ML20216C910

Insp Rept 99900404/98-01 on 980106-07 & 12-13.No Violations, Deviations or Noncompliances Noted.Major Areas Inspected: Observation of Tests Being Conducted at Facility on Circuit Breaker That Failed to Open During Operation on 971218

ML20216C910
Person / Time
Issue date:	04/09/1998
From:	NRC (Affiliation Not Assigned)
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ML20216C895	List: ML20216C890 ML20216C910
References
REF-QA-99900404 NUDOCS 9804150102
Download: ML20216C910 (12)

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U.S. . NUCLEAR REGULATORY COMMISSION OFFICE OF NUCLEAR REACTOR REGULATION Reoort No.: 99900404/98-01 Organization: Westinghouse Electric Company Nuclear Services Division Repair and Replacement Services 2000 Cheswick Avenue Cheswick, Pennsylvania 15024

Contact:

Tom Moser, Manager, Assembly, Qualification & Test (412) 275-3980

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Nuclear industry Safety-related equipment repair and replacement services for I Activity: nuclear power plants f

J Dates: January 6-7; 12-13,1998 Inspectors: Kamalakar R. Naidu, Senior Reactor Engineer Joseph J. Petrosino, Quality Assurance Specialist David Skeen, Reactor Systems Engineer Approved by: Richard P. Correia, Chief l Reliability and Maintenance Section l

Quality Assurance, Vendor Inspection, and Maintenance Branch '

Division of Reactor Controls and Human Factors Office of Nuclear Reactor Regulation l

I Enclosure 9804150102 980409 PDR GA999 EMVWEST 99900404 PDR

1 INSPECTION

SUMMARY

On January 6-7,1998, NRC inspectors observed tests being conducted at the Westinghouse Nuclear Services Division (WNSD), Repair & Replacement Services (RRS) facility in Cheswick, Pennsylvania, on a Westinghouse 660 Type DS-416 circuit breaker that failed to open during operation at New York Power Authority's (NYPA) Indian Point Unit 3 nuclear power plant (IP3) on December 18,1997. The breaker failed to open following a surveillance test run of a residual heat removal (RHR) pump. NYPA requested WNSD to perform a root cause analysis for the breaker failure.

On January 12-13,1998 NRC inspectors performed an inspection of the WNSD Cheswick facihty to continue the review of the activities to determine the root cause of the IP3 breaker failure. Tne inspectors reviewed WNSD's implementation of its quality assurance program relative to the reporting requirements of Part 21 of Title 10, of the Code of Federal Reaulations (10 CFR Part 21) relative to W medium- and low-voltage licensee-identified circuit breaker problems. Issues reviewed inciuded problems with Type DHP (4-kV), and Type DB and DS type (600-volt, and below) breakers. The inspectors also reviewed records associated with your refurbishment of DB-50 circuit breakers for Consolidated Edison of New York's Indian Point Unit 2 (IP-2).

The inspection Bases were Appendix B, " Quality Assurance Criteria for Nuclear Power Plants and Fuel i

Reprocessing Plants," to Part 50 of Title 10 of the Code of FederalRegulations (10 CFR Part 50, Appendix B).

10 CFR Part 21, " Reporting of Defects and Noncompliance" During this inspection, the inspectors identified five unresolved items relative to review of reportability of commercial-grade direct trip attachments (paragraph 3.1.b.2), confirmation of the minimum trip bar force in DB-50 type cired{t breakers (paragraph 3.1.b.3), tests to determine the clearance between the rear are horn arid the molded are chute case in a DHP type breaker (paragraph 3.1.b.5), review of 10 CFR Part 21 program (paragraph 3.2.b) and applicability of I

1 W NSD-TB-91-06-RO to DS 416 type breakers (paragraph 3.3.b).

2 STATUS OF PREVIOUS INSPECTION FINDINGS There were no previous inspection findings reviewed during this inspection.

l 3 INSPECTION FINDINGS AND OTHER COMMENTS. ,

3.1 Westinohouse Circuit Breaker issues

a. Insoection Scoce The NRC inspectors reviewed several recently-identified circuit breaker issues to assess the manner in which WNSD resolved them. The NRC inspectors reviewed the records te determine if WNSD evaluated the following circuit breaker issues for reportability to Part 21.21 (a)(1). WNSD call deviations and failures to comply " potential issues."

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WNSD utilizes Procedure Westinghouse Electric Corporation Energy Systems Business Unit Policy / Procedure (PP) 21.0, " Identification and Reporting of Conditions Adverse to Safety," Revision 2, dated May 29,1997, to evaluate potential issues.

b. Observation and Findinas.

b.1 Hiah-Burden & Standard-Burden Tyoe Closina Coilin Tyoe DB Circuit Breakers: Duke Power Company's (Duke's) Keowee Dam (a two-unit hydro-electric power station) is the safety-related standby power supply for Duke's Oconee Nuclear Station. NRC Augmented Inspection Report 50-269/97-011 documented the events associated with the failure of Keowee Unit 1 to achieve rated voltage following a loss of the Lee Steam i

Station dedicated electrical power path on June 20,1997. Lee Steam Station acts as i

an alarnate standby power source for Oconee. This report identified that "high-burden" closing coils were being used in the W DB-25 type breakers at Keowee. These coils were drawing more current than the " standard-burden" coils and consequently were blowing fuses. The inspectors wanted to determine (1) if WNSD supplied DB-type breakers with high-burden coils for use in safety-related applications, and 2) if there was a problem with fuses blowing in these breakers with high- or standard-burden closing coils, To accomplish this, the inspectors examined different editions of W instruction

' booklets (l.B.s) for DB-type breakers that contained tables which provided information on the currents drawn by closing coils for various control voltages.

In response to the inspector's inquiries, WNSD stated that it hao not supplied high-burden closing coils to any nuclear power plant for safety-related applications and that it was not aware that there was a problem with frequent blowing of control fuses in circuit breakers with standard-burden closing coils. WNSD stated that when control fuses blow, it is usually an indication that the breaker mechanism needs lubrication because the closing coil draws more current when it has to overcome excessive friction. The inspectors determined that high-burden closing coils are used only in breakers at Keowee which were not originally designed for nuclear safety-related service. Further, t

WNSD had not supplied the breakers to Keowee.

b.2 Direct Trio Actuator (480-V Breakers): WNSD informed the inspectors that, in 1994, Eaton/ Cutler-Hammer (ECH), the current manufacturer of W switchgear, made a design  !

chance to the direct trip actuator (DTA). The DTA is typically used on W Type DB and DS breakers with either an Amptector or the newer Digitrip solid state overcurrent trip devices. WNSD sold Amptectors and Digitrip devices with DTAs installed in them or as spare items, to licensees who have other manufacturer's breakers including General l

Electric, and ABB/ITE, as safety-related components. ECH manufactures the DTAs as

! j commercial grade components under its ISO 9000 quality system and supplies them to  !

WNSD who dedicates them for use in safety-related applications.

l The DTA is made up of a permanent magnet, that holds a plunger in place against a spring force. The plunger is linked to a trip lever such that a trip signal from the Amptector counteracts the permanent magnet and allows the spring to move the plunger and actuate the trip lever. In the original W-designed DTA, the magnet po!e piece consisted of a single metal bracket bent in a U-shape held inside the permanent l

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magnet with a screw at the bottom of the "U". For economic reasons, ECH redesigned the actuator so that two separate pieces of metal replaced the single U-shaped piece and the magnet was placed along the side of one of the pieces. A high temperature glue was used to hold the magnet, the core, and the two metal pieces together in the U shape.

In late 1995, the Tennessee Valley Authority (TVA), licensee for the Brow ,s Ferry Nuclear Plant, informed WNSD that an Amptector DTA failed after seve al cycles because a glue joint failed. Vermont Yankee also reported a similar failure of a Digitrip DTA in a GE breaker. Commercial customers also experienced DTA failures and returned them to ECH. However, reportedly, there were no failures of DTA glue joints except on GE breaker installations. Nevertheless, due to these complaints, ECH modified the DTA design to include bolting the asumbly together in addition to glueing.

ECH identified the modified DTAs by either a blue or yellow round sticker on the black plastic casing. For a short period of time, after experiencing problems with the ECH commercial DTAs, WNSD procured limited quantities of DTAs from a Canadian supplier which are identified by either a ; grey or red plastic casing instead of black. WNSD did not experience any problems in the Canadian supplied DTAs. The inspectors determined that WNSD has taken adequate action to controlits use of commercial-grade DTAs in safety-related breakers. According to the 'NNSD-issued Maintenance Program Manual for Safety Related Type DS Metal-Enclosed Switchgear, commercial (glue joint) DTAs with black cases can also be distinguished from the original design black-case DTA by their pink-colcred electrical leads; whereas the old design black-case DTA has screw terminals on the case for connection of leads from the Amptector or Digitrip unit. This manual states that the black DTAs with pink leads are not seismically qualified. The inspectors wiil determine if the issue was reportable under 10 CFR Part 21 at a future inspection. Pending the review, this item is considered unresolved item (URI) 99900404/98-01-01.

b.3 Indian Point Unit 2 -DB-50 Breaker Problems: On October 14,1997, after experiencing recurring problems with DB-50 breakers failing to close, Consolidated kdiwn of New York (Coned), the licensee for IP2, shut the plant down to investigate the cause of the breaker failures. Coned provided details on this event to the NRC in Licensee Event Repor1 (LER)97-024. Coned issued a preliminary Part 21 notification to the NRC on January 14,1998, with plans to submit a full 10 CFR Part 21 later. The licensee also believes that the extra winding on the trip pan spring contributed to the breaker mis-operation. The licensee reported that removal of the three trip pads (one for each phase) from the trip bar as part of a modification to replace the old-style electro-mechanical trip device with the Amptector solid-state trip device may have contributed to failures. The licensee contends that the 6.4 of mass resulting from removal of the trip pads can allow the breaker to trip prematurely. However, the licensee's comprehensive testing program, involving high-speed videography, closing solenoid current traces, and time and motion data, revealed that light trip bar force in conjunction with the kind of vibration or shock produced when the breaker hesitates near the end of the closing stroke is the situation that causes the breaker to occasionally trip open upon closing 4

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The NRC inspectors asked whether WNSD reconciled its original seismic qualification report to determine whether the reduction in mass and or the extra winding on the trip pan spring could adversely affect the operation of the breaker. WNSD stated that there was conservatism in the design, but they had not yet reconciled the change to the qualification test report. WNSD also stated that an upper limit of 31 ounces of force to raise the trip bar a quarter-inch is used as a limiting criterion at the factory, and is published in vendor literature. However, W did not publish a lower limit operational design criterion of 14-ounces which it uses internally for manufacturing and refurbishment guidance at the factory to determine full operability. WNSD staff stressed that the 14 ounce value is not a designed or analyzed number because WNSD did not perform seismic testing to validate the value. WNSD stated that it plans to perform seismic testing in W near future to substantiate its lower limit guidance. ,

WNSD does not believe th t either the removal of the trip pads from the trip bar or the '

extra winding on the trip pan spring is a major contributor to the failures of the IP2 08-50 breakers. WNSD personnel informed the inspectors that it intends to perform seismic and evaluation tests to confirm that the trip pad removal and the extra winding on the trip pan spring do not contribute to unreliable operation of DB type breakers.

The licensee also reported finding that in one of the breakers that had failed in service and that had their trip pads removed as part of the Amptector installa%n, the torsion type trip pan return spring had one additional turn wound into it. Because this is not a standard condition, the licensee originally suspected that the overwound spring might have contributed to misoperation of the affected breaker. However, the licensee f'

L subsequently learned from Westinghouse that the additional turn in this spring actually l

raises the force required to trip the breaker. The licensee suspected that the spring may have been overwound by a technician as an unauthorized measure to compensate for the trip bar force reduction caused by removal of the trip pads. The licensee was concerned that this practice, if wide spread, could potentially cause excessive trip force, possibly leading to breakers failing to trip on demand; although this was not the case l with the failures in question.

l However, the licensee observed a presumably unintended side effect of the increased j

torque, and hence, additional downward force on the trip bar end of the trip pan i

produced by the overwound spring. The other arm of the torsion spring rests against

!. the trip latch and acts as a reset for the latch as well. During a trip free operation, the

! roller on the roller lever must get around the point of the trip latch. The force to move the latch out of the way and separate the latch faces against the force of the reset spring comes from the opening force (including weight) of the moving contact arms. If the torsion spring is overwound it exerts more force on both the trip pan and the trip latch. Therefore, the moving contact arms must rise up enough to generate sufficient feedback force to separate the latch faces and go trip free. In fact, the licensee and the WNSD engineer observed that in this condition, if the breaker goes trip free for another reason (e.g., trip bar not reset or being held up by an unreset trip device) upon attempting to close, the moving contact arms willjump up and move through a significant portion of their travel in the closec' direction before falling back open.

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! in response to the licensee's document stating apparent contributory causes, reportedly given to the WNSD breaker engineer or ite on October 30,1997, the WNSD prepared written commer'ts on the licensee's analysis which explained the effect, as described j above of the overwound opring. The WNSD engineer also explained that the failure in '

service of the breaker with the overwound spring was more likely one of the cases of bad timing, i.e., premature cutoff of the X-relay as opposed to a low trip force with breaker hesitation case.

The NRC inspectors plan to review the results of the tests to see if the removal of the pads from the trip bar made it susceptible to excessive vibrations, and consequently j prevented the breaker from closing or staying closed, and if the 14-ounce value is a  !

reliable design number that licensees could use to verify the minimum trip bar force.

Pending WNSD 's completion of the analysis, this matter is considered an unresolved item ( URI 99900404/98-01-02). I b.4 Shunt Trio Plunaer Shek in a DB-75 Circuit Breaker at Ginna Power Plant Rochester Gas and Electric, the licensee for the Robert E. Ginna nuclear power plant (Ginna),

issued a 10 CFR 21 report concerning a problem with a shunt tnp device on a DB-75 )

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type circuit breaker. The problem was that the plunger in the shunt trip did not return to t the full out position following operation. When the licensee tested the assemblies in stock in the warehouse, the plunger would not return to the ful' out position on 2 of the 10 assemblies. WNSD stated that it was unaware of this issue, because Ginna had not contacted them. The inspectors determined that WNSD did not have any information to evaluate this item to determine if it was reportable.

b.5 Imorocer C'earance for Westinahouse 50DHP350 Breaker Arc Chutes : On May 7, 1997, in a leiter to the NRC, Illinois Power Company's (IPC), stated that five arc chutes,

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part number 56F417G02, for W 50DHP350,1200-ampere,4160-Vac circuit breakers, at its Clinton Power Station had inadequate clearance between the rear arc horn of the arcing contact and the lower edge of the molded case of the arc chute. In a letter dated July 2,1997, IPC reported the issue regarding arc chutes to the NRC under 10 CFR Part 21.

WNSD informed the inspectors that it did not receive the arc chutes and are horn  ;

assemblies from IPC and therefore was unable to determine if a problem did, in fact, l exist. After discussing this issue for several months with WNSD, IPC issued a nuclear I safety-related purchase order (PO), dated November 10,1997, to Westinghouse Electric Corporation, St. Louis, Missouri, so that IPC could ship the arc chute / assembly I

for inspection. The PO specified that Westinghouse / Cutler Hammer was to perform inspections and/or testing of a newly manufactured arc chute, an are chute originally ,

i supplied, and one rear are horn removed from Clinton breaker serial number j 01YN00-5B4.

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In response to this issue, WNSD opened a Regulatory & Licensing Engineer (RLE) potential Part 21 deficiency (PD), document NSD-EDRE-RLE 97-350, and closed the PD on September 19,1997. The closure was:

Based on the inability of Cutler Hammer to repeat the issue and the implied impact if the situation actually exists, this issue will not be considered for reportability pursuant to 10 CFR Part 21 and PD-0272 is closed. If Clinton ever 4 returns the arc chutes and the subsequent evaluation yields different I conclusions regarding the impact on breaker operability, the issue will be reopened.

It was not clear how WNSD concluded that the issue was not reportable without all applicable information.

The NRC inspector determined that WNSD was unable to establish the exact date/ lot numbers of the suspect arc chutes even though the issue was potentially generic. As of February 2,1998, the arc chutes and arc horn were at the ECH facility waiting for IPC ,

and GCH staff to determine test dates. The results of the test will be reviewed during a I subsequent NRC inspection. This matter is considered an unresolved item (URI  !

99900404/98-01-03). '

c. Conclusions The inspectors determined that WNSD had not supplied high-burden closing coils to any nuclear power plant for safety-related applications, and has not supplied commercial-grade DTAs (with the suspect glue joint) to its customers for safety-related applications. j Three unresolved items have been identified in this area: WNSD has not yet determined that either the removal cf trip pads from the trip bar or the extra turn on the trip pan spring, or both affects the operation of the DB-50 type breakers under all conditions (URI 99900404/98-01-01), has not yet reconciled the minimum trip bar force of 14 oz for the DB- 50 type breaker (URI 99900404/98-01-02), and has not yet completed the tests on the IPC arc chutes (URI 9990404/98-01-03).

i 3.2 ImRJementation of 10 CFR Part 21

a. Insoection Scooe L The NRC inspectors reviewed records associated with the circuit breaker issues identified in Section 3.1 abo /e that relate to compliance to 10 CFR 21.21.(a)(1). The NRC inspectors also reviewed Westinghouse Electric Corporation Energy Systems Business Unit Policy / Procedure (PP) 21.0, " Identification and Reporting of Conditions Adverse to Safety," Revision 2, dated May 29,1997, to verify the adequacy and effectiveness of its implementation by reviewing several 10 CFR Part 21-related component issues identified by various licensees that were considered potentially reportable.

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b. Observation and Findinos WNSD stated that ESBU-21.0 covered both the evaluation and disposition of Pls and 3 potential deviations (PDs) described earlier. However, the inspector found no reference I to PDs in the procedure. WNSD conceded that there was no section in the procedure that delineated the process WNSD used to handle PDs. Further, a review of the disposition of selected Pls and PDs revealed that WNSD may have prematurely closed  !

the documents before it specifically determinea if customers needed to be informed.

For example, WNSD closed out PI 97-023, *DB Breaker-Failure to Close," on January 6, 1998, because RLE recommended that the Safety Review Committee (SRC) close PI 97-023 on the basis that the issue is not reportable pursuant to 10 CFR Part 21, and customer notification was planned at a later date pending completion of testing. As discussed in Section 3.1, IP2 identified two concerns with its DB-50 breaker performance: 1) low trip bar forces which may result in a trip free condition when attempting to close the breaker, and 2) overwound trip pan spring which would increase the force necessary to trip the breaker, both are potential generic issues.

Even though testing was required to " verify breaker closing performance," and "all plants using DB circuit breakers where the safety function is performed by closing the breaker are potentially affected" the PI was closed. The NRC inspectors were following up on several recent W circuit breaker problems, and therefore could not fully review the WNSD Part 21 program area. Pending review in this area during a future inspection, this item is considered unresolved (URI 99900404/98-01-04) . i

c. Conclusion The inspectors did not have adequate information to determine if WNSD properly dispositioned potential deviations. URI 9990404 was identified in this area.

3.3 Qbfervation of Tests on Tyne DS-416 (480-V) Circuit Breaker

a. Insoection Scoce and Backaround l l On January 6 and 7,1998, the inspectors observed testing being conducted by WNSD l as part of the root cause of the failure of a DS-416 type breaker to open at IP3 on l

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' December 18,1997. Following a routine residual heat removal pump surveillance, the '

breaker could be opened neither remotely from the control room nor locally at the front of the breaker. While the licensee was preparing to isolate the 480-V bus after the failure, the breaker opened without operator intervention. During its troubleshooting of the failure, the licensee had determined, in consultation with a WNSD technical representative, that the main contact operating linkage could hang up due to pole shaft  ;

over rotation and also possibly excessive friction in various joints due apparently to an '

inadequate overhaul by a now-defunct independent switchgear repair outfit called Power Distribution Technology (PDT), Inc.. The onsite troubleshooting efforts were the focus  ;

of an NRC inspection at IP3 on December 18-23,1997, inspection Report No.50- '

286/97-81. -

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b. Observation and Findinas The WNSD technicians could not duplicate the failure exactly as it occurred in the breaker cubicle. As the licensee had found on site, by removing the reset spring and prying on the insulating link of the main moving contacts, the breaker could be made to hang up and then could not be opened by tripping. Testing the trip function without the reset spring is known as the DS-206 Margin Test as described in WNSD Technical Bulletin NSD-TB-91-06-RO. However, slight pressure applied to the upper side of the insulating link would a!!ow the linkage to fall back into its normal position and the breaker would then open and could be operated normally. The inspectors observed a high speed video of another DS-416 breaker from IP3 taken by the NYPA. This breaker had failed the DS-206 margin test at least once, but had never failed to trip open with its reset spring installed. The video revealed that during the closing cycle, the pole shaft recoiled slightly after the moving main contacts engaged the stationary contacts. The WNSD technicians observed that the pole shaft on the failed breaker was not lubricated in the center where it rotates in recesses in the rear edges of the mechanism side sheets. In addition, the WNSD engineer had found that the W factory-applied proprietary fnrmula dry lubricant *Poxy;ube" had been removed in all required locations (including certain key main contact linkage jcbts) except on the closing spring pin, apparently during the fast overhauls at PDT. The licensee and WNSD postulated that the resultant excessive friction could retard the recoil of the inadequately lubricated pole shaft and its linkages after the moving contacts engage the stationary contacts and result in the linkage getting stuck in a unique position that prevents the breaker from opening either electrically or manually. The act of exercising the breaker during the l ongoing testing may have loosened up the mechanism so that it now worked properly with its reset spring installed. WNSD plans to disassemble the breaker in order to take detailed measurements of subcomponents snd their locations.

Technical Bulletin NSD-TB-91-06-RO was issued after three DS-206 breakers Siled to completely open on demand at a nuclear plant. The bulletin stated that severe binding i

of the moving parts of the main contact assembly may prevent the contacts from fully opening and clearing the normal or fault currents through the Type DS-206 breaker.

l DS-206 breakers are similar in design to the DS-416 breaker except that the latter has a higher current rating. The DS-206 breaker is designe:1 for 600 amp loads, whereas the DS-416 breaker is designed for 1600 amp loads. The TB stated that the larger size l breakers, such as the DS-416, have additional opening (also known as " kick out")

l springs in each pole base assemb!y to disengage the larger heavier contactc and help i

interrupt the higher currents for which the larger breakers,like the DS-416, were designed. Having more and stronger pole-base springs, the larger DS breakerr, were l

not considered at the time to be susceptible to the type of failure described in the technical bulletin. WNSD now believes that the issue may have to be revbited after the failure of the DS-416 breaker at IP-3. The inspectors will conduct a fol!ow up on this l item during a future inspection. Pending thL follow up, this item is considered unresolved (URI 99900404/98-01-05).

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c. Conclusion.

WNSD procedures for conducting the tests appeared to be adequate. However, additionalinformation on the final results of the tests that WNSD is performing is j required to determine the root cause of the failure of the breaker to open. URI '

99900404/ 98-01-05 was identified in this area.

I 3.4 Refurbishment of DB-5AE_rfakgrs for IP 2

a. Insoection Scoce in 1997, Coned experienced unsatisfactory operation of W 480-Volt DB-50 type circuit breakers at IP2. Several of the breakers that failed to close on demand had been j refurbished by WNSD under Con Edison purchase order 6-98814 in 1986. The ,

inspectors reviewed the records in which WNSD documented the refurbishing activities I of IP2 breakers.

b. Observation and Findinos l

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WNSD maintains traceability of records by issuing an engineering work order (EWO) to refurbish a breaker and by referencing the breaker manufacturer original shop order number (and serial number if there is one) stamped on the breaker nameplate. If WNSD performs work on several breakers, then the EWO number is given the suffix j designation of " -1," "-2," etc. WNSD issued EWO 861.072-1 and 861.072-2 to identify j the work performed on breakers with numbers 24Y4800M1 and 24Y4800BA-1 respectively. For these breakers, the applicable procedure was DAR-071585-1, Revision 2, " Test Specification for DB-50 Breaker."

When the breakers were received, records indicated that WNSD personnel performed a receipt inspection which included visual examination of the breakers after removing the arc chutes. WNSD documented adverse findings in material deviation reports (MDRs).

Representatives from manufacturing, and quality assurance were required to concur with the final disposition stated in the MDRs. MDRs 9033 and 9051 identified several findings, including the following:

Handles were welded to the front of the breaker cabinet.

The plating on the back of the frame was stained.

The rivets on the Amptectors were loose.

The corner of the upper stud was bent.

Fine porosity was observed on the Bronze metal of the arcing contacts.

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The inspectors determined that the dispositions of the adverse findings were acceptable. Records indicated that technicians then refurbished the breakers, replacing worn or broken parts as required, and generated lists of all new parts used. '

After completely assembling the breaker, technicians performed specified electrical tests (including contact verification, contact millivolt drop test, AC di-electric hi-pot test on the main poles and insulation resistance of the control wiring), and mechanical tests (including manual breaker closing and tripping). The clearances between the trip bar and the shunt tnp attachment and the DTA were measured to verify that they were within specifications. The current settings of the Amptector were verified. The pertinent >

records were legible and retrievable. However, the signatures of the persons who performed the inspection and the dates when they performed the inspection were missing on some of the documents.

c. Conclusion The inspectors did not observe any indications that WNSD refurbishing contributed to  !

the failures of the DB-50 breakers at IP2. However, some inspection records were  !

incomplete.

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3.5 Entrance andfxit Meetings  !

At the entrance meetings on January 6 and 12,1998, The NRC inspector discussed the scope of the inspection, outlined the areas to be inspected, and established interactions with WNSD management and staff. In the exit meeting on January 13,1998, the inspectors discussed their findings and observations including five unresolved items. An unresolved item is a matter about which more information is required to determine whethe. the issue in question is an acceptable item, a deviation, a nonconformance, or a violation.

4. PERSONS CONTACTED G.W. Dillion Manager, Repair and Replacement Services M.A. Ahmed Fellow Engineer, Equipment Qualification T. Cntchlow Medium Voltage Lead Engineer P. Folmar DB 3reaker Engineer C.G. Geis DB/DS Breaker Engineer P. Kushner DS breaker Engineer R. Miller Regulatory & Licensing Engineer T.D. Moser Manager, Assembly, Qualification & Test l D.E. Rygg Manager, Engineering 11

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( ITEMS OPENED, CLOSED, AND DISCUSSED Opened I

~_Jtem Number Iyps Descriotion J I

99900404/98-01-01 URI Review to determine the reportability of problems in I DTAs.

99900404/98-01-02 URI WNSD to complete tests to confirm that minimum I trip bar force is 14 oz and to confirm if the removal of the pads on the trip bar and the overwound trip pan spring affects the operation of the breaker or 1 its qualification.

99900404/98-01-03 URI WNSD to complete tests to establish tne minimum clearance between the rear arc horn and the arc chute molded case of a DHP breaker, 99900404/98-01-04 URI NRC to review selected WNSD 's Pls and PDs to determine if they have been closed before informing affected customers.

99900404/98-01-05 URI WNSD to determine if NSD-B-91-06-RO is also applicable to DS-416 type breakers.

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