IR 05000324/1988021

Safety Insp Repts 50-324/88-21 & 50-325/88-21 on 880605- 0706.Violations Noted.Major Areas Inspected:Previous Enforcement Matters,Maint Observation,Surveillance Observation Review & HPCI Steam Admission Valve Failure

ML20207G469
Person / Time
Site:	Brunswick
Issue date:	08/04/1988
From:	Fredrickson P, Levis W, Ruland W, Schnebli G NRC OFFICE OF INSPECTION & ENFORCEMENT (IE REGION II)
To:
Shared Package
ML20207G447	List: IR 05000324/1988021 ML20207G444 ML20207G462
References
50-324-88-21, 50-325-88-21, NUDOCS 8808240127
Download: ML20207G469 (18)

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DNITEo STATES

[d3 E8 Cog NucLEAh REGULATORY COMMISSION REGION H

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y Report Nos. 50-325/88-21 and 50-324/88-21 Licensee: Carolina Power and Light Company P. O. Box 1551 Raleigh, NC 27602 Docket Nos. 50-325 and 50-324 License Nos. OPR-71 and DPR-62 Facility Name: Brunswick 1 and 2 Inspection Conducted: June 5 - July 6, 1988 Inspectors: WAM_-J/d A ._ $N/88 W. H. lulanu ~ ~ Vy"' Cafe' Signed (.LevTT1 m ~ 12A A

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'tfinebli gr rtPCI F001 #Fobl Approved by: d %

P. E. Fredrickson, Section Chief k

Date Signed Division of Reactor Projects SUMMARY Scope: This routine safety inspection by the resident inspectors involved the areas of followup on previous enforcement matters, maintenance observation, surveillance observation, ourational safety verifica-tion, in office Licensee Event Report (LER) review, HPCI steam admission valve failure (Unit 1), service water leak (Unit 2), diesel generator service water pressure switches, followup on unresolved items, and Unit 2 HPCI inboard steam isolation valv Results: In the areas inspected, three violations were identified: (1) no schedule provided in special report for repair of fire doors; (2) failure to environmentally qualifv Silicon Controlled Rectifier controllers for the Standby Gas Trr : at systems; and (3) failure to perform required post-maintenanc' ' sting of the High Pressure Coolant Injection system. Two u... aolved items regarding diesel '

generator pressure switch supports and DC motor valve operability were also identified. No deviations were found, b$K $$000y$PN

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REPORT DETAILS Persons Contacted  :

Licensee Employees i

• Biggs, Engineering Supervisor F. Blackmon, Manager - Operations T. Cantebury, Mechanical Maintenance Supervisor (Unit 1) 1 G. Cheatham, Manager - Environmental & Radiation Control R. Creech, I&C/ Electrical Maintenance Supervisor (Unit 2)

• C. Dietz, General Manager - Brunswick Nuclear Project

• W. Dorman, Supervisor - QA 4 *K. Enzor, Director - Regulatory Compliance

W. Hatcher, Supervisor - Security

• A. Hegler, Superintendent - Operations

• R. Helme, Manager - Technical Support 4 J. Holder, Manager - Outages >

P. Howe, Vice President - Brunswick Nuclear Project L. Jones, Director - Quality Assurance (QA)/ Quality Control (QC)

• M. Jones, Director - Onsite Nuclear Safety - BSEP -

• R. Kitchen, Mechanical Maintenance Supervisor (Unit 2)

J. Moyer, Manager - Training

• J. O'Sullivan, Manager - Maintenance B. Parks, Engineering Supervisor

• R. Poulk, Senior NRC Regulatory Specialist

• J. Smith, Manager - Administrative Support R. Warden, 18C/ Electrical Maintenance Supervisor (Unit 1) '

B. Wilson, Engineering Supervisor

• T. Wyllie, Manager - Engineering and Construction Other licensee employees contacted included construction craftsmen, engineers, technicians, operators, office personnel, and security force member )

Other Organizations J. Chappel, Engineering Manager, Anchor-Darling Company )

D. Worsing Engineering Manager, Limitorque Corporation  ;

• Attended the exit interview i

Acronyms and abbreviations used in the report are listed in paragraph 1 l l Followup on Previous Enforcement Matters (92702)

(OPEN) Violation 325/88-18-05 and 3:4/88-18-05, HPCI/RCIC High Steam Line Flow Instruments Inoperable. This item continues to be under review for l potential escalated enforcement action. During this inspectice several l

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additional problems were found by the licensee related to this matter (detailed information provided in LER l-88-014). These additional problems are as follows: -

All Unit 1 and Unit 2 RCIC instruments and both Unit l' HPCI '

instruments were declared inoperable on June 6,1988, when licensee discussions with GE revealed that the setpoints were non-conservative as established at that time. TS 3.0.3 was entered for both units and-shutdowns were started. CP&L requested and Region II : granted enforcement discretion to allow the licensee to continue to have the1 otherwise operable high pressure systems remain in standby rather j than isolate them as. required by the instrument TS. This maintained the high pressure systems still capable of injecting water while the i units were shutting down. The licensee.recalibrated the instruments, r stopped the shutdowns, and returned the units to full power operation- :

on June 7, 198 *

During followup testing (SP-88-026) after the above event, and '

subsequent record review, the licensee found, on June 24, 1988, that

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the Unit 2 HPCI N005 instrument's associated transmitter had its high and low pressure piping tt reversed. The licensee isolated the ,

HPCI system per TS, rerouted the piping at the transmitter per '

PM-88-016, recalibrated the instrument under WR No. 88-ARLZ1, and ,

returned the instrument to operable status on June 27, 198 ,

A control operator reported that the HPCI inboard steam. isolation

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valve, 2-E41-F002, failed on June 26,19E3, due to its supply breaker tripping during system testing after the N005 instrument was returned to service. (See paragraph 11 for a complete discussion.) <

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After review of the SP-88-026 data..the licensee found, on June 30, ,

1988, the Unit 1 and Unit 2 N004 instrument .again set with

non-conservative setpoints. The licensee had not considered the l l negative standby readings of the instruments when establishing the setpoints. Tlie licensee again corrected the setpoints and declared ;

the instruments and HPCI systems operabl >

The above items are additional examples of conditions that rendered the )

! instruments inoperable per the T l Additional examples of a previous violation were identifie A

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significant issue was identified ralating to reversed piping on one instrumen The actual safety significance of the non-conservative setpoints has not yet been completely characterize ! MaintenanceObservation(62703) i i  !

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The inspectors observed maintenance activities, interviewed personnel, and reviewed records to verify that work was conducted ir. accordance with approved procedures, Technical Specifications, and applicable industry l

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. 3 codes and standardo. The inspectors also verified that:1 redundant components were ope.able; administrative controls were followed; tagouts were adequate; personnel were qualified; correct replacement parts were used; radiological controls were proper; fire protectinn wa3 adequate; quality control hold points were adequate and -observed; adequate post-maintenance testing was performed; and independent verification requirements were implemented. The inspectors independently verified that

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selected equipment was properly returned to servic Outstanding work requests were reviewed to ensure that the licensee gave priority to safety-related maintenance. The inspectors observed / reviewed portions of the following maintenance' utivities:

87-BBQXI Rebuild of Pressure Regulating Valve 2-SW-PRV-2870 e

88-AMXM1 Replacement of 5/16" Silicon Bronze Bus Bar Bolts in MCC

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2XJ 3 88-APSU1 COibration of DG Engine Start Air Tank A Pressure

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88-ARNG2 Unit 2 HPCI F002 Valve Wurk ,

The inspector reviewed licensee activities with respect to the post

maintenance testing following the repair of the Unit 1 HPCI steam admission valve F001 complated on June 6, 198 Followin; the completion of the maintenance, which included valve disc replacement and motor replacement, the licensee stroke tested the F001 valve under. actual differential pressure conditicos to verify valve operabilit The inspector questioned the licensee about the adequacy of this testing, The

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inspector noted that the F001 valve is interlocked with the F006 '

(injection valve) such that the F006 valve will not open if the F001

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indicates shut. The inspector's work request rev %w indicated it was not clear what boundaries were disturbed during the disassembly / reassembly process which occurred twice during valve repair. In response to the inspector's question, the licensee did the following:

Demonstrated the interlock operable with testin i

Reviewed work order and interviewed maintenance personnel to

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determine what boundariet were disturbe *

Issued a Standing Instruction (SI-88-056, June 9, 1988) to operations persconel reminding them to verify valve interlocks associated with

limit switches if necessar The licensee determined that sufficient procedural and quality require-ments were in effect dciing the termination portion of the maintenarce ,

activity which ensured the operability of the F001/F006' interlock. This determination was based on the licensee's review of the work order and interviews with maintenance personne I

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On June 14, 1988, LCO A2-88-1132 was initiated for Unit 2 HPCI preventa-tive maintenance. The technicians were scheduled to perform OPIC-FIC001, ,

HPCI Flow Controller Calibration. Step 6.2.1.1 of Attachment 1 to this procedure requires that PT-9.2 be performed on liPCI to verify operability following the completion of the calibration. This PT was not performed prior to declaring HPCI operable and (Daring the LC0 on June 16, at 2:40 Subsequent questioning by maintenance personnel revealed to the shift foreman that PT-9.2 should have been accomplished and was no HPCI was then declared inoperable at 3:30 p.m. , on June 17, 1988, and LC0 A2-88-1169 was initiated. PT-9.2 was then satisfactorily run and HPCI was declared operable at 5:24 a.m., on Jur.e 18, 198 The requirement to run PT-9.2 to verify operability was missed by the maintenance planner when the work request was generate In addition, the STA/SRO review also missed the requirement to run the P ;

Although the safety significance of this issue is minimal, since the total ;

time that HPCI was inoperable was within allowable TS limitations and ,

other required ECCSs were operable during this time, the missed '

surveillance constitutes a failure to follow procedure and accordingly-is listed as a Violation: Failure to Perform Required Post Maintenance i Testing of HPCI System (325/88-21-03). i One violation was identified regarding failure to verify operability of :

HPC . SurveillanceObservation(61726)  ;

The inspectors observed surveil?ance testing required by Technical Specifications. Through observation, interviews, and record review, the

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inspectors verified that: tests conformed to Technical Specification requirements; administrative controls were followed; personnel were

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i qualified; instrumentation was calibrated; and data was accurate and ;

complete. The inspectors independently verified selected test results and '

proper return to service of equipmen The inspectors witnessed / reviewed portions of the following test l activities: )

IMST-RCIC24Q r RCIC Steam Leak Detection .hannel Check 2MST-ADS 21M ADS RX Water LL1 Trip Unit Channel Calibration No significant safety matters, violations, or deviations were identifie l

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. 5 Operational Safety Verification (71707)

The inspectors verified that Unit 1 and Unit 2 were operated in compliance with Technical Specifications and other regulatory requirements by direct observations of activities, facility tours, discussions with personnel, reviewing of records and independent verification of sifety system _ status.

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The inspectors verified that control room manning requirements of 10 CFR 50.54 and the Technical Specifications were met. Control operator, shift supervisor, clearance, STA, daily and standing instructions, and jumper / bypass logs were reviewed to obtain information concerning operating trends and out of service safety systems to ensure that there ,

were no conflicts with Technical Specification Limiting Conditions for Operation Diract observations were conducted of control room panels, instrumentation and recorder traces important to safety to verify operability and that operating parameters were within Technical Specification limit The inspectors observed shift turnovers to verify that continuity of system status was maintained. The inspectors verified the s+atus of selected control room annunciator Operability of a selected Engineere.d Safety Feature division was verified weekly by ensuring that: each accessible valve in the flow path was in ,

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its correct position; each power supply and breaker was closed for components that must activate upon an initiation signal; the RHR subsystem

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cross-tie valve for each unit was closed with the power removed from the i

valve operator; there was no leakage of major components; there was proper !

4 lubrication and cooling water available; and a condition did not exist '

which might prevent fulfillment of the system's functional requirement Instrumentation essential to system actuation or performance was verified operable by observing on-scale indication and proper instrument valve

, lineup, if accessibl The inspectors verified that the licensee's health physics policies / )

procedures were followed. This included observation of HP practices and a j

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review of area surveys, radiation work permits, posting, and instrument ,

calibratio l l

Additionally, the inspectors verified that: the security organization was I properly manned and security personnel were capaole of perfonning their I assigned functions; persons and packages were checked prior to entry into the protected area; vehicles were properly authorized, searched and escorted within the PA; persons within the PA displayed photo identifi-cation badges; personnel in vital areas were authorized; and effective compensatory measures were employed when require The inspectors also observed plant housekeeping controls, verified position of certain containment isolation valves, checked a clearance, and i verified the operability of onsite and offsite emergency power source I l

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~ 6 Diesel Generator Building Fire Doors

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The inspector noted, during the week of June 6,1988, that virtually every diesel generator building fire door was still inoperable. Some

, of the problems included broken doors and latches, ovars unable' to auto close due to ventilation problems, and missing handles. These fire barrier penetrations (fire doors) are required to be operable by TS 3.7.8. Two DG building doors had been declared inoperable on March 7, 1986. The licensee administratively combined these doors with other DG building fire doors which had been inoperable for year *

As per the ACTION statement of TS 3.7.8, the licensee must:

With one or more of the above required fire barrier penetrations nonfunctional, within one hour' establish a continuous fire we.tch

on at laast one side of the affected penetration or verify the-OPERABILITY of firc detectors on at least one side of the

, nonfunctional fire barrier and establish an hourly fire watch patrol. Restore the nonfunctional fire barrier penetration (s)

to functional status within 7 days or, in lieu of any other report required by TS 6.9.1, prepare and submit a Special Report '

to the Commission pursuant to TS 6.9.2 within the next 30 days outlining the action taken, the cause of the nonfunctional 2 penetration, and plans and schedule for restoring the fire barrier penetration (s) to functional statu During the inspection, the licensee had established an hourly fire watch patrol. On June 8, the licensee showed the inspector a -Special Report dated April 7,1986, that was submitted pursuar.t to the above specification. The letter stated:

l The subject fire doors are susceptible to intermittently occurring excessive differential pressure conditions which )

adversely affect closing capability of the doors. The specified j seven-day time frame of the involved LCOs was exceeded on

, March 14, 198 Until the excessive differential pressure problem is resolved, the involved LCOs, with apprv#.itely

, stationed fire watches, will be maintaine No plan or schedule was submitted in the Special Report, as required by TS 3.7.8. This is a Violation: No Schedule Provided in Special

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Report for Repair of Diesel Generator Building Fire Doors (325/88-21-01 and 324/88-21-01).

I On June 20, 1988, after the inspector's questions, the licensee

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submitted a supplement to the Special Report which included a

{ schedule for repair. A plant modification will be installed during the upcoming Unit I refueling outage to correct the excessive

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J HPCI Room Doors l

_During direct observation of work on the Unit 1 HPCI steam admission valve, the inspector noted that both doors to the HPCI. room were open. The inspector questioned the Unit 1 mechanical supervisor, who was present in the room, regarding the status of the doors. .The ,

, supervisor reported that the shift foreman allowed the doors to remain open if someone remained in the room. He stated that the HPCI room C0 system ha of litt$e concern.d been Thedeclarer'

inspectorinoperable informed theand thus the doors were mechanical-supervisor and Unit 1 shift foreman of his concerns regarding the ficoding potential of both RHR rooms with a single leak source. The licensee initiated an OER regarding the event. The licensee closed one door shortly after being informed of the problem. The inspector will J

review the licensee's actions when the OER is completed. This is an Inspector Followup Item: Review of HPCI Room - Door OER (325/88-21-05), Ur.it 1 Fuel Leak During the current Unit 1 fuel cycle, the licensee has noticed a slightly elevated I-131 activity in the reactor coolant and slightly elevated gaseous activity release rate. The gaseous activity release ;

rate from the steam jet air ejectors was still less than 3% of the TS 3.11.2.7 release rate of 243,000 microcuries/second. With a change in control rod pattern, a "normal" 2,200 microcuries/second release rate increased to about 7,000 microcuries/second during the weekend of June 25 and 26. The gaseous activity levels in the turbine building increased due to various steam leaks. The activity levels were less than 2 MPC hours and thus did not require personnel to wear respirators.

, The licensee rearranged their rod pattern to reduce the gaseous levels. They continued to take actions to locate the leaking rod (s)

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i and reduce the steam leaks. The inspector concluded that the licensee's actions regarding the small fuel leak were appropriat The inspector will follow the licensee's actions during future '

routine inspection No sir,1ficant safety matters, one violation, and no deviations were l identifie . In Office Licensee Event Report Review (90712)

The below listed LERs were reviewed to verify that the information )

provided met NRC reporting requirements. The verification included '

adequacy of event description and corrective action taken or planned, '

existence of potential generic problems and the relative safety signifi-

cance of the even I

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(CLOSED) LER 1-88-10, Automatic Isolation of Units 1 and 2 Comon Control

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Building Heating, Ventilating, Air Conditioning System and Emergency Air Filtration System During Routine Maintenanc (CLOSED) LER 2-88-10, Auto-Isolation of Reactor Water Cleanup. System Inlet Inboard Isolation Valve While Placing B RWCU Filter Demineralizer Into Servic No significant safety matters, violations, or deviations were identifie . HPCI Steam Admission Valve Failure - Unit 1 (93702) ,

On July 1, 1988, the Unit 1 HPCI steam supply valve, 1-E41-F001, failed to open during post maintenance testing prior to returning the HPCI system to an operable status. The system had been previously isolated and declared out-of .earvice on June 30, 1908, to change the setpoints on the high steam line flow instruments to more conservative value ,

Troubleshooting was imediately initiated by the licensee and a task force was establishe Preliminary investigation indicated that the motor for the valve actuator had failed. Bridge and megger testing of the motor i confirmed shorting of internal windings. The motor was removed from the ,

actuator and delivered to the licensee's Research and Development Department at Harris Energy Center in Raleigh, North Caro *:ina, for ,

~i detailed failure analysis. This analysis indicated the motor appeared to fail due to high current in a stalled or semi-stalled conditio Motor ;

insulation damage occurred in the high temperature areas. There were no i indications cf failure due to high voltage surges. The insulation resistance of the shunt and series windings were satisfactory. The

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insulation resistance between the shunt and series windings was also

] satisfactory. The armature bars were grounded because one of the interpolar windings in series with the brushes was grounded to the

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housin Insulation in high temperature areas was bake The above analysis indicated this motor failure mechanism was dissimilar to the failure on December 31, 1987, discussed later in the report, which was due to a short circuit between the series and shunt field windings because of induced voltage trr.nsients in the shunt field.

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A replacement motor was obtained from Pilgrim Nuclear Plant end receipt inspected using the licensee's normal procurement procedures. The original motor was a 240 VDC, 1900 RPM, 60 FT-LBS motor. The replacement

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motor obtained was a 250 VDC,1900 RPM, 60 FT-LBS motor. Due to the differences between the motors, voltage and documentation associated with EQ and seismic requirements, an Engineering Evaluation Report, EER No. 88-0334, was initiated. This EER found the replacement motor to be acceptable for use as a temporary repair until December 31, 198 ,

Limitorque, the valve actuator vendor, concurred with the licensee's '

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. 9 In parallel with the motor troubleshooting, the licensee began testing of the valve / actuator to determine if the valve caused the motor failur This testing commenced in the evening of July 1,1988, and showed the -

following:

The actuctor assembly had turned approximately 26_ turns of the handwheel prior to motor failure. This would allow for the play in the gear train to be taken up and make contact with the lugs on the

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stem nut of the actuator. The worm gear and stem nut lugs should normally collide to give a hammer blow to the valve ste *

The initial pull out torque at the bandwheel, as measured with a torque wrench, was 80 FT-LB The valve had previously been seated at about 72 FT-LBS as indicated by MAC signature analysis data previously obtained on the valve. This pull out torque measurement was taken about 30 minutes after the upstream steam isolation-valves (1-E41-F002 and F003) were opened. This time frame s ecreated the conditions existing at failure.

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The valve was then closed to the position of failure, 26 turns open,-

nd allowed to heat up for 2 hour2.314815e-5 days <br />5.555556e-4 hours <br />3.306878e-6 weeks <br />7.61e-7 months <br /> Pull out torque was then

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measured at 50 FT-LB *

The licensee and valve vendor stated that pull out torque is normally less than seating torque unless binding is presen The licensee concluded that some type of binding was present at the ti.ne of failure due to the initial pull out torque of 80 FT-LBS. Based on the t initial data, the licensee completely disassembled the valve (Anchor-i Darling,10" - 600 # flexible wedge gate) and the actuator (Limitorque -

1 Model SMB-1). The internals were inspected by the licensee and both vendors, who were on site, and no problems were identified with the valve or actuato The valve and actuator were then reassembled and meetings were continued to determine the root caus The task force meetings were attended by the licensee, the Limitorque vendor representative, the A/D vendor representative, and the NRC inspectors. The following issues were identified and discussed:

Based on the high pull out torque required to initially open the valve and no identified problems upon disassembly, the team concluded that thermal binding may have contributed to the motor failure. The licensee told the A/D vendor they thought the thermal binding issue had been resolved by a previous modif: cation to the valve which involved drilling a small hole in the upstream (steam supply) face of 1 the flexible wedge (see valve maintenance history dated May 28, 1988, later in this report). The A/D vendor stated the hole was drilled to eliminate "bonnet overpressure" binding and not "thermal" bindin This type of binding is caused by w6ter being trapped in the bonnet and between the flex 111e wedge when '.he valve is cold. Mter heatup i

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the water expands or flashes to steam causing pressure to increase in the valve bonnet area and between the wedges of the valva disk. This pressure increase causes the wedges to press . tightly against the '

seats thus causing the valve to bind and hinder-the opening of the valve. "Thermal" binding, on the other hand, is caused by closure of the valve when it is hot and then subsequently isolating the valve

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end allowing it to cool dow Then the different expansion and contraction characteristics of the valve body end disk causes the valve to bind when attempting to open. This scenario fits the aperating conditions the valve was subjected to prior to failur ,

• In order to determine if thermal binding caused the failure, the task force developed special . troubleshooting procedure SP-88-032,

1-E41-F001 Themal Binding Troubleshooting Pla This procedure entailed closing the valve with a torque wrench to approximately 75 FT-LBS, the torque value at which the valve would norma?iy close ,

at electrically, based on previous data obtained for the valve. The valve would then be opened at various equilibrium temperatures / times using a torque wrench and MAC diagnostic equipment to ~ detemine if ,

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thermal binding occurred. For the initial test, the valve was shut :

at 75 FT-LBS with the line and valve cold (ambient), then the upstream isolation valves 1-E41-F002 and F003 were opened, followed by opening the F001 valve with a torque wrench. The maximum pull out ,

torque observed was from 20 - 25 FT-LBS. The line and valve were then allowed to warm up to hot ambient conditions and the valve was

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hot torqued closed to about 75 FT-LBS. The valve was then isolated by shutting the upstream isolation valves (F002 and F002) and allowed to cool to ambient conditions (about 193 degrees F). The valve was 4 then unisolated by opening F002 and F003 and again the F001 valve was

, opened with a torque wrench. This time the maximum pull out toroue

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recorded was about 55 FT-LBS. Although this torque value was not as high as the as-found condition of the valve after failure 1

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(80 FT-LBS), a graph of torque value versus number of handwheel turns I was very similar in appearance, but not the magnitude, for the two 1 cases. In addition, this test indi;ated some thermal binding was I present 'n test conditions due to the differences in pull out torque for cold and hot testing (25 FT-LBS cold versus about 55 FT-LBS hot).

The licentee was to continue this sequence of testing, hot torque 1 closed fo1%wed by opening after cooldown to ambient; however, the 1 F001 valve would be warmed up for various times prior to openin This woult, allow a determination as to what warn up period would ensure tbJt thermal binding would not occur. Further testing could !

't not exaczly duplicate the torque values found after the F001 failur !

The licensee issued Standing Instruction 88-066 on July 3,1988, requiring the operators to wait four hours between placing HPCI in j standby till declaring the system operabl l l  !

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Another area of concern was identified in that the GE provided design for the licensee's DC MCC cubicles include the use of a starting rusistar for DC motor operated valves. The starting resistors are installed to limit the DC current buildup until the motor starts to accelerate toward rated speeo and the counter EMF has built up sufficiently to limit the motor accelerating current to an acceptable :

value. The resistors can also reduce the required starting contactor '

size in the circui These resistors are in the circuit for a l nominal two seconds. With the starting resistors in the circuit, the motor initially starts at reduced voltage and current and, when the

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valve actuator gearing reaches the point where the lugs on the worm gear make contact witn the lugs on the drive gear, the motor may stall until the starting resistors drop out of the circui This virtually eliminates the "hammer blow" effect of the actuator and the j valve must open nn motor torque only. The actuator manufacturer l indicated this would reduce the efficiency of the actuator by about I 25 percent. The licensee, with the vendors, initially concluded that l the F001 valve was operable prior to the failure with starting i l resistors in the circuit and using the design value of 85% degraded l voltag However, the 60 FT-LB motor would not have been selected <

l for the F001 valve had the vendors been aware of the starting

resistors. Furthermore, Limitorque did not recommend the use of ;

l starting resistors with their motor actuator This also did not i take thermal binding into account.

l Subsequent review of the torque requirements for F001 indicated that I there would be inadequate torque available from the motor at minimum bus voltage without the starting resistors bypassed. In order to obtain more margin the licensee prepared a modification package, PM-88-019, to accomplish the following:

(1) Remove the starting resistors to ensure the "hamer blow" effect l occurs when opening the valv (2) Increase the wire size from the MCC to the actuator from No. 10 AWG to No. 6 AWG, increasing the current available at the moto (3) Increase the gear relio of the actuator by a gear change to l

provide more output torqu *

Based on the issues identified concerning the F001 valve, the licensee identified several other safety-related valves in the plant which may have the same proble These are the HPCI F006 valve for both units and the RCIC F013 valve for both units. The HPCI F001 for Unit 2 was determined not to be an issue at tt.ls time ban * on MAC diagnostic data fer the valve indicating lower seating and pullout l torque These lower values probably occurred because the Unit 2

valve has never been rebuilt and does not fit as tightly as the l Unit I valve. This non-ideal valve would allow more rapid heating and lower differential pressure across the valve seat. However, the same modification package discussed above will have to be accom-plished to ensure operability sfter valve rebuild.

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12 l The licensee reporta.i that preliminary analysis indicated the rcd, ,

F013 to be operable for both units with starting resistors and degraded voltag However, analysis of the HPCI F006, the HPCI system injection isolation valve, was. determined not to be operable at the design basis D/P with starting resistors and degraded voltag ;

Therefore, these valves for both units were declared inoperable at 1:13 p.m., on July 5, 1988. The licensee was working on a JC0 at the end of the reporting period. Additional information will be provided in a subsequent inspection repor '

A review of historical data for recent fa' lures of the HPCI F001 valve showed the following:

On October 8,1986, the F001 valve failt' Nhen the ' reaker u was tripping on magnetics. The licensee found the motor "bad" through bridge and megger readings, and dccumented in WR No. 86-BPML2 that the cause of the trouble appeared to be normal wear. The licensee had reviewed the maintenance hici.ory and found no previous problems with the installed moto The licensee replaced the motor and returned the valve to operable statu ,

o At 1:00 a.m., on December 31, 1987, while performing the operability test of the Unit 1 HPCI system (E41), PT-09.2, the HPCI turbine steam supply isolation valve, E41-F001, would not open (see LER 1-87-023).

E41-F001 would not open due to failure of the valve's DC mote The valve motor was replaced, the valve was returned to service, an. at 8:45 p.m., on January 2, 1988, HPCI was returned to standby i readines Failure analysis of the E41-F001 valve motor conducted by an independent analysis laboratory determined the incurred failure was i due to high voltage transients in the motor shunt coil, which occur whenever the motor power supply breaker was opened. To correct this '

design problem, plant modifications will be implemented to install surge protection within the shunt coil circuitry of DC motor control circuitry on Units 1 and 2 by January 20, 198 ,

Presently, if (

possible, the licensee manually installs a variable resistor at the breaker in the MCC to dissipate the voltage transient whenever

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t opening the motor power supply breake Otherwise, the valve is cycled after the breaker is reclose This has been operation's ;

practice since May 1, 1988, t f

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At 9:30 p.m., on May 28, 1988, while performing the operability test '

of the Unit 1 HPCI system (E41), PT-09.2, the HPCI turbine steam supply isolation valve E41-F001, would not open (see LER 1-88-012).

At that time, the licensee determined that the E41-F001 would not '

cpen due to failure of the volve motor windirgs resulting from mechanical and thennal binding of the valve disk within the valve

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bod This was due to inadequate disk-to-body clearance tolerances for the valve disk guides, resulting from a prior rebuild of the valve during the Unit's 1985 refueling / maintenance outage. The inadequate valve disk-to-body tolerances are attributed to procedural inadequacies and lack of in-depth valve repair training of the i personnel involved with the rebuild of the valv A hole was drilled in the valve dia, per valve vendor recommen-dations, to alleviate the thermal binding problem. The valve was rebuilt and satisfactorily tested, and on June 6,1988, the HPCI system was, returned to standby readiness. The respective Unit 2 valve was satisfactorily tested for proper operation on June 14, 198 Limitorque stated in the meetings attended by NRC inspectors- that l- they were unaware of the starting resistors in the MCCs. This led to apparent design deficiencies of the HPCI F001 and F006 valves and possibly degraded designs of other DC motor operated valves. This is

, an Unresolved Item pending further NRC review: Valve Operability With Respect to Starting Resistors in DC Motor Control Centers (325, 324/88-21-07). Further inspector review will be documented in a subsequent inspection repor In the areas inspected, two significant safety issues were identifie thermal binding of gate valves was not adequately reviewed by the licensee, and starting resistors were not considered in the design of Linntorque actuators. No violations or deviations were identifie '

l Unit 2 Service Water Leak (62703)

I An auxillary operator found a through wall leak in a section of 20-inch service water piping on July 3, 1988. The leak was about 1/4 GPM through the cernant-lined carbon steel pipe at field weld 2-FW-13. The weld is >

located la the discharge header downstream of the "B" RHR heat exchanger ,

in the "B" core spray room. The vital header return line, which contains ;

service water from the room coolers and RHR pump motor seal coolers, taps ,

into the discharge header 15-inches below the leaking weld. Four UT I indications were found at the weld with one circumferential indication about 11-inches long and 7f% through wall in place ;

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The PNSC reviewea EER 88-335, that accepted the piping as is till the !

temporary repair was completed. The licensee has welded a band around the !

affected weld. The affected lection of pipe will be replaced during the l next refuelir.g outage wht;h .. scheduled for August 198 )

The licensee has ultrasonically er.amined similar welds and found no significant indications. The licensee's temporary repair, performed under WR-88-ASAR1 and EER-88-0336, was in place on July 9, 1988. A region based

NDE inspector reviewed the area. (See inspection report 325,324/88-26.)

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No F.gnificant safety natters, violations or deviations were identifie ,

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14 I 4 DieselGenerate-ServiceWaterPressureSwitches(62703)

The licensee idenrf ted that the diesel generator service water pressure switches were mounted on non-seismically qualified supports. The pressure '

switches trip if service water pressure drops below 10 psig to the diesel generato The service water supply would be swapped from the normal supply to the alternate or other unit supply. A failure of the pressur switches due to a mounting failure may have caused failure of the alternate supply to be availabl The licensee discovered the problem on June 17, 1988, and declared the supports short-term qualified. However, subsequent review showed that the supports could not be qualified as is, and the licensee developed EER .88-327 to support continued operation till the supports were modified. On June 29, 1988, the inspectors questioned certain assumptions of the EE Based on the inspector's questions, the licensee reevaluated the condition and reported the event via the ENS at 5:56 p.m., that same da The licensee modified the supports and declared them operable on July 2, 198 This matter remains unresolved pending issuance of the LER and '!

further inspecto review: DG Pressure Switch Support Inadequate Seismic Design (325/88-21-06 and 324/88-21-06). *

No significant safety matters, violations or deviations were identifie . FollowuponUnresolvedItems(92701) i

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(CLOSED) Unresolved Item 325/88-18-02 and 324/88-18-02, Failure to [

Environmentelly Qualify SCR Controllers. Based on further management l

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review, this matter is deemed a violation since the licensee had completed L the corrective accion for the previous similar violations and the licensee i reasonably could have prevented this violation from occurring. This is a l

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Violation: Failure to Environmentally Qualify SCR Controllers for the ;

SBGT System (325,324/88-21-02).

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No significant safety matters, one violation and no deviations were identifie . Unit 2 HPCI Inboard Steam Isolation Valve Reported Failed (62703)

At the time of the failure, the control operator reported that the valve ,

tripped on thermel overload. Maintenance, under WR No. 88-ARNG1, bridged I

and meggered the motor, 'ound no problems, and returned the valve to l

operable status at 3:36 a.m., on June 27, 1988, after stroking the valv I j Plant management reported to the inspector at about 9:00 a.m., that the F002 valve was still inoperable when the valve had already been declared

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operable as noted abov Based on that new information, plant management directed that the valve be declared inoperable again. The thermal l overload, its associated annunciator, and current traces taken while operating the valve, all indicated that the valve operated satisfactorily l during subsequent testing. A followup interview by the operations '

superintendent of the control operator and auxiliary operator involvec in

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the event, revealed that the F002 valve did not trip on thermal overloa I

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No annunciator came in during valve operation. The C0 normally opens the F002 in approximately 1 second increments to admit steam to the HPCI steam' '

line without creating a water hamer. Normally during this evolution, the red & green control room indicating lights dim when the valve control ,

1 switch is taken to the open position. After several opening increments, >

the lights no longer dimed during this event. The C0 interpreted this indication 6s a thermal overload trip and sent the A0 to reset the thermal overload at the motor control center 2X .

The inspector expressed concern regarding the following issues raised by this event: Failure of management to stay fully informed.

' Inadequate C0 knowledge of plant equipment operation.

' Failure to aggressively pursue a motor operator valve proble '

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Manageme'it needs to address these issues. Since the valve was never  ;

inoperable, no actual safety event occurred; however, management weaknets

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was demonstrated and resulted in reduced HPCI availability. The inspector

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will review the licensee's actions regarding this even This is an Inspector Followup Item: Management Issues Related to HPCI F002 Operation i

(324/88-21-04).  !

j 1 ExitInterview(30703)

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The inspection scope and findings were sumarized on July 8,1988, with those persons indicated in paragraph 1. The inspectors described the -

areas inspected and discussed in detail the inspection findings listed

belo Dissenting coments were not received from the license Proprietary information is not contained in this repor Item Number Description / Reference Parsgraph 325,324/88-21'-01 VIOLATION - No Schedule Provided in Special

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Report for Repair of Diesel Generator Building

, Fire Doors (paragraph 5.a). ,

325,324/88-21-02

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VIOLATION - Failure to Environmentally qualify SCR Controllers for tne SBGT System

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(paragraph 10).

VIOLATION - Failure to Perform Required Post

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325/88-21-03 Maintenance Testing of HPCI System (paragraph 3).

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325,324/88-21-07 * URI - Valve Operability With Respect to i Starting Resistors in DC Motor Control Centers

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(paragraph 7).

An Unresolved Item is a matter about which more information is required tt determined whether it is acceptable or may involve a violation or deviation.

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325,324/88-21-06 URI - DG Pressure Switch Support. Inadequate

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SeismicDesign(paragraph 9).

324/88-21-04 IFI - Mana

Operation (gement paragraphIssues 11). Related to HPCI F002 j 325/88-21-05 IFI -

Review of HPCI Room Door OER (paragraphs.b). *

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13. List of Abbreviations for Units 1 and 2

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A/D Anchor-Darling ADS Automatic Depressurization System  ;

A0 Auxiliary Operator ,

BSEP Brunswick Steam Electric Plant C0 Control Operator CP&L Carolina Power and Light Company DC Direct Current '

DG Diesel Generator D/P Differential Pressure

ECCS Emergency Core Cooling System

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EER Engineering Evaluation Report 4 EMF Electro-Motive Force ,

ENS Emergency Notification System l

F,0 Environmental Qualification ESF Engineered Safety Feature ,

F Degrees Fahrenheit '

GE General Electric

GPM Gallons Per Minute ,

HP Health Physics i HPCI High Pressure Coolant Injection

, I&C Instrumentation and Control 1 IE NRC Office of Inspection and Enforcement IFI Inspector Followup Item .

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IPBS Integrated Planning Budget System

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JC0 Justification for Continued Operaticn LCO Limiting Condition for Operation l LER Licensee Event Report LPCI Low Pressure Coolant Injection MAC Motor Actuator Characterizer )

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MCC Motor Control Center MPC Maximum Permissible Concentration

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NRC Nuclear Regulatory Commission i OER Operating Experience Report

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PA Protected Area PM Plant Modification PNSC Plant Nuclear Safety Committee PT Periodic Test QA Quality Assurance QC Quality Control RCIC Reactor Core Isolation Cooling RHR Residual Heat Removal RPM Revolutions Per Minute RWCU Reactor Water Cleanup RX Reactor SBGT Standby Gas Treatment SCR Silicon Controlled Rectifier SI Standing Instruction SP Special Procedure SR0 Senior Reactor Operator STA Shift Technical Advisor TS Technical Specification uCi Microcurie VT Vitrasonic Test URI Unresolved Item UT Ultrasonic V Volt WR Work Request i

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