ML20044G407
| ML20044G407 | |
| Person / Time | |
|---|---|
| Site: | Comanche Peak  |
| Issue date: | 05/26/1993 |
| From: | William Cahill, Reimer D TEXAS UTILITIES ELECTRIC CO. (TU ELECTRIC) |
| To: | NRC OFFICE OF INFORMATION RESOURCES MANAGEMENT (IRM) |
| References | |
| LER-93-006, LER-93-6, TXX-93217, NUDOCS 9306030040 | |
| Download: ML20044G407 (8) | |
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L J Log # TXX-93217 C C File # 10020 Ref. # 50.73(a)(2)(1)(b) : TUELECTRIC May 26, 1993 Williaan J. Cahill, Jr. -! Group Vice President i U. S. Nuclear Regulatory Commission i Atte.: Document Control Desk Washington, DC 20555 ,
SUBJECT:
COMANCHE PEAK STEAM ELECTRIC STATION (CPSES) DOCKET NO. 50-445 FAILURE TO SATISFY TECHNICAL SPECIFICATION SURVEILLANCE ; REQUIREMENT FOR PRIMARY PLANT ESF EXHAUST FILTRATION UNIT LICENSEE EVENT REPORT 93-006-00 Gentlemen: Enclosed is Licensee Event Report 93-006-00 for Comanche Peak Steam Electric Station' unit 1 " Failure to Satisfy Technical Specification Surveillance Requirement for Pirmary Plant ESF Filtration Unit". Sincerely, E- /1, William J. ahill, Jr. OB:tg , Enclosure , cc: Mr. J. L. Milhoan, Region IV Mr. L. A. Yandell, Region IV Resident Inspectors, CPSES (2) 9306030040 930526 020095 f[ I i PCR ADDCK 05000445 P. O. Box 1002 Glen Rose Texas 76043-1002 S pop e
l i I Enclosure to TXX-93217 N4G FO4M 3% U S. NUCLE AH Ht.GuLATORY COVM$SION APPFOVED OMB NO. 3150-0104
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Aoom m io 14w . w s,.snaco - n .nre) oc> In February 1993, Mechanical Maintenance personnel replaced the upstream High Efficiency Particulate Adsorber (HEPA) filter cartridges in Primary Plant ESF Exhaust Filtration Unit CPX-VAFUPK-16 with Prefilter cartridges. The root causes of the event were determined to be less-than-adequate equipment labeling, specification of the wror:g procedure for the task, and a discrepancy in the Master Equipment List (MEL) Parts List. Corrective actions to be taken are; a) the nomenclature on the labels for the HEPA filters on all atmospheric cleanup filtration units will be changed to eliminate confusion; b) maintenance planners will review this incident for lessons learned to ensure that Preventive Maintenance (PM) activities run for the first time are more closely reviewed; and, c) changes have been made to the appropriate procedures to require review by Procurement Engineering of Design Change Not!ces (DCNs) which modify any part/ component as originally supplied by a vendor and to revise the MEL Parts List accordingly.
Enclosure to TXX-33217 ! m FOHM 3m A , U.S. NUCLE An REGULATORY COMM 55ON FN OMB NO. 3150W ESTIM ATED BURDEN PER RES S COMPLY WITH THIS INFORM ATICA E S " ^" " " LICENSEE EVENT REPORT (LER) 7lE$', ",,"M, T lR l *ANO 0R MA AG TEXT CONTINUATION ""^""'""'#*'""'**"***" ""'** * ***" * " DC 20%$ AND TO THE PAPERWORK REDUCTION PROJECT (31540104). OFFICE OF M ANAGEME NT AND BUDGET. WASHINGTON. DC. 20503. j F actuy Narts (1) Ducket Nurrt;er (2) LLH Number (6) Pa;pe Q) w ; m COMANCHE PEAK-UNIT 1 015 Ol0l014l4l5 9 3 - 0 0 6 - 0 0 02 or 04 1.n -. - . - - .,_ u~ ~am, n
- 1. DESCRIPTION OF THE REPORTABLE EVENT '
A. REPORTABLE EVENT CLASSIFICATION . Any operation or condition prohibited by the Technical Specifications. B. PLANT OPERATING CONDITIONS PRIOR TO THE EVENT On February 8,1993, Comanche Peak Steam Electric Station (CPSES) Unit 1 was in Mode 1, Power Operations, at 100 percent rated thermal power. CPSES Unit 2 was in Mode 6, refueling operations, with the core unloaded. C. STATUS OF STRUCTURES, SYSTEMS, OR COMPONENTS THAT WERE - INOPERABLE AT THE START OF THE EVENT AND THAT CONTRIBUTED TO THE EVENT There were no inoperable structures, systems or components that contributed to the event. D. NARRATIVE
SUMMARY
OF THE EVENT, INCLUDING DATES AND ' APPROXIMATE TIMES On Februar walkdowns,y 8,1993, noted that thean auxiliary differential operator pressure gauge(utility labelednon-licensed), as X-PI-6177Awhile was readingperforming h 1.6 inches of water column-gauge (inwg). This reading exceeded the limits specified in the procedure. The operator indiated a work request to have the "prefilter" on CPX-VAFUPK-16 (Ells (FLT)(VA)) changed out. ;
Enc-losure to TXX-93217 f44C f OHM :sebA , d5. NJCLEAR ikMATOHV GOMM450N APPROVED OMB M 3W104 ESTIMATED BURDEN PER RES S MPLY WITH THIS INFORM ATOA LICENSEE EVENT REPORT (LER) $$$*",",',T*1s /cn"%o[*L Q 1,'8 1"a^",c" , TEXT CONTINUATION ""'" " " " " " ^*"'"**' "* " * ' * * * " " " * " " ' "- DC. 20556. AND TO THE PAPERWORK REDUCTON PROXCT (3150-0104). OFFCE OF MANAGEMENT AND DVDOET. WASHINGTON, DC. 20503. f autsy Narne p) Da*e:Nurrber (2) LLH Nurmur M Papa Q) v- w:: , a COMANCHE PEAK-UNIT 1 1.e. n . - ~ N~ w.w n 0l5l0l0 0l4l4l5 9 3 - 0 0 6 - 0 0 013 os 04 : t On February 10,1993, utilizing the Preventive Maintenance (PM) program, a work order was generated by the mechanical maintenance planner (utility non-licensed). The PM ' activity specified a specific maintenance procedure to be used in performing the work order. A step of this procedure required that a Technical Specification surveillance test be perforrned on the filters after the work was complete. Since the work request (which was i translated into il .e work order) was for change out of a "prefilter", the maintenance engineering technician (utility non-licensed) informed the planner that a surveillance tcst was not required. The panner eliminated the surveillance test step from the work order. On February 12,1993, the mechanics removed the upstream HEPA filter cartridges and replaced them with prefilter cartridges. The mechanics noticed the difference between the filter cartridges that were removed and the prefilter cartridges which were to be installed. A reverification of MEL was performed and it was concluded by the mechnics that the cartridge to be replaced was approved for use in CPX-VAFUPK-16. Hence, no post work testing was required. E. THE METHOD OF DISCOVERY OF EACH COMPONENT OR SYSTEM r FAILURE, OR PROCEDURAL OR PERSONNEL ERROR On April 26,1993, while conducting a routine surveillance test, maintenance engineering aersonnel discovered the prefilter cartridges installed where the HEPA cartridges should lave been installed. !
- 11. COMPONENT OR SYSTEM FAILURES A. FAILURE MODE, MECHANISM, AND EFFECT OF EACH FAILED COMPONENT Not applicable - there were no component failures associated with this event.
B. DURATION OF SAFETY SYSTEM TRAIN INOPERABILITY , Not applicable - there was no safety related equipment rendered inoperable during or as a result of the event. l l l l l l
Enclosure to TXX-93217 NHC & OHM 'sfLA . ub. NAEAR REGJLATOHY C.OMM.55 ON APPROVED OMB NO. 311io-0104 ESTIM ATED BURDEN PER RES T COMPLY WITH THIS INFORMATOk LICENSEE EVENT REPORT (LER) BURDEN ESTIMATE TO THE RECORDS AND REPORTS MANAGEMEN'
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COMANCHE PEAK-UNIT 1 05 0l0l0 4 4 5 9 3 - 0 0 6 - 0 0 04 or 04 1.-._., . .,_~HCso,-A.m q l C. SAFETY CONSEQUENCES AND IMPLICATIONS OF THE EVENT q Credit for 95 percent iodine filtration by the Primary Plant Ventilation System (PPVS) l Engineered Safety Featured (ESF) filters is applied for ESF system leakage during a Loss of Coolant Accident (LOCA). It is assumed that 50 percent of the core lodine inventory will be released from the containment sump and circulated outside containment via the ESF systems. The ESF systems are assumed to leak, releasing radioactive material (via steam) into the building where it is eventually filtered and exhausted to the atmosphere via the PPVS. The PPVS charcoal beds are provided to remove primarily elemental iodine and organic iodines, while the HEPA filter should remove particulate iodines. The LOCA scenario postulated in accordance with Reg. Guide 1.4 assumes an iodine distribution of 91 percent l elementaliodine,5 percent particulate, and 4 percent organic iodines released from the fuel and containment. Therefore, only a small percentage of iodine assumed to be released may be in particulate form which would be filtered by the HEPA filters. Using a pre-filter instead of a HEPA filter in unit CPX-VAFUPK-16 is not as efficient as a HEPA (85 percent efficiency versus 99 percent), but it does perform a filtering action by removing particulate matter, however, particulates not removed by the are-filter may pass through the charcoal bed and load the downstream HEPA filters. Having the upstream HEPA filters installed instead of the pre-filters assures optimum particulate removal. The effect of having the are-filters installed instead of the HEPA filters is that the filtration unit's charcoal beds anc downstream HEPA filters may be loaded slightly faster than having a set of upstream HEPA filters. Any particulates that pass through the charcoal beds would be trapped by the downstream HEPA filter bank. It should be noted that the downstream HEPA was tested and it met the acceptance criteria. HEPA filters are tested to take credit for 99 percent efficiency. This may have limited the duration the filtration unit, which would have been available. If this were to occur, the operator would switch operating filtration units. These factors provided reasonable assurance that installation of pre-filters in lieu of the upstream HEPAs would not have adversely affected the unit's capacity to maintain 95 percent efficiency:therefore the unit can be considered operable. Based on this evaluation it was concluded that the event did not adversely impact the safe operation of Unit 1 or the health and safety of the public. l,
Enclosure to TXX-93217 NRG FOHM 36bA , b 5. NJGLEAR REGJLATOM GOMwS50N APPROVED OMB NO 31540104
. EXPIRES:4/3092 ESTPMATED BURDEN PER RESPONSE TO COMPLY WITH TH:S INFORMATOh LICENSEE EVENT REPORT (LER) % % ",1 ,', ,,'; / ," ," yo',o",* M o",'17",RE E TEXT CONTINUATION "'*"*"'^""'"""""******"**'"'
DC. 20555. AND TO THE PAPERWORK REDUCTON PROJECT rJ1540104). OFFCE OF M ANAGEMENT AND BUDGET, WASHINGTON. DC. 20503. Ianley Narre (1) DDL*at fumer (2) LkR Nunther (6) Page (3) Year g gy y COMANCHE PEAK-UNIT 1 1._. - . ~. --i n 015l0l0 0 4l4l5 9 3 - 0 06 - 00 05 or 07 111. CAUSE OF THE EVENT Several factors contributed to this event. A discussion of each follows: Equipment Labeling Change Process was Less-Than-Adequate. The filter banks in the filtration units are not individually labeled or tagged. Operations and Maintenance personnel used the labels on the differential pressure gauges to identify the filter type. The nomenclature for the Differential Pressure (DP) gauges for prefilter filter banks and for upstream HEPA filter banks are identicalin all atmospheric cleanup filtration units. All of the DP gauges are named as " PRIMARY PLANT VENT EXHAUST FILTER X-{ filter no.} and AFTFILT DIFF PRESS IND { channel no.}", however, neither wordings were clear. When the filtration unit was modified in 1989 by Design Change Request - DMRC 88-X-248, the prefilter was removed and replaced with a demister bank and heater bank. The differential pressure gauge for the prefilter was abandoned in place. When labels were installed on the gauges, the label for the upstream HEPA filter bank DP gauge was placed next to the abandoned gauge which was now reading DP across the demister bank. Incorrect Procedure Specified in the Procedure Used The PM activity which was specified as the controlling procedure for this task was written prior to it's first conduct in February 1993. The request in February 1993 to change the filter cartndges was the first such request for filtration unit X-16. The work order should have referenced a different procedure which applied to ESF filtration units X-01, X-02, X-15, and X-16, and does not have a section covering the installation / removal of arefilter cartridges. If the planner had referenced the correct procedure, the mechanics wou d have stopped work and sought a procedure revision. The error would have been discovered while resolving that problem. MEL Parts List Not Updated The MEL Parts Ust is used by maintenance personnel to determine what parts are approved for use in a particularcomponent. During the performance of the task the mechanics noticed that the filters to be installed were different than the filters to be removed. They reverified the part number for the replacement prefilter cartridges against the MEL Parts List and concluded that the prefilter cartridges were approved for use in the fiiiretion unit. A review by Procurement Engineering after the event revealed that the MEL Pads Usts for filtration units X-15 and X-16 were identical to the MEL Parts List for non-ESF filtration units X-03 through X-14, which led to this error.
Enclosure to TXX-93217 l NHC FORM 306A , U.S. NUGLEAR HECnA ATORY COMM1550N APPROVED OMB NO. 31!iO4104 EXPIRES:4rJoe2 i ESTIM ATED BUROCN PER RESPONSE TO COMPLY WITH THIS INFORM ATOh & M M REWEST: E0 HRS. MWARD COMMENTS RNDM { LICENSEE EVENT REPORT (LER) BURDEN E. STIMATE TO THE RECORDS AND REPORTS MANAGEMEN' , BRAN H M uSMEAR REMMNMMIS$10N.WASHMM TEXT CONTINUATION DC,20555, AND TO THE PAPERWORK REDUCTON PROJECT (31500104). 1 OFFCE OF MANAGEMENT AND BUDGET WASHINGTON, DC. 20503. - _; i f avbry Name (1) Otxmet Nunts (2) LER Nunte (6) Pa08 (3) !
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i l IV. CORRECTIVE ACTION
-i A. IMMEDIATE The prefilter cartridge was removed, a HEPA filter cartridge was installed and the required ,
testing was completed with acceptable results. A walkdown of all atmospheric cleanup 1 units outside the containment building was performed to ensure that the filter cartridges ; presently installed are the correct type. B. ACTIONS TO PREVENT RECURRENCE r Equipment Labeling was Less-Than-Adequate l t A label request has been initiated to change the nomenclature of the gauges for the l upstream and the downstream HEPA filter banks in all atmospheric cleanup units. The ; gauges on filtration units X-15 and X-16, which have been abandoned in place, will be ! labeled as such. Procedures have been revised prior to this event which require revision ! to the labels as part of the design modification process. l o incorrect Procedure Specified { The procedure which governs the modification process will be revised, to require the -t cognizant personnel to assess the impact of design modifications on standard step instruction stored in the computer data base. ; i Maintenance planners will review this event for lessons learned. PM work orders ; generated from standard steps which are to be worked for the first time will be reviewed for : equipment design changes prior to implementation. 1 MEL Parts List Not Updated i This discrepancy occurred in 1989 when many design modifications were being-implemented. Many of the original personnelinvolved are no longer employed at CPSES and the programs and procedures have been revised several times since 1989. TU Electric believes that this is an isolated occurence.
y l Enclosure to. TXX-93217 NHC FOHM 366A , U.S. NJCLEAR HiGULAIORY GOuM65 EON APPROVED OMB NO. 3150 0104 EXPIRES:4/3M12 ESTIMATED BURDEN PER RESPONSE TO COMPLY WITH THIS INFORMATOh ME Tm RE UEST: E0 HRS. F RWAR MMENTS REGAROM LICENSEE EVENT REPORT (LER) BURDEN ESTIMATE TO THE RECORDS AND REPORTS MANAGEMEN' TEXT CONTINUATION ""^*"(" * "*'" " ^""' *^ " " " ' * * " ' * * * " " " DC. 20555, AND TO THE PAPERWORK REDUCTIDN PROJECT (3154010s). OFFICE OF MANAGEMENT AND BUDGET, WASHINGTON, DC. 20503. F ammy Name(1) CAxmat Nurfts (2) LLH Nurmer (6) Page (3)
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0 0 6 - 0 0 0l7 OF 0l7 i Similar events will be precluded by changes which were made prior to this event to engineering procedure to require reviews by Procurement Engineering of DCNs which , modify any part/ component as originally supplied by the vendor and to revise the MEL Parts Ust accordingV. V. PREVIOUS SIMILAR EVENTS No other similar events regarding ESF filtration units have been identified at CPSES. 7 7 l}}