IR 05000348/1992034

Insp Repts 50-348/92-34 & 50-364/92-34 on 921207-09 & 930126.No Violations or Deviations Noted.Major Areas Inspected:Review of Licensee Investigation of Exposure of Workers TLD to 3,770 Mrem

ML20128F995
Person / Time
Site:	Farley
Issue date:	01/29/1993
From:	Rankin R, Shortridge R NRC OFFICE OF INSPECTION & ENFORCEMENT (IE REGION II)
To:
Shared Package
ML20128F970	List: IR 05000348/1992034 ML20128F966
References
50-348-92-34, 50-364-92-34, NUDOCS 9302120107
Download: ML20128F995 (5)

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JAN 2 81933 l Report No.: 50-348/92-34 and 50 364/92 34 ,

Licensee: Southern Nuclear Operating Company, In North 18th Street Birmingham, AL 35291 0400 Docket No.: 50-348 and 50-364 License No.: NPF 2 and NPF-8-Facility Name: Farley 1 and 2 Inspection Conducted: December 7-9, 1992 and January 26, 1993 l Inspector: .

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1. D' ate igned Approved by: M T.~ O ankin, C ief

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Facility Radiation Protection Section i Radiological Protection and Emergency Preparedness Branch Division of Radiological Safety and Safeguards -

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SUMMARY l

Scope:

This routine, unannounced inspection was conducted to review the licensee's investigation of the exposure of a workers thermoluminescent dosimeter (TLD) ,

to 3770 millirem (mrem).

Results:

l Based on a review of licensee data, interviews with.the worker with the hig TLD reading and health physics (HP): supervision, the inspector determined that  :

the licensee conducted an adequate investigation and their findings were-

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acceptable. These findings were reported in Licensee Event: Report 92 1102,- - .

l dated January 26, 1993. It was concluded that the high TLD badge rest 0ts did ~

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not represent an ex)osure to the individual. Based on the licensee's - _

evaluation, a whole)ody dose of 330 mrem was assigned to the individual for ,

the month of November 1992.

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9302120107 930120 '

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l e REPORT DETAILS

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' Persons Contacted Licensee Employees G. Bouler, Acting Plant Health Physicist

• p. Harlos, Auditor, SAER

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• R. Hill, General Manager, Plant Farley .

• R. Livingston, Environmental Supervisor l

• R.' Marlow, Technical Supervisor

• M. Mitchell, Superintendent, Health Physics

• C, Nesbitt, Manager, Operations *

• J. Osterholtz, . Assistant General Manager, Support

• L. Stinson, Assistant General Manager, Operations

• J. Thomas, Manager, Maintenance

• J. Walden, Operation Supervisor, Health Physics Other licensee employees contacted during this inspection. included -

craftsmen, engineers, operators, mechanics, security force members, technicians, and administrative personne NRC Resident inspector

• F. Cantrell, DRP Section Chief

• G. Maxwell, Senior NRC Resident

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• Attended Exit Meeting Description of the Event (92700)

On December 1, 1992, the licensee discovered during the regular TLD *

processing _for the month of November, that a Waste and.Decon Technician's (W&DT) TLD read 3770 mrem. The licensee's TLD.had two -

chips (1st and 2nd) behind a stainless steel shield to record-deep dose and one chip (3rd) under a' window (opening in the TLDl holder) to record-

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shallow dose. The licensee read the first and third chip'and determined.

L the deep dose delivered to the TLD was 3770 mrem.. The worker was ,

excluded from the radiologically controlled area (RCA) of the plant until the high TLD reading could be satisfactorily resolved.- The licensee sent the TLD to the vendor to read the second chip which-wa backup for the first chip under the stainless-steel shiel Investigation lhe licensee performed the following to determine-the circumstances-surrounding the high TLD reading. -The 1iconsee . i removed all digital alarming dosimeters- (DADS) from. service:that the W&DT-had.used in November. All checked out within' calibration when recalibrated on December 7,:1992. The subject workers' DADS were processed for the month'of November and~showed cumulative dose of 290 mrem in-lieu'of the 3770 mrem as. registered on the TLD. The W&DT also wore extremity dosimetry during-the month of'

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flovember. The extremity badges were issued at the start of the job and were to be worn for all high radiation work done at Iarley fluclear Station in the 4th quarter. The worker routinely wore his extremity dosimetry during all high radiation work in both October and flovember. The licensee contacted all coworkers that worked alongside the W&DT during flovember to ascertain their DAD exposure and their TLD exposure. All pertinent personnel were interviewed to gather the facts of the event and circumstances surrounding dose intensive work in flovembe The licensee found through a review of DAD records for the W&DT for flovember that on the 14th the worker was exposed to a field of 3004 mrtm per hour and on the 18th the worker was exposed to a -

field of 1205 mrem per hour. The job on llovember 14, 1992, involved removing the "B" steam generator (S/G) platform tent and on llovember 18, 1992, required the W&DT to clean the trough of the Unit I containment sump and stree Investigation Results The vendor processed the second (backup gamma) chip of the TLD on December 3, 1992, and reported a reading of 4210 mrem deep dos The vendor noted no damage to the chips or foreign material on them, thus verifying that an exposure occurred to the TLD above regulatory limits. However, DAD readings for the month were in the order of 150-300 mre The W&DT's extremity dosimetry read 330 mrem for the right hand, 330 mrem for the left hand, 270 for the right foot and 270 for the left foot. When the DADS that were used by the W&DT during flovember were calibration checked, all as found data was satisfactory and within calibration tolerance Both jobs dealing with high intensities of radiation on the 14th and 18th were reviewed for sufficient cause for the exposure. The -

W&DT stated when interviewed that during the cleaning of the sump trough on the 18th of flovember, he noted that his DAD alarmed several times. The DAD was in a plastic bag along with the TLD and tied to the workers chest. The W&DT stated that in the process of tapping the DAD to turn the alarm off, (the alarm can be silenced three times by tapping before a fourth alarm which is continuous and requires the worker to exit the RCA), that crud from the sump trough was deposited via his gloves onto the plastic bag. The TLD was thou( . to be in front of the DAD in the plastic bag and thus the exposure to the TLD was determined to have occurred. Statements by other co-workers substantiated the W&DT's account of the event on November 18, 1992. The total reading for the DAD, which was between the source (crud) and the body was 47 mrem. Licensee general area surveys showed radiation levels of 20 to 120 mrem /hr with bags of trash and crud being removed from the trough reading as high as 1000 mrem /hr. After working in the area for one and one half hours, the worker unsuited and transferred the plastic bag with the DAD and TLD to the step off pad with cotton gloves on (a normal practice at some power plants). After removal of the cotton gloves and during

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monitoring, the W&DT was found to have contaminated hands which indicates that substantial levels of contamination could have been on the plastic bag containing the dosimetry and been transferred to the worker's hands. The W&DT hands were deconned, his TLD pulled for processing, and he was restricted from work in the RCA until resolution of the exposure was complete The inspector interviewed the W&DT to better understand all aspects of the unplanned exposure to the TLD. The W&DT had six years experience in his field and displayed a good knowledge of radiological concepts and precautions to take to maximize one %

exposure. The W&DT stated to the effect that based on the type of work he had performed, that he did not believe the TLD exposure of ,

3770 millirem was possible and that his coworkers dosc during the month better ap3roximated his dose. The W&DT also was knowledgeable a)out biological effects of radiation and stated that had the dose of 3770 mrem been to the whole-body that no discernable effects from the radiation would be experienced. The

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inspector concluded the Interview noting that there was no information that the licensee did c already have, c. Regulatory implications 10 CFR 20.101(b)(1) states that during any calendar quarter the total occupation dose to the whole body shall not exceed 3 rems '

(3000 mrem).

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10 CFR 20.405(a)(1) states in addition to any notification required by 20.403 of this part, each licensee shall make a report in writing concerning -any one of the following types of events within 30 days of its occurrence: (i) each exposure of an individual to radiation in excess of the applicable limits'in 20.101 or 20.104(a) of this part, or the licens The inspector reviewed all licensee data related to the high TLD reading and interviewed the superintendent of Health Physics.and the Waste and Decon Technician. At the completion of the inspection the licensee had not completed their investigation; '

however, on January 26, 1993, Region 11 received the licensee's Plant Event Report 92-002 detailing the. investigation 1and final-

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corrective actions. Review of.the report noted that the licensee did conclude that the bag containing the subject TLD was-l contaminated resulting in the-high reading.. An exaosure of 330 mrem was assigned to the employee for the monti of November 1992,-based on the highest _ m remity TLD value (also the most conservative of the-various m asured exposures)._ Based _on the licensee's investigation findings and NRC onsite review of-the findings, interviews and a' review of data, the NRC concluded-that the_ investigation was adequate, that the extra precautions to record personnel exposure taken by the licensee were prudent and resulted in assigning a more correct whole body dose to the 's&DT- -

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than-that indicated by the TLD.

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! 4 Exit Interview The inspection scope and results were summarized on December 8, 1992, with those persons indicated in paragraph 1. The inspector acknowledged that the licensee's investigation was not yet completed and that additional communication regarding the inspection might be necessary upon the completion for the inspector to close out the inspection. The licensee agreed to forward a completed copy of the investigation to Region 11 via the Resident inspector. The inspector did not receive any dissenting remarks or review any proprietary materia The licensee's final evaluation of this matter was contained in Licensee Event Report 92-002 which was received and reviewed by the NRC on January 26, 1993. Based on this review, the NRC considered the licensee's evaluation and actions on this matter to be adequat _

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