IR 05000354/1993023

Insp Rept 50-354/93-23 on 931004-1103.No Violations Noted. Major Areas Inspected:Review Licensee Corrective Actions of Previously Identified Edsfi Findings

ML20059F502
Person / Time
Site:	Hope Creek
Issue date:	12/15/1993
From:	Bhatia R, Ruland W NRC OFFICE OF INSPECTION & ENFORCEMENT (IE REGION I)
To:
Shared Package
ML20059F483	List: IR 05000354/1993023 ML20059F480
References
50-354-93-23, NUDOCS 9401140046
Download: ML20059F502 (11)

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n U. S. NUCLEAR REGULATORY COMMISSION i

REGION I

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REPORT / DOCKET NOS. 50-354/93-23 LICENSE NO.

NPF-57

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LICENSEE:

Public Service Electric and Gas Company

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P. O. Box 236 11ancocks Bridge, New Jersey

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FACILITY NAME:

Ilope Creek Nuclear Generating Station.

INSPECTION AT:

Hancocks Bridge, New Jersey INSPECTION DATES:

October 4-7,1993 and November 1-3, 1993

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INSPECTORS:

Scott Morris, Reactor Engineer, DRP Douglas Weaver, Reactor Engineer, DRP

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Ram Bhatia, Reactor Engineer Date

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Electrical Section, EB, DRS

APPROVED BY:

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William II. Ruiand, Chief Date Electrical Section, EB, DRS i

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1 9401140046 931229 PDR ADOCK 05000354 G

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l Areas Inspected: This was an announced inspection to review the licensee's corrective -

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actions of previously identified electrical distribution system functional inspection (EDSFI)

findings.

-i Results: No violations or deviations were identified. Six open items reviewed were found to

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be adequate and the items are closed. The inspector noted that your staff evaluation of the i

fast-transfer design scheme and the root cause analysis of the load tap changer problems were i

comprehensive and thorough.

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DETAILS

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1.0 PURPOSE

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The purpose of this inspection was to review and verify the licensee's corrective actions for previously identified NRC findings during the 1992 Electrical Distribution System Functional Inspection (EDSFI) for Hope Creek Generating Station.

2.0 FOLLOWUP OF PREVIOUSLY IDENTIFIED FINDINGS 2.1 (Closed) Unresolved Item 50-354/92-80-02 pertaining to the study to review plant fast transfer scheme logic design verification

During the followup EDSFI inspection in October 1992, the inspectors noted that the hcensee

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had completed the design review of the transfer scheme design operational concern and determined that the recovery voltages for the 4.16 kV and 480 Volt motors would remam

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above the 90% perbrmance values under LOCA conditions for all safety load sequence i

steps. In addition, the licensee determined that under a degraded voltage condition, the

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4.16 kV bus voltages would not approach the degraded relay pick up setpoint of 92% Also, to prevent an operational flip / flop concern, the licensee had implemented an administrative control and revised the applicable procedures for blocking this condition by utilizing the existing designed push buttons to keep them in the depressed mode (energized position). The

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inspectors had no concerns with this portion of the issue at that time; however, this item was left open because of an event, which occurred on May 13,1993, where a transient fault on the 13.8 kV ring bus feeder resulted in transfer to an alternate source and eventually to the emergency diesel generators (EDGs) because of a low voltage condition suspected during the

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bus transfer condition.

During this inspection, the intpector reviewed the licensee's May 13, 1993, event analysis, computer simulation analysis, and additional study completed by the licensee's contractors to

confirm the voltage conditions experienced during this event and the existing design adequacy. This study focused on evaluatin;; the adequacy of the existing fast transfer design of the Hope Creek under transient condition.

The inspectors noted that the licensee had concluded that the Hope Creek electrical power distribution system performed as designed during the transient faulted condition on the 13.8 kV feeder of the ring bus. The licensee further concluded that sufficient controls remained in place for the operators to.nanually take control of the alternate source infeed breaker for l

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closing had the onsite ac power failed to start and supply the emergency buses under the-accident conditions to mitigate the accident. Based on the inspectors review of the existing control scheme drawings and the licensee's evaluation of the event, the inspectors found no concerns. The inspectors review of the computer simulated analysis study (PSE&G Calculation No. E-15.10, PTl Report # R 52-93) revealed that to achieve a successful fast.

transfer of the 1E buses, the 13.8 kV source voltage should be above 0.92 pu and 4.16 kV Class IE bus voltages should be above 0.70 pu, respectively. In addition, these minimum voltages also had to exist simultaneously. The simulated analysis of the May 13,1993, event

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determined that both the above system voltage levels were determined to be below the minimum acceptable values. The analysis concluded that the alternate power source voltas;e had dropped below the 0.92 pu, while the Class 4.16 kV IE bus voltages rose from 0.4 pu to 0.65-0.8 pu as the recovery began. Since the low voltage conditions on both affected safety buses were below the acceptable values, this event led to starting of the respective EDGs.

i The inspectors review of this analysis revealed no concerns. In addition, the review of the i

study completed by the contractor did not identify any major concern; however, it concluded that the present design could be further improved under transient faulted conditions.

Per discussion with the licensee, the inspector determined that the licensee was in the process of reviewing the recommendations of the contractor study. Upon completion of the above review, any additional improvements considered necessary by the licensee in 4.16 kV fast bus transfer system design would be done under routine design changes at a later date, based on the station priority system.

I Based on the review of the above completed evaluations to confirm that the present design

was adequate, as per the present design requirements, and no concerns were identified by the i

inspectors during this inspection review, and the additional design improvements could be

followed up during the NRC routine engineering inspections, the inspectors concluded that

this item is closed.

2.2 (Closed) Unresolved Item 50-354/92-80-07 regarding the inadequate documentation for the EDG crankcase exhaust piping mounting condition (

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During the EDSFl inspection, the team noted that the licensee's Hope Creek seismic II/I evaluation program identified potential II/I interactions between the emergency diesel generator (EDG) engme and the crankcase exhaust (vacuum) system. Documentation submitted by the licensee at the time of the original inspection did not indicate that a proper seismic analysis of the exhaust piping had ever been done. The team was concerned that a

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failure of the crankcase exhaust system piping could result in explosive gas accumulation in

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I the diesel engine room and affect the performance of the EDGs operation.

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To resolve the above concern, the licensee performed an evaluation of all applicable design documentation (HCGS UFSAR, Volume 14, Chapter 9, P&ID M-30-1, Drawing 1-P-KJ-09)

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and determined that all the EDGs crankcase exhaust piping system was adequately supported j

as classified in their design drawings as seismic, Category II.

The inspectors reviewed the above design documentation and identified no concerns. The i

inspectors also confirmed by visual inspection that the installation of EDG crankcase exhaust system piping and hangers were in accordance with the design drawings and identified no i

concerns. All EDGs systems were found to be configured as per the design drawings.

l Based on the inspector's verification and adequate design in place by the licensee, the I

inspectors concluded that this item is closed.

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2.3 (Closed) Unresolved item 50-354/92-80-10 pertaining to the auto load tap changer failures on station transformers

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During the previous EDSFI inspection, the team determined that four automatic load tap

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changer (LTC) failures occurred on the 1 AX501 and IBX.501 station service transformers in i

the previous three years. The root causes of these failures were not known to the licensee at that time. The team was concerned that a failure of station service transformer LTCs could

i affect the available voltage at the 480 Volt motor control centers loads (MCCs) and affect their performance. In addition, on May 4,1993, a similar LTC failure was observed by the licensee on the I AX501 station service transformer.

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During this inspection, the inspectors noted that the licensee had completed an extensive

investigation to review the LTC failure concern by reviewing similar concerns with other utilities, vendors and inspection of failed components. In addition, the licensee had changed the operations log and procedure to alert the operators of a potential LTC concern. The minimum and maximum allowed bus voltage values were also added in the procedure to alert operators of potential LTC problems, should bus voltage fall outside the acceptable values.

i Based on the licensee's investigation and the inspectors visual inspection of the selected LTC '

failed circuit cards, evidence of corrosion was on the cards. Per discussion with the licensee, the inspectors determined that the licensee had concluded the cause of the LTC failures was due to the existence of corrosion on the solid-state LTC control cards. These l

control cards are located inside the control housings of the station transformers. The licensee's inspection determined that corrosion was visible only on the control cards associated with the transformers that had LTC failures and no corrosion was evident on the units that did not fail.

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The inspectors noted that the licensee had taken the following corrective. actions to prevent future LTC failures.

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Replaced station service transformer LTC control cards with new improved cards (scaled relays, solder etched on both sides, better control transformer, and covering with a conformal coating to protect against corrosion and moisture),

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Revised the preventive maintenance procedure to inspect the internals of the transformer control housing and examination of the LTC control card for evidence of.

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corrosion.

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Performed the walkdown of all similar transformer control cabinets to verify integrity of the door seals and latches and operation of the internal space heaters.

'i Based on the inspectors' review'of the licensee's corrective actions, documentation review,

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and visual inspection of both the old and new control cards, and no abnormal LTC transients

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i noted since the above actions, the inspector concluded that this item is closed

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2.4 (Closed) Unresolved Item No. 50-354/92-80-12 pertaining to the test record i

documentation concerns identified in 1986 pre-operational test During the previous EDSFI inspection, the licensee was not able to provide adequate documentation to justify this resolution for several concerns identified by the team. The specific areas of concerns were identified with respect to the fuel oil day tank size, fuel oil l

consumption rate and other issues identified in the emergency diesel generators pre-operational test (PTP-BB-3, Part A). At that time, the team did ec consider any one of these issues to be an operability concern. The licensee committed to evaluate these concerns and demonstrate that adequate corrective actions were taken to resolve this issue.

l During this inspection, the licensee had collected all of the applicable documentation from

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the above pre-operation test and completed the evaluation of the above test exemption concerns identified in the 1986 test. The licensee found that all test concerns had been adequately resolved and appropriate followup actions had been completed to adequately resolve the test concerns. Based on this evaluation performed, no additional actions were required to address the above issue. The inspectors review of the documentation pertaining to the pre-operational test conducted in 1986 revealed a total of 45 test exemptions.

To satisfy the above team concern, the inspectors randomly selected eight test exemption (TE) items from the previous inspection concerns. These items pertained to the EDG fuel oil day tank capacity, fuel oil day tank size and other concerns (TE-27, 29, 32, 33, 34, 35, 36 and 38). The inspectors review of the licensee's corrective actions taken to satisfy the EDG pre-operational test documentation revealed no concerns. A brief description and its resolution of each item observed by the inspectors during this inspection is noted below:

hem Concern Resolution TE-27 and The EDG A, B and D fuel oil The fuel oil day tank level alarms

day tank level alarm were readjusted and calibrated.

annunciated in 24 minutes instead of required specified 70 minutes, per the test procedure

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TE-32 Three core spray pumps Troubleshooting found missing (AP206, CP206 and DP206)

wires in switchgear cubicles, after started in 10 seconds instead of rewired as required per design and 6 seconds time after the bus re-successfully completed test on energization specified in test 2/16/86.

procedure.

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i TE-33 The EDGs day tank fuel volume Technical evaluation made by the

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was not available (recorded) to licensee used only the storage calculate the fuel consumption capacity tank differential level and rate, only the storage tank level assumption was made that the day

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differential data was used to tank level would stay approximately I

calculate fuel consumption rate the same after the run. The

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licensee evaluation concluded that L adequate fuel oil was available in the storage tank (53,000 gallons i

good for 179.3 hours3.472222e-5 days <br />8.333333e-4 hours <br />4.960317e-6 weeks <br />1.1415e-6 months <br />) to satisfy the 168 hour0.00194 days <br />0.0467 hours <br />2.777778e-4 weeks <br />6.3924e-5 months <br /> (7 days) for each EDG -

required time in the storage tank.

TE-34 The EDGs lube oil consumption Technical evaluation concluded that j

rate was found to be slightly 1.63 gallons / hour rate was not l

higher (1.63 gallons / hour) than excessive. In addition, the licensee

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the manufacturer's keeps a minimum of 550 gallons of recommended value of 1.55 lube oil onsite in their warehouse to gallons / hour as listed in the test satisfy the UFSAR question procedure and it failed to meet response 430.131 to the NRC as the 7 days storage requirements.

committed. It is more than adequate for makeup for EDGs demand in the emergency.

TE-35 EDG "D" fuel consumption Technical evaluation made by the calculated to be 163.07 hours8.101852e-5 days <br />0.00194 hours <br />1.157407e-5 weeks <br />2.6635e-6 months <br /> licensee used only the storage tank versus 168 hours0.00194 days <br />0.0467 hours <br />2.777778e-4 weeks <br />6.3924e-5 months <br /> to satisfy the capacity differential level and Regulatory Guide 1.137 assumption was made that the day requirements of 7 days fuel oil tank level would stay approximately -

storage requirements the same after the run. The licensee evaluation concluded that adequate fuel oil was available'in '

the storage tank (53,000 gallons good for 179.3 hours3.472222e-5 days <br />8.333333e-4 hours <br />4.960317e-6 weeks <br />1.1415e-6 months <br />) to satisfy the l

168 hour0.00194 days <br />0.0467 hours <br />2.777778e-4 weeks <br />6.3924e-5 months <br /> (7 days) for each EDG required time in the storage tank.'

TE-36 The actual EDG test data The licensee evaluation found that'

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values specified in the pre-procedure was not accurate for the i

operational procedure for no

"no load" EDG conditions. The ~

load conditions, such as KVAR procedure values were revised i

rating, field amperes, etc.

accordingly,

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TE-38 The A, C and D EDGs The engineering evaluation exhibited excessive frequency determined that the momentary overshoot during initial starting overshoot of the frequency observed (63.8,62.8 and 62.0 hertz) for EDGs A, C, and D, above the nominal 60 hertz value was acceptable. No conflict with the UFSAR requirements or design deficiency was determined during this test.

i The inspector's review of the above selected documents, including the technical evaluations, startup deviation reports, design modifications, procedure changes, startup test and supplemental test results revealed no concerns. The inspector concluded that the licensee had taken adequate corrective action to resolve the pre-operational concerns of 1986 testing and had adequate documentation to demonstrate their resolution. Therefore, this item is closed.

2.5 (Closed) Unresolved Item (50-354/92-80-14) pertaining to excessive EDG time response for an accident condition during the monthly surveillance testing i

During the EDSFI inspection, the team observed that the "B" EDG was inoperable for a long I

time while it was being " barred over" just prior to the monthly surveillance test. The team was concerned that during this EDG preparation period, the surveillance test procedure contained no precautions designed to limit the amount of time the diesel would be inoperable.

The diesel was observed to be inoperable for approximately 30 minutes during that test.

In a February 26,1992, letter to the NRC, the licensee agreed to establish various

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precautionary steps to alleviate the potential consequence of an inoperable EDG dunng testing. These steps include: 1) limiting the inoperable time to 15 minutes each test; 2)

dispatching an operator to the EDG room to provide prompt response to the control room

demand: 3) not scheduling an EDG test when a redundant train is inoperable; and 4)

providing additional training to operators and technicians of the potential problem during EDG testing.

During this mspection, the inspectors reviewed the licensee EDG Operating Procedure HC.OP-SO.KJ-001(Q), Rev.13. The procedure contained specific prerequisites and precautions to limit the amount of time the diesel could be inoperable prior to performing the monthly surveillance with a stated goal of 15 minutes. The inspectors reviewed several of the log entries related to this surveillance and noted an average inoperable time of approximately 8 minutes was achieved by the licensee staff. The inspector also conducted interviews with licensed operators and personnel involved with the scheduling of surveillance. Each person interviewed displayed a clear understanding of the status of the diesel requirements prior to and during the monthly surveillance testin _. _ -

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However, during the above review, the inspectors noted that some disparity existed among j

operators in the documentation being performed when Technical Specification Action j

Statements were entered for brief periods during surveillance. Specifically, some operators consider this and document the entry and exit in the Action Statement Tracking Log and some do not. The procedure which governs the Action Statement Tracking Log, HC.OP-AP.ZZ-0108(Q), Rev. 6, " Removal and Return of Equipment to Service," was noted to be ambiguous with respect to whether all Action Statement entries needed to be logged.

To address the above concern, the licensee initiated a revision of the above procedure.

Operators will be required to document in the operating log the time the engine was barred

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over. The procedure update was expected to be completed by the end of this year and was t

being tracked on the ATS system as Item No. 354/92-80-14.

Based on the adequate licensee's corrective actions taken, including procedural changes and

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interviews with plant personnel and time verification from the past surveillance tests, the inspectors concluded that this concern had been adequately addressed by the licensee. Since the above minor documentation concern were being monitored by the licensee on their tracking system, the inspectors concluded that this item is closed.

2.6 (Closed) Unresolved Item 50-354/92-80-15 pertaining to the inadequate transformer oil analysis During the previous EDSFI inspection, the team reviewed the licensee's station transformer

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oil analysis program for both main power and station service transformers. The team also

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conducted independent evaluations of transformer oil sample data by means of the industry accepted Roger's Method in accordance with ANSI /IEEE C57.104. Based on this independent assessment, the team concluded that the adequacy of the Hope Creek oil analysis program for important-to-safety transformers was questionable, and that the material condition of some of the transformers may be degraded.

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l In a followup EDSFI inspection (50-354/93-10), the inspector concluded after reviewing i

various input data from the licensee and their contractor analysis, that there was no problem with the station transformers, even though the oil data indicated a previous heating and i

degradation of some of the units. However, the inspectors also noted that the continued

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trending of the oil data was necessary to verify the integrity of the transformers.

During this inspection, the inspector reviewed the licensee evaluation 'and station transformer i

oil sample _ data for the main power and station service transformers to evaluate their current condition and the evaluation process. In addition, discussions with system engineers were i

conducted to determine the methodology by which the data were evaluated.

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The licensee did not dispute, based on all available analysis, that some overheating and

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degradation was experienced in the noted transformers in the past. However, the gases

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generated from these past events were retained in the oil and were not likely to ever diffuse

out of the system. Therefore, in reviewing, the post-overheating event oil data were being

taken into consideration for the new higher baseline levels for generated gases. Deviations

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from the new baseline levels were being evaluated for potential transformer degradation.

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The inspectors review of all oil data since the initial overheating events indicated no-significant rising trend in the evolution of gases. The inspectors noted that, in the main -

power transformers, levels of total combustible gases had actually been slowly decreasing.

The licensee had effectively documented the above findings, and had taken further steps to i

ensure the adequacy of transformer cooling (radiator cleaning, etc.). The licensee's current _

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method of sampling, analyzing, and documenting transformer oil data appeared to be

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adequate and technically sound.

Based on this review, the inspector concluded that the licensee has acceptably resolved this issue and that this item is closed.

3.0 EXIT MEETING The inspector met with licensee representatives denoted in Attachment 1 on November 3,1993. The inspector summarized the purpose, scope and findings of the

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inspection. The licensee's representatives acknowledged the findings and did not express any disagreement with them,

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ATTACHMENT 1

Persons Contacted and Exit Meeting Attendees i

Public Service Electric and Gas Comnany

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• V. Ciarlante, Senior Supervisor - ALARA

• J. Clancy, Technical Manager - Hope Creek l

S. Funsten, Maintenance Manager, Hope Creek

• M. Gray, Licensing Engineer

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R. Griffins, Manager, Station QA - Hope Creek

• R. Hovey, General Manager - Hope Creek B. O'Malley, OPS Manager - Hope Creek J. Rucki, Technical Engineer - Hope Creek

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• B. Smith, Licensing Engineer

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U. S Eugjear Regulatory Commission f

• C. Marschall, Sr. Resident Inspector

• Denotes attendance at the exit meeting on November 3,1993.

The inspector also contacted other licensee personnel during the course of the inspection.

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