IR 05000289/1989013

Insp Rept 50-289/89-13 on 890626-0707.No Violations Noted. Major Areas Inspected:Corrective Actions Resulting from IE Bulletin 85-003 Addressing Improper Limit Switch & Torque Switch Settings in motor-operated Valves

ML20247B934
Person / Time
Site:	Three Mile Island
Issue date:	08/22/1989
From:	Anderson C, Thomas Koshy, Julio Lara, Woodard C NRC OFFICE OF INSPECTION & ENFORCEMENT (IE REGION I)
To:
Shared Package
ML20247B924	List: IR 05000289/1989013 ML20247B918
References
50-289-89-13, IEB-85-003, IEB-85-3, NUDOCS 8909130188
Download: ML20247B934 (18)

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-U.S. NUCLEAR' REGULATORY COMMISSION

' REGION I Report No 50-289/89-131

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Docket No. 50-289

License th . DPR-50 Licensee: 'GPU Nuclear Corporation P.-0. Box 480 Middletown, Pennsylvania 17057 Facility Name: Three Mile Island Unit 1 Inspection At: Middletown, Pennsylvania Inspection Conducted: June 26 - July 7, 1989

Inspectors: d'

Thomas Koshy, Selior Reactor Engineer '

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date PSS, En ineering Branch DRS 3 * 8 [

Julio F. Lara, Reactor Engineer .date PSS, Engineering Branch, DRS hY Carl H. Woodard, Reactor Engineer 8bt/89

' date:

PSS, Enginee 1g Branch, DRS Approved by:

C. J.// Anderson, Chief 9 LL if

'date PSS, Engineering Branch, DRS Inspection Summary: Inspection on June 26 - July 7,1989 (Inspection Report Number 50-289/89-13)

Areas Inspected: Special announced inspection to review the corrective actions that resulted from IE Bulletin 85-03 that addressed improper limit switch and torque switch settings in motor operated valves. This inspection reviewed the engineering and maintenance activities to assure the operational readiness of the motor operated valves and the licensee's program to ensure the quality of the emergency diesel generator fuel oi Results: The licensee has not completely addressed all the 'significant aspects of the bulletin. Three items pertaining to the bulletin remained unresolved at the end'of the inspection. One' unresolved item resulted regarding the site practices of operating circuit breakers following electrical faults. One pre-viously issued unresolved item on electrical coordination was closed. There was also an unresolved item regarding licensee actions needed to assure emergency diesel generator fuel oil qualit .

8909130188 890901 PDR- ADOCK 05000289

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1 -2-Summary of Inspection Findings

, Unresolved Items Section Number 50-289/ Adequacy of Torque Switch Settings 89-13-01 1.1 Control of Switch Settings .2 MOV Demonstration of Operability . MOV Thrust Output at Low Voltage . Criteria.for Retesting MOVs . Electrical Corrective Maintenance Practices Sampling / Analysis of EDG Fuel Oil Previous Insp'ection Findings (Closed) Design Analysis not available for 118 VAC circuits

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l DETAILS 1.0 Person Contacted l 1.1.1 GPU Nuclear Corporation - June 26-30 IEB 85-03 Inspection J Bowman, Electrical Maintenance T. G. Broughton, Director, O&M TMI-1 J. J. Colitz, Director, Plant Engineering

• • 8. Condran, QC

J. Correa, Mechanical Components Engineer C. E. Hart: tan, Plant Engineering Manager D. Hassler, Licensing Engineer J. C. Herman II, QA Auditor M. L. Moore, Plant Materiel Engineer H. B. Shipman, Ops Engineering, Manager D. M. Shov11n, Plant Materiel Director R. G. Zimmerman, Plant Engineer

• • P. Wagner, Electrical Supervisor M. C. Wells, Communications 1.1.2 GPU Nuclear Corporation - July 5-7 EDG Fuel Oil Inspection T. G. Broughton, Director, OEM G. Chevalier, Plant Engineer J. J. Colitz, Director, Plant Engineering H. D. Hukill, Director, Vice President C. L. Incowati, Audit Manager, QA M. R. Knight, Manager, Licensing L. Lucas, Plant Chemist J. R. Pearce, Plant Materials Engineer J. G. Reed, Plant Engineer M. H. Schaeffer, Plant Engineer C. G. Seitz, Operations C. W. Smyth, Manager, Licensing 1.2 Commonwealth of Pennsylvania S. M. Peleschak, State Representative U.S. Nuclear Regulatory Commission (NRC)

D. M. Johnson, Resident Inspector T. A. Moslak, Resident Inspector

Via Telephone

• • Not present at the exit meeting i

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-4-2.0 Purpose The purpose of this inspection was to review the licensee's actions taken in response to IE Bulletin 85-03, motor operated valve (MOV) common mode failures during plant transients due to improper switch settings and to review the licensee's program to assure the operational readiness of the motor operated valves covered under this bulletin. In addition, the inspectors also reviewed the licensee's program to ensure the quality of EDG fuel oil (see Section 7.0).

3.0 Background On June 9,1985, the Davis-Besse Plant experienced a complete loss of main and auxiliary feedwater which was caused, in part, by MOV failure This event resulted in IE Bulletin 85-03 that promulgated NRC requirements to assure the operational readiness of MOVs in the high pressure coolant injection / core spray and emergency feedwater systems. The bulletin specified that licensees take the following action (a) Review and document the design basis for the operation of each valve, including the maximum differential pressure expected during the normal and abnormal operatio (b) Using the above data, establish the correct switch settings for torque, torque bypass, position limit and overload for each valve and perform the modifications as neede (c) Individual valves should be demonstrated to be operable by testing the valve at the maximum differential pressure based on the performance requirements. In the absence of differential pressure testing, a justification should be provide (d) Prepare and revise procedures to ensure that correct switch settings are determined and maintained throughout the life of the plan ,

(e) Submit a schedule to accomplish the above program including a final submittal with the results of (b) through (d).

Item (a) was reviewed by the NRC office of Nuclear Reactor Regulation (NRR). The scope of this inspection was to review items (b) through (d).

4.0 GPU Nuclear Corporation response to IE Bulletin 85-03 (TI-2515/73)

4.1 Status of Commitments The licensee's letters of May 27 and September 15, 1986, February 27 and June 25,1987 (Ref.1,2,3,4 Attachment-1) contained their {

response to the bulletin. A request for additional information was '

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~5-n transmitted to the licensee in a Region.I letter dsted September 9,

. 1987 (Ref. 5 Attachment-1); The licensee responded to this request on October 14,1987 (Ref. 6 Attachment-1).

p" The licensee's June 25, 1987 letter provided a final written report on the completion of the program required by the ' bulleti The' motor operated valves identified for Three Mile Island Unit 1 for IEB 85-03 consideration are listed in Table .2 Switch settings Item (b) of the bulletin requires that the correct-switch settings for' torque,' torque bypass, position limit and overload for each

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valve be established. ,These items are addressed belo Open Torque Switch and Open Bypass Limi This switch is normally used to limit the mechanical thrust applied to the valve in the open direction. This switch is usually bypassed

.during the' initial valve unseating which is the most challenging portion of the open strok Failure to set this switen to the required value or not bypassing this switch in the initial opening stroke, can prevent the valve from openin The licensee has elected to set the open torque switch such that the MOV " rides on" the switch until the open lirait switch contact open As the valve is not backseated, the valve is not subjected to any undue strai The licensee has set the open bypass limit switch at 8 to 14% of the valve travel beyond the unseating of the valve. This setting is sufficient to prevent the actuation of the opening torque switch during the initial spike of the opening stroke. A subsequent diagnostic testing using MOVAT equipment confirms the switch operations at the required settin Close Torque Switch The close torque switch is used to stop the motor rotation on the completion of valve travel in the close direction. Since this switch provides a normal control function and is exercised on every closure stroke, this switch setting needs more careful consideration than the open torque switch. The limiting requirement of the close torque switch is at the end of the closure stroke when the thrust requirements are the highest. The thrust at the point the torque switch trips should equal the most limiting closure tarust require-ment including the thrust needed to overcome the differential pres-sure across the valve. Differential pressure testing using process

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-6-system pumps'with appropriate' data; gathering _and diagnostic' evaluatio is the positiveLmeans of assuring'the adequacy of the. torque switch

set point. ~ Other approaches' based on' similarity and analysis may also be acceptable with sufficient basis.

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TThe setpoints for the TMI valves were calculated based on the thrust-required to operate the valve at the design condition with a'45 percent margin. :The. licensee calculated thrust' values'from Limitorque tech-r inical data _and has utilized the most conservative' values with a

. margin to set;the torque switches. After, leaving.the switch at the desired setting, the licensee has performed differential pressure testing for valves MU-V-16A/B/C/D, MU-V-36, and MU-V-37. These tests confirmed the operation of. the valves at the most limiting conditions

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of. operation For the valves which were not differential pressure tested, the licensee has verified the maximum thrust developed at the valve seat through M0 VATS testing. These settings are also set at 145% of the calculated thrust values. See Section 4.3 for applicability of the TECO test _results to TMI- The licensee. currently relies on previous MOVATs test data to deter-mine the required torque switch settings. These results are not documented in a controlled document to ensure that the correct setpoint is maintained. These setpoints, and corresponding thrust values, are retained in uncontrolled files located at.the maintenance shop. This situation could least to the use of obsolete setpoint values during maintenance. This is an ur. resolved item pending NRC review of the program to control the MOV torque switch sctting (50-289/89-13-01)

The licensee committed to address this item by October 31, 1989, i

Close Limit Switch This switch is usually used with the close torque switch in series i

for over-torque protection. For high speed operators, where torque I .- switches cannot react in sufficient time, the close limit switch deenergizes the motor and the remaining inertia forces seat the valve GPU Nuclear is not utilizing the close limit switch to deenergize the mator for valves covered under this bulletin. All the valves in the scope of this bulletin are seated using the torque switche Close Torque Switch Bypass The close torque switch bypass acts in the same manner as the open torque switch bypass; however, contrary to its counter part C____________--.--_--_____ _

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-7-L function, it normally bypasses the torque switch during the ligntest duty portion of the stroke, the beginning of the' closing strok The use of-this switch is not critical; however, if utilized it g should be set to operate during the initial part of the stroke, to

! assure that valve closure is not prevented by the torque switc The Unit I close torque bypass switch is set such that at the o starting of the motor, the torque switch is bypassed, and for the L remainder of the valve stroke, the torque switch is used in the control circui Open Limit Switch This switch provides the control function for determining the upper

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limit of the valve stem travel in the open direction and stops the motor rotation by opening the circuit. The setting of this switch must assure adequate valve opening and should prevent back seatin Valve backseats are normally to provide a seal that is redundant to the valve packing it; order to allow valve packing replacement without the need to drain down the process system. Using the motor power to backseat can and has' caused valve stem shearing and stem-thread twisting. Therefore: it is important to set the open limit switch away from the back seat with enough margin to allow for motor deenergization and inerti GPU Nuclear has set the open limit switch such that the valve does not back seat by inertia. No problem was identified witn this arrangemen Thermal Overload Relay Thermal overload relays are used to protect motor winding insulation from breakdown during overload conditions. Devices used appear to uniformly consist of heaters at the motor control center which trip a heat sensitive relay, the contacts of which either interrupt current to the contractor closure coil (which stops the motor) or-initiates an overload alarm, or both. Where thermal overload relays stop operator motor rotation on tripping, the heaters must either be sized to prevent inadvertently. stopping the motor or the overload relays must be bypassed when motor operation is important to safety They should also be sized to protect the motor windings from thermal damage. Regulatory Guide 1.106, thermal overload protection for electric motors on motor operated valves provides guidelines on the design criteria for thermal overload Designs that are being used at this time to eliminate the threat of inadvertent motor trips include: (1) removing the heaters or relay contacts from use; (2) using the relay contacts for alarm only; (3)

bypassing the relay contacts during all operating modes except when I

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-8- q a valve is being exercised for testing; (4) bypassing the. relay contacts only during the' presence of an automatic safety actuation signal; and, (5) oversizing the thermal overload The licensee currently selects the overload relay and heater sizes at 300% of rated full load current. This oversizing design philosophy generally fails to provide adequate motor protection under locked rotor current conditions. The licensee has internal commitments to review this design philosophy to determine if the overload relay and heater sizes should be reduced. The inspector had no further questions regarding this matte .3 Demonstration of Operability This involves demonstrating the valve to be operable by testing the valve under maximum differential pressure after changing the individual valve settings, as appropriate, based on the design base In the absence of testing with full differential pressure across the

.<alve, a justification is to be provided. The use of a MOVATS data base to arrive at a torque switch setting for a particular type of valve is ccnsidered as an acceptable approach to exclude differential pressure testing. This type of valve should have sufficient test data to establish similarity. A test is still needed to establish that the desired thrust is available at the valve seat for closur As described in Section 4.2, six (6) valves were demonstrated operable by differential pressure testing while the parameters were measured with MOVATs equipment. For the remaining six (6) valves not subjected to actual differential pressure testing, the licensee calculated the required torque switch setting. GPUN reviewed the test results from Toledo Edison and determined they were also applic-able to TMI-1. Although the licensee considers the TECO test results applicable to TMI-1, valve specific analysis to establish similarity between the tested MOVs at Toledo Edison and those installed in TMI-1 has not been developed to fully support operability.

This is an unresolved item pending further NRC review for the l demonstrated evidence to support the adequacy of the present torque switch setpoint. (50-289/89-13-02).

l The selection of the target thrust at 145% of the calculated required thrust provides reasonable assurance that there is no immediate safety concern with respect to the operability of the subject MOV .4 MOV Operation during Undervoltage Conditions The effects of undervoltage conditions on the operation of MOVs must be considered since a low voltage at the MOV terminals results in a reduced thrust output by the motor. Reduced voltages and cable voltage drops must be taken into consideration when evaluating l l l

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l-whether valves will be able to. close or open under maximum differen-tial pressure conditions. The~ adequacy of motor torque at a reduced voltage was not addressed by the licensee before this inspectio This appifes to both AC and DC valves.

Of the 12 valves within the scope of the bulletin, only two (2) have de motors. These valves however, do not.close automatically, and are therefore not cycled during the most demanding interval of a battery's operating cycle. The licensee has not completed calcula-tions to verify that the AC motors are able to produce the required thrust'under low voltage' conditions. Preliminary results indicate-that sufficient margin is present to ensure the operability of the valves under the postulated under voltage condition This is an unresolved item pending.NRC review cf the completed calculations documenting the adequacy of the motor torque for the subject MOVs during'undervoltage conditions. (50-289/89-13-02)

4.5 Maintenance and procedures The bulletin requires that licensees prepare or revise procedures to er.sure that correct switch settings are maintained throughout the

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life' of the plant and also to ensure that applicable industry recommendations are considered in the preparation of the procedur The inspectors reviewed the procedures listed in Attachment 1. The licensee had revised these procedurcs for maintaining the limit and torque switch settings. The specific instructions on installing and setting limit and torque switches incorporated industry recommendation Two safety related motor operated valves, MS-V-2A and MS-V-2B were physically inspected. These valves are part of the main steam system and were the only ones available for physical inspection. For both valves the limit switch compartments were opened. The internal components were examined and the torque switch setpoints were verifie Inspection of MS-V-2A revealed that the internals included a splice for which a Thomas and Betts nylon wire cap had been used. Since the valve is located in a zone subject to a high normal temperature and to a High Energy Line Break (HELB) with 100% relative humidity, the licensee was requested to provide qualification documentation for the wire cap and SCEW sheets for the two valves involve Regarding the wire cap, the licensee furnished two inter-office memoranda, from L. Cavaliere to D. V. Hassler, dated November 30, 1988 and February 1,1989. Both memorsnda justified qualification on the basis of qualifications testing which included thermal aging for an equivalent of 8 years at 125 F and a HELB at 270 F peak

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temperature. However, the latter memorandum. recommended replacement of the wire cap with a qualified Raychem Splice. .In view of the licensee's recommendation and plans for replacement, the analysis provided was considered to be adequate.-

Review of the. valves' SCEW Sheets revealed that licensee had specified an' aging temperature of 90*F for the particular mounting zone. The specified temperature appeared to be low when compared to the value identified in the memoranda described above (105*F max) and to the L one ' observed during the walkdown. Discussions with the licensee l

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indicate that the normal ambient aging temperatures were obtained by field survey of the plant zone These temperatures wert collected in GPUN specification ES-010, dated June 2, 1988. The documentation is currently being updated. For the zone in question, the aging temperature is being revised to be 95*F which is lower than the qualified temperature of 130* The inspector had not further question Testing The. inspectors observed that licensee procedures do not identify the circumstances which prompt the retesting of the valves covered under this bulletin. . Certain corrective and preventive maintenance activities can influence the as-left conditions of the torque switch setting. A replacement of the torque switch or spring pack will lead to changes in the available torque for closing / opening.the valv Currently the cognizant engineers determine the retesting need based on the MOV maintenance performed. However, guidelines for recognizing the need for retesting are not documented in any procedures. The licensee has committed to develop the guidelines establishing the

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need for retesting valves that have undergone maintenance activitie This is an unresolved item pending NRC review of the specific condi-tions which would require retesting of valves covered in the bulleti (50-289/89-13-03)

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5.0 Followup of Previous Inspection Findings

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(Closed) Unresolved Item 50-289/86-12-13: Electrical Coordination Analysis Not Available for 118Vac Circuit This item pertained to the design analyses of various safety-related electrical systems. Review revealed that some 118Vac vital buses also feed non safety-related loads, such as the integrated control system and the backup manual controllers for the emergency feedwater flow control valves. These loads exceed the rating of individual safety-related loads on the same bus, but no analysis was available to demonstrate the capabi-lity of the breakers to isolate and clear electrical faults on the non-safety related circuit _ _ _ - - - - - - _ - - . .

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During this inspection, the licensee presented calculation No.

i C-1101-735-5350-002. This calculation showed the maximum short circuit current available at various points in the system and demonstrates the clearing time of the breakers. The present coordination curves establish proper coordination between main and feeder breaker This item is close .0 Electrical Equipment Corrective Maintenance practices,

i During the plant visit, the inspectors examined the licensee's maintenance l log which indicated poor operation and maintenance practices. On June 28, 1989 maintenance personnel found a connection block in the AH-C-38B contactor cabinet burnt and an expansion joint was subsequently replace Following this corrective action, operations personnel attempted to close the circuit breaker but it trippe personnel attempted three (3) more times to close the breaker and each time the breaker tripped. Repeated attempts to reclose a circuit breaker which continued to trip, indicates poor practice by the plant personne Further investigation is warranted whenever a circuit breaker con'.inues to trip as it can lead to significant damage to equipment. According to the maintenance log entry, during the third attempt to close the breaker, wires were observed to be smoking. In looking at the connection block it appeared that water was laying on top of the block and, upon repeated attempts to reclose, the circuit breaker was subjected to a phase-to phase and all three phases to ground faul The contacts were found to be burned. The circuit breaker could not be tested to verify its operability as the test set w > out for calibratio Maintenance personnel reviewed applicable drawings and unted discrepancies between the drawing and the installed breaker. The drawing indicated an M125 breaker with no adjustable settings while the installed was 125A breaker with adjustable settings set on low. The drawing was assumed to be incorrect by the personne The above evolution provides examples of poor practices in correctiva maintenanc First, the condition which initially caused the connect!on block to burn was not verified to be cleared. Resistance measurements are typically warranted to ensure that any previously existing faults have been cleared. Secondly, repeated attempts to reclose a circuit breaker following subsequent trips is not considered an acceptable practic Further review is necessary to prevent any possible equipment damag ;

Thirdly, once discrepancies between drawings and field installations are identified, resolution requires a thorough evaluation to correctly deter- ]

mine the equipment which is require At the conclusion of the inspection, the licensee was examining the personnel prac...es and considering corrective actions. Though the circuit breaker in question is non-class IE equipment, the inspectors were concerned that these practices could potentially apply for IE equip- 1 ment. This is an unresolved item pending NRC review of the licensee's j evaluation and corrective actions to prevent these practices from being i repeate (50-289/89-13-04)  !

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7.0 Emergency Diesel Generator (EDG) Fuel Oil (TI 2515/100)

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7.1 Background

. For proper operation of the standby diesel generators, it is neces-sary to ensure the proper quality of the. fuel oil. Appendix B to 10 CFR 50, as supplemented hy Regulatory Guide (RG) 1.137, serves as an' acceptable basis for-licensees to maintain a program to ensure the quality-of EDG fuel oil.

I In response to recent industry problems on January 16, 1987, the NRC issued Information Notice 87-04 to alert licensees of potentially significant problems pertaining to the long-term storage of fuel oi This information notice documents the inoperability of an emergency diesel generator due to a high concentration of particulate in the fuel oil. Assurance of the proper fuel oil requires purchasing the correct fuel oil and a receipt inspection to verify that the fuel oil is proper prior to addition to the starage tanks. Since fuel oil degrades with time and external sources contribute contamination, periodic inspection is required to assure continued fuel oil qualit The inspection was performed to determine the licensee's program for the procurement, receipt, storage.. handling and control of EDG fuel oil to ensure edequate quality of the fuel oi TMI Number 2 Diesel Fuel Oil System Basic Description The licensee's number 2 diesel fuel oil system for the site consists of a 200,000 gallon oil receipt / storage tank which provides pumped fuel to a 50,000 gallon intermediate storage tank. This tank, in turn, provides-gravity fed fuel to the auxiliary boiler feed pumps, the fire pumps storage tanks, the UPS ' storage tank, and to the EDG Common 30,000 gallon storage tank. Fuel is pumped from this tank to each of the EDG day tanks by means of a 460 Vac pump with a 240 Vdc backup pump. Either pump is adequate to sustain continuous EDG operatio .2 Fuel Oil Quality The licensee procures all Number 2 diesel fuel oil for the site as

"important to safety," QA material using a blanket purchase order which requires that the fuel be in accordance with GPU specification SP-1101-38-016. This fuel oil specification matches or exceeds the requirements of both the ASTM D 1975-81 standby diecel fuel oil spect-fication and the EDG manufacturer's recommendations, as specified by Regulatory Guide 1.137. The fuel oil specifications and purchase order include requirements for the sampling and analysis of new fuel upon receipt and, also, provide for inspections at the vendors faci-lities to establish compliance. The NRC inspector determined that the licensee's program and documentation for the procurement of the proper quality emergency diesel generator fuel was satisfactor _. _ _ - _ _ - _ _ _ _ _ _ _ - - - . . - - A

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. ~t j Fuel' Oil Chemistry - Sampling and Analysis l

l The quality of the fuel oil is' determined by sampling and analysis at

various points and times. A review was made of the~ licensee's chemistry

. program procedures that are used in :naking both on-site and off-site analysis of. diesel fuel. The licensee's samp' ling / analysis procedures, l' as cited in Specification.SP-1101-38-016, were found to'be in accord-ance with the appropriate ASTM specification, rethod, test or procedure for evaluating No. 2 diesel fuel oil.

I When new fuel arrives on-site, samples are taken and analyzed on-site for water and sediment, specific gravity and viscosity. Samples of the fuel are sEnt to the outside corporate laboratory for complete aralysis to determine compliance with the fuel specification. In a similar manner, before trMsferring fuel from the 50,000 gallon. tank'

to the EDG storage tank, samples are taken for both the on-site and the complete off-site analyses. In addition, weekly samples are '

taken from the 50,000 gallon tank, after recirculation agitation, for complete' analysis. Recent analyses covering the preceding six months were reviewed. No deficiencies in these analyses were observe However,'an. observation was made that the data from the off-site analyses were usually received three to four weeks after the samples were taken. This delay could present a problem if the samples were from the fuel in the EDG storage tank. However, the TMI diesel fuel system is such that new fuel is received in a 200,000 gallon bulk tank. From here the fuel is. pumped to a 50,000 gallon bulk tan Then, when the EDG fuel' storage tank requires fuel, the fuel is fed from the 50,000 gallon tank. These large bulk tanks serve as a buffer to the EDG 30,000 gallon storage tank. The licensee is of the opinion that the infrequent topping of the EDG storage tank with a few thousand gallons of fuel which has been' frequently sampled / analyzed in the other tanks, provides reasonable assurance of the quality of the fuel in the EDG storage tank. However, the inspector noted that the EDG fuel storage tank has a locked tanker truck fill connection and a procedure for its use. However, (according to the licensee) it has not been used for many years. In response to the inspector's concern that the use of this connection for putting unanalyzed fuel in the tank could lead to the common mode failure of all diesel generators, the licensee committed to revise the procedure and to ,

include appropriate precaution The review of the licensee's fuel sampling / analysis procedures dis-closed that no sampling / analysis is ever made of the EDG fuel stored in the common 30,000 gallon tank. This tank has been in use for more than 15 years and it has never been sampled / analyzed, partially or fully drained, cleaned, inspected recirculate / filtered or filled with new fuel. However, due to an EDG problem which required an unusual amount of extra run time about three years ago, the fuel was effectively cycled approximately 1 times. Because of the extremely low fuel usagt (approximately 200 gallops per hour of operation per diesel)

and the resulting long residence time of fuel in this tank without

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.the use of antioxidants or biocides, the inspector expressed concern for. fuel degradation, biological growth, contamination and water which could_ lead to the come.co mode failure of.both diesel generator As a consequence of these concerns, the licensee took five. samples from the tank as follows: tank bottoms, inch above the bottom, six inches above the bottom (EDG fuel pick up height), and at approximatel five and-nine feet above the bottom. 'These samples were analyzed on site and also sent to the'.off-site corporate laboratory for a complete fuel analysi Like the EDG fuel storage tank, the 550 gallon day tanks were never sampled, analyzed,; drained or tested to determine fuel' qualit By telephone conference on August 15 with Mr. R. Knight et al of the

. licensee's staff, the licensee reported that the fuel oil samples met all'of the' ASTM specification acceptance criteria except for the bottoms and the sample taken h-inch above the bottom. These samples exceeded the water and sediment criteria by a small amount, either 0.01 or 0.05 percent. (There was a discrepancy between the on-site and off-site analysis findings.) However, there we no immediate diesel operability concerns, since the fuel contamination level was low and confined. to a level well below the EDG fuel pick-up level which is six inches above the tank bottom. However, there is potential for the water and sediment level to eventually build-up to the fuel pick-up level which could cause EDG operability problem As a consequence, the licensee committed to re-sampling the fuel storage tank to confirm if the fuel is contaminated by September 30 and if' contaminated to resolve this problem by December 1,1089. 1he licensee further agreed that periodic. sampling / analysis of the stored fuel'is needed to assure fuel quality and stated that evaluations will be concluded and long term technical specification surveillance procedures will be in place by December 31, 1989. This item is unresolved pending NRC review of the license's evaluations and corrective actions to assure EDG fuel quality (50-209/89-13-05).

Information Notice 87-04 The inspector reviewed the licensee'c actions taken in response to IN 87-04. This information notice addresses the problems which occurred at other plants as a consequence of fuel degradation and biological growth which led to plugging of filtration devices and to engine shutdown. The licensee responded to this IN by implementing preven-tive maintenance consisting of an annual blowdown cleaning of the fuel strainers. The response did not address the root cause of the fuel contaminates but only the ~ periodic removal of these contaminates from the strainers. Presently the licensee has no program for the periodic cleaning of the fuel tanks, recycle filtration, replacement of the fuel with new fuel, or the addition of anti-oxidants or biocides to the fuel. During the inspection, the licensee committed as part of an overall EDG fuel study to evaluate the need for changes in these areas.

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? -15-73 EDG Fuel System Operation-l .The EDG units are provided with on-skid duplex filters located after -

the engine and 125Vdc motor driven fuel pumps located ahead of the fuel injectors. The duplex arrangement permits a switchover to'the alter-nate filter,;during EDG operation, without shutdown. Filter cleaning /

l replacement is done on an annual preventive maintenance basis. The filters are instrumented to provide both' pressure indication an alarm. Alarms for the EDG fuel system in the control room include storage tank "Lo Level," " Min Level," and " Emergency Level"; Day Tank

. Level, Fuel Pump Pressure, DC Electric Fuel Pump, and EDG Common-L -Trouble. The EDG fuel system part of the EDG skid, the EDG control /

[ alarm panels, and the fuel control alarms in the control room were l seismically qualifie The diesel. fuel to the engine is controlled by the positioning of the fuel rack by means of the Woodward governor which has both electrical and mechanical / hydraulic control features. . As long as control power is provided to the governor, it acts as an ebetro-mechanical governo Upon loss of the 125 Vdc power source, the governor begins to control speed as a mechanical / hydraulic governor. The governor is also pro-vided with a 125 Vdc shutdown solenoid which functions to trip the governor to drive the fuel racks to the no-fuel position and shutdown the engine. The inspector determined that the TMI EDG units require 125 Vdc to shutdown; therefore, loss of 125 Vdc will not shutdown the engine. However, further investigation revealed that there is a generator field shorting relay that, upon loss of 125 Vdc shorts the field and causes a collapse of the EDG output voltage. This circuit could cause a reduction in the availability of the EDG units since it results in the shutdown of an operating EDG. This circuit also could cause problems when the units are undergoing testing and are synchro-nized with the grid. Under these circumstances, the loss of 125 Vdc power, with the resulting loss in generator output, could result in the generator acting as a motor and driving the diesel engine, if the EDG output circuit breaker failed to trip open because of the loss of 125 Vdc power. If this condition were to occur, both the engine and generator could be damaged. The licensee agreed to study these concerns to determine if actions are warrante .4 Conclusions The licensee's EDG futi program / system is considered to meet the

guidelines established by Regulatory Guide 1.137 with the exception of routine periodic means for ensuring the quality of the stored EDG fuel oil. This issue is being addressed currently in order to establish and implement the procedures require _ _ _ _ _ _ - - - - _ - _ _ . _

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. 8.0 Unresolved Item Unresolved items are matter for which more information is required in order.to ascertain whether they are acceptable, violations, or deviation Unresolved items are discussed in Sections 4.0, 5.0, 6.0 and 7.0 of this repor .0 Exit Intervie The inspectors met with the licensee' representatives at the conclusion of the inspection on June 30 and July 7,1989, as denoted in Section The inspector summarized the scope and findings of the inspection at that

. time. No written material was given to the licensee during this inspectio l

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ATTACHMENT 1 References l '. Licensee letter from H. D. Hukill to Thomas E. Murley, NRC, dated May 27, 198 ~ Licensee letter'from H. D. Hukill to Thomas E. Murley, NRC, dated L September:15,'198 . ' Licensee. letter from H. D. Hukill to Thomas E. Murley, NRC, dated February 27, 1987.

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. Licensee letter from'H. D. Hukill to NRC dated June 25, 198 . NRC letter from W. F. Kane, H. D. Hukill, Gpun, dated September 9,1987.

, Licensee letter from H. D. Hukill to NRC dated October 14, 1997.

Maintenance Procedures

1420-LTQ-1, " Trouble shooting Limitorque Valve Operators and Control Circuits, Removal and Replacement of'Limitorque Valve Operators"

1420-LTQ-7, " Procedure for Testing.Vhrious Motor Operated Valvis Using

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the MOVATS-2100/2150 system"

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- 1420-LTQ-7," Procedure for Testing Various Motor Operated Valves Using the MOVATS-2100/2150 system"

• E-13, "Limitorque Valves" l

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TABLE 1 i

MOVs within Scope of IEB 85-03 Valve Tag N Function MU-V-14 A, B MU Pump Suction from BWST MU-V-16 A, B, C, O High Pressure Injection MU-V-36, 37 MU Pump Recir MS-V-2 A, 8 Steam Dump Header Supply MS-V-10 A, B EFW Pump Steam Supply

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