05000461/LER-1998-001, :on 970929,failure of Division 2 SR Battery Charger Was Noted.Caused by Deficient Supplier Soldered Connections.Insp of Division 1,2 & 4 SR Battery Chargers Are Complete & Have Been Reworked & Repaired
| ML20203B169 | |
| Person / Time | |
|---|---|
| Site: | Clinton  |
| Issue date: | 02/17/1998 |
| From: | Wagner M ILLINOIS POWER CO. |
| To: | |
| Shared Package | |
| ML20203A984 | List: |
| References | |
| REF-PT21-98 LER-98-001, LER-98-1, NUDOCS 9802240219 | |
| Download: ML20203B169 (10) | |
| Event date: | |
|---|---|
| Report date: | |
| Reporting criterion: | 10 CFR 50.73(e)(2)(x) 10 CFR 50.73(a)(2)(ii)(3) 10 CFR 21.21(d)(3) |
| 4611998001R00 - NRC Website | |
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With the plant in Cc:.D sNUTDot.18 and no operable Alternating current (AC) powr sources, a safety-related battery charger failed to operate as expected. Operators received an alarm in the Main Control Re,oa indicat.ng low voltage on the Division 2 Direct Current (DC) bue. 2ndicatione also included aero ampe output from the battery charger, and DC bus voltage stabilised at about 124 volte DC which is the expected voltage for a lose of the battery charger. The battery charger appearad to be stopps.ng and starting itself ' electronically"; the DC voltage and output current decreased to zero and then returned to normal. Isveral types of deficiencies were Ldentified during tr*. Dieshooting. However, the cause of this event is attacibuted to
- Peficient supplier worlunenship it. soldered wire connections at transforiner ilA and fuse F-7 in the battery charger during manuf acture. These'immues were also applicable to the other safety-related Mttery chargers. The safety-related bm.tery chargers hare been rowerited/ repaired. This event is also reportable under 10CE21.
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DESCRIPTION OF EVENT
On september 29, 1997, the plant was in Mode 4 (CCLD SNUTD MrN) for the ef.xth refueling autege (RF-4), and reactor (RCT) coolant temperature was being maintained within a band of 100 to 120 degrees Fahrenheit (F) and pressure was toro poundo per equare inch.
The three divisions of safety-related Alternating Current (AC) electrical power were inoperable due te degraded voltage and circuit breaker issuse.
At about 1010 hours0.0117 days <br />0.281 hours <br />0.00167 weeks <br />3.84305e-4 months <br />, the Division 2 eafety-related battery chargwr (1DC07E) (BYC] f ailed to cperate as expected. Operatore received an alaru in the Main Control Room (NCR) indicating lev voltage en the Division 2 Direct Current (DC) bus (au)(3J).
Indications also included soro aspe output from the Division 2 battery charger, and DC bue voltage etabilteed at about 120 Volte Direct current (VCC) which is th's expected voltage for a lose of the bettsry charger.
Nortnal DC bus voltage is approximately 130 to 133 volte. An electriciaa dispatched to the Division 2 battery charger to investigate the problem noted that the battery charger appeared to be stopping and starting itself 'electrenically's the battery charger DC output voltage decreased and the battery charger DC output current decreased to spro and then returned to normal. Maintenance Work Request (MWR) D78223 was initiated to investigate the failur3 of the Division 2 battery charger.
In reryonse to the Division 2 battery charger f ailure, the operatione Shift Supervisor (ss) implemented ths Required Actions of Technical specification 3.8.5, "DC Sources - Shutdown,'
by placing a restraint against performing core alteratione and movement of irradiated feel casamblies in the primary and secondary containment and operations with a potential for dre,ining the reactor, and ordering that actions be taken to restore required DC electrical power subsystems to operable status.
On cetober 4, 1997, during continued troubleshooting in accordance with MWR D78223, inadequate wLre connections were identified throughout the Division 2 battery charger.
Exa:eples of inadequate wire connections included improper / lease soldered connections in the Silicon Centrolled Rectifier (ACR) (SCR] firing circuit cards and on fuse F-7 (FU) in the sCA firing circuit.
In addition, a broken wire was identified at transformer T1A (Xnot) and is suspected to have been hanging by a few wire strands at the soldered connection Prior to the battery charger failure. Condition Report sCR) 1-97-10-C90 was initiated to trcck an evaluation and resolution of theen wire connection issues.
Improperly soldered scnnections on the firing circuit -ards and in various other locations were also found in the Division 1 eafety-related battery cha ger, une sonu seaa m.oes
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Cn October 7, 1997, during continued troubleshooting of the Division 2 battery charger in accordance with MWR D78223, four additional defiLencies were noted.
SCRs had an excessive k unt of Wakefield Type 120 heat transfer compound arolled te meanting eurfaces.
This etndition r:an cause potenti.:1. b.st spots and long term degradation of the ECRs, thus long t:rin degradation of the battery charger. SCR gate and cathode leads were not twisted; twl: ting the leads provides sone immunity to notes. The force causa used to deterinine the amount of fore:e being applied to the SCRs was marginal. The SCRe require 2200 pounds of fcree, plus or minus 10 percent; however, the force gauge provides readings 1.n 500 paune.
insremente, with a maximum reading of 2000 pounds. Therefore, Maintenance technicians were installing replacement SCRs based on the minitum acceptable force rather than the eniddle of an ecceptable force range.
Improper force on SCRs may cause premature degradation of the SCR3, thereby creating the potential for the charger to not operate as designed.
Seldered pine for SCA gate and cathode leads on firing circuit carda were loose.
CR 1-97-10-123 was initiated to track an evaluation and resolution o* these issuaa.
These four issues were niso found in the Divisione 1 and 4 (1DC081) saf
- - related battery chargers.
On October 11, 1997, during continued troubleshooting of the Division 2 battery charger in accordance with MWR D78223 Illinois ?ower (IP) identified that replacement circuit carde obtained from stores were t.ot the same as the installed circuit cards; the affected circuit ca.rds included amplifier, firing, sense, aid High Voltage Alarm (Shutdown)(D8RV) circuit scrds. The spare safety-relcted battery charger (1DC113) and a non-safety battery charger us d for training purposes were found to have loose soldered terminations on the SCR firing circuit cards. elmilaz to the deficiencies found in the Division i battery charger. CR l-91-10-201 was initiated to track an evaluatica and resolution of these issues. Engineering Change Noticea (EC3s) 30302, 30609, and 30431 were issued to allow the use of the non-ltire-fer-like carde. No bettery charger failed or could fail as a result of the these diecimilar circuit cards.
On October 13, 1997, during continued troubleshooting of the Division 2 battery charger in tecordance with MWR D78223, IP identif twd that the mounting screws supplied with r: placement DC filtering capacitors (CAP)' for electrical terminations were not the correct 1Cngth for certain Clinton Power 8tation (CPS) applications and would not provide sufficient threac engagement to meet seismic qualification requiremente.
Screws with insufficient leagth also were found installed. This issue was also identified in the Divisiona 1 and 4 safety-related battery chargers. CR l-97-10-208 was initiated to track an evaluation and resolution of this issue. The affected battery chargers are considered to have been inoperabic because they f ailed to meet seismic qualification requireeents.
On octobair 15, 1997, during continued troubles'iocting of the Division 2 battery charger in tenordance with MWR D78223, IP noted 2 anomalies with the DSHV circuit card.
The installed DSHV circuit card had an approximately 16-second time delay, however, the time delay for tha replacement DSHV circuit card from atores was approximately 6 seconde.
The purchase cpecification required a 30-second tinie delay. The reset voltage notpoint of the DSH7 circuit card was too low to allow the DSHV circuit card to reset during a momentary woltage trc uient while the battery charger was in the equalize mode. These iscues were also identified in the Divietone 1 and 4 eafety-related battery chargere.
CR 1-97-10-241 was initiated to track an evaluation and resolution of the DsHV circuit card issues.
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0F 10 sun in mm esce is meuuse, var scenioner cooles of NRC fenn 366N 01l On December 4, 1997, at about 2018 hours0.0234 days <br />0.561 hours <br />0.00334 weeks <br />7.67849e-4 months <br />, the Main Control Room received a Division 1 DC bus voltage alare.
The computer point for the Division 1 DC bus voltage indica 'd that bus voltage had drifted down 1.6 VDC to about 128.4 VDC.
In response to the voltage drift, the PLvielen 1 bettery charger float voltage was adjusted to approximately 130 VDc and the clarm was cleared. The Division 1 battery charger (1Dc04E) had been recently repaired under hWR D75956 and battery charger float voltage regulation was measured as 0.21 percent frrm no-load to full-load output current. The maximum expected voltage change was 0.28 VDc throughout thle range.
NWR Dal'189 use initiated to elatermine the cause of the drifting 11 oat voltage.
CR 1-97-12-100 was initiated to track an evaluation and resolution of the float voltage drift problem.
On January 16, 1998, an evaluation of these issues concluded that the inadequate soldered cannection issues in the T1A transforeer and the F-7 fuse resulted in a f ailure of ibe Division 2 battery charger while it was performing its safety function and caused the Division 2 safety-related battery charger to be inoperable. The other deficient solderra connections and the inadequate ' capacitor screw isngths had the pota.ntial to cause the loss of the Divisions 1, 2, and 4 safety-related battery chargers during a satanic event. The D8W circuit card time delay and reset voltage setpoint devt ation could have led operators to an inc.orrect conclusion that a loss of a safety-related battery charger during a armentar/ voltage excursion was initiated by a f ault in the charger, thereby delaying r:storation of the charger anti extending the Juration of the event. The combination of the inapp-spriate time c elay and reset voltage setpoints had the potential to cause a loss of i
the safety function of the battery chargers. Therefore, Ip determined that these issues should be reported undsr the provisions of 10CTRSO.13.
Na automatic or c-nually initiated safety system responses were necessary to place the plant in a safe and stable condition. This event was not affected by other inoperable equipment or components.
CAUSE OF EVENT
Th3 cause of the Division 2 battery charger f ailure is attributed to deficient supplier workmanship in soldered wire connections at transformer 21A and fuse F-7 during manuf acture of the Division 2 eafety-related battery charger. The following discussion provides the causes for the various squipment deficiencies noted during this event.
Th3 bre ken wire at transformer T1A was inspected and a few ends of the wire strands appeared bright in appearanco. The majority of strand ends were tarnished, indicating that Gnly a few Strands were providing continuity, and there Right have been high resistance at th3 termination prior to the Division 2 battery charger failure on september 29, 1997. The brsken wire at transformer f1A appears to have been the result of a deficiency caused by tha battery charger supplier prior to initial installation at CPS.
The wire at fuse F-7 had been tinnell into a J-hook; however, it was not soldered to it., connection.
The sonnection at fuse F-1 aviveled, providing intermittent continuity.
The cause of this inedequate connection is attributed to deficient workmanship in soldering by the battery chtrger supplier prior to initial installation at CPS.
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Evaluation of tho wiru strand ende suggeste that the wire connection from transformer T1A, which provides a sigur.1 to the scR firing circuit cards, broke nn september 29, 1997, and comb'aed with an intermittent open circuit at fuse F-7 to cause this event. Testing at CPS using the training battery chargpr supports this theory: the testing was able to re-create th3 conditions which caused an output response identical to the condition observed during tho f ailure of the Division 2 battery charger on september 29, 1997. With both faults instrted, the charger appeated to shut down as the battery (8TRY) maintained DC bus voltage at cyproximately 124 VDC and supplied the Dc loads. Once the intermittent iault on fuse F-1 was made up, the charger reaped up to the preset level of approximately 132 VDC.
To an rbocrver the charger would appear to be restarting itself and charging the battery Chile supplying the bue loads. The testing was observed by an independent third party, static Prwer conversion systems, who confirmed the theory.
Inv:stigation revealed that Maintenance perschnel incorrectly applied excessive heat transfer compound to the Divisione 1, 2, and 4, and spare safety-related battery chargers and failed to twist ScR gate and cathode leads during previous maintenance activitisc. The ceuce of these issues is attributed to the lack of guinanca for applying heat transfer sompound and twisting leads.
The force gauge used to determine the required' amount of force applied to SCRe reads a eaminum of 2000 pounde in 500 pound incremens. The sCRs are a sandwich-type design ecunted between twc heat minks and require 2200 pounds plus o'r minus 10 percent (1980 to 2420 pounds) of force. Per discussion with the battery charger supplier, the SCR aes:mblies are tightened to 200C p.. unde on the bench prior to installation into the battery sherger, allowing technicians to look directly at the force gauge indicator, thereby rzducing pasrallax error. The actual force value applied to the SCRs is subject to the insta11er's interpolation of the terce gauge indicator device. During field installation, th2 SCR can be acunted to the heat sink, which is already assembled into the charger, thus increasing the potential for parallax error due to the line-of-sight required to verify the indication. An alternate method for sesembling of the scas has bean identified that does nst use the force gauge, but instead uses a bolt rotation mothed. Whilsi there is some inaccuracy in the bolt rotation method, it is judged co he me:e accurata than the force gauge method, making it a.more desirable method.
Irivestigation into improper / loose soldered wire connections identified that loose terminal pott connections are attributed to the application of heat to the poste while soldering the internal field wires to the firing board. The battery charger suppliar acknowlengte that tha terminal poste are susceptible to loosening when soldering the internal fleid connectione. The battery charger supplier re-applies solder to the reverse and of the terminal poet, ao required, to replace any solder lost into the hollow terminal at the terminal base when connecting the wiring. The guidance on seidering this tyn of esunection was not previously available to Maintenance personnel performing the acidering, j
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OF 10 isai Uf enore ween is requhwC use odefitionalcafes of NMC form J66M (11l An inspection of the spare safety-related battery charger (1DC11E) idsntified loose coldered tereinations on thS SCR firing circuit card. The investigation of the cause of ths loose terminations identified that Clinton Power Station (CPS) maintenance personnel coldered there deficient connectior.s while installing the SCR firing circuit card during a previous maintenance activity. This deficiency probably would have caused a less of function of the spare safety-related battery charger during a seismic event, if the spare charger had been installed without correcting the deficiea.cy.
Electrical termination mounting screws supplied with replacement DC filteriag capacitors w;re not the correct length and thus provided insufficient thread engagement. Replacement c.apacitor kits come with screws for applications that have criaped lug tereinations. CPS tPPlicatione are a bus bar configuration which uses flat and star washore ar.d requires a lenger screw for proper thread engagement. During previous maintenance ac':1vities CPS ole :trical maintenance personnel did not recognise that the replacer.ent screws were die s.amilar. The vendor manual did.not identify the length of acrews needvid for the CPS application where the termination was made to a bus bar.
Investigation of the time delaye in the installed D5W circuit cards identified that they w;re approximately 16 seconde. The original CPS purchase specification required 30 second tise delays. The new replacement DSHV circuit cards had time delays of approxiettely 6 a::conds. The battery charger supplier pravided time delays that were not in accordance with the purchase specification.
The inarpropriate reset voltage setpoint for the DsHV circuit-card wau prescelbed by sargent & Z, undy for the eafety-related battery chargers, and was in effect since original installation.
Th3 cause of the Di. vision 1 battery charger voltage drift is attribated to a recently installed SCR firing circuit' card. The SCR firing circuit card har been replaced and the deficient card has been returned to the vendor for "f ailure analysis."
CORRECTIVE ACTTON Inspections of the Diviaions 1, 2, and 4 safety-related battery chargers are complete and these chargers have been reworked / repaired in accordance with Mwks D75956, D78223, and D75957, respectively. The spare safety-related battery charger has been inspected for deficiencies, and NWR D75960 has been initiated to track repair of identified deficiencier.
ND inadequate solder connections were identified in the Division 4 battery charger.
Th3 inadequate soldered wire corinactions on the scR firing cards, the broken wire at trcasformer T1A, and the inadequately soldered wire connection at fuse F-7 in the Division 2 battery charger were reworked under MWR D18223.
lThe battery charger supplier has provided guidance for correctly applying heat transfer and cathode leads. This information has been incorporated compound and twisting SCR gatr e into vendor manual K2989-0001, emc poses assa e.ssi
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CF 10 ixxi ter mee emece is,nutred. use etenenet tw or mc rerm asam n n An alternate method for installing 8CRs using the bnit rotation method has been added to vendor manual K2989-0001.
The SCR firing circuit card tenainal poste for the Division 2 bettery charger were re-coldered to ensure the as-left connections were adequate. The soldering technique for ficid wiring to SCR firing circuit card terminal poets will be added to vendor reanual K4989-0001.
Instructions have been added to vendor manual K2989-0001 identifying the correct eine acrews for the electrical termination rounting of cc filtering capacitors to bus bar cennections.
Engineering Change Notice (ICN) 30431 was Lemued to change the time delay in the Desv circuit card to 10-15 seconds and raise the reset voltage setpoint from 132 volta to 135 valts. Replacement cards meeting the time delay and reset voltage setpoint requirements h ;e been inctalled in the Divisione 1, 2, and 4 safety-related battery chargers, CPS is S 21uatirag con.rol and iseuance of the circuit cards.
Tho battery charger deficiencies identified during this event were determined to potDatially affect other safsty-related equipment supplied by the same manufacturer, including the Divisione 1, 2, and 4 Nuclear Systems Protection system regulating bypass traneformers (1RP01E, 1RP02E, 1RPO42), the Divisione 1, 2, and 3 regulating transformers (0ZF54Ea, CIP55BB, IIP 78E), and the A and B Reacter Protection System (RPS) bypass regulating transformer (1c713008A, ic7150053). In addition, two non-safety switchyard battery chargare and two non-safety balance of plant battery chargers were identified as potentially affected by these issues. 27 will also inspect and rework / repair, as nscessary, this equipment. The Division 3 safety-related battery charger (n22-7 312) was cupplied by a different supplier and has not exhibited sun 11ar evidence of degr.Jaticar however, 7P will perform an inspection of this charger fer deficiencies similar to those found in the Division 2 battery charger.
ANALYS!$ OF EVENT This event is reportable under the provisions of 10CFR50.73(a)(2)(ii)(3) due to the plant boing in a condition that was not in accordance with the design basis.
an assessment of the safety consequences and implications of this event concludes.that this evsnt had pecential safety significance. The inadequate soldered connection issues resulted in a f ailure of the Division 2 battery charger while it was pericming its safety '
function.
Th3 improper heat transfer compound application and/or lack of sCR lead twist?.ng has not caused a direct charger failure, we past or present conditions of improper heat transfer compound application or SCR gate and cathode lead twisting have presented a challenge to th2 chargare in performing their safety function. However, there was a potential for the itse of charger function in thc future due to long-tsem heat degradation of ScRe and power dic$es or' unwanted noise introduction if these con 11tions had continued uncorrected.
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OF 10 TEKT Mmore sper h nquw, use admonalcopies of MC km SW) nW An inspection of the apara safety-related battery charger (1DC11E) identified loose cald: rad terminations on the firing circuit card. This deficiency probably would have ccus:6 a loss of function of the spare safety-related battery charger during a seismic cvent, if installed uncorrected. The spara safety-related battery charger had been pr:vitusly installsd as the Division 2 safety-related battery charger until 1995.
The inadequate thread engagement of mounting screws for the electrical terrinations of the DC filtering capacitore had the potential to cause the lons of the Divisions 1, 2, and 4 cafety-related battery chargers during a seismic event.
Tho reset voltage setpoint providad by Sargent & Lundy (132 VDc) for the DSHV circuit card was lower than the nominal 135 VDC equalising potential operation of the battery chargers.
Iho loss of a safety-related hattery charger would occur during a tremantary voltage excursion above 138 VDC, even if the excursion were tosperary, because the reset setpoint would never be reached while the charger is operating at equaliaing potential. This condition could lead operators to an incorrect conclusion that the event was initiated by a fcult in the charger, thereby delaying restoration of the charger and extending the duration of the event. The combination of inappropriate time delay and reet.t voltsgo c0tpsints had the potential to cause a loss of the safety functier rf the battery chargers if it had continued uncorrected.
Tho Division 1 battery charger was not considered to te operable at the time the 3CR firing circuit card caused the bus voltage drift on December 4,1997.
However, the Division 1 battery charger could have be2n declared operable (with the deficient circuit card installed) prior to the veltage transient, and if so, the deficient SCR firing circuit car 3 wruld have caused a lose of the Division 1 battery chargc.
During normal operation, the Dc leads are powered from the battery chargers (primary sturce) with the batteries (secondary source) in a afloat-charge" configuration on the system. A loss of either power source does not interrupt power flow to the Dc bus. The bittsry chargere have sufficient capacity to operate all non-accident shutdown loads es:uming the battery is not available.
In the case of a lose of normal power to the b:tt:ry charger, the DC loads are automati; ally powered frem the Engineered safety Feature (ESP) batteries. The batteries are sized to supply shutdown loads for a minimum of four h1urs without the chnggere operating. Any abnormal voltage and current conditione of the b:ttari charger are alarmed in the McR.
Tho most limiting transient for the DC system is the station Blackout event which assumes thct all Ac pcwor is lost, including the battery chargers. When the battery chargers f ail t3 sperate during a Utatian Blackout event, the ESF batteries provide power until the em:rgency diesel genwratora become available.
ADDITIONAL INTOPXATION Duritg thie event, the Division 2 battery charger f ailed to perform its function. The Divicions 1, 2, and 4, and spara safety-related battery chargare are Modal 3SC-130-300 cupplied by Power converelen products, Inc.
The DSHV reset voltage setpoint was provided by sargent & Lundy.
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0F to TEK1 Itt onore space is esquked, une eeditionel espiot 09 NRC form 365e) (11l IP previously reported 1.ER 97-015 which discussed the inappropriate use of solder flux and petr worlenanship during rework of MCR noon indicator light sockets.
For further information regarding this everit, contact M. D. Wagner Plant Engineering, at (217) 935-8881, extension 4071.
10CTR, PART 21 REPORT 21-94-044/047 en January 16, 1994, an evaluation of these issues concluded that the inadequate soldered wire connection issues caused the Division 2 battery charger to fail while it was performing its safety function, on January 28, 1998, IP completed the evaluation of the hattery charger deviatione and concluded that thead issues should be reported under the Provisions of 10C'R21 (referenca IP letter U-602920). The basis fo: the reportable ccnclusion is that some of the ocider issues, and the DSHV time delay and reast voltage ettpoint circuit card issues, were suppiter deviations that left uncorrected could have caused a loss of the safety function of the Division 2 battery charger.
IP is providing the following information in accordance with 10CFR21.31(d)(4). Initial attification of this matter will be provided by facsimile of this letter to the 1"RC Optratione Center la accordance with 10crR21.21(d)(3) within two days of the date the expensible officer signs this letter.
(1)
Walter C. HacFarland, Chief Nuclear of ficer of IP, Clinton Power station, Highway 54, 6 Miles East, Clinton, Illinole, 61727, is informing the Wuclear Regulatory Commission of a condition reportable under the provisions of 10CFR, Part 21.
(ii) The basic component involved in this condition Le the Division 2 safety-related battery charger, manufacturer Model 3sc-230-300, and the DSHV circuit card, model D SW120T2-03.
(iii) The Division 2 eafety-related battery charger and the DsRV circuit card were supplied to Clinton Power Station by Powe" Conversion Products. The DSHV circuit card reset voltags setpoint was provided by sargent & Lundy.
(iv) During troubleshooting of the september 29, 1997, Division 2 battery charger failure, IP identified inadaquate soldered connections thrcughout the Divielen 2 battery charger. Examples of inadequate wire connections included improper / loose soldsred connections in the Silicca controlled Rectifier (SCR) firing circuit cards and on fuse F-7 in the SCR firing circuit, and a broken wire at transformar T1A hanging by a few strands at the soldered connection.
In addition, IP noted 2 anomalies with the DSHV circuiu card.
The time celay for the installed DSHV circuit card wac approximately 16 seconde. the time delay for the replacernant DsEV circuit card was approximately 6 seconda, and the purche se specificatit.n required a 30-second time delay. The remet voltage setpoint of tac DSHV circuin card was too low to allow the DSHV circuit card to roset during a momentary voltage transient while the battery charger was in the equalize mode.
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The identified tolder connection deficiencies caused the Division 2 battery charger to f ail to perform its safety function en September 29, 1997.
During a momentary voltage excursion abova 138 VOC, a loss of the L vision 2 safety-related battery charger would occur, even if the excursion were te=perary, because the reset setpoint would never be reached while charger is operating at equalizing potential. This condition could lead operators to an incorrect conclusion that the event was initiated by a fmult in the charger, thereby delaying restoration of the charger and extending the duration of the event. The combination of the inappropriate time delay and reset voltage sotpointe had the potential to causa a loss of the safety function of the batter) chargers if it had continued uncorrected.
(v)
The inadequate solder connections were identified on october 4, 1991, and detez=ined to be potent 2 ally reportable under e.he provisions of 10CTR21. The DSHV ci cuit card deficiencies were identified on Cs. ser 15, 1997, and determined potentially reportable ut. der the provisions of 10CFR21. IP notified the NRC in a letter U-602876 cated Decceter 3,1997, that the investigation of these issues was not craaplete, and additional time was needed for complation. IP notified the NRC in a lotter U-602920 dated January 28, 1998, that this condition was reportable under the provisions of 10CFR21 anc 10CFRSO.73.
(vi) CP3 has four safety-relatsd battery chargers having the affected model number, the Divisions 1, 2, and 4, battery charger, and the safety-related spare battery charger.
IP is not awars of othar f acilities that could be affected by this deficiency.
(vii) The corrective action that IP is taking for these issues is identified in the CCRRECTIVE ACTION portion of this re,wrt.
(viii)IP has no advice for other purchasets or licensees regarding this issue.
I ac co.hes.
I