IR 05000382/1998013

Insp Rept 50-382/98-13 on 980831-0901 & 981005-08.No Violations Noted.Major Areas Inspected:Maint Using Guidance of Temp Instruction 2515/137, Insp of Medium-Voltage & Low-Voltage Power Circuit Breakers

ML20195H842
Person / Time
Site:	Waterford
Issue date:	11/17/1998
From:	NRC OFFICE OF INSPECTION & ENFORCEMENT (IE REGION IV)
To:
Shared Package
ML20195H825	List: IR 05000382/1998013 ML20195H819
References
50-382-98-13, NUDOCS 9811240126
Download: ML20195H842 (14)

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.f ENCLOSURE

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U.S. NUCLEAR REGULATORY COMMISSION

REGION IV

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Docket No.: 50 382  ;

License No.: ~ NPF-38 i

. Report No.: .50-382/98-13 l

Licensee: Entergy Operations, In ;

" Facility: Waterford Steam Electric Station, Unit 3 ,

Location: Hwy.18 -

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Killona, Louisiana  !

Dates: August 31 through September 1, and October 5-8,1998

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Team Leader: . P. Gage, Senior Reactor inspector, Mainter:ance Branch j inspector: S. K. Mitra, Electrical Engineer, Electrical Engineering Branch s Division of Engineering I Office of Nuclear Reactor Regulation ,

~ Accompanying F. Burrows, Electrical Engiiteer, Electrical Engineering Branch t -

Personnel: Division of Enginee' ig L Office of Nuclear Pator Regulatio K. Naidu, Reactor Engineer, Quality Assurance, Vendor Inspection, and

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Maintt. nance Branch

Division of Reactor Controls and Human Factors Office of Nuclear Reactor Regulation Approved By: Dr. Dale A. Powers, Chief j Maintenance Branch Division of Reactor Safety j

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l ATT, .CHMENT: %pplemental Information l

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EXECUTIVE SUMMARY Waterford Steam Electric Station, Unit 3 NRC Inspection Report 50-382/9813 An inspection was conducted using the guidance of Temporary instruction 2515/137,

" Inspect. ion of Medium Voltage and Low-Voltage Power Circuit Breakers," issued March 199 The inspection team was comprised of Region IV and the Office of Nuclear Reactor Regulation personnel. The report covers an onsite inspection from August 31 through September 1, and October 5-8,1998, with an exit neeting conducted on October 8,199 Maintenance

The switchgear and the surrounding areas were adequately maintained, and in good visible material condition. Similarly, the electrical equipment maintenance training lab provided an adequate environment to facilitate breaker maintenance training (Section M2.1).

The preventive maintenance procedures recently developed for the medium-voltage breakers to include reduced voltage and time response tests included appropriate qualitative and quantitative acceptance criteria, however, the time response results were not trended. The low-voltage power circuit breakers were not overhauied or refurbished, except on an as needed basis, which was nonconservatively inconsistent with the current industry practice (Section M3.1).

• The licensee's root-cause determinations and corrective actions for the medium- and k.w-voltage power circuit breaker failures over the last 5 years met regulatory reqdrements (Section M4.1).

• The licensee was complying with 10 CFR 50.65, " Maintenance Rule," with regard to the treatment of safety-related, medium- and low-voltage power circuit breakers. The licensee's approach to consider only the safety-related functional operation of the reactor trip breakers for Maintenance Rule at the system level was nonconservative and narrowly focused (Section M4.2).

• The licensee's procedures and internal communication paths for the resolution of circuit breaker issues expressed in NRC generic communications, industry operating experience reports, and vendor letters were appropriate (Section 6.1).

• The calculation of direct current control circuit voltage drop lacked the normal rigor involving conservative design inputs for safety-related calculations, since an average ambient temperature was assumed in lieu of a maximum value to determine the limiting resistance and corresponding voltage conditions (Section 8.1).

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Report Details

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Summary of Plant Status l During the onsite inspection periods, the plant operated at full powe ;

l The focus of the inspection was to verify the adequacy of licensee programs, pacedures, training, equipment, and supporting documentation for the maintenance of medium- and low-voltage power circuit breakers. The overall scope of the inspection was defined .n Temporary Instruction 2515/137, " Inspection of Medium-Voltage and Low-Voltage Power Circuit Breakers,"

Revision 1, issued March 199 !

II Maintenance ,

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M2 Maintenance and Material Condition of Facilities and Equipment '

M2.1 Walkdown of Switchaear Areas l l Inspection Scope  ;

i The team performed a walkdown inspection of the switchgear areas. The inspection included the safety-related and nonsafety-related medium-(4160 Vac and 6900 Vac)

and low- (480 Vac) voltage switchgear. At the team's request, the licensee opened a l few breaker compartment doors to allow viewing the interior compartments with the )

installed power circuit breakers. The team inspected the electrical equipment i maintenance trainirg facility to assess its suitability to support breaker maintenance trainin Observation and Fhdinas The team found the switchgear and surrounding areas were well maintained, with no broken or missing parts observed, and painted surfaces in good condition. However, the team observed spare safety-related breakers in 480 Vac Switchgears 31 A,31B, and )

31 AB in their racked out positions. NRC Information Notice 97-53, issued on July 18,1997, documented several industry problems with seismic qualification of l

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breakers in a racked-out position. Information Notice 97-53 emphasized that for breakers positioned in other than the seismically qualified racked-in position the Class 1E switchgear may not function as required during a design-basis earthquake. The team discussed the issue of breakers in a racked-out position with the licensee's staff, and found that the evaluation of information Notice 97-53 was completed on May 26, 1998. The licensee had initiated a Condition Report 96-1905 and issued an evaluation j and guidance concerning breakers in their racked-out position on April 29,1998. The

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team found that this evaluation examined the seismic qualification for various operating

. conditions and reevaluated, for certain cases, the seismic qualification for GE 4160 Vac

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Magne-Blast and 480 Vac AKR power circuit breakers. The team concluded that the

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licensee's evaluation of racked-out breakers with respect to impact on seismic qualification was adequat The team found that the electrical equipment maintenance training lab was clean, well lit, and well equipped. In particular, the team noted that the lab had both 4160 Vac and 480 Vac breakers and cubicle mockup stands to facilitate student access, with readily i l

accessible test equipmen Conclusions The switchgear and the surrounding areas were adequately maintained, and in good visible material condition. Similarly, the electrical equipment maintenance training lab l provided an adequate environment to facilitate breaker maintenance trainin ;

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M3 Maintenance Procedures and Documentation l M3.1 Maintenance Procedures for Low- and Medium-Voltaae Power Circuit Breakers Inspection Scope The team reviewed the preventive maintenance procedures for the low- and medium-voltage power circuit breakers. The procedures were compared to the maintenance section of the manufacturers' instruction manuals. The procedures were reviewed for goed industry practice involving breaker maintenance, as well as the specific guidance in Temporary Instruction 2515/137. These documents and concepts provided a  ;

framework for assessing the quality of the maintenance procedures. The acceptance ;

criterion applied by the team was that the procedures were of a type appropriate to the !

circumstances and included appropriate qualitative and quantitative acceptance criteria, as stated in 10 CFR Part 50, Appendix B, Criterion V, " Instructions, Procedures and Drawings." Observations and Findinas The team observed that the maintenance procedures were clear, detailed, incorporated sign-offs on individual steps by craft personnel and supervisors, and included appropriate quality cv.> trol hold points. The team observed that data sheets provided a good record of the res !ts of all measurements made and breaker condition at the time the maintenance was [ erformed; however, breaker closing and tripping operation at the

.mnin, im calculated votages were not performe The proc 3dures for ein uit breakers reviewed by the team were (1) ME-004-145, "480V Breaker (t/pe AKR)," Revision 12, (2) ME-004-131, "4.16KV Breaker (type AM)

Procedure, Revision 12, and (3) ME-004-155, " Reactor Trip Switchgear Breakers (type AK)," Revisior; 10. The team found that the maintenance procedures generally followed the ir.structions of the associated vendor's manua ,

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. The team noted that the preventive maintenance intervals of the low- and the medium-voltage breakers were not consistent. Depending on the surrounding environment, application, and the number of cycles of operation of the breakers, preventive maintenance was varied from 18 to 72 months. The team noted that preventive maintenance on the reactor trip breakers was performed every 18 months. The preventive maintenance for other low- and medium-voltage circuit breakers (safety-related or nonsafety-related) was done every 36 to 72 months. Preventive maintenance for more frequently operated breakers in harsh environment was accomplished at 36-month intervals, and less frequently operated breakers in less harsh environment were performed every 72 months. The team noted that any preventive maintenance interval greater than 36 months as inconsistent with the current industry practic The team found that the breaker refurbishment program was also inconsistent. With the exception of the reactor trip breakers that were refurbished at 5-year intervals and some low-voltage AKR breakers, no other overhauls were performed since plant startup in 1985. The team noted that recently, in 1998, the licensee initiated a refurbishment program on mediurn-voltage Magne-Blast breakers. The licensee's representative stated that the implementation plan for refurbishment of these breakers was scheduled for completion by the year 2002, however, there was no existing plan to refurbish the AKR breakers. This was based on their past reliabic operating history and preventive maintenance practices. The industry practice for refurbishment of breakers, however, is generally every 10 year '

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The team observed that appropriate procedures were recently revised to implement reduced control voltage and response time tests for medium-voltage breakers. Only eight Magne Blast breakers have been tested during routine preventive maintenanc Licensee representatives stated that no current plans existed to implement similar tests for the low voltage AKR breakers, which were tested at 125 Vdc nominal voltage. The vendor design minimum control voltage, specified for both low- and medium-voltage breakers, wao 90 Vdc for closing coil and 70 Vdc for trip coil. Control voltage testing at 125 Vdc nominal voltage does not demonstrate that the breakers will operate l

satisfactorily at substantially lower voltage available under worst-case accident l conditions. The team considered response time trending as a useful tool to verify the

condition of power circuit breakers. The team noted that although response time tests were performed on medium-voltage and reactor trip breakers, the results were not trende c. Conclusions l l 1

! The preventive maintenance procedures recently developed for the medium-voltage breakers to include reduced voltage and time response tests included appropriate qualitative and quantitative acceptance criteria, however, the time response results were not trended. The low-voltage power circuit breakers were not overhauled or refurbished, except on an as needed basis, which was nonconservatively inconsistent with the current industry practic .e.

M4 Maintenance Staff Knowledge and Performance M4.1 Root-Cause Evaluation and Corrective Action for Circuit Breaker Failures Inspection Scooq At the team's request, the licensee provided summaries of corrective action documents (condition reports) and work documents issued on safety-related, medium- and low-voltage power circuit breakers since June 1,1993. The licensee also provided a breaker data matrix for the safety-related, medium- and low-voltage breakers. The team reviewed the data matrix, summary reports, and discussed maintenance activities, failures, and corrective actions with the cognizant engineer Observations _pnd Findinas From the licensee's summary of the condition reports, the team selected several reports for review. The team's review found cause determinations and corrective action as documented on the selected condition reports and associated documents to be satisfactor The team reviewed a summary of corrective maintenance activities performed in the last 5 years for safety-related, medium- and low-voltage circuit breakers. The total number of failures was not independently established by the team. Three work authorizations representing failures were reviewed, and the root-cause determination and corrective actions were found to be satisfactory. The list of breaker functional failures being maintained pursuant to Maintenance Rule requirements listed sixteen functional failures of power circuit breakers, of which three were considered maintenance preventable functional failure Conclusions The licensee's root-cause determinations and corrective actions for the medium- and low-voltage power circuit breaker failures over the last 5 years met regulatory requirements.

M4.2 Maintenance Rule Issues Inspection Scoce The team reviewed the licensee's compliance with 10 CFR 50.65, Requirements for Monitoring the Effectiveness of Maintenance at Nuclear Power Plants, with regard to safety-related, medium- and low-voltage power circuit breakers. The team selected a sample of seven safety-related power circuit breakers by load and function, and reviewed equipment maintenance records for the last 5 years. The records were reviewed to determine whether the licensee's program, in terms of the interval between maintenance and the scope of maintenance, was implemente !

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b. Observations and Fndings Review of the maintenance records confirmed that the specific intervals betwesn preventive maintenance were equal to or less than that specified by the licensee's stated program. The records reviewed, as part of the selected sample, were complete according to the procedures governing the Maintenance Rule program, and did not contain any anomalies. The Maintenance Rule procedure, reviewed by the team, was UNT-006-029, "The Maintenance Rule," Revision 1. The licensee defined an electrical distribution system for Maintenance Rule purposes, which included incoming and tie power circuit breakers. Load-side breakers were monitored as part of the associated structures, systems, and components that they supported. Tne team noted that breakers were not treated as a separate class or component across systems or trains, therefore, common mode breaker problems which affect more than one system were not explicitly considered within the licensee's Maintenance Rule program. The team found that breaker failures were attributed to the affected system supplied by the breaker, and that any generic review was accomplished by the system engineer and inhouse events and analysis grou The team found that the licensee had performance measures for safety-related, medium- and low-voltage circuit breakers that were comrnensurate with safety. The licensee supplied a list of circuit breaker functional failures. The team found that this list was consistent with failures identified through review of corrective maintenance work requests. The team found that, generally, system engineers reviewed surveillance test results, preventive maintenance tasks, and corrective maintenance history records for trends to identify performance-related problem The team noted that the control element drive system consisted of the reactor trip breakers and the associated motor generator sets that provide the normal source of power for the control element drive mechanisms, which subsequently position the control element assemblies in the core. The licensee appropriately classified the control element drive system as a standby risk-significant system. The team observed that the licensee's Maintenance Rule program established three functions for the control element drive system; a nonsafety function to provide power to the control element assemblies, and two safety functions, which provide interrupt capability of the power to the control assemblies. The team found that the guidance provided for functional failure determinations to be any failure that could prevent a train from performing a system function. The team observed that no guidance was provided to clarify or define the application of the term " train," as used in this syste The team observed that several occurrences were documented regarding reactor trip breaker failure to close following testing and breaker operations. These failures resulted in plant management's decision to include the reactor trip breakers on the top ten equipment issues list. During the review of several condition reports over the past 5 years, the team noted that no clear root cause had been determined for the failure of reactor trip breaker failure to close. The team found that the problem appeared random, in that, not all breakers have been affected and the identical conditions were not

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-8-not repeatable. These failures were tracked through the normal corrective action process and not through the Maintenance Rule progra The team observed that the reactor trip breakers were included in the control element drive system, which was placed in Category (a)(1) on January 9,1997, and appropriate goals were established. The team found that the numerous reactor trip breaker failures to close were not considered maintenance preventable functional failures since their associated safety function to open was satisfied. Further, licensee representatives stated that the system function to supply or interrupt power was always maintaine The team viewed the approach to consider only the safety function operation as narrowly focused and a nonconservative invitation to masking associated breaker i

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problem During the inspection, licensee personnel documented, through Condition Reports 98-1222 and 98-1312, two failures of reactor trip breakers to open during routine testin The team observed that the functional failure determinations had not been performed i

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for the effected reactor trip breakers. The team noted that the reliability performance measure for the control element drive system was no more than one maintenance l preventable functional failure for a 2-year period. The licensee acknowledged that l these failures of the reactor trip breakers to open would be considered for evaluation of '

the control element drive system to maintain a Category (a)(1) status with appropriate corrective actions and goals established to address the new conditio Conclusions The licensee was complying with 10 CFR 50.65, " Maintenance Rule," with regard to the treatment of safety related, medium- and low-voltage power circuit breakers. The licensee's approach to consider only the safety-related functional operation of the reactor trip breakers for Maintenance Rule at the system level was nonconservative j and narrowly focused. Equipment and maintenance records for seven safety-related power circuit breakers indicated that the maintenance program had generally been satisfactory implemente M6 Maintenance Organization and Administration M6.1 Review and Evaluation of Industry Operatina Experience Inspection Scope The team reviewed the licensee's resolution of all the NRC information notices, bulletins, and vendor letters listed in Temporary Instruction 2515/137 applicable to the type of switchgear used at the facilit To assess the licensee's effectiveness in implementing these programs for circuit breakers, the team examined the licensee's circuit breaker vendors' manual binders in

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which the'various vendor technical documents (e.g., technical manuals, technical bulletins, etc.) were file The team reviewed the licensee's breaker operation and maintenance procedures to determine whether relevant technical information, as mentioned above, had been appropriately incorporated into procedures.

, Observations and Findinas l

The team found that for safety-related, medium-voltage (4160 Vac) switchgear, vendor technical bulletins consisting of service information letters and service advice letter ,

The team determined that the Vendor Equipment Technical Information Program (VETIP) had been established using industry guidelines that had been developed in response to Generic Letters 83-28 and 90-0 From a random sample of 15 service information letters and service advice letters, the team observed that the vendor manuals and/or their latest revisions were maintained in the vendor manual binders. Finally, the team noted that service advice letters were being received by the plant though the VETIP with few exceptions, which were identified, tracked, and corrected periodically in conjunction with the other Entergy-operated nuclear facilitie The team noted that the licensee's operational experience engineer and VETIP coordinator had performed a comprehensive review of industry-related information, using the guidance in Temporary instruction 2515/137. The team found this review to l have been generally thorough and objectiv The team found that the licensee had received and adequately responded to the applicable information, as previously discussed. Specifically, in the team's review of the licensee's response to NRC information Notices 83-04, 83-76, 85-58, 88-38, and i

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95-19 found that the related maintenance and surveillance procedures were appropriately revised to incorporate the applicable information regarding industry-related issues involving reactor trip breakers. In general, the team deterrnined that licensee personnel evaluated breaker-related operating experience review information for applicability to the facility appropriately, and had dispositioned it accordingl Conclusions The licensee's procedures and internal communication paths for the resolution of circuit breaker issues expressed in NRC generic communications, industry operating experience reports, and vendor letters were appropriate.

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M8 Miscellaneous Maintenance issues M8.1 Breaker Control Power issue I Inspection Scope i

' The team reviewed the licensee's calculations to determine whether satisfactory l breaker operation was assured at minimum operating voltage, as specified in the l vendor's manual, or minimum calculated voltage, whichever is the lowest, as stated in i the temporary instructio ) Observation and Findinas

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The team requested the calculation for the minimum voltage determination at the de l

control circuit trip and closing coils for electrically operated breakers (both medium- and low-voltage). The licensee's representative provided Calculation EC-E89-014, Revision 1 2, dated May 21,1992, and the corresponding calculational change sheets. The team noted that one of the assumptions used in the calculation of cable resistance (No.14 ;

AWG control cable) was an average ambient temperature of 25'C. The calculation '

used the resultant cable resistance to determine the effected voltage drop associated with the cable. The team considered the assumption of an average ambient i temperature inappropriate, since the facility's final safety analysis report appropriately l assumes the more conservative maximum ambient temperature of 40* Additionally, the team noted the calculatica failed to account for the contribution of i additional heat from any other cables in the racewa !

The licensee's representatives contended that the heat contribution by the other cables l in the raceway should be negligible. The licensee's representative verified, with a l preliminary calculation, that the minimum design voltage requirements were met for the closing coil and trip coil with an assumed ambient temperature of 65'C. The licensee's representative agreed to revise the effected calculation and that this action item was tracked by WATS Item 8831 Conclusions The calculation of direct current control circuit voltage drop lacked the normal rigor involving conservative design inputs for safety-related calculations, since an average ambient temperature was assumed in lieu of a maximum value to determine the limiting resistance and corresponding voltage conditions. The team was assured by a preliminary calculation that all equipment associated with the breaker close and trip circuits would have voltage above the required minimum-allowed voltag I l

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t 11 V, Manacement Meetinas X1 Exit Meeting Summary The team discussed the progress of the inspection on a daily basis, while on site, and presented the inspection results to members of licensee management at the conclusion of the inspection on October 8,1998. The licensee's management acknowledged the findings presente The team asked the licensee's staff and management whether any materials examined during the inspection should be considered proprietary. No proprietary information was identified.

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- ATTACHMENT SUPPLEMENTAL INFORMATION-PARTIAL LIST OF PERSONS CONTACTED Ucens9e E. Brauner, Superintendant, System Engineering

.T. Brown, Superintendent, Electrical Maintenance

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R. Burski, Director, Site Support

R. Douet, Maintenance Manager C. Dugger, Vice President, Operations

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E. Ewing, Director, Nuclear Safety and Regulatory Affairs C. Fugate, Superintendent, Operations P. Gropp, Manager, Design Engineering ,

A. Harris, Manager, Plant Engineering

. T. Leonard, General Manager

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G. Pierce, Director, Quality A. Wrape lil, Director, Design Engineering

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-J. Keeton, Resident inspector V

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INSPECTION PROCEDURES USED TI-2515/137 " Inspection of Medium Voltage and Low-Voltage Power Circuit Breakers,"

l Revision 1 LIST OF PROCEDURES PcVIEWED ME-04-101 "6.9KV Switchgear Maintenance," Revision 8 ME-03-325 "6.9KV Breaker (type AM) Procedure (technical specification breaker),"

Revision 9 l l

ME-04111 "6.9KV Breaker (type AM) Procedure," Revision 10 ME 04-121 "4.16KV Switchgear Maintenance," Revision 7 ME-03-327 "4.16KV Breaker (type AM) Procedure (technical specification breaker),"

Revision 9 ME-04 10 - "4.16KV Breaker (type AM) Procedure," Revision 12 ME-04-132 "4.16KV Limitamp Motor Controller," Revision 4  ;

ME-04-115 "6.9KV/4.16KV Breaker Overhaul," Revision 0

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ME-04141 "480V Switchgear Maintenance," Revision 8 ME-03-330 "480V Breaker (type AKR) Procedure (technical specification' breaker)," l Revision 8

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ME-04-145 = 480V Breaker (type AKR) Procedure," Revision 12 -

l ME-04-143 "480V Breaker (type AK) Procedure," Revision l

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ME-03-314 "480V Breaker Overcurrent Device (ECS/SST technical specification),"

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Revision 7

. ME-07-060 "480V Breaker Overcurrent Device (ECS/SST)," Revision 6 ME-07-061 "480V Breaker Overcurrent Device (MICROVERSATRIP)," Revision 4 ME-04-155 " Reactor Trip Switchgear Breakers (type AK)," Revision 10

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ME-07-062 " Reactor Trip Breaker Overcurrent Device (SURE-TRIP)," Revision 1 ME-07-100 -. " Reactor Trip Breaker Overcurrent Device (EC)," Revision 2

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ME-04-143 "480V Breaker (K-LINE) Procedure," Revision 5 UNT-006-029 'The f.iaintenance Rule," Revision 1

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i UNT-004-035 Control of Vendor information," Revision 5 l

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OP-004-004 " Control Element Drive," Revision 8

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OP-903-006 - " Reactor Trip Circuit Breuker Test," Revision 7 i OP-903-107 " Plant Protection System Channel A B C D Functional Test," Revision 14 j OP 903-127 kaactor Trip Breaker Post-Maintenance Retest," Revision 2 OEEP-103 " Operating Experience Review," Revision 2 l

. LIST OF DOCUMENTS REVIEWED l Condition Reports

96-0209 96-1344 96-1802 96-1905 97-0406 L 97-0426 97-0873 97-1012 97-1594 97-1746

97-1814 97-1820 97-1860 97-1877 97-1943

.97-2021 97-2138 97-2245 97-2360 97-2420 97-2614 97-2657 97-2692 97-2763 98-0002 I

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98-0070 .98-0079 98-0456 98-0513 98-0526

'98-0615

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jj 98-0740 98-0801 98 1096 98-1222.-

.98-1281 98-1284 98 130 .98-1312- 98-1319 '

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