ML20154B051

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Forwards Text from Augmented Insp Team Insp Rept 50-293/87-53,describing Findings & Open Items from Evaluation of Loss of Offsite Power Event on 871112
ML20154B051
Person / Time
Site: Pilgrim
Issue date: 03/08/1988
From: Warren C
NRC OFFICE OF INSPECTION & ENFORCEMENT (IE REGION I)
To: Highfill K
BOSTON EDISON CO.
Shared Package
ML20154B016 List:
References
NUDOCS 8805170044
Download: ML20154B051 (5)


See also: IR 05000293/1987053

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UNITED 8TATES

NUCLEAR REGULATORY COMMISSION

j ~g REGION 1

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  • ,t 475 ALLENDALE ROAD

'$ [ KING OF PRUSSI A, PENNSYLVANI A 19408 ,

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ATTACHMENT 2

March 8, 1988

MEMORANDUM FOR: K. Highfill, Station Director

FROM: C. Warren, Senior Resident Inspector - Pilgrim

SUBJECT: NRC FOLLOWUP TO AIT INSPECTION 50-293/07-53

An NRC Augmented Inspection Team was dispatched to Pilgrim to evaluate a loss

of offsite power event occurring on November 12, 1987. The recults of this

inspection are documented in inspection report 50-293/07-53. In trder to

coordintte and track NRC inspection f ollowup we have collected pertinent

raport text, and grouped the findings into five appropriate areas.

, Description of the findings and corresponfing open item numbers are attached.

Item A.1 end E.2 have been designated at restart itemc.

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Thank you for your time and attention to these matters.

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Si r.c er ol y,

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Clay C. Warren

Attachment

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l R. Blough

J. Wiggins

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S. Collinc

W. Kane

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PDR ADOCK 050002 3

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ATTACHMENT

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A. Menacement Issues and Commitments (Unresolved Item 87-53-01):

1. During the inspection the licensee identified several actions they are

considering taking to improve the stations ability to respond to future

similar events. These actions included completing the installation of

the third emergency diesel, installation of a backup instrument air

compressor and installation of additional instruments to analyze

switchyar d transients. All of the foregoing equipment changes will be

completed before reactor restart.

. Reference: Report cover letter, Section 6.3. A written response

! describing the details of these actions was requested.

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2. Overall management of the recovery effort was somewhat fragmented and

f unclear. Coordination and communication between groups would be

substantially enhanced by well defined management guidelines for this  ;

' type of event (i . e. one in which the formal emergency response -

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organization is not mobilized).

Reference: Report Section 2.3, 5.3 and 5.4. A written response was .

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requested.

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! 3. Develop and implement procedural guidelines f or administrative 1y staf fing

] the TSC to support the operating organization in situations where

4 Emergency Plan activation is not appropriate. r

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Reference Report section 5.3, 5.4 and 5.0. .

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B. Ocerations (Unresol ved Item 07-53-02): ,

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i- The operators were not aware of the alarm indicating the reduced voltage

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on the 345 kV of f site power source prior to the loss of of f site power.

They were also unaware of the alarm indicating the blown f uses in the

analog trip system power supply. The f ailure to utilize these alarms

should be reviewed and appropriate corrective actions developed.

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Reference:' Report sections 2.3, 4.1.1.2, 4.1.1.6, and 4.1.2.4. A written '

response was requested.

2. The plant configuration bef ore the event and the equipment that was out

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of service f or maintenance created operational situations that could have

j been more serious under other circumstances with substantial dccay heat.

1 Describe what considerations will be made in tne future to assure that

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essential and non-esser.tial equipment removed from service for outage

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maintenance de not create undue operational inflexibilities.

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Reference Report sections 2.3, 5.4 and 5.P,. A written response was

j requested.

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OL Re-evaluate energency action levels regarding loss of onsite and offsite

power f or situations where f uel is loaded in the reactor vessel and RCS

temperature is less than 212 degrees F.

Reference: Report sections 5.2 and 5.8.

4. Certain procedures governing degraded plant conditions (e.g., loss of

power and loss of instrument air) may not be sufficient to clearly guide

recovery actions from events of this nature. Also procedures for

restoring offsite power should be reviewed against past operating ,

experience, especially events caused by severe weather, and revised to

reflect lessons learned and anticipated problems which may need

resolution to optimize power recovery time.

Reference: Report section 4.3.3, 4.3.5, 5.8, 6.3 and 6.4.

5. Strengthen communications practices to assure clear understanding and

directed actions.

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Reference: Report section 5.4 and 5.8.

6. In reviewing procedure 2.4.25, Loss of Shutdown Cooling it was noted that

the immediate operator actions provided no specific guidance on action

required to restore shutdown cooling. Similarly, the subsequent operator

actions did not specify any mitigating actions to be taken for conditions

other than f ull buses A5 and A6 and PCIS logics available, i

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During the event, when the "B" Diesel Generator was out of service and

panel Y-4 was without power, the licensee initiated a temporary

modification scheme to provide power to the control circuit of the RHR

suction outboard valve 47. Contingency proceduresfor the' single failure ,

of either onsite emergency power system train (i . e. , loss of either Y-3

i or Y-4) should be considered. -

References Report section 4.1.2.4 and 6.4.

. C. Maintenance (Unresolved Item 87-53-03):

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1. The inoper.pbility of the "B" emergency diesel generator (EDG) during the

event resulted from inadequate or incomplete maintenance procedures. The

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binding of the prelubrication pump and the leaking fuel injectors could ,

have been prevented from interfering with the recovery operations if

adequate procedures for repair and post ma,intenance testing were

employed. Maintenance requests contain very brief descriptions of actual

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material conditions f ound (as-found) and few specific details of work

performed, parts replaced and post work testing. More aAtention to

detail in preparaticn, execution and disposition of safesy-related

maintenance requests should be evaluated.

4 Reference: Report section 2.3, 4.2.2.2 and 4.2.3. A written response was

! requested.

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2. BECo should continue actions to reduce ing ess of ground water to the

process building and the consequential radiological bu-den. t

Reference: Report sections 5.7 and 5.8.

3. The practice of having the main generator bus quick disconnect links

installed during an outage should be reviewed relative to the recent

event.

l References Report section 5.8.

4. Procedure 3.M.3-9 should be revised to reflect operational consideration

for backfeeding with offnormal electrical system lineups.

Reference: Report sections 4.1.1.3.2 and 4.1.1.6.

5. On April 26, 1987 the "B" EDG lube oil temperature switch low (LOTSL) was

replaced after failure (MR 87-61-33). The switch that failed was

. actually a lube oil temperature switch high (LOTSH) which had been

' installed in place of the LOTSL under MR 87-61-15 during some previous

maintenance activity. It was not evident at the time of the inspection

what controls were applied to MR 87-61-15 in substituting a LOTGH for a

LOTSL. The evaluation of acceptability of this replacement is an issue

to be f ollowed up in f uture NRC inspections.

Reference Report section 4.2.2.2.

6. The post repair testing of the current transformer did not consider the

effect of the high voltage overstressing of the circuit components. The

circuit should be properly tested to assure no lat4nt f aults are present.

Reference Report sections 4.2.2.1 and 4.2.3. ,

.D. Gurveillance (Unresolved item 87-53-04):

1. Develop procedures that describe and control testing activities on switch

yard equipment and transformers.

Reference ' Report sections 4.1.1.3.3 and 4.1.1.6.

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2. Some emergency diesel generator instrumentation, although being read and

recorded, was not being evaluated and trended for consistency. An

assessment should be made of the surveillance readings being taken and a

determination made regarding the readings that are necessary and useful.

Further, responsibility for evaluating these readings should be assigned,

e.g., output current on each phase is neither monitored, recorded nor

trended. In addition, a review should be conducted to ascertain if all

appropriate instrumentation in being monitored and recorded during the

conduct of the EDG surveillance testing for determination of operability

of the equipment.

Reference: Report sections 4.2.2.1 and 4.2.3.

E. Continuino Technical Evaluations (87-53-05):

1. The operation of the startup transf ormer dif f erential lockout relay was

. apparently the result of a transient for which the protection was not

designed. The transformer did not experience an internal fault and the

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. operation of the lockout delayed the re-energization of the station from

offsite power sources. The actual cause of the differential lockout

needs to be conclusively established.

Reference: Report sections 2.3 and 4.1.1.6. A written response was

requested.

2. The blown f uses in the analog trip system were the apparent result of a

common cause. The cause of this condition should be identified and

corrected or determined to be acceptable before the reactor is restarted.

Reference: Report sections 2.3 and 4.1.2.4. A written

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response was

requested.

3. Additional investigation such as strainer and 'ilt'er inspection would be

l appropriate to ensure that the f oreign materitl that damaged the EDG

prelube pump was not externally generated (i . s. , from some other failed

component). The licensee agreed to open both the lube oil strainers and

j the filter on "B" EDG at the next opportunity.

Ref erencer, Report section 4.2.2.2.

4. The licensee's actions taken in response to IE Notice 87-28 will be

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reviewed separately as part of ongoing NRC inspection activities.

Reference: Report section 4.3.3 and 4.3.5.

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5. The 11 censee's FLM No.87-641 review, including determination of a

requirement for root cause analysis and corrective action plan, was not

I yet complete at the end of the AIT inspection. The licensee's further

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actions regarding Ft<M No.87-641 will be reviewed during a subsequent NRC

inspection.

Re,ference Report section 4.3.3.

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