ML20062J982

Intervenor Exhibit I-MFP-52,consisting of 930512 Rev 0 to Draft Ncr DC1-93-EM-N019

ML20062J982
Person / Time
Site:	Diablo Canyon
Issue date:	08/18/1993
From:	AFFILIATION NOT ASSIGNED
To:
References
OLA-2-I-MFP-052, OLA-2-I-MFP-52, NUDOCS 9311190402
Download: ML20062J982 (14)

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NCR DCl-93-EM Y DRAFT: Ma 2, 1993

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MANAGEMENT

SUMMARY

On April 1, 1993, AR A0301192 was~ written to document that the rear hinged panel of the Unit 1 RHF panel was found with no fasteners installed to secure the hinged panel to the main panel. The fasteners were in a plastic bag in the bottom of the panel. This condition was considered a potential loss of seismic qualification that could have impacted the operability of vital 4kV bus F and its j associated diesel generator during a seismic event.

Preliminary root cause: Responsibility for panel _. .

restoration was not assigned to any of the grpups performing concurrent work in the panel.

Corrective actions are to be determined.

This draft, dated May 12, 1993, includes the meeting minutes from the 5/12/93 TRG. The TRG discussed the preliminary-

root cause analysis, event safety analysis, and. proposed l corrective actions. The TRG will reconvene at the end of I July to finalize root cause and corrective actions.

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J NCR DC1-93-EM-N019 Rev. 00 DRAFT: Mey 12, 1993 G. Method of Discovery:

Quality Assurance personnel, during the performance of an inspection in the cubicle, identified the problem.

H. Operator Actions:

None.

I. Safety System Responses:

None.

III. Ca_use of the Event A. Immediate Cause:

l The fasteners for the rear hinged panel of the l Unit 1 RHF panel were not re-installed following l maintenance / construction related activities.

B. Determination of Cause:

1. Human Factors:

a. Communications: Theru is a potential for lack of communication between various groups performing work on the vital bus.

l *1 b. ProceduresT* Procedures do"$bt normally go " " '  !

l to the level of detail requiring l individual bolt removal / reinstallation.

j c. Training: Potential for increased l awareness on ownership of activities j related to fasterners.

l d. Human Engineering: Less cumbersome hinged j panel fasteners could increase probability j of proper refastening in future.

l Presently there are 15 bolts required.

l e. Management System:

2. Equipment / Material:

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NCR DCl-93-EM-N019.Rev. 00 DRAFT: May 12, 1993

a. Material Degradation: ' N/A'

b. Design: See~ Human Engineering above.

c. Installation: .N/A

d. Manufacturing: N/A:

e. Preventive Maintenance: N/A

f. Testing: N/A

-g. End-of-life failure: .N/A-C. Root Cause:

Preliminary root cause: : Responsibility'for. panel restoration was not assigned to anylof the groups performing concurrent' work in the panel.

D. Contributory Cause: .

To be determined. ,

IV. Analysis of the Event-A. Safety Analysis: t As discussed in the initialLTRG' meeting on-April l 15, 1993 and in the NSARA licensing. positions (ref. .5), seismic ~ events'and' seismic qualification need not be considered'when determining.

I operability.for this component. Evaluations ort j the tracking and initiating'ARs-(ref. 2) will-l document that the F bus and itsfassociated DG

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would'have been operable ~afore_and after'a i postulated seismic event. In addition 7 only'two ~

l vital 4kV buses are required to safely shut down l the plant, and busesLG and H were verified as l having the hinged panel fasteners installed.

In addition, a review of the FSAR, Chapter 15' l regarding a Loss Of Offsite Power.(LOOP),

i determined that the existing' analysis bounds;this event. Plant vital instrumentationfrequired for reactor trip will lxa feed'from DC power, the steam generatorLsafeties will provide heat dissipation if the PORV's are not available. The AFW' system is not assumed until 122~ seconds into the LOOP event. Assuming a 30Lsecond seismic' event,.a ten second subsequent diesel start, and worst case sequenced timing of 28 seconds for Bus H results in a total AFW time of 58 seconds. Furthermore, 93NCRWP\93EMN019.Kn*R Page 5 of 14 l

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- .. - - - . . . . ~ - - . . . . . - -. . -. . - . . -

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?.- .i NCR'DCl-93-EM-N019-Rev. 00  ;

-DRAFT: May 12, 1993 j there is sufficient AFW system redundancy to withstand a single active failure in addition to- i the subject Bus F unavailability during a seismic event.

Therefore, this condition did not adversely. affect i the health and safety'of the public.

B. Reportability:

1. Reviewed under QAP-15.B and determined to be-  !

non-conforming in accordance with Section  ;

2.1' 2 as'a significant.non-routine: event that may-adversely affect the~ safe operation of:the plant and may require reporting'to the NRC.

2.

Reviewed under 10 CFR 50.72.and 10-CFR)50'73 .

per NUREG 1022.and: determined to be'not reportable in accordance with 10 CFR 50.73 (a) (2)-(i) (B) as an operation or-condition'  ;

prohibited by the Technica1TSpecifications, i since the bus and the DG: were not inoperable- '

in excess of the allowedLoutage' time due to  ;

this condition. ,

In addition, this condition.was determined to be not reportable under 10.CFR.50.72  !

(b) (2) (iii) ( A) L and 50.73 (a) (2).(v) (A) as a  ;

condition that alone could have prevented a' safety function, and notireportable under. i

50. 72 (b) (1) (li) _and ' 50.'73 (a) (2) (ii) as- a O condition ou'-ide the' design basis'that- . _

significantly compromised plant: safety. The-condition represented a potential loss'of seismic qualification, and "alone" - (i . e. ,- ,

without assuming a' concurrent seismic event) is not significant. In addition,the two redundant 4kV buses.G and H were. verified not to be in this nonconforming. condition. See

" Safety Analysis" above..

3.

Reviewed under 10 CFR Part 21 and determined that~this conditionLwill not require a.10.CFR 21 report, since'(a) Lit is'being evaluated '

under 10 CFR 50.'72/73, and (b)' it doessnot involve defects in vendor-supplied services / spare parts in~ stock.

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A NCR DC1-93-EM-N019 Rev. 00

' DRAFT: May.12; 1993

4. This condit'lon will not lxa reported via an INPO Nuclear Network entry..

U

5. Reviewed under l'O.CFR 50.9'and determined to~

be not reportable-since-this' event does not' have a significant implication for public health and safety or common defense and 'i security.

6. Reviewed under the' criteria of.AP C-29 requiring'the issue and approval of;an OE and determined that an OE is not. required.

V. Corrective Actions A. Immediate Corrective Actions:

1. The fasteners were. replaced on the same day they were discovered uninstalled'(ref. 2).

2. The fasteners were verifiedito be installed on the similar panels in vital 4kV-buses'G.and H. ,

B. Investigative Actions:

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1. Evaluate the design ~basisoof the fasta-crs.for l the RHF hingedLpanel.

RESPONSIBILITY: M. Khan ECD: ' RETURN DEPARTMENT: NES Seismic

, Tracking AR: A0303415, AEL #01

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2. Evaluate the. potential for rel'y a contact chatter on the RHF hinged panel, Land the resulting impact on operability before and after a postulated seismic event.

l RESPONSIBILITY: M. Khan . . ECD: 5/22/93 DEPARTMENT: NES - OcasMic Tracking AR: 'A0303415, AE #02

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3. Develop a timeline of events to assist in determining appropriate corrective actions.

RESPONSIBILITY: Hanson/Shortt ECD: RETURN DEPARTMENT: Electrical Maintenance j Tracking AR: A0303415, AE #03- H 93NCRWP\93EMN019.KWR Page 7 of 14

NCR DC1-93-EM-N019 Rev. 00 -

DRAFT: May 12, 1993

4. Determine the consequences of a loss of offsite power concurrent with a seismic event.

The concern is that with Bus F unavailable during a seismic event due to the missing fasteners, and assuming a single active failure of another vital bus, does this result in being out91de of the design basis?

RESPONSIBILITY: B. Supremo ECD: 7/15/93 DEPARTMENT: NES Electrical Engineering Tracking AR: A0303416, AE #06

5. Investigate development of a bus maintenance i procedure and/or checklist to ensure proper

! line up of bus components following si;nificant maintenance or construction activities.

RESPONSIBILITY: Foat ECD: 07/15/93 DEPARTMENT: Electrical Maintenance Tracking AR: A0303415, AE #07 C. Corrective Actions to Prevent Recurrence:

1. Write an AT-EWR for a design change to the Unit 1 4kV safeguards panels to replace the multiple screws securing *he rear hinged panel with one bolt, similar to the Unit 2 panels.

i RESPONSIBILITY: R. Hanson ECD: RETURN l DEPARTMENT: E-lectrical Maintenance l Tracking AR: A0303415, AE #04 ,

Outage Related? No  ;

OE Related? No NRC Commitment? No CMD Commitment? No The May 12, 1993, TRG determined that this is

{i a prudent action. Not required for NCR l closure.

• • • PROPOSED ***

. (Require some mechanism, for example a j maintenance procedure, when groups report off of an extended bus outage, in order to ensure the configuration of knife switches, bolting, etc. are satisfactory. This would be similar 93NCRWP\93EMN019.KWR Page 8 of 14 i

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NCR DC1-93-EM-N019.Rev 00' -

l DRAFT: May 12, 1993 to.a valve checklist to ensure the proper line-up of-components prior to' returning-the system to. service.)

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' RESPONSIBILITY: ECD:- f DEPARTMENT: -

Tracking AR: A0 , AE.# ,

Outage Related? Yes/No. OUTAGE:(_R_.or U_FO)f ,

OE Related? .Yes/No NRC Commitment? Yes/No-CMD' Commitment? Yes/No D. Prudent Actions (not-required for NCR closure) ,

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• • • PROPOSED *** Develop a lamacoid for~ thel ,

vital bus RHF, RHG,-and RHH: panels indicating that-the fasteners-are required'for seismic qualification of the associated relays, i

RESPONSIBILITY: Hanson ECD:

Tracking AR: A0 l VI. Additional Information 1 A. Failed Components:

None.

-- B. -Previous Similar Events:. s l NCR DCO-89-EM-N075, " Loose or Missing Fasteners in Electrical Equipment": lThe common factor in this' l previous NCR.was a lack of programmatic. guidance in resolving fastener problems. The corrective l actions amounted to the establishment of a' program for identification and resolution of-loose,-

missing, or damaged-fasteners. Although this program did help in evaluating and determining immediate actions after.the current event, it did .

not prevent the current event, where fasteners were not reinstalled after work by multiple groups during an extended bus outage-during 2R5.

NCR DCO-90-EN-N016, " Control' Panels, Inadequate- ,

Seismic Qualification": The two root causes of.

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> ** t NCR DC1-93-EM-N019 Rev. 00 -

l DRAFT: May 12, 1993 this previous NCR were a lack of procedural guidance on coordinating design chhnges with Westinghouse and a lack of documented seismic design bases. The corrective actions did not prevent the current NCR because the current problem was with maintaining the existing seismic qualification, not with documenting changes to the i design.

]

NCR DCO-91-EM-N005, "4kV Switchgear": This previous NCR dealt specifically with the 4kV l switchgear door bolts. Root causes were less-than-adequate design and lack of guidance / criteria for " tight" bolts. Because the NCR stas specific to the outer door bolts, it did not p:revent the ,

current event regarding the inner rear hinged '

panel bolts.

C. Operating Experience Review:

1. NPRDS:

Not applicable. 1

2. NRC Information Notices, Bulletins, Generic Letters:

To be determined. ,

3. INPO SOERs and SERs:

To be determined. 1 D. Trend Code:

Responsible department __, and cause code __.

To be determined.

E. Corrective Action Tracking:

1. The tracking action request is A0303415.

2. Are the corrective actions outage related?

To be determined.

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so-NCR DC1-93-EM-N019 Rev. 00 DRAFT: May 12, 1993 F. Footnotes and Special Comments:

None.

G.

References:

1. Technical Specification 3.8.1.1

2. Initiating Action Request A0301192 Action Request A0300421, AE02

3. PG&E drawing nos. 441354 and 441357

4. Operations Department Policy B-24, " Vital 4kV Switchgear Operability," Rev. 3 (5/08/92)

Memorandum from NECS - Project Engineer (M.

Tresler) to DCPP - Maintenance Services (B.

Giffin), dated June 12, 1990, "4kV Switchgear Bus Opened Doors and Panels" (CHRON 153041)

5. Memorandum from the Manager, NSARA (J. Hoch) to Electrical Engineering (R. Hanson),

dated January 22, 1993, " Input to TRG for NCR DCO-91-EM-N005" (CHRON 202236)

Memorandum from the Manager, NSARA (J. Hoch) to Various, dated February 5, 1993,

" Licensing Position Regarding Concurrent Seismic Event and Loss-of-Coolant Accident" H. TRG Meeting Minutes:

On April 15, 1993, the initial TRG convened and considered the following:

1. Previous problems with bolting on the 4kV switchgear were concerned with the door bolting. However, the previous conclusions regarding operability (Ops Policy B-24, NSARA memo) appear to be applicable to the current situation, since relay contact chatter would only be an issue during concurrent seismic and LOCA events.

i l 2. NES - Seismic is continuing to evaluate the I design basis of the fasteners. Their initial evaluation is that the structural integrity of 93NCRWP\93EMNOl9.KUR Page 11 of 14

Os NCR DC1-93-EM-N019 Rev. 00 DRAFT: May 12, 1993 the panel is maintained, and that the panel would remain functional after a postulated seismic event. Therefore, using the NSARA memo, this condition is a non-reportable "outside design basis" and is not a violation of a TS LCO.

3. The TRG discussed Operations management's recommendation to consider implementing a mechanism to ensure that electrical component configuration is satisfactory when reporting off an extended clearance on a bus -- this would be analogous to the valve checklists used prior to returning a piping system to service.

4. T.iis TRG is tentatively scheduled to reconvene on Thursday, 4/22/93 at approximately 10AM.

On April 22, 1993, the TRG reconvened and considered the following:

1. The TRG reviewed the determinations at the previous meeting that the event was not reportable, since operability did not need to consider a seismic event coincident with a LOCA. The 6/12/90 Engineering memo that is the basis for Ops policy 0-24 again goes back to structural integrity of the cabinets and doesn't really discuss the internal relay board fasteners.

2. The chronology of work activities in and near the area was not conclusive. It did show, however, that there were several different groups working in the panel during the outage.

l The screws were often found unfastened, and

! therefore left unfastened by one group, j because of concurrent work by another group.

3. The TRG further discussed the possibility of adding a checklist to walk down the bus configuration prior to the PMT. However, some concerns were discussed: Should the scope be focused on only the 4kV vital switchgear?

Would the walkdowns be required only after ma]or bus outages, or after any work? Would a procedure, or a generic work order step, or 93NCRWP\93EMN019.KWR Page 12 of 14 I

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NCR DC1-93-EM-N019 Rev. 00 DRAFT: May 12, 1993 some other mechanism require them? What about work done without using a clearance or other paperwork (e.g., Rev. A walkdowns)? The SFM should not be bogged down with worrying about 4kv relay board fasteners in addition to all his other duties. Ops does not want to revise the existing B-24 policy to also cover internal fasteners - since they are inside the cabinet, how could an operator on rounds verify they are installed tight?

4. Electrical Maintenance will discuss these concerns with management. Meanwhile, a corrective action to prevent recurrence of this specific incident will be to request a DCN to replace the Unit 1 fasteners with the simpler, seismically qualified Unit 2 design (one knob to close and secure the panel).

5. This TRG will reconvene in mid-May 1993.

l On May 12, 1993, the TRG reconvened and considered the following:

1. The safety analysis and associated reportability was re-visited. There was concern expressed that a Loss of Offsite Power (LOOP) is not considered in the safety analysis and therefore, may not have been addressed when the reportability determination  ;

was made. The TRG members agreed that as long ~ j

- , . ., as the existing Chapter 15 Analysis bounds l this event, then there is no design basis j reportability concern. Preliminary review by I regulatory compliance determined that the existing analysis bounds this event. Refer to Safety Ana]ysis section. A new investigative action will be assigned to engineering for evaluation and documentation of the consequences of a LOOP concurrent with a l seismic event for this situation.

2. Preliminary root cause analysis.was presented by electrical maintenance. No definitive root cause has been determined, but it appears to

be related to a lack of responsibility for panel restoration by the groups performing

, concurrent work within the panel. The TRG 93NCRWP\93EMN019.KWR Page 13 of 14 i

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NCR DC1-93-EM-N019 Rev. 00 .

DRAFT: May 12, 1993 further discussed that this is an isolated event since the majority of activities within a panel are associated with a single work activity.

3. Although this event is considered isolated, the TRG looked at overall bus restoration activities and determined that there is a potential programmatic weakness (i.e. a bus restoration procedure may have prevented this event).

4. Proposed corrective action discussed to develop a maintenance procedure for returning an inoperable bus to service. This procedure could be developed on a " cubicle" basis-and could be tracked via TS tracking sheets. An investigative action was assigned to address this potential corrective action.

5. Initiation of a " lessons learned" memorandum was discussed. This could be a-prudent action, but would become a corrective action only if personnel error or training is an issue.

6. The TRG will reconvene at the end of July i provided no design basis reportability issues l are determined by regulatory compliance.

I. Remarks:

None.

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