05000482/LER-1950-482, FOIA Request for Documents Re Plant LER 50-482/88-028 W/All Revs & Suppls

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FOIA Request for Documents Re Plant LER 50-482/88-028 W/All Revs & Suppls
ML20134G971
Person / Time
Site: Wolf Creek Wolf Creek Nuclear Operating Corporation icon.png
Issue date: 10/10/1996
From: Omealia M
AFFILIATION NOT ASSIGNED
To: Kammerer C
NRC OFFICE OF ADMINISTRATION (ADM)
Shared Package
ML20134G957 List:
References
FOIA-96-411 NUDOCS 9611130455
Download: ML20134G971 (1)
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LER-2050-482, FOIA Request for Documents Re Plant LER 50-482/88-028 W/All Revs & Suppls
Event date:
Report date:
4822050482R00 - NRC Website
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! October 10,1996 t

FOIA/PA REQUEST j

i Mr. Carlton C. Kamwrer, Dimetor Division ofPmedom ofInformation Case No: 9d M

! and Publication Services Date Rec'd- /o-/bilo Omcc c(Mministration W 0#/ ha i U.S. Nuclear Re Commission W Casm j Washington, D. 205 5 i

Re: We ofIntneviimeinni h C;;e.ae j i j Dear Mr. hw.c.

l l Pursuant to the necdom ofInfonnation Act (5 U.S.C. I 552) and the U.S.

Nuclear Regulatory Commission's (NRC) re ons i

mquest acopy ofWolfCreek Cweing S 's Ih(10w C.P.R. Part 9, Su A), I Event Report 1 )50-482-

! 88428 with all mvisions and supplements. This IER is referenced in the " Additional

! Infonnation" sectwo of Wolf Creck's IER 92 007 which is attached for your convenience.

j IER 88428 couE act be located through a database search of the NRC Public Document Room's Bibliographic Retrieval System.

{' Iwould appreciateyour rt;' vest as provided.0by  ;;xompt response widdn ten (10) working days of the mceipt o C.F.R. Part 9 and the NRC's policies. If you require additional

informa, tion, please let me know. I can be rmhed at (202) 634-1439.

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i Michael K. O'Mealla Enc.: as stated l

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] ATTN: Document Control Desk  ;  ;

i Mail Station F1-157  ?

! Washington, D. C. 20555 '

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! subjects Docket No. 50-482: Licensee Event Report 92 007-00 i 'l i -

l Gentlement i

! The attached Licensee Event Report (LER) is submitted pursuant to j 10 CFR 20.405(a)(1)(1) concerning an exposure of an iMividual in excess of ,

j the applicable limits in 10 CFR 20.101.

l Very truly yours.

l Jted. A .

John A. Bailey i

'l

! Vice President t Operations

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j Attachment 4

$ ces A. T. Howell (NRC), w/a j R. D. Martin (NRC) w/a i C. A. Pick (NRC), w/a

] W. D. Reckley (NRC), w/a i

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i UCENSEE EVENT REPORT (LER) kk 6n , .t e, oor.g , e a e, . ao m i Wolf Creek Generating Station o.510tolola1812:llorID E .

i W '8' Hot Particle Picked Up During Reactor Coolant System Shim Restraint Rework ' Pp  !

Inspection Results In Exposure Exceeding 10 CrR 20.101 Requiresnents tsa neene, i ne o , e.te ,,, ot en e.es,..g e,vot veo e, wee cate e.

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] e t:tr:sveussoroartu [ a.o 0.'t vv l l as' w : a ~ e,  :: u . .. . are... ~.<r et ...ae < r ee.. i.ase . esi er March 26 1992, an engineer in the Radiologically Controlled Area was discovered to have a localized area of centamination on the left cheek. The cent amir.ation was determined to be a hot particle which probably originated f rem verk previously performed which required breaching the Reactor Coolant Sy< tem (P'J). The exposure was conservatively estimated, using the VARSKIN .

(.erputer code, to be 27.8 Rem to the skin of the whole body. This exposure (

esteeds t he 10 CFR 20.101 quarterly dose limit for the skin of the whole i body. The particle was sent to Battelle Pacific Northwest Laboratories for l f ur ther analys t e t o better determine its origin. 1 This event probably resulted f rom the transf er of a hot particle to the individuals left cheek during use of plant comunications equipment. In order to reduce the probability of recurrence. Volf Creek Nuclear Operating Corporatien is reviewing the hot particle control program and policies regarding the use of cor:rnunications equipment in contaminated areas for possiMe enhancement s.

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$ l LICENSEE EVENT REPORT (LER)

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Wolf Creek Generating Station 01610101.0 L41812_JJ2 0 l0 l7 0 l 0 0l2 0r 0 E' enre e ,ee .e ,en===w unsoe sneaow n u INTuoDUCTIon on. March 26, 1992, an engineer in the Radiologically Controlled Area (RCA) was discovered to have a loca11:ed area of contamination on the lef t cheek. i subsequent evaluation indicated that the resulting esposure exceeded the 10 l CFR 20.101 quarterly dose limit for the skin of the whole body. This report l 1s being submitted in accordance with 10 CFR 20.405(a)(2)(1). The l

! informatio'n required by 10 CFR 20.405(a)(2)(b) is provided separately as an I a t t a c hment to this report. l l

DF.5CRIPTION OF EVDr?

l On March 26, 1992, at approximately 0745 CST, a non-licensed Nuclear Plant i

Engineering (NFE) engineer entered the bloshield area of loop 'A' in the Centairment Building (NH) to perform inspection activities on the Reactor l Coolant System (RCS)( AB) crossover leg restraint clearance between the

< addle blocks and support structures (AB SPT] after shims were welded in plar c. The plant was in Mode 3. Not Shutdown at the time of the event.

This ac tivit y was part of the actions being taken to correct conditions which led to the noise heard in contair. ment on February 28. 1992.

To perform the inspection activities, the engineer used a multiple thickness feeler gauge to massure clearances. At approximately 1000 CST. the feeler gauge became disassembled. Two or three blades and the retaining nut fell t

into the 'A' crossover leg support structure floor indentation which is two o three inches lower than the surrounding floor. The engineer noted a right clearance between the side of the indentation and the support structure. The engineer picked up the the fallen pieces with the left hand and re-assembled the feeler gauge.

At approximataly 1100 CST, the engineer left the bloshield to use the  ;

gaitronics (plant public address system) [F1) to call for relief. Upon exiting the Containment Building at approximately 1200 CST. the engineer frisked in accordance with plant procedures using an Eberline Radiation Monitor, model RM.14, with an HP.210 probe. The engineer discovered a locallred area of contamination on the left check and. in accordance with plant procedures contacted Health Physics personnel. A Health Physics l technician immediat ely escorted the engineer to the decontamination eres.

Using a tot ton swab. the Health Physics t echnician removed a hot particle

from the engineer's face. Subsequent surveyn verified that there was no remaining contamination of the engineer.

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) The hot particle was sent to Chemistry for isotopic analysis and found to be  ;

composed of S.37 microcuries of Cobalt 60. Because of the source strength of the hot particle, the particle is believed to have resulted from a

< planned breach of the RCS during steam generator [AS-SG) bowl draining i during this or previous refueling outages. The hot particle has been shipped to Battelle pacific Northwest Laboratories for further analysis to better determine its source.

4 Initial conservative calculations of the exposure assumed that the hot particle was on the engineer's face from the time of entry into containment

at approximately 0745 CST. until it was removed at approximately 1215 CST.

j Using this exposure period (4 hours4.62963e-5 days <br />0.00111 hours <br />6.613757e-6 weeks <br />1.522e-6 months <br /> 30 minutes) and the source strength of j

S.37 microcuries the " tineer's exposure was conservatively estimated to be j 99.7 Rem using the VARSAIN compu*.er program.

The engineer, 6..d others, working in the area were interviewed in an attempt to determine the mo'st likely time and location that the hot particle had

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' been picked up. In addition to these interviews. previous surveys and contamination reports, a shim work video tape, radiation work permits. and training records were reviewed.

This inventination indicated that the engineer was most likely contaminated ,

while using the gaitronics to call for relief. It is believed that the j j particle was originally picked up at approximately 1000 CST when the l 1 engineer retrieved the pieces of the disassembled feeler gauge from the l l

indentation near the support structure and transferred to the left cheek l j during the use of the gaitronics at approximately 1100 CST.

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Using this sequence of events, the engineer's exposure was divided into two separ at e periods. First, for the period from approximately 1000 CST to 1100 CST the hot particle was assumed to be on the engineer's left hand: then, from approximately 1100 CST to 1215 CST. it was assumed to be on the left cheek. Using these elapsed times and a S.37 microcurie source, the engineer's exposure was recalculated using the VARSKIN computer code. The dose to the hand was determined to be negligible because of the rubber gloves and cotton glove liners worn during the work. The dose to the skin of the whole body, due to the hot particle on the cheek, was found to be 27.8 Rem. This estimated dose received by the skin of the whole body exceeds the 10 CFR 20.101 permissible er.cupational dose of 7.S Rem per Quarter to the skin of the whole body.

This diise a s s e n tment and its rarrifiestions have beeri disrun ted wit h t he enynneer. In addit ion, because of the ilote ret elved the engineer wse ineligible for work in the RCA unt il Apr il 20. 1992.

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l ROOT.CAUSE AND CORRECTIVE ACTIONS i

l Investigation of this event has indicated that the engineer was most likely  !

l contaminated when a hot particle picked up while retrieving parts of a '

disassembled tool, was transferred to the f ace during use of the ,

i gaitronics. Analysis of the particle has shown that it probably came from j l j the RCS during the steam generator bowl drain down activities during  ; .

previous refueling outages.  !

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l The work area was louediately surveyed by Health Physics personnel. One j additional particle was found but its activity level was less than that )

required by the Wolf Creek Nuclear Operating Corporation (WCNOC) hot j particle program for declaring the area a hot particle zone. Additional .

j surveys of the area during the remaining work activities showed no further evidence of hot particles. The work activity was completed with no further I contamination events and the plant returned to normal operatioca. Follow-up

[ surveys of the gaitronics station used by the engineer were performed during ,

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a routine Containment entry. No contamination of the gaitronics station was .

l found. Because this sequence of events was developed after the unit had returned to power operations. a survey of the indentation for hot particles was not performed. The support structure indentations of all four loops I will be examined during the next outage of sufficient duration to perform an j inspection of the area.

t to further reduce the potential for future hot particle contaminations, procedure RPP 02 510. ' Hot Particle Contamination Contro1*, will be evaluated to determine if hot particle definitions and guidelines should be ,

revised. This would reduce the possibility of hot particle cent amination I

  • i because the hot particle control program would be entered upon discovery of j particles with much lower activity levels. Hot particle control will be 1 emphasized during work planning for Steam Generator bowl draining
  • i activities. The Radiation Work Permit used to perforu Steam Cenerator bowl I draining will be revised to include specific information to reduce the i possibility of hot particle generation or spread. A discussion of this I event will be included in General Employee Training. Radiation Vorker j l training, and Radiation Worker Requalification training. 1 l

i I A policy for the use of communication equipment in contaminated areas will j j be defined so that workers do not inadvertently contaminate equipment or '

! themselves after working in contaminated areas. These actions will be j completed by December 31. 1992.

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0 l0 0 l5 o' 0 l5 en a mee esse e s. em sene.ne, svac re= sesaw pa ADDITIONAL INFORNATION i The engineer involved in this event was current in all required radiation j worker training and followed the requirements of the appropriate Radiation , )

Work Permit at the time of the overexposure. j LER 482/88-028 01 reported a previous hot particle contamination event which resulted in an overexposure beyond 10 CFR 20.101 limits.- A review- of* the --

hot particle contamination control program was performed and it was determined that the program adequately addressed hot particle concerns. )

Not particles, usually microscopic in nature, come primarily from two '

sources f ailed fuel and neutron activated corrosion and wear products. A ,

hot particle on the skin results in a high beta dose to a small area. The area used to calculate a beta dose is one square centimeter at a depth of 7 E-3 centimeter per the VARSKIN computer code. There is scientific evidence indicating that highly localized exposttre of the skin by a hot particle is less binlogically damaging than a more uniform irradiation by the same quantity o. radioactive material. The VARSKIN computer code was

  • developed by Battd ie Pacific Northwest Laboratories in 1987 and is used industry-wide in accordance with NUREG/CR-4618 for calculating the dose l received during skin contamination.

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