ML17328A433

Informs of Preliminary Assessment of 900713 Electrical Contact Accident at Facility.Investigation Concludes That No Safety Rules Violated

ML17328A433
Person / Time
Site:	Cook
Issue date:	08/27/1990
From:	Blind A INDIANA MICHIGAN POWER CO. (FORMERLY INDIANA & MICHIG
To:	Davis A NRC OFFICE OF INSPECTION & ENFORCEMENT (IE REGION III)
References
NUDOCS 9009120147
Download: ML17328A433 (11)

Text

ACCELERATED . UTION DEMONS'ATION SYSTEM

! REGULATORY INFORMATION DISTRIBUTION SYSTEM (RIDS)

ACCESSION NBR:9009120147 DOC.DATE: 90/08/27'OTARIZED: NO DOCKET FACIL:50-315 Donald C. Cook Nuclear Power Plant, Unit 1, Indiana 6 05000315 50-316 Donald C. Cook Nuclear Power Plant, Unit 2, Indiana 6 05000316 AUTH. NAME AUTHOR AFFILIATION BLINDPA.A. Indiana Michigan Power Co. (formerly Indiana & Michigan Ele RECIP.NAME RECIPIENT AFFILIATION DAVIS,A.B. 'egion 3 (Post 820201)

SUBJECT:

Informs of preliminary assessment of 900713 electrical contact accident at facility.

DISTRIBUTION CODE: IE22D COPIES RECEIVED:LTR g ENCL ~ SIZE'D TITLE: 50.73/50.9 Licensee Event Report (LER), Incident Rpt, etc.

NOTES:

RECIPIENT COPIES RECIPIENT COPIES ID CODE/NAME LTTR ENCL ID CODE/NAME LTTR ENCL PD3-1 LA 1 1 PD3-1 PD 1, 1 COLBURN,T. 1 1 INTERNAL: ACNW 2 2 AEOD/DOA 1 1 AEOD/DSP/TPAB 1 1 AEOD/ROAB/DSP 2 2 NRR/DET/ECMB 9H 1 1 NRR/DET/EMEB9H3 1 1 NRR/DLPQ/LHFB11 1 1 NRR/DLPQ/LPEB10 1 1 NRR/DOEA/OEAB11 1 1 NRR/DREP/PRPB11 2 2 NRR/DST/SELB 8D 1 1 NRR/DST/SICB 7E 1 1 R LB8D1 1 1 NRR/DST/SRXB 8E 1 1 REG FILE 02 1 1 RES/DSIR/EIB 1 1 FILE 01 1 1 EXTERNAL EGGG BRYCE g J ~ H 3 3 L ST LOBBY WARD 1 1 NRC PDR 1 1 NSIC MAYSPG 1 1 NSIC MURPHYPG.A 1 1 NUDOCS FULL TXT 1 1 NOTE TO ALL "RIDS" RECIPIENTS:

PLEASE HELP US TO REDUCE WAS'ONTACT THE DOCUMENT CONTROL DESK.

ROOM P 1-37 (EXT. 20079) TO ELIMINATEYOUR NAME FROM DISI'RIBUTION LISTS FOR DOCUMENTS YOU DON'T NEED!

TOTAL NUMBER OF COPIES REQUIRED: LTTR 31 ENCL 31

Indiana Michigan Power Company Cook tJuciear Plane One Gook Place Bridgrnan. I",:I 49',0" 616 465 59G'r August 27, 1990 INEllANA NICHlGiAN POWM United States Nuclear Regulatory Commission Region 799 III Roosevelt Road Glen Ellyn, IL 60137 ATTN: Mr. A. Bert Davis, Regional Administrator

Dear Mr. Davis:

The purpose of this letter is to inform you of our prelim-inary assessment of the electrical contact accident that occurred at the Donald C. Cook Nuclear Plant on July 13, 1990.

At approximately 1 p.m., a contractor electrician working on our site contacted an energized 4KV electrical feed cable in breaker cubicle T21C1. The ensuing electrical flash resulted in one fatality and three seriously injured personnel. We have conducted an investigation and have provided the pre-liminary report and additional information, as requested, to our resident inspectors and members of an investigative team from the NRC Office for Analysis and Evaluation of Opera-tional Data (AEOD). In addition, the Michigan Occupational Safety and Health Administration (MIOSHA) ha's completed their investigation and determined that no safety rules were violated. This letter also provides the results of the assessment of our work control process and the action we are taking to prevent a similar occurrence.

Immediately after the accident, an accident investigation team was formed that consisted of three personnel from other locations within the Indiana Michigan Power Company (IGM),

including the I&M Safety Director and two Plant personnel.

Additionally, an electrical engineer from the plant and an electrical engineer and a fire protection engineer from American Electric Power Service Corporation provided technical support to the investigation team. Also working with the accident investigation team for several days was the Safety Manager for Nuclear Support Services, Inc. (the employer for the contract employees involved in the accident) .

The team visited the accident site, reviewed documentation associated with the activity that was to be conducted, and interviewed a large number of personnel to develop the attached preliminary investigation report that describes the accident. This preliminary report, is essentially the same as the one that was provided to the resident inspectors and the 9009120i47 900827 PDR ADOCK 05000315

.S PNU AUG 81 gg

Mr. Bert Davi August 27, 1990 Page 2 AEOD team.

Because the investigation team has been unable to directly interview the three survivors of the accident, we are keeping the investigation open until we are able to complete the interview process. Information from the contract electrician (now in Nebraska) obtained by his employer and information from a 20-minute telephone conversation from the I6M Maintenance Mechanic A (electrician) has been considered in developing the preliminary accident report. The IBM Instrumentation and Control (I&C) technician's critical condition still precludes a direct interview. While the investigation remains open and.the report is not finalized, we have obtained enough information to begin corrective action to-prevent a similar occurrence.

The accident investigation team was not able to positively determine why the deceased contract electrician approached close enough to the energized conductors to initiate a fault.

It appears that none of the individuals at the job site knew the exact physical location of the current transformers that they were looking for. Nevertheless, it is an I6M safety policy that potentially energized equipment should be considered energized until positively proven or shown that the equipment, is de-energized. This policy is commun'icated to all personnel as part of the Nuclear General Employee Training received prior to obtaining unescorted access. From our interviews it is also our understanding that experienced electricians do know that they should verify that high-voltage equipment, is properly cleared/isolated and grounded where appropriate. Records on site indicate that the men involved in the accident, particularly the electricians, were experienced individuals.

In addition to the requirement to check that equipment is de-energized before starting work on it, we have in place at the Cook Nuclear Plant several processes that should have pre-vented this accident. We have reviewed the Design Change packages and the job order packages associated with the accident. The packages did not contain information on the location of the current transformers. We did find that there are drawings on site that, while not showing a great amount of detail, did show generally where the current transformers are located. Additionally, it was determined that the on-site design change engineer and the Request. For Change lead engineer in AEPSC did know the physical location of the current transformers. They had not received any request from the work group to help them locate 'the current transformers.

We also reviewed the clearance request. associated with this event. In this particular event the clearance request was prepared by the ISC technician involved in the accident. But

Mr. Bert Davis August, 27, 1990 Page 3 as noted in the attached report, the clearance request was deficient. The clearance was hung as requested. We also determined that the control room personnel who hung the clearance did not have drawings that show the physical location of the current transformers available to them in the control room. They were of the understanding, based on the request, that the clearance that they had approved and had hung was adequate for the work the I&C technician would be do3.ngo We do require that the supervisor responsible for an activity ensure that an appropriate job briefing is conducted. In this event the instrument maintenance supervisor that was responsible for installing the design change did conduct a job briefing with the Maintenance Mechanic A and the electricians. His direct report, the I&C technician, two'ontract had already been working on the activity. During the job briefing the supervisor did state that he was unsure of the current transformer location. We also have indication that the maintenance mechanic A stated during the briefing, in response to a statement by the supervisor that he always checked for voltage.

We have reviewed our work control and training processes that were used and have found nothing inherently wrong in the processes nor any violations that significantly contributed to the event other than a failure to check that the equipment was de-energized. We are, however, investigating to see there are changes we can make to strengthen the work control if processes to preclude similar events. Although the individ-uals involved in the event appeared qualified to work in and around high-voltage equipment,, we are reviewing our training program to see if we should emphasize more strongly our Company's fundamentals of safety. That, is, we are reviewing to see if we should emphasize more strongly that all electrical equipment should be considered energized unless appropriately verified that it is deenergized. It is also possible that the team from AEOD may find something that we have missed. We know that the team is taking a very close look at our clearance permit process and our job planning process. Any recommendations from the AEOD will be evaluated and incorporated into our processes as appropriate.

As stated, we have investigated the accident and are looking at changes in our training and work processes that will help preclude any similar events. We will keep our NRC Resident Inspectors advised available.

if any significant new information becomes r

Also, the Michigan Occupational Safety and Health Admini-stration (MIOSHA) conducted an investigation. Their repre-sentative met with us on August 20, 1990. The verbal de-

Mr. Bert Davis August 27, 1990 Page 4 scription of their investigation of the accident appears to agree with our findings. MIOSHA will not be issuing any violations or citations.

'If you should require any additional information, please do not hesitate to let me know.

Yours truly, A. A. Blind

/fc Attachments c: Brent Clayton Timothy Colburn NRC Resident Inspector M. P. Alexich S. J. Brewer J. E Rutkowski R. E. Walker

DE iPT ION Of ACC IDENT - July 13, 0 On July 13, 1990 at approximately 1300, a contract electrician contacted energized feed cables in the back of an ITE metal clad breaker cabinet. The resulting flash resulted in one fatality and three injured personnel. The following is a description of what happened.

A request for change package (RFC) DC-12-3008 was prepared to revise electrical protective equipment to imp'rove overall circuit coordination. The specific portion of the RFC being worked at the time of the accident was subtask 6. In part, this subtask involved installing an additional G.E. I.A.C. relay and current transformer (C,T.)

on the bus - side of breaker T21C1. This 1200 amp breaker is part of an ITE 5HK250, SKV Metal-Clad breaker cabinet located in Unit-2 4KV Breaker Room. A typical drawing of this cabinet and the actual electrical one line is attached (see attachments 1 and 2 respectively). A plant job order, B43965, was written and issued to the Maintenance Department on July 4, 1990. After review by the Instrument Maintenance Supervisor, the job was assigned to the I8C Technician. The 18C Technician began working on the job several days before 'the accident. He submitted a clearance permit request on July 11, 1990. Equipment requested to be cleared was the 4KV T21C bus. Specific tagout requirements requested were breakers T21CI, T21C2, T21C3 and grounding the bus. The new G.E. I.A.C.

relay was installed and the control wiring nearly completed for breaker T21Cl.

On the morning of the accident, the I&C Technician worked on the T21C1 relay control wi ring. The I&f1 Maintenance Hechanic "A" (MMA) worked on an unrelated job in the plant.

Two Nuclear Support Services (NSS) contract electricians (NSS-1; NSS-2) were working with another ISN Maintenance Mechanic "A" on an unrelated job in an adjoining room.

Later in the morning, the Electrical Maintenance Supervisor assigned the ISH HMA, NSS-1, and NSS-2 the job of assisting the ISC Technician with the installation of the CT.

Since the Electrical Maintenance Supervisor did not have any detail of the job, he did not conduct a job briefing.

Shortly after lunch, at approximately 12:45 p.m., the HliA, NSS-l, and NSS-2 went to the Instrument Maintenance Supervisor's office for a job briefing. During the discussion,

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the Instrument Maintenance Supervisor stated his belief that the CTs could be reached from the front of the breaker cabinets There was no drawing with the job package showing the CT location. The Instrument Maintenance Supervisor then took the men to the I&C shop to meet the I&C Technician. The I&C Technician and the NSS-2 proceeded to the Unit-2 4KV Breaker Room. The MMA told the NSS-1 to get the high voltage tester and insulating gloves and meet him in the 4KV Breaker Room. The MMA's intention was to check things out and then get the needed tools. The MMA then went to the Shift Supervisor's office to sign on the clearance permit 82900759. This clearance included, in part, breakers T21C1, T21C2, T21C3, 21C1, bus T21C, and transformer TR21C. A ground had been placed on the 4KV side of transformer TR21C. The 4KV breaker room door entry record showed that the I&C Technician and NSS-2 entered at 12:57 p.m. and the NSS-1 entered at 12:58 p.m. The record also shows that the Electrical Maintenance Supervisor entered at 12:58 p.m. and the llf1A entered at 13:00 p.m. The Electrical Maintenance Supervisor was on his way to check a job in an adjoining room and, when he saw the men, stopped at the front of T21C cabinet to briefly discuss the job. The Electrical Maintenance Supervisor did not remember who was present. During the discussion, he cautioned them of possible backfeed from potential transformers in the cabinet. He walked around to the back of breaker T21Cl and commented that the CTs may be behind the bus bars. He said that the back cabinet door was open. He then left through the north fire door to the adjoining room. The MMA said that he arrived at the job site as the Electrical Maintenance Supervisor and the NSS-1 were talking behind the breaker cabinet. Due to the noise, the MMA could not hear their conversation. He said the NSS-2 and the I&C Technician were standing behind the NSS-1. He also said that he thought it was strange that the men were behind the breaker. cabinet because he was not sure everything had been checked out. The MMA said that he looked around and did not see a high voltage tester or insulating gloves. The MMA said that he told the NSS-1 to leave the cabinet alone. The MMA added that he would go to get the high voltage tester and insulating gloves. He turned to leave and within seconds, he heard an explosion.

The Electrical Maintenance Supervisor who was in an adjoining room, grabbed a fire

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extinguisher and reentered the breaker room. NSS-1 was on the floor behind the T21C1 cabinet. The Electrical Maintenance Supervisor extinguished the fire on the NSS-1 and then moved to the main entrance where he extinguished at least one other man.

Door entry records show that the tlHA exited at 13:01 p.m. The Electrical l1aintenance Supervisor exited at 13:02 p.m. EI1T and fire brigade personnel began arriving in response to alarms and started treating the victims.

From the physical evidence, it appears that NSS-1 contacted the energized 4KV feed cables with his upper inside left arm and right chest. The resultant three phase fault was calculated at between 38,000 to 48,000 amps. The fault was cleared by overcurrent relays for breaker 2C6 in approximately 40 to 70 cycles. Analysis of bubbled and charred paint on walls indicate approximately 85% of the heat went left or north of the cabinet.

The attached accident scene reconstruction drawing (see attachment 3) shows probable temperature profiles and probable individual's positions. The actual location of the CTs were on the stationary breaker stabs accessed from the front of the cabinet. The HflA, 1&C Technician, and NSS-2 were wearing hard hats. NSS-1's hard hat was found near another breaker cabinet and showed no signs of heat damage. There was no high voltage personal protective equipment or high voltage test equipment found at the job sl l:e.

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