ML20150E214
| ML20150E214 | |
| Person / Time | |
|---|---|
| Site: | Pilgrim |
| Issue date: | 01/20/1988 |
| From: | Durr J NRC |
| To: | Wiggins J NRC |
| Shared Package | |
| ML20150E217 | List: |
| References | |
| FOIA-88-198 NUDOCS 8803300047 | |
| Download: ML20150E214 (7) | |
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s JAN 2 01988 MEMORANDUM FOR: James T. Wiggins, Chief, Projects Branch 3, ORP FROM:
Jacque P. Curr, Acting Deputy Director, ORS
SUBJECT:
PILGRIM AIT OUTSTANDING ISSUES The Augmented Inspection Team made several recommendations to the Boston Edison Company in the AIT report to improve the station's ability to cope with future i
similar events. One of thest, recommendations is presented as a restart issue.
In addition, the licensee made commitments which are restated in the cover I
letter transmitting the AIT Report.
The issues are listed in enclosure 1 and are referred to your branch for tracking and followup.
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By copy of this memorandum, NRR is informed that there are no issues requiring NRR action.
/_ Wkw Jacqtre P. Ourr Acting Deputy Director DRS Cc:
R. Blough C. Warren J. Lyash
- 0. Ha.verkamp B. Boger, NRR 1
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- 1 Issues:
Commitments i
During the inspection you identified several actions you are i
i considering taking to improve the stations ability to respond to i
future similar events. These actions icluded completing the installation of the third emergency diesel, installation of a backup l
instrument air compressor and installation of aeditional instruments I
to analyze switchyard transients.
All of the foregoing equipment I
l changes will be completed before reactor restart.
In your response l
to the recommendations of this inspection, we request that you i
provide us with the details of these actions.
j Scurce:
Report Cover t.etter, formal response requested of licensee f
hsues:
Recommendations I
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5ections 4.1.1.6 and 4.1.2.4 I
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The operators were not aware of the alarm indicating the reduced
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l voltage on the 345 kV offsite power source prior to the loss of offsite power. They were also unaware of the alarm indicating the i
j blown fuses in the analog trip system pcwer supply.
The failure to r
utflize these alarms should be reviewed and appropriate corrective i
actions developed.
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Section 4.1.1.6 I
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The operation of the startup transformer differential lockout relay l
was apparently the result of a transient for which the protection was not designed. The transformer did not experience an internal fault and the operation of the lockout delayed the re-energiration of the j
station from offsite power sources.
The actual cause of the i
differential lockout needs to be conclusively established, f
Source: Report page 3, formal response requested of licensee.
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Issues:
Recommendations 1
Section 4.1.2.4 t
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1 The blown ~ fuses in the analog ~t71p system were the apparent result of j
a comon cause. The cause of this condition should be identified and i
I corrected or determined to be acceptable before the reactor is i
re sta rted.
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Section 4.2.3 The inoperability of the "B" emergency diesel generator during the l
1 event resulted from inadequate or incomplete maintenance procedures.
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The binding of the prelubrication pump and the leaking fuel injectors
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could have been prevented from interfering with the recovery operations if adequate procedures for repair and post maintenance testing were a
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employed.
Section 5.8 The plant configuration before the event and the equipment that was l
out of service for maintenance purposes created operational situations
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l that could have been nore serious under other circumstances with substantial decay hest. Describe what considerations will be made i
in the future to assure that essential end non essential equipment j
removed frca service for outage maintenance do not create undue
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operational inflexibilities.
l Source: Report page 3. formal response regt.ested of licensee.
Issues:
Recommendations Misoperation or spurious operation of the differential relay for i
faults outside the zone of protection lead to lockout of the startup 4
transformer requiring thorough investigation of the unit before i
e returning it to service and loss of access to offsite power during I
l that period.
Hence, the root cause of the relay operation must be determined and corrected in order to increase the reliability of fast access to the offsite power source.
The licensee is continuing the j
investigation of the relay operation on the initial astumption of i
increased volts per-hertz being the root cause. However, the Itcensee
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l has not investige'.ed other possible reasons for the operation of the i
relay. Current transformer performance, calibration checks and other j
operation and maintenance actions recommended by the relay manufacturer l
t should be considered.
section 4.1.1.2 discusses the failure of plant operators to respond t
i to the degraded 345 kV grid voltage clarm.
Similarly an observation l
in Section 4.1.2.4 of this report identifies an annunc,iated alarm that was not factored into the operator's analysis of the spurious primary containment isolation signal upon restart of the RHR pumps.
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These two events should be reviewed and a determination made regarding the appropriateness of the operator's responses to these alarms if a training deficiency exists, t
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Procedure 3.M 3-9 should be revised to reflect operational consideration l
for backfeeding with of f normal electrical system lineups.
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i Develop procedures that describe and control testing activities on 4
switchyard equipment and transformers.
Source: Report page 23 l
Issues:
Recommendations I
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There was confusion in the control room concerning the leading on the "B" diesel generator and on what actions should be taken to restore power to the RPS buses.
The operators did not notice the fuses blowing on channel A even though they were annunciated on the computer.
This failure to notice or acknowledge computer alarms wes i
also evidenced in the 345 kV system at 1:27 A.M. on November 12 when i
the line 342 low voltage alarm came in on the computer.
It appears that operators are not routinely analyzing computer alarm data to assist in assessing plant status. A review of the operator actions J
should be made to assess the appropriateness of operator actions and i
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+ heir analysis of plant data for this event.
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ihe 10 amp fuses that blew in the Analog Trip Cabinets - one in 1
C2228-A1, two in C2228-A2 and one in C2229 were apparently due to a common cause connected with either the starting of the A-RHR l
pump or the switching of the RPS power supplies.
The licensee is 1
investigating the root causes of the blown fuses. Had the other fuse f
i in C2229-81 also blown, operators would not have been able to reset i
1 RHR shutdown cooling isolation.
Corrective actions based on the i
results of the investigation should be initiated and completed before i
j reactor restart.
During the event, when the B Diesel Generator was out of service and i
panel Y-4 was without power, the licensee initiated a temporary modification scheme to provide power to the control circuit of the j
1 RHR suction outboard valve 47.
Contingency procedures for the single i
failure of either onsite emergency power system train (i.e., loss of l
1 either Y-3 or Y-4), should be considered.
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l In reviewing procedure 2.4.25, Loss of Shutdown Cooling it was noted that the immediate operator actions provided no specific luidance on
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action required to restore shutdown cooling.
Similarly, the subsequent j
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oprator actions did not specify any mitigating actions to be taken for conditions other than full buses A5 and A6 and PCl$ logics available.
The adequacy of this procedure should be reviewed relative to the LOOP event.
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i Source: Report pages 28 and 29.
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Issues:
Commitment J
l Additional investigation such as strainer and filter inspection would
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be appropriate to ensure that the foreign material that damaged the pump was not externally generated (i.e., from some other failed component). As a result.of these discussions the licensee agreed to 1
open both the lube oil strainers and the filter on "B" EDG at the I
next opportunity.
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Source:
Report page 33 i
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!ssues:
NRC Commitment i
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One additional item was noted in reviewing diesel MRs. On April 26, j
1937 the "B" EDG 'ube oil temperature switch low (LOTSL) was replaced l
i af ter failure (MR 87-61-33).
The switch that failed was actually a i
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lube oil temperature switch high (LOTSH) which had been installed in place of the LOTSL under MR 87-61-15 during some previous maintenance 1
activity.
It was not evident at the time of the inspection what-l controls were applied to MR 87-61-15 in substituting a LOTSH for an i
LOTSL. The evaluation of acceptability of this replacement is an
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issue to be followed up in future NRC inspections.
i Source: Report page 34 l
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!ssues:
Recommendations 4
The inoperability of the "B" emergency diesel generator resultad from
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I the performance of maintenance using inadequate or incomplete maintenance l
l procedures. The lastances of the cover flange bolt tightening on the j
prelubrication pt.mp and the leaking injectors should be reviewed and i
appropriate actions taken to prevent recurrence of these and similar i
equiptent failures.
l Maintenance requests contain very brief descriptions of actual saterial conditions four,d ("as-found) and few specific details of work performed, parts replaced and post work testing. More attention to detail in preparation, execution and disposition of safety related i{
maintenance requests should be evaluated, One other area of AIT concern is the apparent lack of attention to I
detail in the area of maintenance on flammable fluid systems, most i
notably diesel fuel cil. Fuel leakage in the quantities encountered i
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during this event pose a fire hazard.
1 The post repair testing of the current transformer did not confider the effect of the high voltage overstressing of the circuit components.
1 The circuit should be properly tested to assure ou latent faults are l
present.
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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 *eadings that are necessary a,d useful.
Further, responsibility f.
evaluating these readings should be assigned, e.g., output current on each phase is neither monitored, recorded nor trended.
In addition, a reviaw should be conducted te ascertain if all appropriate instrumentation is being monitored and recorded during the conduct of the EDG surveillance testing for determination of operability of the equipment.
Source: Report pages 34 and 35 Issues:
NRC Cemmitment The licensee's F&M No.37-641 review, including determination of r requirement for root cause analysis and corrective action plan, was not yet completed at the end of the AIT inspection.
The licenstse's further actions regarding F&M No. S7-641 will be reviewed during a subsequent NRC resident inspection.
Source: Report page 43 Issues:
NRC Commitment The licensee's actions taken in response to IE Notice 87-23 are being reviewed Seoarately as part of the ongoing NRC resident inspection activities, and the delineation of specific recommended actions and their schedule, as addressed in the PNPS status report, is not considered within the scope of the AIT report.
Source:
Report page 45 Issues:
Recommendations Strengthen 'ha management guidelines and roles to assure a clearer ans _ e positive direction to recovery activities following major events, t
Strengthen communications practices to assure clear understanding and directed actions.
Re-evaluate emergency action levels regarding loss of onsite and i
offsite power for situations where fuel is loaded in the reactor 4
i vessel and RC$ temperature is less than 212*F.
Develop and ieplement procedural guidelines for administratively stafng the TSC to support the operating organization in situations where Emergency Plan activation is not appropriate.
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Re-evaluate plant procedures that may be required in loss of power events to assure they are sufficient to guide recovery from degraded plant conditions.
Althou 5 not directly related to human performance. DECO should cont:nue actions to reduce ingress of ground water to the Process Building and consequential radiological burden.
The practice of having the main generator bus quick disconnect links installed during an outage should be reviewed relative to the recent event.
The plant configuration and equipment out of service for outage maintenance created operational inflexibilities during the event whicn. under other circumstances, could have hac serious impacts on the operator's ability to cope with the situation.
BEco should provide a review process for plant configuration and equipment in a maintenance status of assess plant and operator needs during outages to cope with with outage operation oriented transients (i.e. loss of of f site power. loss of shutdown cooling).
Source: Report page 59 and 60.
Issues:
Recommencations The loss of shutdown cooling procedure should be revised to address loss of power to either safeguards panel Y3 or Y4 both with and without offsite power available.
Procedures for restoring of f site 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 optinize power recovery tine.
Source: Report page 66 1
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