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| {{Adams
| | #REDIRECT [[IR 05000266/1987011]] |
| | number = ML20215G320
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| | issue date = 06/15/1987
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| | 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
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| | author name = Greger L, Miller D, Paul R
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| | author affiliation = NRC OFFICE OF INSPECTION & ENFORCEMENT (IE REGION III)
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| | addressee name =
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| | addressee affiliation =
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| | docket = 05000266, 05000301
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| | license number =
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| | contact person =
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| | document report number = 50-266-87-11, 50-301-87-10, IEIN-86-023, IEIN-86-23, NUDOCS 8706230213
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| | package number = ML20215G310
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| | document type = INSPECTION REPORT, NRC-GENERATED, INSPECTION REPORT, UTILITY, TEXT-INSPECTION & AUDIT & I&E CIRCULARS
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| | page count = 16
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| }}
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| See also: [[see also::IR 05000266/1987011]]
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| | |
| =Text=
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| {{#Wiki_filter:E
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| 1
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| U. S. NUCLEAR REGULATORY COMMISSION
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| REGION III
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| Reports No. 50-266/87011(DRSS); 50-301/87010(DRSS)
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| Docket Nos. 50-266; 50-301 Licenses No. DPR-24; No. DPR-27
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| .
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| Licensee: Wisconsin Electric Power Company
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| 231 West Michigan
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| Milwaukee, WI 53201
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| Facility Name: Point Beach Nuclear Plant (PBNP)
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| Inspection At: PBNP; Units 1 and 2, Two Rivers, Wisconsin
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| Inspection Conducted: April 28 through May 19, 1987 l
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| Inspector: 6//5'/B7 _
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| Date 1
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| i
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| 0. 8. 7d$v i
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| D. E. Miller 9 /#/87
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| Cate~
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| "
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| 4- )
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| Approved By: C. . r ge , Chief (>//f/87
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| Facilities Radiation Protection Date
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| Section
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| 1
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| Inspection Summary
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| Inspection oli April 28 through May 19, 1987 (Reports No. 50-266/87011(DRSS);
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| No. 50-301/87010(DRSS))
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| Areas Inspected: Routine, unannounced inspection of the radiation protection
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| program during a refueling outage including: organization and management
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| controls; internal and external exposure controls; posting and access
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| controls; contamination control; two incidents concerning unplanned radiation
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| exposures; and previous inspection findings.
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| Results: Two violations were identified (failure to properly train employees
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| using a radioactive source - Section 10; failure to clearly label the contents
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| ofradjoactivematerialinacontainer-Section11).
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| v!P
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| DETAILS
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| 1. Persons Contacted
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| *R. Bredvad, Plant Health Physicist
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| *D. Johnson, Project Engineer, Nuclear Plant Engineering
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| *T. Koehler, General Superintendent
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| *J. Knorr, Regulatory Engineer, Nuclear Plant Engineering
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| E. Lipke, General Superintendent, Nuclear Plant Engineering
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| *J. Reisenbuechler,. Superintendent, EQRS
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| *J. Zach, Plant Manager
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| *R. Hague, NRC, Senior Resident Inspector
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| *R. Leemon, NRC, Resident Inspector
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| The' inspectors also contacted other plant staff during this inspection.
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| * Denotes those present at one of the exit meetings held on May 8 and 15,
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| 1987.
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| 2. General
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| The onsite inspection which began at 8:00 a.m., April 28, 1987, was
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| conducted to examine aspects of the licensee's radiation protection
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| program during a refueling outage. The inspection included several plant
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| tours, review of posting and labeling, review of personal internal and
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| external exposures, and independent inspection efforts by the inspectors.
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| Also reviewed were selected open items, corrective actions concerning
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| previous violations, and two incidents concerning unplanned personal
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| radiation exposures.
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| 3. Licensee Action on Previous Inspection Findings
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| (Closed) Open Item (266/86016-01; 301/86015-01): Failure to initiate a
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| report form as required by Procedure No. HP 1.11 when portal monitor
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| containination alarms are initiated. The licensee has revised HP 1.11 to
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| better define specific responsibilities for response to portal monitors,
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| revised Procedure HP 2.1.2 to clarify employee responsibility for frisking
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| and notification of personnel when contamination is found, and has
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| initiated a formal training program for security personnel concerning
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| their responsibility for response to portal monitor alarms.
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| (Closed) Open Item (266/86016-02; 301/86015-02): Failure to perform
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| surveys to ensure workers would not exceed 10 CFR 20.103 limits.
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| Frequency of radiation and contamination surveys were increased in the
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| waste evaporator feed cubicle area and other areas subject to changing
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| radiological conditions. Procedure HP 2.5 has been revised to ensure
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| requirements for work activities will be based on timely and adequate
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| surveys of radiological conditions.
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| 2
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| i(Closed) Open-Item (266/85017-01; 301/85017-01): . Developkent-of thel 1
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| training program for_the RCOs. The licensee has developed and. initiated I
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| an RC0 training' program that is-INP0Lcertified. , l
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| i; )
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| (0 pen) Open-ItemL(266/85007-01; 301/85007-01): Turnover rate of RC0 staff / '
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| " :)
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| and the effect on staff. stability. See Section 5. 7
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| , i
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| *
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| 4.- Licensee Response to'NRC Concerns I
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| ;
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| . 1
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| During a previous inspection (Inspection Report Nos.'266/86016; 301/86015)1 J j
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| -programmatic weaknesses concerning health physics coverage, the RWP '! ~1
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| : program, reuse of protective clothing, the A0 qualification program and 1
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| other HP practices were identified. In a letter to the NRC dated' .]
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| February 4,.1987, the licensee addressed tris actions that had been, and y
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| will be..taken to satisfactorily' correct the identified programmatic
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| weaknesses; including a commitment to implement full time HP' coverage
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| < within two years.
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| '
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| 5. Organization, Management Controls, and Staffing
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| '
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| The inspectnrs revfewed the= licensee's organization and management l
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| controls for radistio protection, including changes in the organizational l
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| structure and staffing, effectiveness of procedures and other management'-
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| techniques ~used to implement the program, and experience concerning J
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| self-identification and correction of program implementation weaknesses.
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| *} l
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| '
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| Region -I6was infonned that a corporata ' staff health physicist will '
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| assume a newly' created Superintendecit-Health Physics-(S-HP) position at
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| Point Beach Station effective Jund 1, 1987. The S-HP reports to.the 3
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| General' Superintendent with a direct reporting path to< the Plant Manager ,
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| 33 !
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| as necessary for radiological matters. The Plar,t Health Physicist and the !
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| Radwaste Supervisor will report to the S-HP. According to licensee ,
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| representatives, addition of the S-HP is intendedttd aid creation of a
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| more; professionally oriented radiation protection department. This -
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| cesponds to' observations and recommendations made by NRC inspectors as a , ,
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| , result of past inspections.
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| )- ',
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| During two previoun inspections (Ir.cpection Reports No. 266/85007;
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| 301/8500Fand 266/86004; 301/86004), it was notad that the turnover rate
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| of the technician staff (RCDs and RCOTs) was significantly higher than
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| the turnover rate of other Region III licensees. . This turnover rate
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| affected the' qualification and experience level of the RCO staff and l
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| . appeared.to diminish the stability and effectiveness of the radiation '
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| protection organization. The cause for this turnover rate was attributed
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| to the RCOT-selection system and salary differential between RCOs and I
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| other plant workers which tended to discourage RCO retention. Since then,
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| '
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| the licensee ' improved RC0 trainee selection, Jetreased the salary
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| }' differential between RC0's and other plant workers, increased the HP staff,
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| and is continuing efforts to build a career HP. staff consisting of 12
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| or 13 permanent RCOs. However, the RCO's hoJrly Salary remains l3Wer ,
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| than senior chemistry technicians, mechanical maintenance workers, and y
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| auxiliary operators.
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| 'The current radiation protection staff, supplemented by HP contractors,
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| >
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| appears adequate to sup' port routine radiation protection coverage.
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| However,.there remains. insufficient staffing of permanent qualified RCOs
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| to cover nonroutine functions and the licensee must rely on use of health
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| physics contractors to supplement;the staff during normal and outage
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| activities. The shortage of RCOs appears to have been a factor in an
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| extremity exposure event discussed in.Section 10.
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| The apparent staffing shortage and lack of upgrading of RCOs was
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| discussed at the exit meeting. (266/85007-01; 301/85007-01)
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| '
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| No-violations or deviations were noted.
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| 6. Internal Exposure Control
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| The inspectors reviewed the licensee's internal exposure control and
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| assessment programs, including changes to procedures affecting internal
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| exposure control and personal exposure assessment; determination whether
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| engineering controls, respiratory equipment, and assessment of individual
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| . intakes meet regulatory requirements; planning and preparation for
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| maintenance and refueling tasks including ALARA considerations; and
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| required records, reports, and notifications.
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| The licensee's program for controlling internal exposures includes the use
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| of protective clothing, respirators, and control of surface and airborne
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| h radioactivity. A selected review of air sample and survey results was
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| i made; no significant problems were noted other than those noted in
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| Section 11.
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| Whole body count (WBC) data was reviewed for counts performed during the
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| period August 1, 1986 through March 31, 1987, on company and contractor
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| personnel. Several followup counts were performed on the few persons who
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| showed elevated initial counts. Followup counting was adequate to verify
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| that'the 40 MPC-hour control measure was not exceeded. No problems were
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| noted.
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| No violations or deviations were identified.
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| 7. Personal Contamination Events
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| The licensee initiates Personnel Contamination Event Reports for
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| individual personal contamination events. The report identifies the
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| individual, date, location of contamination, method of detection,
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| disposition of the contamination, and possible cause/ source of the
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| contamination event. This information is entered into a computer program
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| which permits summarization and trending of several parameters.
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| The-licensee periodically generates summary sheets that list individual
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| events by contractor or employee name, location by body or clothing area,
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| and method of detection of contamination (routine frisk, checkpoint frisk,
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| portal monitor, or whole body counter). The licensee uses this
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| information to identify trends, recurrences by individuals, and possible
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| 4
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| programmatic problems. During 1987 through May 6, 1987, there were 50
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| events that met.INP0. reporting criteria. The licensee does not currently l
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| utilize whole body contamination monitors, relying instead upon " friskers."
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| The licensee.does have several PCM-1 whole body contamination monitors on 4
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| order, , Typically, introduction of whole body contamination monitors
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| increases significantly the. numbers of identified personal contaminations.
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| The inspectors noted that about half of the personal contamination events
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| ' involved personal clothing. About one third of the clothing events ,
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| involved shorts, and one third undershirts and socks. The inspectors also i
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| noted that the licensee's prescribed single set of protective clothing
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| used for working in contamination levels <30,000 dpm/100 cm2 includes
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| coveralls with untaped side pocket openings and shoe covers that'do not
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| cover the ankle area. It appears that this prescribed clothing
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| contributes to the potential for contamination of underwear and socks.
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| l
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| According to licensee representatives, the licensee plans to soon begin
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| use of coveralls which do not have side pocket openings. However, the
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| inspectors were not apprised of any plans to alter the type of shoe
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| coverings worn.- This matter will again be reviewed during future routine
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| radiation protection inspections. (50-266/87011-03; 50-301/87010-03)
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| No violations or deviations were identified.
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| 8. l
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| E,xternal Exposure Control and Personal Dosimetry
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| The inspectors reviewed the licensee's external exposure control and
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| personal dosimetry to meet refueling outage needs.
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| For the Unit 1 refueling outage it appeared adequate radiation surveys to
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| identify radiological conditions were performed and sufficient health
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| physics coverage was available to control jobs.
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| The inspectors selectively reviewed Radiation Work Permits (RWPs) and
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| associated radiation surveys and observed work being done in the
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| containment; no problems were identified.
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| The inspectors selectively reviewed exposure records including TLD and
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| self reading dosimetry results. The records indicate that no person
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| exceeded regulatory limits. The occupational external dose for the
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| station in 1986 was 375 person-rem and through April 1987 it was
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| approximately 260 person-rem, most of which was due to the Unit I
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| refueling outage.
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| No violations or deviations were identified.
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| 9 Preplanning - ALARA
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| For this refueling outage, health physics personnel were involved in
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| pre-outage reviews and were aware of the major radiation producing jobs in
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| advance. Outage planners were followed. With the exception of certain
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| small jobs that were not effectively preplanned, no major difficulties
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| were encountered.
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| 5
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| .In accordance with Procedure PBNP 3.7.4, radiological reviews were i
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| performed for certain routine dose activitier for this' outage in.
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| accordance with radiological conditions and work to be performed. The
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| application of these' reviews are part of the' licensee's exposure reduction
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| program, and the use of.the reviews are particularly important during
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| outage conditions for implementing ALARA.
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| -10. Radiolouical Incident Involving Unplanned Radiation Exposures
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| The inspectors reviewed the circumstances surrounding ~an unplanned whole
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| body radiation exposure to a station employee who unknowingly handled a i
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| radioactive source on May 10, 1987. During the review, the inspectors.
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| contacted licensee managers and health physics personnel, and interviewed
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| the individuals involved in the incident. The inspectors observed
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| several physical' reenactments of the incident and reviewed the licensee's
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| investigation findings. Although no overexposures occurred as a result
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| of.the incident, the radiation dose to one worker's~ hands was close to
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| the quarterly extremity dose limit. The following subsections describe
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| the event, causes, licensee and inspector followup, and dose assessment.
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| This matter will be discussed further with the licensee during an
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| enforcement meeting scheduled' for June 18, 1987, in the Region III Office.
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| a. Summary of Event
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| On Sunday, May 10, 1987, two Radiation Control Operator Trainees
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| (RCOTs) and a Health Physics Supervisor (HPS) performed functional
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| tests of two Radiation Monitoring System (RMS) monitors using a i
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| cesium-137 source. On Monday, May 11, 1987, the licensee became
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| aware that one of the RCOTs may have received an extremity
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| overexposure while performing the functional tests. The licensee
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| informed an NRC resident inspector and a Region III radiation
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| specialist of the incident on the afternoon of the same day,
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| and formed a formal investigation committee consisting of the j
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| General Superintendent, NPERS, the Superintendent-Training, an !
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| ISI Engineer, a Project Engineer-Radiological, and a Senior Project j
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| Engineer-Licensing. ]
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| The incident occurred while the three workers were performing
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| functional tests on RMS detectors. The purpose of the tests was to
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| expose the detectors to a radiation source of sufficient strength to
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| actuate containment purge valve trips. The shielded source container
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| " pig" used for these tests has a large removable shield plug in one
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| end which is removed to expose the radiation source. A nominal 71
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| millicurie cesium-137 source is attached to the end of a source plug ,
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| assembly, which is inserted into the " pig" at the end opposite the !
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| shield plug. The source plug is much smaller in diameter than the
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| shield plug. Each plug is prevented from casual removal by a
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| padlock. The two padlocks were operated by the same High Radiation
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| Area key. For these tests, the large plug is removed to expose the
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| monitor to a collimated radiation beam emanating from the radioactive .
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| source.
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| Neither the HPS or the RCOTs had previously_used the " pig"; however,
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| the HPS had observed the use of.the " pig" to test the IRE-211/212 !
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| detectors on one of.the RMSs. None of the three employees were ;
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| aware or had been instructed that the Cs-137 source was attached to !
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| the small plug; they stated that they assumed the two plugs varied -!
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| in size to allow for different size radiation beams. The " pig" was
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| not marked to identify the radiation hazard associated with removal
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| of the' source plug.
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| b. Chronology of the Incident
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| On May'.9, 1987, the HPS completed an 11-hour shift at about 5:30 p.m.
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| At about 8:50 p.m., the HPS, who was the Duty On-Call Supervisor,
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| received a call from the Duty Radiation Control Operator (RCO) who
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| was covering the shift with an RCOT. The RCO stated that he had
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| to leave the site because of a family emergency. The HPS contacted
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| two of the four available RCOs to find one to cover the remainder ,
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| of the shift; the HPS was unsuccessful. The HPS then called in an
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| RCOT to join him and the other RCOT onsite to cover the remainder
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| of the shift. When the HPS arrived onsite, he became aware that his '
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| shift was responsible for conducting the functional trip test of the
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| Unit 1 containment purge valves. The two monitors used to trip the
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| purge valves are the Unit 1 SPING RMS (IRE-305) located in the Unit 1
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| rod drive room and the Unit 1 PNG RMS (IRE-211/212) located in the -l
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| IRE-211/212 cubicle. Both monitors are exposed to the Cs-137
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| radiation source for the test. At about 11:55 p.m., the HPS,
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| after realizing that he had never conducted or observed a trip test
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| on the IRE-305 monitor, called an off-duty HPS who provided the
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| onsite HPS with information concerning the techniques and methods
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| required to successfully conduct the test; there was no discussion
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| of use of the Cs-137 source " pig," which the HPS had observed in use
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| once previously.
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| At about 12:30 a.m. on May 10, 1987, the three workers arrived at
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| the Unit I rod drive room to conduct the functional trip test of
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| IRE-305. At this point, there are two differing accounts of how the
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| test was performed, one by the two RCOTs and one by the HPS.
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| According to the RCOTs, the HPS performed the test at the back side
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| of IRE-305 by removing the small (source) plug from the " pig,"
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| setting it on the floor, and directing the open plug end of the pig
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| toward the shielded IRE-305 monitor. Based on the HPS recollection
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| of the performance of the test, the RCOTs successfully conducted the
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| test on the front side of IRE-305 by removing the large (shield)
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| plug. After the control room ir. formed the workers the test was
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| successful, the plug which had been removed was returned to the pig
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| and the workers departed the area.
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| The licensee later demonstrated that if the radioactive plug was on
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| the floor and not in the " pig" for the test, there would still be
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| sufficient radiation emitted from the unshielded source to cause the
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| containment purge valves to trip closed. These different scenarios /
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| described by the HPS and the RCOTs also were noted during physical ,
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| reenactments. Although the discrepancies concerning the performance
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| of this test are significant in their degree of disagreement, it
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| appears thatleven if the small plug was removed from the pig as
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| described by the RCOTs the length of time and manner in which it
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| ,
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| was handled'would not have caused significant' personal exposure to
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| the'HPS.
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| At about 1:00 a.m. , the three employees began the trip test on
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| channel IRE-212 on the PNG monitor located in the IRE-211/212
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| cubicle. To conduct the test, one RCOT positioned himself behind
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| the monitor. His job was to position the " pig" to ditect the-
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| radiation beam from the open end of the pig at channel IRE-212.
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| The other RCOT was positioned at the side of the monitor near the
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| first RCOT to physically assist and to make radiation surveys. The
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| HPS was located at the front of the monitor and was in radio contact
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| with the control room. To begin the test, the first RCOT apparently
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| renoved the source plug, placed it in front of him on the monitor
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| support (pallet) and attempted to trip the purge valve by pointing
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| the open port of the " pig" at the monitor. After several . failed
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| attempts to trip the system, the HPS changed positions with the .
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| '
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| second RCOT so he could assist in the " pig" handling. During the
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| time the HPS and the second RCOT changed positions, the first RCOT
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| held the source plug for approximately 30 seconds in each hand. He
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| stated that he was unaware that either plug was a radioactive source;
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| he assumed the source plug was merely another shield plug. The
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| other RCOT did not recognize the error even though he measured
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| abnormally high general area radiation levels (200 - 300 mR/hr) when
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| the " pig" was incorrectly used; he stated he was unfamiliar with
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| radiation levels to be expected during the evolution.
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| After the HPS haa exchanged positions, the first RCOT apparently
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| re-installed the small (source) plug in the pig and removed the
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| larger (shield) plug so the test could be performed using what he
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| assumed to be a larger beam size. After additional monitor
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| manipulation with the large plug removed and the small plug
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| positioned in the pig, the control room reported the purge valve
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| . tripped closed; the large plug was subsequently returned to the pig.
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| The workers departed from the area assuming that although they l
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| encountered some difficulty in tripping the valves, the tests were
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| '
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| successfully completed and no unusual incidents or circumstances
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| had occurred.
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| The licensee became aware of the radiation exposure problem on
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| 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
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| realized a significant radiation exposure may have occurred; they
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| so informed health physics management personnel. The licensee then
| |
| formed a formal investigation committee to review the incident. The
| |
| committee conducted several physical reenactments of the events,
| |
| interviewed all personnel involved in or with the event, and
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| performed radiation dose assessments.
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| f4
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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- (
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| instruct the workers.in the proper use of the cesium-137 shielded H
| |
| source container is a violation of 10 CFR 19 requirements. !
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| .(50-266/87011-01; 50-301/87010-01)
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| c. Dose Assessment
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| The licensee calculated whole body and extremity exposures _for each !
| |
| of the workers involved in the incident. 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 assessments.
| |
| 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
| |
| _
| |
| 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 rem. ,
| |
| 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. 86-23.
| |
| 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 precautions.
| |
| 9
| |
| J
| |
| | |
| b; -
| |
| .
| |
| .
| |
| ' 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 incident.
| |
| * -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 key.
| |
| * 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 contributary.
| |
| * 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 sessions.
| |
| 11. 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 another.
| |
| 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 Office.
| |
| a. 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 day. The contamination was subsequently identified as
| |
| several discrete fuel particles.
| |
| 10 1
| |
| i
| |
| i
| |
| | |
| { .
| |
| ..
| |
| Direct radiation and contamination surveys of the health physics.
| |
| ' 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 day.
| |
| 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 packaging.
| |
| 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 coverage.
| |
| 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 obtained.
| |
| 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 wall. 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
| |
| | |
| f .
| |
| -
| |
| handling methods,. assembled plastic bags, and contacted the control
| |
| room to inform them that bags with high radiation readings would be
| |
| handled and transported.
| |
| 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,
| |
| ':
| |
| senior technician removed his low-cut shoe covers and cotton gloves
| |
| at the S0P, donned clean cotton gloves, and carried the bag to the
| |
| .'
| |
| 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-
| |
| .
| |
| 1
| |
| 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,
| |
| -
| |
| ,
| |
| then climbed out. The junior technician then followed the 50P ;
| |
| procedure and the four bags were transferred to the shielding cask
| |
| "
| |
| in the same manner at the first three. The HRA gate was relocked,
| |
| and the shielding cask surveyed to assure adequate postings and ;
| |
| access controls. ;
| |
| 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 friskers. 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
| |
| "
| |
| 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 drum.
| |
| 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
| |
| 12
| |
| | |
| ( . .c
| |
| i
| |
| contra'ctor technician who had performed the majority of the handling
| |
| of._the radwaste bags. The indicated exposures appeared reasonable
| |
| for the job performed. l
| |
| b. 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
| |
| -
| |
| measured at one inch with an R02A survey meter with the beta- ,
| |
| . window closed. The particles were small but generally visible with !
| |
| the naked eye. The licensee collected samples of the particles for ,
| |
| isotopic analysis.
| |
| 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 cask.
| |
| 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 other.
| |
| ~
| |
| 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
| |
| '
| |
| from the reactor vessel, and has probably been in the shielded
| |
| storage area since November 1987.
| |
| 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 cleaning.
| |
| 13 ;
| |
| | |
| p
| |
| . .
| |
| 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 other. Gamma doses were assumed to be
| |
| negligible.
| |
| 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 worn.
| |
| 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, respectively.
| |
| 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
| |
| agreement.
| |
| 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 precautions.
| |
| No violations were identified.
| |
| 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 investigations.
| |
| 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
| |
| spread.
| |
| 14
| |
| i
| |
| l
| |
| | |
| { . .
| |
| <
| |
| *
| |
| 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 established.
| |
| *
| |
| There was no inventory of the contents of the temporary
| |
| shielded area even though the contents were placed there
| |
| .
| |
| i
| |
| because of the need for special handling and disposal.
| |
| *
| |
| 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 arise.
| |
| *
| |
| 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 spread.
| |
| 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 probe. At the request of NRC Region III, the licensee
| |
| instituted the coverall frisking policy and revised Procedure HP 2.7
| |
| " General Use of Protective Clothing" to include the requirement.
| |
| Had this policy not been changed the contaminated PCs would have
| |
| probably been reused with resultant greatly increased personal
| |
| exposures.
| |
| 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
| |
| 15 !
| |
| | |
| $
| |
| ..:
| |
| . ..-
| |
| .
| |
| a. ~ Acknowledged the inspectors comments ~concerning the. identified.
| |
| i
| |
| weaknesses which. contributed to unplanned personal exposures
| |
| .(Sections 10 and 11).
| |
| "'
| |
| 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).
| |
| c. Stated-that efforts will be' continued to increase the' number off
| |
| permanent RCOs on the Radiation Department staff (Section 5).
| |
| j
| |
| i
| |
| ..
| |
| !
| |
| I- 16
| |
| i<
| |
| }}
| |