT WAS ISSUED.

CORRECTIVE ACTION WAS TAKEN NO RELATED TRIPS IN LAST FOURTEEN YEARS 0

CURRENT EVENTS DBD RECONSTITUTION CALCULATION CONCEPTS CALCULATED LOSS OF MCC's

• CALCULATED CABLE OVERLOAD CORRECTIVE ACTION 0

PROBLEM STATEMENT CALCULATIONS GENERATED IN SUPPORT OF THE DBD RECONSTITUTION SHOW THAT A SINGLE BUS DBA WHILE MA!NTA1N N OFT SITE POWER COULD RESULT IN AN OVERLOAD OF THE REMAINING MCC.

THIS COULD, DEPENDING ON THE MAGNITUDE OF THE OVERLOAD, RESULT IN A LOSS OF THE REMAINING MCC,

CURRENT CALCULATIONS HP X (0.746 KW/HP) 1.73X(EFF)X(VOLT)X(PF)

VARIABLES:

HORSE POWER:

BRAKE HORSEPOWER VS RATED EFFICIENCY:

65 - 93%

VOLTAGE:

432 - 504V POWER FACTOR:

.88 -.92

EXAMPLE LOADS LOAD RATED MEASURED HVH-5A 73.5 60.O BORIC ACID TANK HEATERS 1 8.04 19.22 INSTRUMENT AIR COMPRES-SOR 61.0 73.0 SEAL OIL BACKUP PUMP 24.5 9.3 HVS-1 59.0 56.0 RADIATION MONITOR R21 7.6 6.70 SIXTY-ONE LOADS WERE MEASURED UNDER DESIGN CONDITIONS. THIS REPRESENTS APPROXIMATELY ONE-HALF OF THE ELECTRICAL LOADING ON MCC 5&6.

ON THE AVERAGE, THE MEASURED CURRENT WAS APPROXIMATELY 75% OF THE NAME PLATE RATINGS.

LOAD BLOCKS (CURRENT)

MCC 5 MCC 6

TURBINE AUXILIARIES 23 148 SAFETY INJECTION 34 36 SINGLE MCC 254 209 LOAD STRIPPING 210 171

MCC 5 LOADS PRIOR TO OCTOBER 1988 900 NOMINAL TOLERANCE -59 700 800

~

500 soo 471 10 cn 448 C) 400

~30029 zoo 295 200 100 0

NORM HSD SI 1BS LC N 0,R H~sD sl1 BUS LOOP MCC 6 LOADS PRIOR TO OCTOBER 1988 900 Soo NOMINAL 800 772AjN C

TOL..E~RANCE

-C 700 4500-6

,300 200 100 0

NORM HSO SI 1

US

CORRECTIVE ACTION IMMEDIATE LOADS WERE BALANCED BETWEEN MCC 5 & 6

• NON-SAFETY STANDSY LOADS WERE SECURED REFUELING

• TURBINE AUXILIARIES REMOVED

• NON-SAFETY FAN LOADS REMOVED

MCC 5

LOADS 800 PRIOR TO OCTOBER 19SE AFTER OCTOBER 19S 702 600 500 471 U.J 44a8 400 300 296295 200 100 a

NORM HSD SI 1 BUS LOOP MCC 6

LOADS 900 80-772 PRIOR TO OCTOBER 1988 700+l AFTER OCTOBER 1988 soo se 843 827 4002 200 10,01 NORM HSD SI 1 BUS LOOP

CALCULATED CABLE OVERLOAD LIMITED TO MCC 6 FEEDER LMITED TO THE FOLLOWING CONDITION

1. TURBINE ON TURNING GEAR,

2. MCC 5 DEENERGIZED, AND

3. OFF SITE POWER MAINTAINED.

I.

IPCEA P-46-426 POWER CABLE AMPACITIES CABLE CURRENT SIZE RATING REFERENCE CONDITIONS 500 MCM 471 A 7500

COND, 30 0 C AMB DERATING FACTORS

1. CONDUCTORS

% DERATE 4-6 80 7-24 70 25-42 60

>42 50 AMPACITY =

471 X 2 X 0.6

= 565A

MCC 6 CABLE TRAY ARRANGEMENT 0000 00000 0000 IPCEA DOES NOT SPECIFY TRAY DEPTH OR WIDTH MCC 6 CABLES ARE SEPARATED FROM OTHERS DERATING AT 6 AND 42 WERE CONSIDERED

EMERGENCY CABLE RATINGS IEEE-242-1975 THE EMERGENCY OVERLOAD CURRENT IS PROPORTIONAL TO THE SQUARE ROOT OF THE RATIO OF THE TEMPERATURE RISE RESULTING FROM EMERGENCY LOAD CURRENTS TO THE TEMPERATURE RISE RESULTING FROM NORMAL LOAD CURRENT.

UTILIZING AN EMERGENCY TEMPERATURE OF 95"C, A NORMAL TEMPERATURE OF 75*C, AND AN AMBIENT TEMPERATURE OF 300C THE EMERGENCY LOAD FACTOR WILL BE 1.20.

CABLE RATINGS NORMAL EMERGENCY (PCEA 42 CABLES 565 678 IPCEA 6 CABLES 753 904

POWER CABLE AMPACITIES IPCEA P-46-426 THE FOLLOWING TABLES OF CURRENT-CARRYING CAPACITIES REPRESENT THE CONSERVATIVE VIEWS OF ENGINEERS BASED ON OPERATING EXPERIENCE AND LABORATORY WORK AND ARE INTENDED AS A GUIDE TO ASSIST OPERATING ENGINEERS IN SELECTING CABLES FOR SAFETY AND RELIABILITY. THESE CURRENT CARRYING CAPACITIES ARE IN NO MEANS FIXED STANDARDS OR RATINGS.

PRIMFATIVE MODEL 750C CONDUCTOR TEMPEERATURE REQUIRES 750 AMP.

INITIAL AE MODEL FINAL AE MODEL, 750 AMPS RESULTS IN 72.5"C INNER JACKET TEMPERATURE

CORRECIIVE ACTION CABLE WAS REPLACED

SUMMARY

• EARLY EVENTS

1. BREAKERS SET IMPROPERLY

2. BREAKERS WERE COORDINATED

3. TRIPS WERE EXTENDED

4. TRIP DEVICES WERF REPLACED

5. FOURTEEN YEARS WITHOUT INCIDENT CURRENT EVENTS

1. CABLE SIZE SHOWN ACCEPTABLE

2. CALCULATED OVERLOAD FOR WORST CASE ONLY

3. SIMULTANEOUS LOSS OF MCC's NOT LIKELY

4. MEASURED CURRENTS LESS THAN CALCULATED CURRENTS 0

SAFETY SIGNIFICANCE

1. SXMULTANEOUS LOSS OF MCC's IS SAFETY SIGNIFICANT

2. SIMULTANEOUS LOSS OF MCC's WAS NOT LIKELY AFTER 1975

'0

e PRESENTATION TO NUCLEAR REGULATORY COMMISSION FEBRUARY 9, 1989 REACTOR CONTAINMENT FAN COOLERS AND REACTOR HEAD VENT SYSTEM ENVIRONMENTAL QUALIFICATION DEFICIENCIES AT H. B. ROBINSON

AGENDA

1.

HVH PENETRATION SPLICES QUALIFICATION

11. REACTOR VESSEL HEAD VENT SYSTEM QUALIFICATION Ill.

H. B. ROBINSON EQ ASSESSMENT EFFORT

REACTOR CONTAINMENT FAN COOLERS MOTOR FEEDER PENETRATION SPLICE REPAIRS SEQUENCE OF EVENTS

-OCTOBER 27, 1988 SPLICE WALKDOWN

-PLANT NUCLE^

SAFETY COMYMFITEE CONVENED

-REAC TOR CONTAINMENT FAN COOLERS DECLARED INOPERATIVE

-PLANT PLACED IN HOT SHUTDOWN

-SPUCES REPAIRED

-PLANT RETURNED 10 SERVICE OCTOBER 29, 1988

01 ITEM DESCRIPTION I

SILICONE SLEEVNG, VAR FLEX CLA-SSH-A-, 'LII07 2

24TERNAL W.RE'A&SEyM8L 4

CONDUCTOR 5

CONNECTOR, CABLE SEAL 6

SILICONE SLEEVING, VARFLEX.CLASS H-A-I, MLt--18057A 7

SPACER, PH-ENOLIC.

8 POTTING COMPO(UND, EPOXY STYCAST C-PC-S 9

HEAT SHRLNK TUBING, RACLAD R.KF m

55 RT GROUEMHDES P NERTO Cal0 No_ 000V PSLCONE SLEEV4IG VAR LEXCL HoAr F r

2j IGTERA WIRE AEMBL

.T6 CRUS HINSULATORTIO 4V CODUTO 50MM.lr e

als

EQ ASSESSMENT SPLICE REVIEW

1. REVIEWED DOCUMENTATION

-UTILIZED CABLE DATA BASE TO IDENTIFY ALL CABLES

-DOCUMENTED SPLICE CONFIGURATION AT EACH LOCATION

2. WALKDOWN LIST PREPARED

3. WALKDOWN FOUND HVH MOTOR FEEDER PENETRATION PIGTAIL SPLICES INADEQUATE

EQ SPLICE HISTORY 1980

- INSTALLED EQ SPLICES PER IEB 79-01B

- PENETRATION TO PIGTAIL SPLICE CONSIDERED PART OF PENETRATION 1987 REFUELING NO. 12

-INSPECTED SPLICES PER IEN 86-053

-PENETRATION TO PIGTAIL SPLICE CONSIDERED PART OF PENETRATION 1987 EQ INSPECTION

-RAYCLAD ON MULTICONDUCTOR PENETRATION SPLICES

-CROUSE HINDS CONNECTORS 1987 AUGUST

-PENETRATION TO PIGTAIL SPLICES REPAIRED TO PREVENT MOISTURE INTRUSION 1988-OCTOBER

-HVH 1-4 PENETRATION TO PIGTAIL SPLICES FOUND DEFICIENT

APPENDIX B CRITERION XVI KNOWN CONDITIONS ADVERSE TO QUALITY ARE PROMPTLY IDENTIFIED AND CORRECTED CONDITION NOT KNOWN PRIOR TO OCTOBER 27,1988 NRC INSPECTION REPORT DISCUSSED MULTICONDUCTOR PENETRATIONS ONLY

2. MUST DETERMINE CAUSE AND TAKE CORRECTIVE ACTION PLANT IN HOT SHUTDOWN WITHIN HOURS OF DEFICIENCY BEING FOUND

REACTOR VESSEL HEAD VENT SYSTEM

- 9/14/88 HBR DISCOVERED HEAD VENT SYSTEM NOT IN EQ PROGRAM

- SYSTEM ORIGINALLY INSTALLED ENVIRONMENTALLY QUALIFIED

- VALVESCABLE,SPLICES QUALIFIED

- NO CONDUIT SEALS PNTRATO SPLCES NOT UPGRADED

- SYSTEM NOT INCLUDED IN EQ PROGRAM

- SYSTEM UPGRADED BEFORE RETURNING TO OPERATION

- CONDUIT SEALS INSTALLED

- PENETRATION SPLICES UPGRADED

- LIMIT SWITCHES AND TERMINAL BLOCKS REPLACED

- ALTERNATIVES TO HEAD VENT SYSTEM EXISTED

ROOT CAUSE HVH SPLICES-IMPROPER DOR ANALYSIS FOR PENETRATION QUALIFICATION REACTOR VESSEL HEAD VENT SYSTEM-LACK OF PROGRAM CENTRAL CONTROL ACTION TO PREVENT RECURRENCE

- SITE PROCEDURE DEVELOPED FOR DOCUMENTATION PACKAGE DEVELOPMENT

- EQ PROCRAM MORE CLOSELY FOCUSED WITH DEDICATED PERSONNEL

- EQ PROGRAM EVALUATED

H. B. ROBINSON EQ PROGRAM ASSESSMENT SHORT TERM JUNE 15, 1988 THROUGH SEPTEMBER 1, 1988

1. REVIEW INTERNAL AND NRC GENERATED EQ VIOLATIONS

2. CROSS REFERENCE EQ PROCEDURES AND DOCUMENTATION FILES

3. REVIEW DOCUMENT PACKAGES

4. REVIEW PAST MAINTENANCE PRACTICES LONG TERM SEPTEMBER 1, 1988 TO PRESENT

1. PERFORM A RG 1.97 AND NUREG 0737 ASSESSMENT

2. VERIFY AS-INSTALLED CONFIGURATIONS

3. VERIFY COMPLETENESS OF EQ MASTER EQUIPMENT LIST

4. REVIEW THE EQ PROGRAM FOR:

A. MAINTENANCE PRACTICES B. PROCEDURAL CONTROL C. TRAINING

STAFFING

-FOUR ELECTRICAL ENGINEERS (THREE CP&L)

-TWO MECHANICAL ENGINEERS

-THRLL NUCLEAR ENGINEERS

-ONE CHEMICAL ENGINEER

-TWO ENGINEERS WITH DEGREES IN PHYSICS (UK)

-ONE CP&L DESIGNFR

EQ ASSESSMENT ACCOMPLISHMENTS

1. COMPLETED REEW OF NOVsIEBs, AND lENs

2. COMPLETED MAINTENANCE PROCEDURE UPDATE

3. ESTARL SHED EQ CAP! LE DATA BASE

4. ESTABLISHED EQ COMPONENT DATA BASE

5. COMPLETED REVIEW OF EQ MAINTENANCE

6. COMPLETED REVIEW OF SPLICES AND ENTRANCE SEALS

7. COMPLETED REVIEW OF NUREG 0737 REQUIREMENTS

8. COMPLETED FIRST DRAFT OF EQ DESIGN BASIS

CONCLUSION HVH 1-4 PENETRATION SPLICES WERE UNQUALIFIABLE

- HEAD VENT SYSTEM IN UNQUALIFIED CONFIGURATION

- CP&L IDENTIFIED AND CORRECTED

- EQ PROGRAM ASSESSMENT PROVIDES HIGH LEVEL OF ASSURANCE

PRESENTATION TO NUCLEAR REGULATORY COMMISSION FEBRUARY 9, 1989 INTRODUCTION OF HYDROGEN INTO STATION & INSTRUMENT AIR SYSTEMS AT H. B. ROBINSON

PRESENTATION AGENDA

1. SEQUENCE OF EVENTS AND IMMEDIATE CORRECTIVE ACTIONS

11. INVESTIGATIONS & CAUSAL FACTORS Ill. SAFETY SIGNIFICANCE IV. LONG TERM CORRECTIVE ACTIONS V.

SUMMARY

& QUESTIONS

I. SEQUENCE OF EVENTS AND IMMEDIATE CORRECTIVE ACTIONS JANUARY 6, 1989 2130 TURBINE MAINTENANCE REQUESTED THAT A PREVIOUSLY CANCELLED TAGOUT BE REMOVED FROM THE H2 MANIFOLD 2230 AIR TEST BEGUN 2245 SHIFT FORMEN INFORMED THAT AIR TEST WAS IN PROGRESS 2315 SMALL FIRE ON TURBINE DECK.

THOUGHT TO BE WELDING SLAG 2330 TURBINE MAINTENANCE REQUESTED AID ON LINEUP (SYSTEM DEADHEADED) OPERATOR TOLD THEM THAT THEY NEEDED THE SPOOL PIECE

1. SEQUENCE OF EVENTS AND IMMEDIATE CORRECTIVE ACTIONS (Cont.)

JANUARY 7,1989 0130 FIRE ON TURBINE DECK FROM PORTABLE GRINDER.

SHIFT FOREMAN INFORMED THAT H2 MIGHT BE IN AIR SYSTEM 0145 OPERATIONS INVESTIGATED LINEUP AND STOPPED FLOW OF H2 INTO INSTRUMENT AIR.

ALL HOT WORK AND USE OF AIR SUSPENDED.

SAMPL.E OF STATION AIR ON TURBINE DECK APPROX!MATELY 2.5% HYDROGEN 0230 SAMPLE OF STATION AIR ON TURBINE DECK SHOWED APPROXIMATELY 8% HYDROGEN BEGAN SAMPLING ALL AIR SYSTEMS 0236 UNUSUAL EVENT DECLARED 0245 BEGAN BLOWING DOWN AIR SYSTEMS IN TURBINE BUILDING

I. SEQUENCE OF EVENTS AND IMMEDIATE CORRECTIVE ACTIONS (Cont.)

0300 AUX. BLDG. STATION AIR 5.5% & 8%

AUX. BLDG. INSTRUMENT AIR 1.4%

0347 TURBINE BLDG. VENT PATH 0%

CONTAINMENT STATION AIR 8%

0400 BEGAN BLOWING DOWN AUX. BLDG. AIR SYSTEMS S

0500 BEGAN BLOWING DOWN CONTAINMENT AIR SYSTEMS 0540 CONTANMENT STATION AIR 1.7%

CONTAINMENT INSTRUMENT AIR 1.1%

0700 STATION AIR SYSTEM AT OPSI.

CONTAINMENT AND AUX. BUILDING AREA MONITORING SHOW 0% HYDROGEN IN OPEN SPACES 0800 REPRESSURIZED STATION AIR & RESAMPLED ALL SYSTEMS 0

0807 UNUSUAL EVENT TERMINATED

11. INVESTIGATIONS & CAUSAL FACTORS INVESTIGATIONS 1 /7 OPEAfT SQ CR~DFNATORM&

OPERATIONS ENGINEER 1/16 INPO TEAM FOR POTENTIAL SIGNIFICANT EVENT REPORT 1/16 HPES REVIEW BY SHIFT TECHNICAL ADVISOR

II. INVESTIGATIONS & CAUSAL FACTORS (Cont.)

CAUSAL FACTORS

1) LACK OF PROCEDURAL CONTROL

2) LACK OF MANAGEMENT CONTROL OF EVOLUTION

3) INADEQUATE COMMUNICATIONS & WORK PRACTICES

4) INSTALLATION ERROR & LACK OF SYSTEM KNOWLEDGE

I.

SAFETY SIGNIFICANCE POTENTIAL EFFECTS

1. SMALL FIRES WHERE AIR WAS BEING USED IN THE PROXIMITY OF IGNITION SOURCES.

2. ACCUMULATION OF POCKETS OF FLAMMABLE MIXTURES IN CONFINED SPACES NEAR WHERE AIR SYSTEMS WERE IN USE, E.G. ROOM WITH AIR OPERATED VALVES.

1!lT!CATj.lr2 PP*TP

1. IMMEDIATE CORRECTIVE ACTIONS OF STOPPING ALL USES OF AIR AND ALL HOT WORK SIGNIFICANTLY LOWERED POTENTIAL FOR ADVERSE EFFECTS.

2. TWO SMALL FIRES WERE REPORTED AND EXTINGUISED.

NO DETECTABLE HYDROGEN WAS FOUND IN ANY OPEN SPACES IN THE FACILITY.

3. A HYDROGEN EXPLOSION WAS NOT PROBABLE.

Il.

SAFETY SIGNIFICANCE (Cont.)

EXPLOSIVE PROPERTIES OF HYDROGEN

1. FLAMMABILITY LIMITS OF HYDROGEN IN AIR ARE:

4.1 TO 74%.

2. DETONATION LIMITS OF HYDROGEN IN OXYGEN ARE:

18.3 TO 58.9%.

3. CAPABILITY OF HYDROGEN FLAME TO PROPAGATE BACK INTO A CLOSED SYSTEM IS A FUNCTION OF PRESSURE, CONCENTRATION AND ORIFICE SIZE.

SITUATION AT H. B. ROBINSON

1. HIGHEST CONCENTRATION MEASURED WAS 8%

DETONATION WAS NOT POSSIBLE.

2. BECAUSE HYDROGEN AIR MIXTURE WAS AT APPROXIMATELY 95 PSI, ANY FLAMES WERE EFFECTIVELY CONFINED TO OUTSIDE OF SYSTEM - QUENCHING EFFECT OF SURFACES PREVENTED PROPAGATION INTO THE SYSTEM.

3. PLANT WAS IN COLD SHUTDOWN WITH A COLD REACTOR CORE.

RHR, SERVICE WATER, AND COMPONENT COOLING WATER WERE NOT EXPOSED TO ANY DANGER FROM THE INCIDENT.

III.

SAFETY SIGNIFICANCE (Cont.)

CONCLUSION

1. THERE WAS POTENTIAL OF PERSONNEL INJURY DUE TO SMALL FIRES WHICH OCCURRED.

2. NO CONCENTFRTDONS OF WERE FOUND IN OPEN SPACES,- SO NO THREAS TO EQUIPMENT OR FACILITIES OCCURRED.

3. AN EXPLOSION WAS NOT POSSIBLE.

4. PUBLIC HEALTH AND SAFETY WAS NOT AT RISK.

O IV. LONG TERM CORRECTIVE ACTIONS PROCEDURAL CONTROL MODIFY OPERATING PROCEDURE TO TAGOUT HYDROGEN MODIFY OPERATING PROCEDURE TO PROCEDURALIZE AIR TEST MANAGEMENT CONTROL MODIFY iAUUU PROCEDURE TO PROVIDE CLEAR GUIDANCE ON WHAT CAN BE DONE WITHIN A TAGOUT BOUNDARY AND TO SPECIFY THAT OPERATIONS MANIPULATES COMPONENTS FOR TESTING REVIEW METHODS OF CONTROLLING TURBINE MAINTENANCE CREWS AND OTHERS REVIEW GENERIC TURBINE AND OTHER SCHEDULES TO LOOK FOR SIMILAR EVOLUTIONS WHICH MAY REQUIRE PROCEDURE CONTROLS

IV. LONG TERM CORRECTIVE ACTIONS (Cont.)

COMMUNICATIONS AND WORK PRACTICES MANAGEMENT CONTROLS ACTIONS WILL PLACE OPERATIONS BACK IN CONTROL OF EVOLUTIONS AND DIRECTING TESTING ACTIVITIES REFRESHER TRAINING WILL BE CONDUCTED FOR TRAVZHK& WO CREWS WHEN THEY COME BACK ONSITE TO REVIEWV CURRENT PROCEDURE AND WORK PRACTICES, REGARDLESS OF G.E.T. STATUS INSTALLATION ERROR AND SYSTEM KNOWLEDGE PROVIDE PROCEDURES WHERE NECESSARY OPERATIONS WILL DO LINEUPS AND TESTING

V.

SUMMARY

SERIOUS EVENT PEOPLE RESPONDED WELL, BUT PREVENTATIVE BARRIER BROKE DOWN STRIVING TO LEARN FROM EXPERIENCE AND APPLY TO OTHER AREAS REVIEWED WITH 01HER NUCLEAR PLANT MANAGERS - FEBRUARY 7, 1989 QUESTIONS:

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