IR 05000266/1987011: Difference between revisions
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{{Adams | {{Adams | ||
| number = | | number = ML20215G320 | ||
| issue date = | | issue date = 06/15/1987 | ||
| title = | | title = Insp Repts 50-266/87-11 & 50-301/87-10 on 870428-0519, Violations Noted:Failure to Properly Train Employees Using Radioactive Source & Failure to Clearly Label Contents of Radioactive Matl in Container | ||
| author name = | | author name = Greger L, Miller D, Paul R | ||
| author affiliation = NRC OFFICE OF INSPECTION & ENFORCEMENT (IE REGION III) | | author affiliation = NRC OFFICE OF INSPECTION & ENFORCEMENT (IE REGION III) | ||
| addressee name = | | addressee name = | ||
| addressee affiliation = | | addressee affiliation = | ||
| docket = 05000266 | | docket = 05000266, 05000301 | ||
| license number = | | license number = | ||
| contact person = | | contact person = | ||
| document report number = | | document report number = 50-266-87-11, 50-301-87-10, IEIN-86-023, IEIN-86-23, NUDOCS 8706230213 | ||
| package number = | | package number = ML20215G310 | ||
| document type = | | document type = INSPECTION REPORT, NRC-GENERATED, INSPECTION REPORT, UTILITY, TEXT-INSPECTION & AUDIT & I&E CIRCULARS | ||
| page count = | | page count = 16 | ||
}} | }} | ||
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=Text= | =Text= | ||
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1 U. S. NUCLEAR REGULATORY COMMISSION | |||
==REGION III== | |||
a | Reports No. 50-266/87011(DRSS); 50-301/87010(DRSS) | ||
containment purge | Docket Nos. 50-266; 50-301 Licenses No. DPR-24; No. DPR-27 | ||
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and source in | Licensee: Wisconsin Electric Power Company 231 West Michigan Milwaukee, WI 53201 Facility Name: Point Beach Nuclear Plant (PBNP) | ||
Inspection At: PBNP; Units 1 and 2, Two Rivers, Wisconsin Inspection Conducted: April 28 through May 19, 1987 l Inspector: 6//5'/B7 _ | |||
Date 1 i | |||
0. 8. 7d$v i D. E. Miller 9 /#/87 Cate~ | |||
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Approved By: . r ge , Chief (>//f/87 Facilities Radiation Protection Date Section | |||
Inspection Summary Inspection oli April 28 through May 19, 1987 (Reports No. 50-266/87011(DRSS); | |||
No. 50-301/87010(DRSS)) | |||
Areas Inspected: Routine, unannounced inspection of the radiation protection program during a refueling outage including: organization and management controls; internal and external exposure controls; posting and access controls; contamination control; two incidents concerning unplanned radiation exposures; and previous inspection finding Results: Two violations were identified (failure to properly train employees using a radioactive source - Section 10; failure to clearly label the contents ofradjoactivematerialinacontainer-Section11). | |||
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DETAILS 1. Persons Contacted | |||
*R. Bredvad, Plant Health Physicist | |||
*D. Johnson, Project Engineer, Nuclear Plant Engineering | |||
*T. Koehler, General Superintendent | |||
*J. Knorr, Regulatory Engineer, Nuclear Plant Engineering E. Lipke, General Superintendent, Nuclear Plant Engineering | |||
*J. Reisenbuechler,. Superintendent, EQRS | |||
*J. Zach, Plant Manager | |||
*R. Hague, NRC, Senior Resident Inspector | |||
*R. Leemon, NRC, Resident Inspector The' inspectors also contacted other plant staff during this inspectio * Denotes those present at one of the exit meetings held on May 8 and 15, 198 . General The onsite inspection which began at 8:00 a.m., April 28, 1987, was conducted to examine aspects of the licensee's radiation protection program during a refueling outage. The inspection included several plant tours, review of posting and labeling, review of personal internal and external exposures, and independent inspection efforts by the inspector Also reviewed were selected open items, corrective actions concerning previous violations, and two incidents concerning unplanned personal radiation exposure . Licensee Action on Previous Inspection Findings (Closed) Open Item (266/86016-01; 301/86015-01): Failure to initiate a report form as required by Procedure No. HP 1.11 when portal monitor containination alarms are initiated. The licensee has revised HP 1.11 to better define specific responsibilities for response to portal monitors, revised Procedure HP 2.1.2 to clarify employee responsibility for frisking and notification of personnel when contamination is found, and has initiated a formal training program for security personnel concerning their responsibility for response to portal monitor alarm (Closed) Open Item (266/86016-02; 301/86015-02): Failure to perform surveys to ensure workers would not exceed 10 CFR 20.103 limit Frequency of radiation and contamination surveys were increased in the waste evaporator feed cubicle area and other areas subject to changing radiological conditions. Procedure HP 2.5 has been revised to ensure requirements for work activities will be based on timely and adequate surveys of radiological condition f > t :$ | |||
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i(Closed) Open-Item (266/85017-01; 301/85017-01): . Developkent-of thel 1 training program for_the RCOs. The licensee has developed and. initiated I an RC0 training' program that is-INP0Lcertifie , l i; ) | |||
(0 pen) Open-ItemL(266/85007-01; 301/85007-01): Turnover rate of RC0 staff / ' | |||
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and the effect on staff. stabilit See Section , i | |||
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4.- Licensee Response to'NRC Concerns I | |||
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. 1 During a previous inspection (Inspection Report Nos.'266/86016; 301/86015)1 J j-programmatic weaknesses concerning health physics coverage, the RWP '! ~1 | |||
: program, reuse of protective clothing, the A0 qualification program and 1 other HP practices were identified. In a letter to the NRC dated' .] | |||
February 4,.1987, the licensee addressed tris actions that had been, and y will be..taken to satisfactorily' correct the identified programmatic weaknesses; including a commitment to implement full time HP' coverage | |||
< within two year ' Organization, Management Controls, and Staffing | |||
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The inspectnrs revfewed the= licensee's organization and management l controls for radistio protection, including changes in the organizational l structure and staffing, effectiveness of procedures and other management'- | |||
techniques ~used to implement the program, and experience concerning J self-identification and correction of program implementation weaknesse *} l | |||
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Region -I6was infonned that a corporata ' staff health physicist will ' | |||
assume a newly' created Superintendecit-Health Physics-(S-HP) position at Point Beach Station effective Jund 1, 1987. The S-HP reports to.the 3 General' Superintendent with a direct reporting path to< the Plant Manager , | |||
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as necessary for radiological matters. The Plar,t Health Physicist and the ! | |||
Radwaste Supervisor will report to the S-HP. According to licensee , | |||
representatives, addition of the S-HP is intendedttd aid creation of a more; professionally oriented radiation protection department. This - | |||
cesponds to' observations and recommendations made by NRC inspectors as a , , | |||
, result of past inspections. | |||
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During two previoun inspections (Ir.cpection Reports No. 266/85007; 301/8500Fand 266/86004; 301/86004), it was notad that the turnover rate of the technician staff (RCDs and RCOTs) was significantly higher than the turnover rate of other Region III licensees. . This turnover rate affected the' qualification and experience level of the RCO staff and l | |||
. appeared.to diminish the stability and effectiveness of the radiation ' | |||
protection organization. The cause for this turnover rate was attributed to the RCOT-selection system and salary differential between RCOs and I other plant workers which tended to discourage RCO retention. Since then, | |||
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the licensee ' improved RC0 trainee selection, Jetreased the salary | |||
}' differential between RC0's and other plant workers, increased the HP staff, and is continuing efforts to build a career HP. staff consisting of 12 or 13 permanent RCO However, the RCO's hoJrly Salary remains l3Wer , | |||
than senior chemistry technicians, mechanical maintenance workers, and y auxiliary operator .. | |||
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'The current radiation protection staff, supplemented by HP contractors, | |||
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appears adequate to sup' port routine radiation protection coverag However,.there remains. insufficient staffing of permanent qualified RCOs to cover nonroutine functions and the licensee must rely on use of health physics contractors to supplement;the staff during normal and outage activitie The shortage of RCOs appears to have been a factor in an extremity exposure event discussed in.Section 1 The apparent staffing shortage and lack of upgrading of RCOs was discussed at the exit meeting. (266/85007-01; 301/85007-01) | |||
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No-violations or deviations were note . Internal Exposure Control The inspectors reviewed the licensee's internal exposure control and assessment programs, including changes to procedures affecting internal exposure control and personal exposure assessment; determination whether engineering controls, respiratory equipment, and assessment of individual | |||
. intakes meet regulatory requirements; planning and preparation for maintenance and refueling tasks including ALARA considerations; and required records, reports, and notification The licensee's program for controlling internal exposures includes the use of protective clothing, respirators, and control of surface and airborne h radioactivity. A selected review of air sample and survey results was i made; no significant problems were noted other than those noted in Section 1 Whole body count (WBC) data was reviewed for counts performed during the period August 1, 1986 through March 31, 1987, on company and contractor personnel. Several followup counts were performed on the few persons who showed elevated initial counts. Followup counting was adequate to verify that'the 40 MPC-hour control measure was not exceeded. No problems were note No violations or deviations were identifie . Personal Contamination Events The licensee initiates Personnel Contamination Event Reports for individual personal contamination events. The report identifies the individual, date, location of contamination, method of detection, disposition of the contamination, and possible cause/ source of the contamination event. This information is entered into a computer program which permits summarization and trending of several parameter The-licensee periodically generates summary sheets that list individual events by contractor or employee name, location by body or clothing area, and method of detection of contamination (routine frisk, checkpoint frisk, portal monitor, or whole body counter). The licensee uses this information to identify trends, recurrences by individuals, and possible | |||
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i programmatic problem During 1987 through May 6, 1987, there were 50 events that met.INP0. reporting criteria. The licensee does not currently l utilize whole body contamination monitors, relying instead upon " friskers." | |||
The licensee.does have several PCM-1 whole body contamination monitors on 4 order, , Typically, introduction of whole body contamination monitors increases significantly the. numbers of identified personal contamination The inspectors noted that about half of the personal contamination events | |||
' involved personal clothing. About one third of the clothing events , | |||
involved shorts, and one third undershirts and socks. The inspectors also i noted that the licensee's prescribed single set of protective clothing used for working in contamination levels <30,000 dpm/100 cm2 includes coveralls with untaped side pocket openings and shoe covers that'do not cover the ankle area. It appears that this prescribed clothing contributes to the potential for contamination of underwear and sock l According to licensee representatives, the licensee plans to soon begin use of coveralls which do not have side pocket openings. However, the inspectors were not apprised of any plans to alter the type of shoe coverings worn.- This matter will again be reviewed during future routine radiation protection inspections. (50-266/87011-03; 50-301/87010-03) | |||
No violations or deviations were identifie . l E,xternal Exposure Control and Personal Dosimetry The inspectors reviewed the licensee's external exposure control and personal dosimetry to meet refueling outage need For the Unit 1 refueling outage it appeared adequate radiation surveys to identify radiological conditions were performed and sufficient health physics coverage was available to control job The inspectors selectively reviewed Radiation Work Permits (RWPs) and associated radiation surveys and observed work being done in the containment; no problems were identifie The inspectors selectively reviewed exposure records including TLD and self reading dosimetry results. The records indicate that no person exceeded regulatory limits. The occupational external dose for the station in 1986 was 375 person-rem and through April 1987 it was approximately 260 person-rem, most of which was due to the Unit I refueling outag No violations or deviations were identifie Preplanning - ALARA For this refueling outage, health physics personnel were involved in pre-outage reviews and were aware of the major radiation producing jobs in advance. Outage planners were followed. With the exception of certain small jobs that were not effectively preplanned, no major difficulties were encountere E . | |||
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.In accordance with Procedure PBNP 3.7.4, radiological reviews were i performed for certain routine dose activitier for this' outage i accordance with radiological conditions and work to be performed. The application of these' reviews are part of the' licensee's exposure reduction program, and the use of.the reviews are particularly important during outage conditions for implementing ALAR . Radiolouical Incident Involving Unplanned Radiation Exposures The inspectors reviewed the circumstances surrounding ~an unplanned whole body radiation exposure to a station employee who unknowingly handled a i radioactive source on May 10, 1987. During the review, the inspector contacted licensee managers and health physics personnel, and interviewed the individuals involved in the incident. The inspectors observed several physical' reenactments of the incident and reviewed the licensee's investigation findings. Although no overexposures occurred as a result of.the incident, the radiation dose to one worker's~ hands was close to the quarterly extremity dose limit. The following subsections describe the event, causes, licensee and inspector followup, and dose assessmen This matter will be discussed further with the licensee during an enforcement meeting scheduled' for June 18, 1987, in the Region III Offic Summary of Event On Sunday, May 10, 1987, two Radiation Control Operator Trainees (RCOTs) and a Health Physics Supervisor (HPS) performed functional tests of two Radiation Monitoring System (RMS) monitors using a i cesium-137 source. On Monday, May 11, 1987, the licensee became aware that one of the RCOTs may have received an extremity overexposure while performing the functional tests. The licensee informed an NRC resident inspector and a Region III radiation specialist of the incident on the afternoon of the same day, and formed a formal investigation committee consisting of the j General Superintendent, NPERS, the Superintendent-Training, an ! | |||
ISI Engineer, a Project Engineer-Radiological, and a Senior Project j Engineer-Licensin ] | |||
The incident occurred while the three workers were performing functional tests on RMS detectors. The purpose of the tests was to expose the detectors to a radiation source of sufficient strength to actuate containment purge valve trips. The shielded source container | |||
" pig" used for these tests has a large removable shield plug in one end which is removed to expose the radiation source. A nominal 71 millicurie cesium-137 source is attached to the end of a source plug , | |||
assembly, which is inserted into the " pig" at the end opposite the ! | |||
shield plug. The source plug is much smaller in diameter than the shield plug. Each plug is prevented from casual removal by a padlock. The two padlocks were operated by the same High Radiation Area key. For these tests, the large plug is removed to expose the monitor to a collimated radiation beam emanating from the radioactive . | |||
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Neither the HPS or the RCOTs had previously_used the " pig"; however, the HPS had observed the use of.the " pig" to test the IRE-211/212 ! | |||
detectors on one of.the RMSs. None of the three employees were ; | |||
aware or had been instructed that the Cs-137 source was attached to ! | |||
the small plug; they stated that they assumed the two plugs varied -! | |||
in size to allow for different size radiation beam The " pig" was not marked to identify the radiation hazard associated with removal of the' source plu Chronology of the Incident On May'.9, 1987, the HPS completed an 11-hour shift at about 5:30 At about 8:50 p.m., the HPS, who was the Duty On-Call Supervisor, received a call from the Duty Radiation Control Operator (RCO) who was covering the shift with an RCOT. The RCO stated that he had to leave the site because of a family emergency. The HPS contacted two of the four available RCOs to find one to cover the remainder , | |||
of the shift; the HPS was unsuccessful. The HPS then called in an RCOT to join him and the other RCOT onsite to cover the remainder of the shift. When the HPS arrived onsite, he became aware that his ' | |||
shift was responsible for conducting the functional trip test of the Unit 1 containment purge valves. The two monitors used to trip the purge valves are the Unit 1 SPING RMS (IRE-305) located in the Unit 1 rod drive room and the Unit 1 PNG RMS (IRE-211/212) located in the -l IRE-211/212 cubicle. Both monitors are exposed to the Cs-137 radiation source for the test. At about 11:55 p.m., the HPS, after realizing that he had never conducted or observed a trip test on the IRE-305 monitor, called an off-duty HPS who provided the onsite HPS with information concerning the techniques and methods required to successfully conduct the test; there was no discussion of use of the Cs-137 source " pig," which the HPS had observed in use once previousl At about 12:30 a.m. on May 10, 1987, the three workers arrived at the Unit I rod drive room to conduct the functional trip test of IRE-305. At this point, there are two differing accounts of how the test was performed, one by the two RCOTs and one by the HP According to the RCOTs, the HPS performed the test at the back side of IRE-305 by removing the small (source) plug from the " pig," | |||
setting it on the floor, and directing the open plug end of the pig toward the shielded IRE-305 monitor. Based on the HPS recollection of the performance of the test, the RCOTs successfully conducted the test on the front side of IRE-305 by removing the large (shield) | |||
plug. After the control room ir. formed the workers the test was successful, the plug which had been removed was returned to the pig and the workers departed the are The licensee later demonstrated that if the radioactive plug was on the floor and not in the " pig" for the test, there would still be sufficient radiation emitted from the unshielded source to cause the containment purge valves to trip closed. These different scenarios / | |||
described by the HPS and the RCOTs also were noted during physical , | |||
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t reenactment Although the discrepancies concerning the performance of this test are significant in their degree of disagreement, it appears thatleven if the small plug was removed from the pig as described by the RCOTs the length of time and manner in which it | |||
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was handled'would not have caused significant' personal exposure to the'HP At about 1:00 a.m. , the three employees began the trip test on channel IRE-212 on the PNG monitor located in the IRE-211/212 cubicle. To conduct the test, one RCOT positioned himself behind the monitor. His job was to position the " pig" to ditect the-radiation beam from the open end of the pig at channel IRE-21 The other RCOT was positioned at the side of the monitor near the first RCOT to physically assist and to make radiation surveys. The HPS was located at the front of the monitor and was in radio contact with the control room. To begin the test, the first RCOT apparently renoved the source plug, placed it in front of him on the monitor support (pallet) and attempted to trip the purge valve by pointing the open port of the " pig" at the monitor. After several . failed attempts to trip the system, the HPS changed positions with the . | |||
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second RCOT so he could assist in the " pig" handling. During the time the HPS and the second RCOT changed positions, the first RCOT held the source plug for approximately 30 seconds in each hand. He stated that he was unaware that either plug was a radioactive source; he assumed the source plug was merely another shield plug. The other RCOT did not recognize the error even though he measured abnormally high general area radiation levels (200 - 300 mR/hr) when the " pig" was incorrectly used; he stated he was unfamiliar with radiation levels to be expected during the evolutio After the HPS haa exchanged positions, the first RCOT apparently re-installed the small (source) plug in the pig and removed the larger (shield) plug so the test could be performed using what he assumed to be a larger beam size. After additional monitor manipulation with the large plug removed and the small plug positioned in the pig, the control room reported the purge valve | |||
. tripped closed; the large plug was subsequently returned to the pi The workers departed from the area assuming that although they l encountered some difficulty in tripping the valves, the tests were | |||
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successfully completed and no unusual incidents or circumstances had occurre The licensee became aware of the radiation exposure problem on Monday, May 11, 1987, when the two RCOTs were casually discussing their weekend work activities with other members of the health physics staff. During these discussions, some staff members realized a significant radiation exposure may have occurred; they so informed health physics management personne The licensee then formed a formal investigation committee to review the inciden The committee conducted several physical reenactments of the events, interviewed all personnel involved in or with the event, and performed radiation dose assessments. | |||
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10 CFR 19.12 requires that workers receive instruction in precautions or procedures to minimize exposure and in the purposes and functions of protective devices employed. The failure to- ( | |||
instruct the workers.in the proper use of the cesium-137 shielded H source container is a violation of 10 CFR 19 requirement ! | |||
.(50-266/87011-01; 50-301/87010-01) | |||
l Dose Assessment | |||
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The licensee calculated whole body and extremity exposures _for each ! | |||
of the workers involved in the inciden The dose assessments were l calculated based on reenactments (witnessed by NRC inspectors), | |||
sourc'e output and configuration, time of exposure to the source, and , | |||
location of the source relative to the workers, j For the whole body, the results of the calculations indicate the highest dose was approximately 660 mrem to the knees of the RCOT who performed the tests on RE-211/212. Adding previous doses, the RCOT's whole body exposure was less than 900 mrem for the calendar. quarter; no regulatory whole body dose limit was exceeded. The inspectors agree with the licensee's whole body dose assessment The only significant extremity dose was_to the hands of the RCOT who held the source. The licensee calculated this individual's extremity dose using a modified "QAD". computer code which divides the volume source into multiple point sources then calculates dose | |||
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l from each point source to the skin. The licensee calculated a maximum contact dose of approximately 17.5 rem based on the specific source characteristics, a 33-second exposure time, and 7 mg/cm2 dead skin layer. Independent NRC calculations based on generalized source characteristics and the remaining assumptions utilized by the license resulted in an approximate maximum contact dose of 18.75 re , | |||
Assuming the correctness of the licensee's computer code, their ; | |||
calculation should be more accurate than the NRC derived value, which was based on approximate source characteristics. Based on the realistically conservative assumption that the individual's hand was in contact with the surface of the cylindrical source and using the contact dose rate distribution derived by the licensee's computer code, the maximum dose to 1 cmi of skin tissue at a depth of 7 mg/cm2 is approximately 15 rem. (While technical arguments may be made to utilize less conservative assumptions than 1 cm2 skin area and 7 mg/cm2 dead skin layer, these values are specified by NRC as noted in IE Information Notice No. 86-2 The applicable NRC dose limit is 18.75 rems per quarter. Although the extremity dose in this incident (15 rem) did not exceed regulatory limits, such outcome appears fortuitous rather than having derived from licensee planning, training, or precaution J | |||
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' d .' - ' Factors' Contributing to' Incident's Occu'rrence As a result'of the.. licensee's investigation and the inspectors' | |||
review ~of the incident, several major factors were identified which appear.to have contributed to the source handling inciden * -The source container (pig) had no caution markings to identify - | |||
the radiation hazard associated with the removal of the source plug. The two plugs are similar by outward appearance, with only the plug diameters differing. Both plugs are locked by similar key locks that are opened by the same ke * The HPS and the RCOTs were untrained and inexperienced in the use of the source container and in the function and calibration of the RMS. The HPS was unable to provide sufficient technical information to the RCOTs concerning the job they performed, ; | |||
used poor judgement in performing a job for which he was unqualified, and may have been fatigued. The relatively low number of qualified RCOs available to provide health physics coverage also appears to have been contributar * There were no procedures covering the use of the source for functional testing of the RMS channels. Although the licensee recently developed a formal training plan which covers the use of the source container, none of the three participants had attended the training session . Hot Particle Incident On April 21, 1987, two contractor health physics technicians were assigned to move bags of radwaste from one temporary storage location to anothe After the task was done and their protective coveralls drycleaned, hot particles were found in the breast pockets of the coveralls they had worn. The licensee performed a followup investigation to determine the activity of the hot particles, the isotopes in the particles, and the length of time the particles were in the pockets. The inspectors interviewed.the participants in the incident, reviewed the licensee's investigation results and calculational methods, and performed , | |||
independent calculations. No overexposures occurred as a result of the l incident, and no items of noncompliance with regulatory requirements were l identified; however, weaknesses were noted. The licensee's investigation j appeared timely and thorough. This matter will be discussed further with i the licensee during an enforcement meeting scheduled for June 18, 1987, in the Region III Offic Sequence of Events On April 21, 1987, unusually high contamination , | |||
levels were found on two pairs of protective coveralls while frisking j them after dry cleaning. No other contaminated PCs were found nor l was any significant contamination found in the laundry room or the ) | |||
dry cleaning system. The PCs were apparently worn by two I technicians while moving bags of radwaste in the radwaste building earlier that da The contamination was subsequently identified as several discrete fuel particle i i | |||
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Direct radiation and contamination surveys of the health physic ' station, locker. room, maintenance shop, radwaste truck access, and radwaste ATCOR areas were made to identify the source of the contamination and determine if'any contamination had been spread to clean areas. No significant activity was found except in a portion of the ATCOR area of.the radwaste building where the two contract technicians had worked earlier that da After reporting to work on the morning of April 21, 1987, the senior and junior contractor health physics technicians were instructed to ! | |||
remove bagged radwaste materials from behind a temporary shield wall in the ATCOR area of the radwaste building; the bags were to be transferred into a shielding cask'in the nearby truck. bay. The bagged materials had been placed behind the shield wall over the preceding two and a half years because their elevated radiation levels and/or radioisotopic composition dictated a need for special packagin The bags were being moved so that the area could be used to store other_radwaste. The two contractor technicians, who were working under the direction of the chemistry group radwaste supervisor, were to move the bags and provide their'own health physics job coverag At about 0750 hours on April 21, 1987, the senior contractor technician initiated a Radiation Work Permit (RWP) for the bag handling. The radiological conditions he entered on the RWP *:!ere based on a survey he had performed in the general area on April 7, i 1987. The general area survey did not include dose rate or i contamination levels within the temporary shielded area even though entry into that area would be required. One set of protective clothing was prescribed. Extensive dosimetry for the chest area, hands, and forearms was prescribed including integrating alarming dosimeters (set at 65 mR) to be worn on the chest area of each technician. No respiratory protective devices were worn or prescribed. The proper RWP authorizing approvals were obtaine At about 0800 hours the technicians donned the prescribed protective clothing, attached their dosimetry, proceeded to the work area, posted a copy of the RWP at the work site, and unlocked the High j Radiation Area (HRA) gate at the shielded storage room in which the temporary shielded area is constructed in a corner. The temporary shielded walled area is about six feet high and is built of solid concrete blocks supported / braced with scaffolding; the scaffolding is so arranged that a person can climb in and out and bags can be suspended from a horizontal scaffolding railing that is slightly higher than the block wal j Using an extended probe radiation survey instrument, the senior technician surveyed the shielded storage room while entering to verify the exposure rates. He then looked into the temporary shielded storage area and saw about eight bags of waste, three of which had attached ropes that were tied to a horizontal scaffolding railing above the block wall. The technicians discussed possible 11 l | |||
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handling methods,. assembled plastic bags, and contacted the control room to inform them that bags with high radiation readings would be handled and transporte l The senior. technician then pulled out one tied-off bag, transferred it to the step-off pad (SOP) at the HRA gate where the junior technician (on the clean side of the SOP) had a plastic bag ready to " bag-out" the transferred bag. The junior technician then taped > | |||
the outer bag and monitored the radiation level on the bag. The, | |||
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senior technician removed his low-cut shoe covers and cotton gloves at the S0P, donned clean cotton gloves, and carried the bag to the | |||
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shielding cask in the truck bay. This process was repeated for the other two tied-off bags. The senior technician then surveyed the general radiation fields inside the temporary storage area, while standing.on-scaffolding, using the extended probe survey instrument- | |||
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the general area radiation exposure rate was 80-100 mR/hr. The t senior technician then climbed into the temporary storage area, handed the remaining four bags over the wall to the junior technician, | |||
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then climbed out. The junior technician then followed the 50P ; | |||
procedure and the four bags were transferred to the shielding cask | |||
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in the same manner at the first thre The HRA gate was relocked, and the shielding cask surveyed to assure adequate postings and ; | |||
access control ; | |||
It is the licensee's practice when one set of protective clothing'is l worn that the low cut rubber shoe covers remain on the hot side of f the SOP, the cotton gloves are placed in a receptacle at the SOP, and the coveralls and low cut plastic shoe covers are worn back to l the access control area where the coveralls are surveyed to see if l they.are acceptably clean to be placed in the wearer's controlled !' | |||
side locker for reuse. The plastic' shoe covers are discarded. The technicians followed this practice. As the junior technician approached a portable frisker with his hands, the alarm (set at 100 cpm above background) alarmed; the technician switched the frisker meter range from the X1 to the X10 range and began surveying i the arms of the coveralls when the alarm sounded again. Both technicians then discarded their coveralls in the dirty laundry ' | |||
container and began whole body frisking with portable frisker The junior technician identified about 200 cpm on his left wrist, 300 cpm on his shorts, 200 cpm on his socks and 3000 cpm on his shoes. The senior technician identified about 200 cpm on the heel of one shoe. The technician then followed normal decontamination | |||
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and documentation procedures. The personal contamination documentation was taken to a health physics foreman who reviewed the documentation. The technicians did not tell the RCOs that their protective coveralls contained highly elevated contamination levels i when placed in the dirty laundry dru As previously stated, the technicians wore extensive self-reading dosimetry on their chest and wrists including an integrating , | |||
alarming dosimeter on the chest of each technician. The highest reading thus recorded was 80 mR to the right wrist of the senior | |||
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contra'ctor technician who had performed the majority of the handling of._the radwaste bag The indicated exposures appeared reasonable for the job performe l Source and Isotopic Content of Contamination (Hot Particles). | |||
During surveys performed in the shielded storage room and vicinity on the afternoon of April 21, 1987, and on April 22, 1987, several | |||
" hot" particles were identified on the floor of the storage room, and one on the ladder'used while placing the radwaste bags in the : | |||
shielding cask. No additional particles were found in areas traversed by the technicians during or after performance of the ; | |||
radwaste bag handing. The " hot" particles read up to 40 R/hr when | |||
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measured at one inch with an R02A survey meter with the beta- , | |||
. window close The particles were small but generally visible with ! | |||
the naked eye. The licensee collected samples of the particles for , | |||
isotopic analysi Licensee representatives removed the bags from the shielding cask where they were placed by the contract technicians. The bags were observed to see if any had been breached. The licensee noted that the inner bags (three layers), containing a small filter, appeared to be slit. The representative took a contamination swipe of the area surrounding the slits in the inner bags. The swipe was retained for isotopic analysis. According to the contract technicians, the plastic bags containing the small filter were the last handled and transferred to the shielding cas The licensee performed further surveys on the two pairs of coveralls that were retained because of contamination levels. The~ licensee found two hot particles in the breast pocket of each pair. There was total radioactivity of 14.2 pCi in the pocket of one pair of the coveralls and 2.8 pCi in the othe ~ | |||
According to the licensee, the subject filter is a "swarp" filter from a portable underwater cleaning system. The filter is essentially a stainer through which circulated water flows while cleaning underwater debris. The filter sits in a hose coupling fitting and is under water when the cleaning system is in use. The filter is cylindrical, about three inches in diameter, five inches high, has a handling bail on top, and has a thin metal flange seating surface on the bail end. The licensee believes that the filter was used during the Unit 2 outage in 1985 to remove debris | |||
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from the reactor vessel, and has probably been in the shielded storage area since November 198 Using gamma analysis techniques, the licensee determined that the isotopic content of the hot particles found in the coverall pockets, floor of the shielded storage area, and swipe taken on the bag containing the "swarp" filter was mainly Ce-144, Pr-144, Rh-106, , | |||
/ | Ru-106, and Cs-137; the relative abundance of the isotopes was similar. The isotopic content indicates that the original source of the particles was past failed fuel, particles of which were i collected in the "swarp" filter during incore cleanin ; | ||
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i c. Calculated Dose to Contractor Technicians Skin doses were calculated by NRC using the VARSKIN computer code (draft NURGEG/CR 4418 at a skin " depth" of 7 mg/cm2 averaged over 1 cm2 .(IE Information Notice 86-23). Sheilding provided by clothing was measured by the licensee to be 27 mg/cm2 for one of the workers and 39 mg/cm 2 for the othe Gamma doses were assumed to be negligibl Through discussions, re-enactments, and determination that the hot particles were released while the technicians handled the last bag removed from the temporary shielded area, the licensee estimated that the hot particles were in the technicians' coverall pockets for a maximum of 15 minutes while the coveralls were being wor Because the hot particles were in a coverall pocket and not stationary on the skin the maximum calculated dose to 1 cm 2 can be halved based on a conservative estimate of lateral movement of the coveralls, and further reduced because the coveralls were reasonably not always in contact with the technician's skin. By conservatively estimating that the coverall pocket was one centimeter from the skin for half of the 15 minutes, a dose reduction factor of about 15 results for 50% of the exposure time. Based on these assumptions and the licensee determined particle activities 14.2 pCi and 2.8 pCi and isotopic compositions, the calculated skin doses to the two workers were 4.5 rem and 0.75 rem, respectivel The licensee's calculated skin doses, based on a licensee modified QAD computer code and the above assumptions, were 3.5 rem and 0.5 rem, respectively. The licensee and NRC calculations are in reasonable agreemen The applicable NRC dose limit is 7.5 rems per quarter. Although the maximum skin dose in this incident (4.5 rem) did not exceed regulatory limits, such outcome appears fortuitous rather than having derived from licensee planning, training, or precaution No violations were identifie d. Apparent Programmatic Weaknesses Associated with this Event During the inspectors' review of this incident, several associated matters appeared to contribute to the incident's occurrence, its severity, and the eventual promptness of followup investigation These matters include: | |||
* The "swarp" filter was used during vacuuming of a reactor vessel and contained readily dispersible highly radioactive particles, yet it was not packaged so there would be a low probability of package damage and resulting contamination sprea i l | |||
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The "swarp" filter is estimated to have read approximately 25 R/hr when removed from the reactor vessel and transported to the temporary storage area, yet the bag was apparently not well marked / identified nor was the outside of the temporary shield area posted with an instructional posting to indicate its relative hazard. The method of handling during transport to the storage area could not be establishe * | |||
There was no inventory of the contents of the temporary shielded area even though the contents were placed there | |||
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i because of the need for special handling and disposa * | |||
The contractor senior technician prescribed a single set of protective clothing with no respirator even though he was unaware of the contents of the bagged material. He apparently assumed proper past handling of the bagged material and anticipated that no handling problems would aris * | |||
The technicians knew that one set of coveralls was contaminated to a significantly greater extent than would be expected for the work they performed, but did not so inform the RCOs. Such information would have prompted an earlier start to the investigation. Had hot particles been deposited on the cold side of the S0P during the bag-out procedure, earlier followup would have reduced the potential for contamination sprea It is noteworthy that until about April 1, 1987, there was no firm requirement for individuals to survey protective coveralls before placing them in their controlled zone locker, and to place them in the laundry hamper if contamination levels exceed 2,000 cpm using an HP-210 prob At the request of NRC Region III, the licensee instituted the coverall frisking policy and revised Procedure HP " General Use of Protective Clothing" to include the requiremen Had this policy not been changed the contaminated PCs would have probably been reused with resultant greatly increased personal exposure Failure to identify the package contents with a clearly visible ) | |||
label or readily available record providing sufficient information l to permit individuals handling the package to take adequate ! | |||
precautions to minimize their exposure is a violation j with 10 CFR 20.203(f) requirements (Violation 266/87011-02; i 301/87010-02). I 12. Exit Interview The inspectors met with licensee representatives (denoted in Paragraph 1) | |||
at the conclusion of the inspection and summarized the scope and findings of the inspection activities. The inspectors also discussed the likely informational contents of the inspection report with regard to documents I or processes reviewed by the inspectors during the inspection. The l licensee did not identify any such documents or processes as ' | |||
proprietary. In response to the inspectors' comments, the licensee: l l | |||
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. ~ Acknowledged the inspectors comments ~concerning the. identifie i weaknesses which. contributed to unplanned personal exposures | |||
.(Sections 10 and 11). | |||
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b .-- -Stated that results of the_ investigation and dose evaluations concerning the personal unplanned exposures would be made available to Region:III_(Sections 10_and'11). Stated-that efforts will be' continued to increase the' number off permanent RCOs on the Radiation Department staff (Section 5). | |||
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Revision as of 23:09, 26 January 2022
ML20215G320 | |
Person / Time | |
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Site: | Point Beach ![]() |
Issue date: | 06/15/1987 |
From: | Greger L, Miller D, Paul R NRC OFFICE OF INSPECTION & ENFORCEMENT (IE REGION III) |
To: | |
Shared Package | |
ML20215G310 | List: |
References | |
50-266-87-11, 50-301-87-10, IEIN-86-023, IEIN-86-23, NUDOCS 8706230213 | |
Download: ML20215G320 (16) | |
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1 U. S. NUCLEAR REGULATORY COMMISSION
REGION III
Reports No. 50-266/87011(DRSS); 50-301/87010(DRSS)
Docket Nos. 50-266; 50-301 Licenses No. DPR-24; No. DPR-27
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Licensee: Wisconsin Electric Power Company 231 West Michigan Milwaukee, WI 53201 Facility Name: Point Beach Nuclear Plant (PBNP)
Inspection At: PBNP; Units 1 and 2, Two Rivers, Wisconsin Inspection Conducted: April 28 through May 19, 1987 l Inspector: 6//5'/B7 _
Date 1 i
0. 8. 7d$v i D. E. Miller 9 /#/87 Cate~
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Approved By: . r ge , Chief (>//f/87 Facilities Radiation Protection Date Section
Inspection Summary Inspection oli April 28 through May 19, 1987 (Reports No. 50-266/87011(DRSS);
No. 50-301/87010(DRSS))
Areas Inspected: Routine, unannounced inspection of the radiation protection program during a refueling outage including: organization and management controls; internal and external exposure controls; posting and access controls; contamination control; two incidents concerning unplanned radiation exposures; and previous inspection finding Results: Two violations were identified (failure to properly train employees using a radioactive source - Section 10; failure to clearly label the contents ofradjoactivematerialinacontainer-Section11).
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DETAILS 1. Persons Contacted
- R. Bredvad, Plant Health Physicist
- D. Johnson, Project Engineer, Nuclear Plant Engineering
- T. Koehler, General Superintendent
- J. Knorr, Regulatory Engineer, Nuclear Plant Engineering E. Lipke, General Superintendent, Nuclear Plant Engineering
- J. Reisenbuechler,. Superintendent, EQRS
- J. Zach, Plant Manager
- R. Hague, NRC, Senior Resident Inspector
- R. Leemon, NRC, Resident Inspector The' inspectors also contacted other plant staff during this inspectio * Denotes those present at one of the exit meetings held on May 8 and 15, 198 . General The onsite inspection which began at 8:00 a.m., April 28, 1987, was conducted to examine aspects of the licensee's radiation protection program during a refueling outage. The inspection included several plant tours, review of posting and labeling, review of personal internal and external exposures, and independent inspection efforts by the inspector Also reviewed were selected open items, corrective actions concerning previous violations, and two incidents concerning unplanned personal radiation exposure . Licensee Action on Previous Inspection Findings (Closed) Open Item (266/86016-01; 301/86015-01): Failure to initiate a report form as required by Procedure No. HP 1.11 when portal monitor containination alarms are initiated. The licensee has revised HP 1.11 to better define specific responsibilities for response to portal monitors, revised Procedure HP 2.1.2 to clarify employee responsibility for frisking and notification of personnel when contamination is found, and has initiated a formal training program for security personnel concerning their responsibility for response to portal monitor alarm (Closed) Open Item (266/86016-02; 301/86015-02): Failure to perform surveys to ensure workers would not exceed 10 CFR 20.103 limit Frequency of radiation and contamination surveys were increased in the waste evaporator feed cubicle area and other areas subject to changing radiological conditions. Procedure HP 2.5 has been revised to ensure requirements for work activities will be based on timely and adequate surveys of radiological condition f > t :$
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i(Closed) Open-Item (266/85017-01; 301/85017-01): . Developkent-of thel 1 training program for_the RCOs. The licensee has developed and. initiated I an RC0 training' program that is-INP0Lcertifie , l i; )
(0 pen) Open-ItemL(266/85007-01; 301/85007-01): Turnover rate of RC0 staff / '
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and the effect on staff. stabilit See Section , i
4.- Licensee Response to'NRC Concerns I
. 1 During a previous inspection (Inspection Report Nos.'266/86016; 301/86015)1 J j-programmatic weaknesses concerning health physics coverage, the RWP '! ~1
- program, reuse of protective clothing, the A0 qualification program and 1 other HP practices were identified. In a letter to the NRC dated' .]
February 4,.1987, the licensee addressed tris actions that had been, and y will be..taken to satisfactorily' correct the identified programmatic weaknesses; including a commitment to implement full time HP' coverage
< within two year ' Organization, Management Controls, and Staffing
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The inspectnrs revfewed the= licensee's organization and management l controls for radistio protection, including changes in the organizational l structure and staffing, effectiveness of procedures and other management'-
techniques ~used to implement the program, and experience concerning J self-identification and correction of program implementation weaknesse *} l
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Region -I6was infonned that a corporata ' staff health physicist will '
assume a newly' created Superintendecit-Health Physics-(S-HP) position at Point Beach Station effective Jund 1, 1987. The S-HP reports to.the 3 General' Superintendent with a direct reporting path to< the Plant Manager ,
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as necessary for radiological matters. The Plar,t Health Physicist and the !
Radwaste Supervisor will report to the S-HP. According to licensee ,
representatives, addition of the S-HP is intendedttd aid creation of a more; professionally oriented radiation protection department. This -
cesponds to' observations and recommendations made by NRC inspectors as a , ,
, result of past inspections.
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During two previoun inspections (Ir.cpection Reports No. 266/85007; 301/8500Fand 266/86004; 301/86004), it was notad that the turnover rate of the technician staff (RCDs and RCOTs) was significantly higher than the turnover rate of other Region III licensees. . This turnover rate affected the' qualification and experience level of the RCO staff and l
. appeared.to diminish the stability and effectiveness of the radiation '
protection organization. The cause for this turnover rate was attributed to the RCOT-selection system and salary differential between RCOs and I other plant workers which tended to discourage RCO retention. Since then,
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the licensee ' improved RC0 trainee selection, Jetreased the salary
}' differential between RC0's and other plant workers, increased the HP staff, and is continuing efforts to build a career HP. staff consisting of 12 or 13 permanent RCO However, the RCO's hoJrly Salary remains l3Wer ,
than senior chemistry technicians, mechanical maintenance workers, and y auxiliary operator ..
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'The current radiation protection staff, supplemented by HP contractors,
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appears adequate to sup' port routine radiation protection coverag However,.there remains. insufficient staffing of permanent qualified RCOs to cover nonroutine functions and the licensee must rely on use of health physics contractors to supplement;the staff during normal and outage activitie The shortage of RCOs appears to have been a factor in an extremity exposure event discussed in.Section 1 The apparent staffing shortage and lack of upgrading of RCOs was discussed at the exit meeting. (266/85007-01; 301/85007-01)
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No-violations or deviations were note . Internal Exposure Control The inspectors reviewed the licensee's internal exposure control and assessment programs, including changes to procedures affecting internal exposure control and personal exposure assessment; determination whether engineering controls, respiratory equipment, and assessment of individual
. intakes meet regulatory requirements; planning and preparation for maintenance and refueling tasks including ALARA considerations; and required records, reports, and notification The licensee's program for controlling internal exposures includes the use of protective clothing, respirators, and control of surface and airborne h radioactivity. A selected review of air sample and survey results was i made; no significant problems were noted other than those noted in Section 1 Whole body count (WBC) data was reviewed for counts performed during the period August 1, 1986 through March 31, 1987, on company and contractor personnel. Several followup counts were performed on the few persons who showed elevated initial counts. Followup counting was adequate to verify that'the 40 MPC-hour control measure was not exceeded. No problems were note No violations or deviations were identifie . Personal Contamination Events The licensee initiates Personnel Contamination Event Reports for individual personal contamination events. The report identifies the individual, date, location of contamination, method of detection, disposition of the contamination, and possible cause/ source of the contamination event. This information is entered into a computer program which permits summarization and trending of several parameter The-licensee periodically generates summary sheets that list individual events by contractor or employee name, location by body or clothing area, and method of detection of contamination (routine frisk, checkpoint frisk, portal monitor, or whole body counter). The licensee uses this information to identify trends, recurrences by individuals, and possible
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i programmatic problem During 1987 through May 6, 1987, there were 50 events that met.INP0. reporting criteria. The licensee does not currently l utilize whole body contamination monitors, relying instead upon " friskers."
The licensee.does have several PCM-1 whole body contamination monitors on 4 order, , Typically, introduction of whole body contamination monitors increases significantly the. numbers of identified personal contamination The inspectors noted that about half of the personal contamination events
' involved personal clothing. About one third of the clothing events ,
involved shorts, and one third undershirts and socks. The inspectors also i noted that the licensee's prescribed single set of protective clothing used for working in contamination levels <30,000 dpm/100 cm2 includes coveralls with untaped side pocket openings and shoe covers that'do not cover the ankle area. It appears that this prescribed clothing contributes to the potential for contamination of underwear and sock l According to licensee representatives, the licensee plans to soon begin use of coveralls which do not have side pocket openings. However, the inspectors were not apprised of any plans to alter the type of shoe coverings worn.- This matter will again be reviewed during future routine radiation protection inspections. (50-266/87011-03; 50-301/87010-03)
No violations or deviations were identifie . l E,xternal Exposure Control and Personal Dosimetry The inspectors reviewed the licensee's external exposure control and personal dosimetry to meet refueling outage need For the Unit 1 refueling outage it appeared adequate radiation surveys to identify radiological conditions were performed and sufficient health physics coverage was available to control job The inspectors selectively reviewed Radiation Work Permits (RWPs) and associated radiation surveys and observed work being done in the containment; no problems were identifie The inspectors selectively reviewed exposure records including TLD and self reading dosimetry results. The records indicate that no person exceeded regulatory limits. The occupational external dose for the station in 1986 was 375 person-rem and through April 1987 it was approximately 260 person-rem, most of which was due to the Unit I refueling outag No violations or deviations were identifie Preplanning - ALARA For this refueling outage, health physics personnel were involved in pre-outage reviews and were aware of the major radiation producing jobs in advance. Outage planners were followed. With the exception of certain small jobs that were not effectively preplanned, no major difficulties were encountere E .
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.In accordance with Procedure PBNP 3.7.4, radiological reviews were i performed for certain routine dose activitier for this' outage i accordance with radiological conditions and work to be performed. The application of these' reviews are part of the' licensee's exposure reduction program, and the use of.the reviews are particularly important during outage conditions for implementing ALAR . Radiolouical Incident Involving Unplanned Radiation Exposures The inspectors reviewed the circumstances surrounding ~an unplanned whole body radiation exposure to a station employee who unknowingly handled a i radioactive source on May 10, 1987. During the review, the inspector contacted licensee managers and health physics personnel, and interviewed the individuals involved in the incident. The inspectors observed several physical' reenactments of the incident and reviewed the licensee's investigation findings. Although no overexposures occurred as a result of.the incident, the radiation dose to one worker's~ hands was close to the quarterly extremity dose limit. The following subsections describe the event, causes, licensee and inspector followup, and dose assessmen This matter will be discussed further with the licensee during an enforcement meeting scheduled' for June 18, 1987, in the Region III Offic Summary of Event On Sunday, May 10, 1987, two Radiation Control Operator Trainees (RCOTs) and a Health Physics Supervisor (HPS) performed functional tests of two Radiation Monitoring System (RMS) monitors using a i cesium-137 source. On Monday, May 11, 1987, the licensee became aware that one of the RCOTs may have received an extremity overexposure while performing the functional tests. The licensee informed an NRC resident inspector and a Region III radiation specialist of the incident on the afternoon of the same day, and formed a formal investigation committee consisting of the j General Superintendent, NPERS, the Superintendent-Training, an !
ISI Engineer, a Project Engineer-Radiological, and a Senior Project j Engineer-Licensin ]
The incident occurred while the three workers were performing functional tests on RMS detectors. The purpose of the tests was to expose the detectors to a radiation source of sufficient strength to actuate containment purge valve trips. The shielded source container
" pig" used for these tests has a large removable shield plug in one end which is removed to expose the radiation source. A nominal 71 millicurie cesium-137 source is attached to the end of a source plug ,
assembly, which is inserted into the " pig" at the end opposite the !
shield plug. The source plug is much smaller in diameter than the shield plug. Each plug is prevented from casual removal by a padlock. The two padlocks were operated by the same High Radiation Area key. For these tests, the large plug is removed to expose the monitor to a collimated radiation beam emanating from the radioactive .
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Neither the HPS or the RCOTs had previously_used the " pig"; however, the HPS had observed the use of.the " pig" to test the IRE-211/212 !
detectors on one of.the RMSs. None of the three employees were ;
aware or had been instructed that the Cs-137 source was attached to !
the small plug; they stated that they assumed the two plugs varied -!
in size to allow for different size radiation beam The " pig" was not marked to identify the radiation hazard associated with removal of the' source plu Chronology of the Incident On May'.9, 1987, the HPS completed an 11-hour shift at about 5:30 At about 8:50 p.m., the HPS, who was the Duty On-Call Supervisor, received a call from the Duty Radiation Control Operator (RCO) who was covering the shift with an RCOT. The RCO stated that he had to leave the site because of a family emergency. The HPS contacted two of the four available RCOs to find one to cover the remainder ,
of the shift; the HPS was unsuccessful. The HPS then called in an RCOT to join him and the other RCOT onsite to cover the remainder of the shift. When the HPS arrived onsite, he became aware that his '
shift was responsible for conducting the functional trip test of the Unit 1 containment purge valves. The two monitors used to trip the purge valves are the Unit 1 SPING RMS (IRE-305) located in the Unit 1 rod drive room and the Unit 1 PNG RMS (IRE-211/212) located in the -l IRE-211/212 cubicle. Both monitors are exposed to the Cs-137 radiation source for the test. At about 11:55 p.m., the HPS, after realizing that he had never conducted or observed a trip test on the IRE-305 monitor, called an off-duty HPS who provided the onsite HPS with information concerning the techniques and methods required to successfully conduct the test; there was no discussion of use of the Cs-137 source " pig," which the HPS had observed in use once previousl At about 12:30 a.m. on May 10, 1987, the three workers arrived at the Unit I rod drive room to conduct the functional trip test of IRE-305. At this point, there are two differing accounts of how the test was performed, one by the two RCOTs and one by the HP According to the RCOTs, the HPS performed the test at the back side of IRE-305 by removing the small (source) plug from the " pig,"
setting it on the floor, and directing the open plug end of the pig toward the shielded IRE-305 monitor. Based on the HPS recollection of the performance of the test, the RCOTs successfully conducted the test on the front side of IRE-305 by removing the large (shield)
plug. After the control room ir. formed the workers the test was successful, the plug which had been removed was returned to the pig and the workers departed the are The licensee later demonstrated that if the radioactive plug was on the floor and not in the " pig" for the test, there would still be sufficient radiation emitted from the unshielded source to cause the containment purge valves to trip closed. These different scenarios /
described by the HPS and the RCOTs also were noted during physical ,
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t reenactment Although the discrepancies concerning the performance of this test are significant in their degree of disagreement, it appears thatleven if the small plug was removed from the pig as described by the RCOTs the length of time and manner in which it
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was handled'would not have caused significant' personal exposure to the'HP At about 1:00 a.m. , the three employees began the trip test on channel IRE-212 on the PNG monitor located in the IRE-211/212 cubicle. To conduct the test, one RCOT positioned himself behind the monitor. His job was to position the " pig" to ditect the-radiation beam from the open end of the pig at channel IRE-21 The other RCOT was positioned at the side of the monitor near the first RCOT to physically assist and to make radiation surveys. The HPS was located at the front of the monitor and was in radio contact with the control room. To begin the test, the first RCOT apparently renoved the source plug, placed it in front of him on the monitor support (pallet) and attempted to trip the purge valve by pointing the open port of the " pig" at the monitor. After several . failed attempts to trip the system, the HPS changed positions with the .
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second RCOT so he could assist in the " pig" handling. During the time the HPS and the second RCOT changed positions, the first RCOT held the source plug for approximately 30 seconds in each hand. He stated that he was unaware that either plug was a radioactive source; he assumed the source plug was merely another shield plug. The other RCOT did not recognize the error even though he measured abnormally high general area radiation levels (200 - 300 mR/hr) when the " pig" was incorrectly used; he stated he was unfamiliar with radiation levels to be expected during the evolutio After the HPS haa exchanged positions, the first RCOT apparently re-installed the small (source) plug in the pig and removed the larger (shield) plug so the test could be performed using what he assumed to be a larger beam size. After additional monitor manipulation with the large plug removed and the small plug positioned in the pig, the control room reported the purge valve
. tripped closed; the large plug was subsequently returned to the pi The workers departed from the area assuming that although they l encountered some difficulty in tripping the valves, the tests were
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successfully completed and no unusual incidents or circumstances had occurre The licensee became aware of the radiation exposure problem on Monday, May 11, 1987, when the two RCOTs were casually discussing their weekend work activities with other members of the health physics staff. During these discussions, some staff members realized a significant radiation exposure may have occurred; they so informed health physics management personne The licensee then formed a formal investigation committee to review the inciden The committee conducted several physical reenactments of the events, interviewed all personnel involved in or with the event, and performed radiation dose assessments.
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10 CFR 19.12 requires that workers receive instruction in precautions or procedures to minimize exposure and in the purposes and functions of protective devices employed. The failure to- (
instruct the workers.in the proper use of the cesium-137 shielded H source container is a violation of 10 CFR 19 requirement !
.(50-266/87011-01; 50-301/87010-01)
l Dose Assessment
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The licensee calculated whole body and extremity exposures _for each !
of the workers involved in the inciden The dose assessments were l calculated based on reenactments (witnessed by NRC inspectors),
sourc'e output and configuration, time of exposure to the source, and ,
location of the source relative to the workers, j For the whole body, the results of the calculations indicate the highest dose was approximately 660 mrem to the knees of the RCOT who performed the tests on RE-211/212. Adding previous doses, the RCOT's whole body exposure was less than 900 mrem for the calendar. quarter; no regulatory whole body dose limit was exceeded. The inspectors agree with the licensee's whole body dose assessment The only significant extremity dose was_to the hands of the RCOT who held the source. The licensee calculated this individual's extremity dose using a modified "QAD". computer code which divides the volume source into multiple point sources then calculates dose
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l from each point source to the skin. The licensee calculated a maximum contact dose of approximately 17.5 rem based on the specific source characteristics, a 33-second exposure time, and 7 mg/cm2 dead skin layer. Independent NRC calculations based on generalized source characteristics and the remaining assumptions utilized by the license resulted in an approximate maximum contact dose of 18.75 re ,
Assuming the correctness of the licensee's computer code, their ;
calculation should be more accurate than the NRC derived value, which was based on approximate source characteristics. Based on the realistically conservative assumption that the individual's hand was in contact with the surface of the cylindrical source and using the contact dose rate distribution derived by the licensee's computer code, the maximum dose to 1 cmi of skin tissue at a depth of 7 mg/cm2 is approximately 15 rem. (While technical arguments may be made to utilize less conservative assumptions than 1 cm2 skin area and 7 mg/cm2 dead skin layer, these values are specified by NRC as noted in IE Information Notice No. 86-2 The applicable NRC dose limit is 18.75 rems per quarter. Although the extremity dose in this incident (15 rem) did not exceed regulatory limits, such outcome appears fortuitous rather than having derived from licensee planning, training, or precaution J
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' d .' - ' Factors' Contributing to' Incident's Occu'rrence As a result'of the.. licensee's investigation and the inspectors'
review ~of the incident, several major factors were identified which appear.to have contributed to the source handling inciden * -The source container (pig) had no caution markings to identify -
the radiation hazard associated with the removal of the source plug. The two plugs are similar by outward appearance, with only the plug diameters differing. Both plugs are locked by similar key locks that are opened by the same ke * The HPS and the RCOTs were untrained and inexperienced in the use of the source container and in the function and calibration of the RMS. The HPS was unable to provide sufficient technical information to the RCOTs concerning the job they performed, ;
used poor judgement in performing a job for which he was unqualified, and may have been fatigued. The relatively low number of qualified RCOs available to provide health physics coverage also appears to have been contributar * There were no procedures covering the use of the source for functional testing of the RMS channels. Although the licensee recently developed a formal training plan which covers the use of the source container, none of the three participants had attended the training session . Hot Particle Incident On April 21, 1987, two contractor health physics technicians were assigned to move bags of radwaste from one temporary storage location to anothe After the task was done and their protective coveralls drycleaned, hot particles were found in the breast pockets of the coveralls they had worn. The licensee performed a followup investigation to determine the activity of the hot particles, the isotopes in the particles, and the length of time the particles were in the pockets. The inspectors interviewed.the participants in the incident, reviewed the licensee's investigation results and calculational methods, and performed ,
independent calculations. No overexposures occurred as a result of the l incident, and no items of noncompliance with regulatory requirements were l identified; however, weaknesses were noted. The licensee's investigation j appeared timely and thorough. This matter will be discussed further with i the licensee during an enforcement meeting scheduled for June 18, 1987, in the Region III Offic Sequence of Events On April 21, 1987, unusually high contamination ,
levels were found on two pairs of protective coveralls while frisking j them after dry cleaning. No other contaminated PCs were found nor l was any significant contamination found in the laundry room or the )
dry cleaning system. The PCs were apparently worn by two I technicians while moving bags of radwaste in the radwaste building earlier that da The contamination was subsequently identified as several discrete fuel particle i i
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Direct radiation and contamination surveys of the health physic ' station, locker. room, maintenance shop, radwaste truck access, and radwaste ATCOR areas were made to identify the source of the contamination and determine if'any contamination had been spread to clean areas. No significant activity was found except in a portion of the ATCOR area of.the radwaste building where the two contract technicians had worked earlier that da After reporting to work on the morning of April 21, 1987, the senior and junior contractor health physics technicians were instructed to !
remove bagged radwaste materials from behind a temporary shield wall in the ATCOR area of the radwaste building; the bags were to be transferred into a shielding cask'in the nearby truck. bay. The bagged materials had been placed behind the shield wall over the preceding two and a half years because their elevated radiation levels and/or radioisotopic composition dictated a need for special packagin The bags were being moved so that the area could be used to store other_radwaste. The two contractor technicians, who were working under the direction of the chemistry group radwaste supervisor, were to move the bags and provide their'own health physics job coverag At about 0750 hours0.00868 days <br />0.208 hours <br />0.00124 weeks <br />2.85375e-4 months <br /> on April 21, 1987, the senior contractor technician initiated a Radiation Work Permit (RWP) for the bag handling. The radiological conditions he entered on the RWP *:!ere based on a survey he had performed in the general area on April 7, i 1987. The general area survey did not include dose rate or i contamination levels within the temporary shielded area even though entry into that area would be required. One set of protective clothing was prescribed. Extensive dosimetry for the chest area, hands, and forearms was prescribed including integrating alarming dosimeters (set at 65 mR) to be worn on the chest area of each technician. No respiratory protective devices were worn or prescribed. The proper RWP authorizing approvals were obtaine At about 0800 hours0.00926 days <br />0.222 hours <br />0.00132 weeks <br />3.044e-4 months <br /> the technicians donned the prescribed protective clothing, attached their dosimetry, proceeded to the work area, posted a copy of the RWP at the work site, and unlocked the High j Radiation Area (HRA) gate at the shielded storage room in which the temporary shielded area is constructed in a corner. The temporary shielded walled area is about six feet high and is built of solid concrete blocks supported / braced with scaffolding; the scaffolding is so arranged that a person can climb in and out and bags can be suspended from a horizontal scaffolding railing that is slightly higher than the block wal j Using an extended probe radiation survey instrument, the senior technician surveyed the shielded storage room while entering to verify the exposure rates. He then looked into the temporary shielded storage area and saw about eight bags of waste, three of which had attached ropes that were tied to a horizontal scaffolding railing above the block wall. The technicians discussed possible 11 l
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handling methods,. assembled plastic bags, and contacted the control room to inform them that bags with high radiation readings would be handled and transporte l The senior. technician then pulled out one tied-off bag, transferred it to the step-off pad (SOP) at the HRA gate where the junior technician (on the clean side of the SOP) had a plastic bag ready to " bag-out" the transferred bag. The junior technician then taped >
the outer bag and monitored the radiation level on the bag. The,
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senior technician removed his low-cut shoe covers and cotton gloves at the S0P, donned clean cotton gloves, and carried the bag to the
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shielding cask in the truck bay. This process was repeated for the other two tied-off bags. The senior technician then surveyed the general radiation fields inside the temporary storage area, while standing.on-scaffolding, using the extended probe survey instrument-
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the general area radiation exposure rate was80-100 mR/hr. The t senior technician then climbed into the temporary storage area, handed the remaining four bags over the wall to the junior technician,
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then climbed out. The junior technician then followed the 50P ;
procedure and the four bags were transferred to the shielding cask
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in the same manner at the first thre The HRA gate was relocked, and the shielding cask surveyed to assure adequate postings and ;
access control ;
It is the licensee's practice when one set of protective clothing'is l worn that the low cut rubber shoe covers remain on the hot side of f the SOP, the cotton gloves are placed in a receptacle at the SOP, and the coveralls and low cut plastic shoe covers are worn back to l the access control area where the coveralls are surveyed to see if l they.are acceptably clean to be placed in the wearer's controlled !'
side locker for reuse. The plastic' shoe covers are discarded. The technicians followed this practice. As the junior technician approached a portable frisker with his hands, the alarm (set at 100 cpm above background) alarmed; the technician switched the frisker meter range from the X1 to the X10 range and began surveying i the arms of the coveralls when the alarm sounded again. Both technicians then discarded their coveralls in the dirty laundry '
container and began whole body frisking with portable frisker The junior technician identified about 200 cpm on his left wrist, 300 cpm on his shorts, 200 cpm on his socks and 3000 cpm on his shoes. The senior technician identified about 200 cpm on the heel of one shoe. The technician then followed normal decontamination
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and documentation procedures. The personal contamination documentation was taken to a health physics foreman who reviewed the documentation. The technicians did not tell the RCOs that their protective coveralls contained highly elevated contamination levels i when placed in the dirty laundry dru As previously stated, the technicians wore extensive self-reading dosimetry on their chest and wrists including an integrating ,
alarming dosimeter on the chest of each technician. The highest reading thus recorded was 80 mR to the right wrist of the senior
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contra'ctor technician who had performed the majority of the handling of._the radwaste bag The indicated exposures appeared reasonable for the job performe l Source and Isotopic Content of Contamination (Hot Particles).
During surveys performed in the shielded storage room and vicinity on the afternoon of April 21, 1987, and on April 22, 1987, several
" hot" particles were identified on the floor of the storage room, and one on the ladder'used while placing the radwaste bags in the :
shielding cask. No additional particles were found in areas traversed by the technicians during or after performance of the ;
radwaste bag handing. The " hot" particles read up to 40 R/hr when
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measured at one inch with an R02A survey meter with the beta- ,
. window close The particles were small but generally visible with !
the naked eye. The licensee collected samples of the particles for ,
isotopic analysi Licensee representatives removed the bags from the shielding cask where they were placed by the contract technicians. The bags were observed to see if any had been breached. The licensee noted that the inner bags (three layers), containing a small filter, appeared to be slit. The representative took a contamination swipe of the area surrounding the slits in the inner bags. The swipe was retained for isotopic analysis. According to the contract technicians, the plastic bags containing the small filter were the last handled and transferred to the shielding cas The licensee performed further surveys on the two pairs of coveralls that were retained because of contamination levels. The~ licensee found two hot particles in the breast pocket of each pair. There was total radioactivity of 14.2 pCi in the pocket of one pair of the coveralls and 2.8 pCi in the othe ~
According to the licensee, the subject filter is a "swarp" filter from a portable underwater cleaning system. The filter is essentially a stainer through which circulated water flows while cleaning underwater debris. The filter sits in a hose coupling fitting and is under water when the cleaning system is in use. The filter is cylindrical, about three inches in diameter, five inches high, has a handling bail on top, and has a thin metal flange seating surface on the bail end. The licensee believes that the filter was used during the Unit 2 outage in 1985 to remove debris
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from the reactor vessel, and has probably been in the shielded storage area since November 198 Using gamma analysis techniques, the licensee determined that the isotopic content of the hot particles found in the coverall pockets, floor of the shielded storage area, and swipe taken on the bag containing the "swarp" filter was mainly Ce-144, Pr-144, Rh-106, ,
Ru-106, and Cs-137; the relative abundance of the isotopes was similar. The isotopic content indicates that the original source of the particles was past failed fuel, particles of which were i collected in the "swarp" filter during incore cleanin ;
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i c. Calculated Dose to Contractor Technicians Skin doses were calculated by NRC using the VARSKIN computer code (draft NURGEG/CR 4418 at a skin " depth" of 7 mg/cm2 averaged over 1 cm2 .(IE Information Notice 86-23). Sheilding provided by clothing was measured by the licensee to be 27 mg/cm2 for one of the workers and 39 mg/cm 2 for the othe Gamma doses were assumed to be negligibl Through discussions, re-enactments, and determination that the hot particles were released while the technicians handled the last bag removed from the temporary shielded area, the licensee estimated that the hot particles were in the technicians' coverall pockets for a maximum of 15 minutes while the coveralls were being wor Because the hot particles were in a coverall pocket and not stationary on the skin the maximum calculated dose to 1 cm 2 can be halved based on a conservative estimate of lateral movement of the coveralls, and further reduced because the coveralls were reasonably not always in contact with the technician's skin. By conservatively estimating that the coverall pocket was one centimeter from the skin for half of the 15 minutes, a dose reduction factor of about 15 results for 50% of the exposure time. Based on these assumptions and the licensee determined particle activities 14.2 pCi and 2.8 pCi and isotopic compositions, the calculated skin doses to the two workers were 4.5 rem and 0.75 rem, respectivel The licensee's calculated skin doses, based on a licensee modified QAD computer code and the above assumptions, were 3.5 rem and 0.5 rem, respectively. The licensee and NRC calculations are in reasonable agreemen The applicable NRC dose limit is 7.5 rems per quarter. Although the maximum skin dose in this incident (4.5 rem) did not exceed regulatory limits, such outcome appears fortuitous rather than having derived from licensee planning, training, or precaution No violations were identifie d. Apparent Programmatic Weaknesses Associated with this Event During the inspectors' review of this incident, several associated matters appeared to contribute to the incident's occurrence, its severity, and the eventual promptness of followup investigation These matters include:
- The "swarp" filter was used during vacuuming of a reactor vessel and contained readily dispersible highly radioactive particles, yet it was not packaged so there would be a low probability of package damage and resulting contamination sprea i l
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The "swarp" filter is estimated to have read approximately 25 R/hr when removed from the reactor vessel and transported to the temporary storage area, yet the bag was apparently not well marked / identified nor was the outside of the temporary shield area posted with an instructional posting to indicate its relative hazard. The method of handling during transport to the storage area could not be establishe *
There was no inventory of the contents of the temporary shielded area even though the contents were placed there
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i because of the need for special handling and disposa *
The contractor senior technician prescribed a single set of protective clothing with no respirator even though he was unaware of the contents of the bagged material. He apparently assumed proper past handling of the bagged material and anticipated that no handling problems would aris *
The technicians knew that one set of coveralls was contaminated to a significantly greater extent than would be expected for the work they performed, but did not so inform the RCOs. Such information would have prompted an earlier start to the investigation. Had hot particles been deposited on the cold side of the S0P during the bag-out procedure, earlier followup would have reduced the potential for contamination sprea It is noteworthy that until about April 1, 1987, there was no firm requirement for individuals to survey protective coveralls before placing them in their controlled zone locker, and to place them in the laundry hamper if contamination levels exceed 2,000 cpm using an HP-210 prob At the request of NRC Region III, the licensee instituted the coverall frisking policy and revised Procedure HP " General Use of Protective Clothing" to include the requiremen Had this policy not been changed the contaminated PCs would have probably been reused with resultant greatly increased personal exposure Failure to identify the package contents with a clearly visible )
label or readily available record providing sufficient information l to permit individuals handling the package to take adequate !
precautions to minimize their exposure is a violation j with 10 CFR 20.203(f) requirements (Violation 266/87011-02; i 301/87010-02). I 12. Exit Interview The inspectors met with licensee representatives (denoted in Paragraph 1)
at the conclusion of the inspection and summarized the scope and findings of the inspection activities. The inspectors also discussed the likely informational contents of the inspection report with regard to documents I or processes reviewed by the inspectors during the inspection. The l licensee did not identify any such documents or processes as '
proprietary. In response to the inspectors' comments, the licensee: l l
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. ~ Acknowledged the inspectors comments ~concerning the. identifie i weaknesses which. contributed to unplanned personal exposures
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b .-- -Stated that results of the_ investigation and dose evaluations concerning the personal unplanned exposures would be made available to Region:III_(Sections 10_and'11). Stated-that efforts will be' continued to increase the' number off permanent RCOs on the Radiation Department staff (Section 5).
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