ML20059D218

Intervenor Exhibit I-MFP-216,consisting of Nonconformance Rept & Mgt Summary DCO-90-SE N080,dtd 920128

ML20059D218
Person / Time
Site:	Diablo Canyon
Issue date:	08/23/1993
From:	AFFILIATION NOT ASSIGNED
To:
References
OLA-2-I-MFP-216, NUDOCS 9401070074
Download: ML20059D218 (15)

Text

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hl12. NCR I. Evaluation Plant Conditiona Attached on the MCR 112.Text Cause Contirnaation of Probles Sheets V. Corrective Actions  !

! A II. Description of Problem IV. Analysis of Problem VI. Additional Information i L

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14. Estimated 15. Responsible I s 13. 2 rend Other Completion Organization l

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I R 16. 10CT1t50.73 17. Potentially 10CrR21 18. 10CrR50.9 C I Reportable Reportable 19. Reference Other I A

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20. Basts refer to attached

A Initial 21. Time Limit 22. Method 23. Notified By 24 Ties 25. Date R B Report N/A

N/A N/A N/A N/A L Tollowp 26. Required 1 Report

27. Time Limit 28.1.E3t No. 29. Date  ;

-i Yes [ } No[XI N/A N/A

. T N/A l si Y 30. Other Agencies Notified none .

31. Remarks ERP 90-13 tracks the actions which have been and will be taken to recover from R

o this event. Th+s NCR is a result of ERP 90-13.

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DCO-90-SE-N080 l January 28, 1992 )

MANAGEMENT

SUMMARY

On November 19, 1990 at 1519 hrs. PST Operations received an annunciator outpt- for ventilation system smoke detection.

An operator was sent to investigate. At the same time, Security received an advisory on the SAS and CAS CRTs of an alarm condition in the Security power supply inverter. An officer was dispatched to investigate. Investigation of the area determined that there was a fire in one of the security diesel area power supply panels. The fire brigade utilized CO2 to suppress the fire while in parallel the panel was l

deenergized. The fire was declared out at 1604 hrs. PST.

The cause of the fire was a' loose terminal on a 480vac feeder breaker. An Unusual Event was not declared because-active flames were not observed during tha event. Following the event a courtesy notification was made to CDF and SLO county pgrsonnel.

The root cause of the event is unknown, however the most probable cause was a faulty compression termination during installation work performed for a jumper in 1990.

Corrective actions to prevent recurrence include replacement with lug type connectors, thermal scanning of similar l

installations and issuance of a maintenance bulletin emphasizing correct practices for compression terminations.

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4 DCO-90-SE-N080 January 28, 1992 DCO-90-SE-N080 FIRE IN ELECTRICAL PANEL IN SECURITY INVERTER ROOM I. Plant Conditions:

Unit 1 and Unit 2 were in Mode 1 (Power Operation) at 100% power.

II. Descriotion of the Problem:

A. Problem:

On November 19, 1990 at 1519 hrs. PST, Operations received an annunciator output for inverter trouble. An operator was sent to investigate. At the same time, Security received an advisory on the SAS and CAS CRTs of an alarm for the security inverter. An officer was dispatched to investigate the area. Upon entry into the security diesel area, smoke was detected. Further investigation determined the smoke was coming from

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a 480vac electrical panel that apparently had an internal fire. A radio report to CAS conveyed this information. In parallel, a mechanical helper observing the scene placed a 779 telephone report of the condition, sounding the fire alarm at 1523 hrs. .PST. The fire brigade arrived at

,1533 hrs. PST. A plan of action to use CO2 as the primary fire suppressant with a backup of fire main water was developed. At 1535 hrs. PST the

fire brigade entered the security diesel area. A request was made at 1552 hrs. PST to have breaker 22M-09 opened. No active flames were observed during this event, thus an Unusual Event was not 4

declared. At 1604 hrs. PST the fire was declared out. Security implemented compensatory measures j

as required to provide continued Plant security.

A courtesy notification was made to the California

' Department of Forestry (CDF) / San Luis Obispo '(SLO)

County personnel regarding the event.

' A request was made of CDF to provide the services of a fire investigator to assist in determining the cause of the fire. His evaluation concluded that equipment failure alone was the cause of the

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fire.~'" ~ ~ '

90NCRWP\90SEN080.JCN Page 2 of 11

DCO-90-SE-N080 January 28, 1992 The Quality Control Manager also inspected the damage evidence and concluded "..the fire resulted from an electrical fault either in the breaker on the inlet side or at the terminations of the large copper cables."

Technological and Ecological Services (TES) performed a detailed review of the damage and concluded "...the evidence and described events are consistent with an equipment failure resulting from progressive deterioration of the connection, excessive voltage, or improper installation."

Although the feeder breaker was damaged to the extent that a detailed cause of the failure was impossible to make; the most probable cause was determined to be an inadequate compression wiring termination installation which resulted in increased electrical resistance across the termination resulting in heating until semi-combustible materials in the area began to smolder.

B. Inoperable Structures, Components, or Systems that Contributed to the Problem:

480vac panel PPS, component ID: 0 66 E GN SECDSL.

C. Dates and Approximate Times for Major Occurrencec.

1. November 19, 1990; 15:19 PST: Event date.

Annunciator output received by Operations.

Alarm received by security at SAS and CAS, Operations notified.

2. November 19, 1990; 15:20 PST: Discovery date. Site fire alarm.

sounded.

3. November 19, 1990; 15:33 PST: Fire brigade

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DCO-90-SE-N080 January 28, 1992 arrives at security diesel.

4. November 19, 1990; 15:35-PST: Fire brigade enters the security diesel room.

5. November 19, 1990; 16:04 PST: Fire declared out.

D. Other Systems or Secondary Functions Affected:

Various security electrical circuits lost power during this event but none were required for safe shutdown of either Unit and adequate compensatory measures were implemer.ted to ensure continued security for Plant operation.

E. Method of Discovery:

Operations personnel monitoring the annunciator output sent an operator and Security personnel monitoring the CRTs in SAS and CAS observed an advisory alarm and dispatched an officer to investigate. Upon entering the security diesel area smoke was detected. In parallel with this a-mechanics helper observed the smoke and dialed 779

• to activate the site alarm.

F. Operator Action..

Operators notified the fire brigade and assisted in deenergizing the affected panel. Following extinguishing the fire, Operations did a courtesy notification for appropriate CDF/ SLO County personnel.

G. Safety System Responses:

None.

III. Cause of the Problem:

A. Immediate Cause:

PGLE believes a loose electrical termination to 90NCRWP\90SEN080.JCN Page 4 of 11

DCO-90-SE-N080 January 28, 1992 the panel feeder breaker caused high resistance, heating and eventually the semi-combustible material in the vicinity began to smolder.

B. Determination of Cause:

1. Human Factors:

a. Communications: N/A.

b. Procedures: N/A.

l c. Training: N/A.

d. Human Factors: N/A.

e. . Management System: An effort was made in the '70s"to change compression electrical terminations in class I, high voltage equipment. A conscious, economic t decision was made at that time to not change them in class II equipment'-(an-accepted IEEE-practice for this type equipment).

2. Equipment / Material:

a. Material Degradation:- N/A. j

b. Design: Compression ~ terminations were acceptable for use in the applicable design documents.

c. Installation: It can only be assumed the termination was not adequately connected during the jumper installation in February 1990. Prior.to this work the same type connection performed satisfactorily for approximately 10 yr.

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d. Manufacturing: The Westinghouse breaker (HKB 2225T) was confirmed not part of bulletin 88-10 traceability concern.

e. Preventive Maintenance: There'is no specified PM.

f. Testing: N/A.

g. End-of-life failure: N/A.

C. Root Cause:

The most probable root cause was a faulty compression termination during the jumper installation (and removal)-during 1990. The physical evidence was destroyed by arcing.

D. Contributory Cause:

Compression electrical terminations are dependent on the skill of the installer for acceptable results.

IV. Analysis of the Problem:

A., Safety Analysis:

Failure of this panel has no effect _ cn1 the safe shutdown capability of either Unit. Thus the health and safety of the public were not adversely effected by this event.

B. Reportability:

1. Reviewed under QAP-15.B and determined to be non-conforming in accordance with Section 2.1.8.

2. Reviewed under NUREG 1022 and determined not to be reportable in accordance with 10 CFR 50.73.

3.

Reviewed under 10 CFR 73.71(b) and determined to be reportable.

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1 DCO-90-SE-N080 January 28, 1992

4. This problem does not require a 10 CFR 21 r( c :' art .

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1 Network entry.

6. Reviewed under 10 CFR 50.9'and determined tof i be not reportable since this event does not have a significant implication for public-health and safety or common defense and security.

7. This event was reported to CDF/ SLO County; personnel in accordance with administrative procedure C-11 and its: supplements. ,

V. Corrective Actions:

A. Immediate Corrective' Actions:

The fire brigade entered the security diesel area, requested breaker 22M-09 be opened, confirmed no active flames were present and declared the fire out. Security implemented compensatory measures as required to provide continued plant security.

A courtesy notification was made to the California Department of Forestry (CDF)/ San Luis Obispo (SLO) y County personnel regarding the event. >

B. " Corrective Actions to Prevent Recurrence:'

1. As a prudent action, similar-. panels-will be scanned with an infrared detector to identify any hot spots. ,

RESPONSIBILITY: H. Phillips Complete Tracking AR: A0209382, AE #02 Not outage related.

No JCO commitments ~ required.

No NRC commitments required.

2. Lug crimp connections will be used in:

rebuilding this panel.

RESPONSIBILITY: H. Phillips Complete Tracking AR: A0209382, AE #03 Not outage related.

No JCO commitments required.

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DCO-9 0- SE-N 08 0 January 28, 1992 No NRC commitments reg' ired.

3. Electrical Maintenance has issued a Maintenance Bulletin emphasizing correct practices to be utilized when making electrical connection such as proper wire stripping and cleanliness. (This bulletin was also sent to GC electrical installation)

RESPONSIBILITY: J. Rappa Complete Not outage related.

No JCO commitments required.

No NRC commitments required.

VI. 2dditional Information:

A. Failed Components:

480Vac panel PPS, 0-66-E-GN-SECDSL, primary feeder breaker electrical terminations.

B. Previous NCRs on Similar Problems:

None in the last five years. An effort was made in the '70s to change all the class I panels with compression terminations to crimped-lug style terminations.

C. , Operating Experience Review:

1. NPRDS.

None.

2. iiRC Notices, Bulletins, Generic Letters:

None.

3. INPO SOERs and SERs:

None.

D. Trend Code:

RE (GC Electrical) - C3 (Material deficiency, installation)  ;

1 E. Corrective Action Tracking: I I

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DCO-90-SE-N080 January 28, 1992

1. The tracking action request is A0209382.

2. The corrective actions are not outage related.

F. Footnotes and Special Comments:

ERP 90-13 tracks the actions which have been and will be taken to recover from this event. This NCR is a result of ERP 90-13.

G.

References:

1. Initiating Action Request A0209246.

2. CDF Investigation Report (Case SLU 3201-90),

dated November 19, 1990.

3. TES Metalurgical Investigation, EPS Breaker Box Fire, dated December 17, 1990.

4. Qualit'y Control Department Management Review Report QCR 90-0005, dated January 17, 1991.

5. Physical Security Event Report (PSER) 90-S14.

6. INPO Nuclear Network Entry OE 4905, dated

• 10/91.

H ., TRG Meeting Minutes:

1. On November 28, 1990 at 1:00 pm PST in room l 533 of the administration building the TRG {

convened and considered the following: the l failure of safeguards equipment will be  !

reported in compliance with 10 CFR 73.71, {

details will not be included in the NCR.  !

Electrical Maintenance will provide a  !

recommendation as to the extent of additional panel inspections to be performed. '

Reliability Engineering will be invited to the j next TRG reconvene. NECS-Electrical i Engineering will review the DCM for 480vac i systems to determine the level of detail for l terminations for class II panels.

2. On December 6, 1990, at 1:00 pm PST in room 425 of the administration building the TRG reconvened to discuss the root cause of this 90NCRWP\90SEN080.JCN Page 9 of 11

P DCO-90-SE-N080 January 28, 1992 event. Discussion established that the exact I

root cause cannot be determined since the electrical termination was destroyed. The most likely cause was not a bad installation since this panel functioned acceptably since last February and the failure, when it occurred, took place in less than 15 minutes.

Therefore, there must have been a mechanism to-cause loosening of this electrical termination, most likely thermal cycling.

This TRG will reconvene on Wednesday, December 12, 1990 at 1:00 pm PST to evaluate the Security LER submittal and sign this NCR.

3. The TRG reconvened on Wednesday, December 12, 1990 at 1:00 pm PST in room 604 of the administration building and discussed.the replacement of the 480Vac panel. Crimped lugs will be used in the rebuild of this panel.

Security will circulate the report draft to the appropriate reviewers for information.

This TRG will reconvene at some future time to sign the NCR.

4. On February 28, 1991 at 2:00 pm PST in room 516 of the administratica building the TRG reconvened to discuss delaying reconstruction

, of the permanent electrical panel due to the need for taking the security computer off. .Ine during the installation. This would be very difficult during 1R4 because of all the extra personnel on Site. The temporary panel is functioning acceptably and should continue to do so past the end of 1R4. The TRG will reconvene following the installation of the permanent electrical panel, on or about May 1, 1991.

5. On May 30, 1991, the TRG reconvened and reviewed the formal investigation reports from CDF, QC manager and TES. The TRG concluded that due to the destruction of physical evidence by the failure itself the root'cause is unknown, however the most probable root cause was improper installation in February j 1990. The TRG concurred that the required l actions taken are complete and upon )

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9 DCO-90-SE-N080 January 28, 1992 incorporation of comments into the minutes this NCR may be forwarded to PSRC for concurrence and QA closure.

I. Remarks:

1. AR A0211618 was drafted as a suggested prudent action to provide for an inspection of clamped or screwed type compression terminations for stranded wire.

2. GC training on circuit termination problems, conducted on December 12, 1991, has been enclosed in the NCR for information.

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