IR 05000272/1988025
| ML18093B448 | |
| Person / Time | |
|---|---|
| Site: | Salem  |
| Issue date: | 02/07/1989 |
| From: | Nimitz R, Shanbaky M NRC OFFICE OF INSPECTION & ENFORCEMENT (IE REGION I) |
| To: | |
| Shared Package | |
| ML18093B446 | List: |
| References | |
| 50-272-88-25, 50-311-88-25, NUDOCS 8902140084 | |
| Download: ML18093B448 (12) | |
Text
Report N ~88-25 50-311_88-25 Docket No. 50-272 50-311 License N DPR-70 DPR-75 U.S. NUCLEAR REGULATORY COMMISSION
REGION I
Priority Category Licensee:
Public S~rvice Electric and Gas Company
. P. 0. Box 236 Hancocks Bridge, New Jersey 08038 Facility Name:
Salem Nuclear Generating Station, Units 1 and 2 Inspection At:
Hancocks Bridge, New Jersey Inspection Conducted: November 30, 1988 - January 20, 1989 Inspector:
Approved by:
R. L. N1m1tz, Senio*? Radiation Specialist M. ~~~ities Radiation Protection Section
Inspection Summary:
c c date Areas Inspected:
Special, announced Radiological Controls Inspection of the circumstances, licensee evaluations and corrective actions associated with two events where personnel were contaminated with hot particles resulting in potential high exposures to small areas of the skin of the individuals. The licensee's action on previous NRC concerns was also reviewed. The inspection involved an onsite review of the events during the period November 30 - December 2, 1988 and a review of various data and documentation, including dose evaluations through January 20, 198 Results:
One apparent violation was identified ( Failure to implement radiation protection program procedures as required by Technical Specification 6.11, Details sections 4 and 5).
Some weaknesses were identified in the area of dosimetry processing and personnel understanding of procedure requirement *
DETAILS 1.0 Individuals Contacted 1.1 Public Service Electric and Gas Company
- G. Roggio, Statio~ Licensing Engineer
- J. Wray, Radiation Protection Engineer, Salem
- L. Miller, General Manager, Salem Operations
- J. Trejo, RP/Chem Manager, Salem Operations D. Mohler, RP/Chem Supervisor K. O'Hare, RP Supervisor Gray~ Licensing Engineer
- T. Cellmer, Radiation Protection Engineer, Hope Creek Other licensee and contractor personnel were also contacted or interviewed during the course of this inspectio * Denotes those personnel attending the exit meeting on December 2, 1988.
- Participated in the January 26, 1989 telephone discussion of inspection finding.0 Purpose and Scope of Inspection This inspection was a special, announced Radiological Contr-ols Inspectio Areas reviewed were the circumstances, licensee evaluations and corrective actions associated with two personnel exposur~ events involving hot particles. Also reviewed were several previously identified NRC concern.0 Licensee Actions on Previous Findings (Closed) Unresolved Item (50-272/88-18-03; 50-311/88-18-03):
NRC to review licensee implementation of Technical Specification 6.13 relative to use of flashing lights to warn personnel of High Radiation Areas in lieu of construction of lockable enclosures around the are Inspector review indicated three areas appear to be affected by this requirement. These were the Fuel Pool Skimmer area, the Fuel Transfer Canal filter area and a valve alley inside the bioshield on the Reactor containment 20 foot elevatio The licensee was assigning personnel to control access to the one area which exhibited radiation dose rates in excess of 1000 millirem/hr at 18 inches ( Fuel Transfer Canal Filter area). Since the effected area was transient in nature, personnel were only assigned on an as needed basi The licensee indicated all areas potentially affected by this technical specification would be reviewed to ensure the areas were controlled properl In addition procedures would be reviewed to ensure appropriate guidance was contained in radiation protection program implementing procedures. This item is close *
3 (Closed) Unresolved Item (50-272/88-18-04; 50-311/88-18-04): NRC to review circumstances and licensee evaluation of a hot particle personnel exposure event which occurred on September 28, 198 This matter is discussed in section 5 of this report. This item is close.3 (Closed) Unresolved Item (50-272/88-18-05; 50-311/88-18-05): NRC to review licensee evaluation of airborne particulate alpha radioactivity identified in Unit 2 Reactor Cavit The samples which indicated apparent high alpha airborne radioactivity were subjected to alpha spectroscopy. Licensee review of the analysis results indicated an overall low MPC value for the alpha emitter Because the apparent high sample results were not recognized by Radiation Protection Supervision, the licensee indicated the procedures would be reviewed and enhanced, if necessary, to ensure timely evaluation of apparent high sample results, selection of an appropriate MPC value for use in evaluating the results and for selection of appropriate respiratory protection devices to be worn by personnel working in the area. This item is closed; enhancements will be reviewed during subsequent inspection.4 (Closed) Unresolved item (50-272/88-18-06; 50-311/88-18-06): NRC to review circumstances associated with an individual working in the radiological *
controlled area without a radiation work permit. This matter is discussed in section 5 of this report. This item is closed 4.0 Hot Particle Contamination Event Individual A Background On October 18,1988 at about 8:15 AM a contractor worker was identified to be contaminated with a hot particle. The individual had previously loaded a carousel into a tube plugging machine on the 21 Steam Generator cold le The particle was located on the lower left leg of the individual, just above the ankle. The particle measured about 25 R/hr on contact (gamma) and 200 mR/hr (gamma) at 18 inche Beta radiation absorbed dose rates could not be immediately measured because the instrument used was off scale (greater than 50 rads/hr).
The worker had spent an estimated seven minutes on the platform performing the carousel loading.in preparation for tube plug~ing. The particle was detected during whole body surveying of the individual immediately after descending the ladder from the platfor The radiation protection technician performing the survey acted promptly to remove the particle. The particle was recovered and saved for analysi *4.2 Licensee Evaluation and Corrective Action The inspector met with cognizant personnel involved in the event and those involved in reviewing i *
The inspector's discussions indicated the following:
The hot particle was immediately removed from the contractor and saved for subsequent analysis. A licensee time and motion study indicated that the particle was on the individual's protective clothing about seven minute All work on the 21/23 Steam Generator platforms was stoppe The contractor was removed from the radiological controlled area and prohibited from further entry therein pending performance of a dose evaluatio A survey was performed of the 21/23 Steam Generator platforms prior to allowing work to restar No other hot particles were foun The licensee enhanced radiological surveys of the platform areas to require a special hot particle gamma survey once every two hours (Teletector with ear phones).
A Radiological Occurrence Report was initiated at 9:30 AM on October 18, 1988 (ROR No. 88-51 ).
A preliminary dose estimate was completed at 6:30 PM on October 18, 198 The dose to a small area of the skin directly above the ankle was estimated to range from 50 rads to about 450 rad The licensee notified the onsite NRC resident inspector on October 18, 198 A Station Incident Report was issued on October 19, 198 The licensee enhanced personnel contamination surveys to require surveys at lest once every half hour for personnel on the platform or whenever personnel come down from the platform, whichever is earlie The licensee initiated a comprehensive dose evaluation for the contracto The particle was sent to a National Laboratory for detailed analysi.3 NRC Review and Evaluation The inspector performed an independent review and evaluation of the circumstances associated with the event, the radiological surveys performed prior to and following the event, the licensee's time and motion study for the affected worker, the adequacy of the licensee's dose evaluation methodology and the adequacy of Radiation Work Permits and procedures controlling the jo *
4.. Evaluation of licensee performance in this area was based on review of documentation, discussion with cognizant personnel and independent inspector observation Circumstances and Licensee Time and Motion Study The inspector's review indicated the licensee's description of the circumstances associated with the event and the time and motion study were accurat The individual spent an estimated seven minutes on the platform ( including ascent and descent).
Radiological Surveys Performed Prior to Event The inspector review indicated the following:
A radiation and contamination survey of the 21/23 Steam Generator Platform was performed at about 8:00 on October 18, 1988. This survey was performed about 15 minutes prior to the contractor worker's entry onto the platfor The survey was not performed in accordance with licensee Radiation Work Permit (RWP) No. 88-2S-00979, revision 1, which required that the surveys be performed with Masslin cloth every four hours in the entire work area. Inspector discussions with cognizant radiation protection technicians. indicated the hot particle surveys on the steam generator platforms were being performed and formally documented only once per shift. Also no other Masslin surveys were performed the previous shift on the platform *inspector review of the above survey and other surveys of the platform indicated the surveys were performed with NUCON disc smears. The inspector noted cloth smears provided a capability to smear check a larger area. This provided a higher probability of detecting hot particles which may be presen Administrative Procedure AP 24, Radiation Protection Program, requires in section 5.4 that radiation work permits (RWPs) be adhered to. Radiation Protection Procedure RP 202, Radiation Work Permits, requires in section 7.3.12 that applicable check lists including the Hot Particle Check list be incorporated into the RW The inspector stated that failure to implement the survey requirements contained in the Hot Particle Check list which was incorporated into RWP 88-2S-00979 was an apparent violation of Technical Specification 6.11 which requires that radiation protection procedures be established, implemented and maintained for those operations involving personnel radiation exposure. (50-311/88-25-01)
- Inspector discussions with licensee radiation protection technicians indicated that the technicians had elected on their own initiative to use disc smears since the Masslin smears became "too radioactive" due to the high levels of contamination on the platforms thereby masking hot particle No apparent action had been taken to revise the procedure or obtain management concurrence in changing the contamination survey methodology specified in approved procedure Licensee Procedure 808, Discrete Radioactive Particle Exposure and Contamination Control, did not contain any guidance regarding-the method of performance of radiation surveys to detect hot particles or the types of radiation survey instruments most appropriate for these survey Inspector discussions with cognizant licensee radiation protection technicians indicated that no specific guidance regarding methodology for performance of radiation surveys for hot particles was provide The inspector considered this poor in that the general area dose rates on the 21/23 Steam Generator platform ranged from 80 mR/hr to 150 mR/hr with dose rates caused by shine from steam generators to be up to 350 mR/h Consequ~ntly performance of routine general area radiation surveys wcruld be marginally adequate in detecting hot particles due to the high background which masked the dose rates emanating from the particle The licensee had performed similar work on 22/24 Steam Generators(i.e eddy current testing and tube plugging) prior to moving to the 21/23 Steam Generators. A number of hot particles with dose rates ranging up to 10 R/hr on contact were identified on the 22/24 Steam Generator Platform. In addition, licensee surveys indicated the presence of a hot particle measuring about 3.6 R/hr on contact on the 21/23 platform area on October 16, 198 Because the licensee had not seen the same frequency of hot particles on the 21/23 generators, the hot particle survey requirements for personnel contamination were reduced from once every half-hour to once every hou Workers however were being whole body frisked after they exited the platform which was effective in identifying particles. Workers usually were on the platform no more than 10 minute The inspector concluded that, considering the activity of particles previously identified, the licensee should consider using periodic radiation surveys of the platform in addition to the use of Masslin cloth to identify hot particle *
Inspector discussions indicated that during tube plugging operations, 4-6 carousels were changed per shift. The tube plugging machine could drag hot particles out of the steam generators into the work area Personnel did not perform surveys of equipment prior to handling it on the platform The radiation work permit (No. 88-2S-00675) used to control the work on 22/24 Steam Generators included criteria for maintenance of contamination levels below 500,000 disintegrations per minute (dpm) on the platform No such requirement was included in the RWP for work on the 21/23 Steam Generators. Inspector revie indicated contamination levels on the 21/23 platform ranged from 8 mrad/hr to 240 mrad/hr, well in excess of 500,000 dpm, prior to the worker's entry on to the platfor The failure to maintain contamination levels low on the 21/23 Steam Generator platform hampered detection of hot particle Licensee Procedure AP 24, Revision 9, Radiological Protection Program, states in Section 6.2.1, Work in The Radiologically Controlled Area, "Radiation Protection surveillance shall be provided as appropriate to ensure planned precautions are observed and that potential radiatio~ and/or contamination hazards are addressed in a timely manner." The inspector concluded that the surveillance provided for this work activity was weak for the following reasons :.
There were no specific procedures or directions provided to the radiation protection personnel covering steam generator work regarding performance of gamma surveillance to detect hot particle Such guidance was appropriate considering 1) the high gamma background radiation levels present which could mask the hot particles present on the platforms 2) the high levels of contamination which could mask hot particles present on Masslin cloths and 3) the frequent handling of highly contaminated equipment on the platform by steam generator workers which could be also contaminated by hot particle The surveillance by radiation protection supervisiors and radiation protection management did not ensure that procedurally specified contamination surveys (i.e., smears with Masslin cloths and smears every 4 hours4.62963e-5 days <br />0.00111 hours <br />6.613757e-6 weeks <br />1.522e-6 months <br /> ) were being performed as required. Radiation protection supervisors signed off on surveys that were not performed in accordance with procedure requirement.4 Dose Estimates The inspector reviewed the licensee's evaluation of the do~e to Individual (A) resulting from hot particle contamination of the lower left leg just above the ankle. The inspector concluded that excellent licensee effort was used to estimate the dose to a small area of the ski *
A mock-up and time and motion study using the actual collected particle (where appropriate) was use The worker's boot was cut up to simulate appropriate density thicknesses of material shielding the worker's ski Because the apparent absorbed dose estimate is significantly effected by distance and particle activity, the licensee sent the particle to a national laboratory to estimate the particle's activity and initiated further action to estimate the particle's distance from the ski The licensee concluded that the best estimate exposure was about 5.15 rem maximum to one square centimeter of skin and 0.66 rem at a depth of 1 centimeter to the area just above the left ankle for the fourth calendar
~quarter of 198 The inspector noted that no regulatory dose limit was exceede *
The following weaknesses were noted:
The licensee assumed that the skin of the body below the knee was subject to the same dose limit as the feet and ankles (18.75 rem per calendar quarter). This conclusion apparently was based on reading of Information Notice 81-26, Sub Part 3, Clarification of Placement of Personnel Monitoring Devices for External Radiation, Supplement 1. This Notice described placement of dosimetry to measure whole body dose. The actual limit is 7.5 rem per calendar quarte As a result of the above the inspector requested that the following matters be addressed:
Review current dosimetry record system and exposure control methods to ensure appropriate exposure limits are imposed therei Review a representative sample of previous exposure records to ensure an inadervertent overexposure had not occurred due to application of the incorrect exposure limit to that portion of the leg between the ankle and kne Examine a representative sample of dose records (discussed above) to ensure no other significant exposures had occurred and had not been identified due to.. er.r.ors* in transposing dat Licensee personnel indicated the above matters would be reviewed in a timely fashion. The above matters are considered unresolved and will be reviewed during a subsequent inspection (50-311/88-25-02).
5.0 Hot Particle Contamination Event (Individual B) Background An individual, involved in surveying the waterbox of No. 22 Steam Generator on September 28, 1988 was identified as having a TLD badge (right forearm badge ) which indicated about 107 rads total exposure to the forearm based on reading of the individual's skin equivalent (shallow dose)
TLD chi The 10 CFR Part 20 limit for exposure of the forearm, of which the skin is a part, is 18.75 rem per calendar quarter The gamma dose to the forearm, based on reading the deep dose equ1valent TLD chip, was 1 re The wrist pocket dosimeter indicated 800 millire The right fingertip TLD strip indicated 767 millirem. Because of the uniformity of gamma penetrating radiation the licensee believes the exposure to the chip was caused by a hot particle. Other dosimetry located on the individual did not indicate any anomalous reading The licensee prohibited the individual from radiation work pending outcome of the dose assessmen.2 Description of Event The following sequence of events was generated based on discussions with cognizant personnel:
Individual (B), a contractor radiation protection technician, was involved in surveying the No. 22 Steam Generator on September 28, 198 At about 4:30 PM on that day, the individual experienced some apparent heat stress and exited the are The dosimetry devices were collected from the individual at about 5:00 PM on September 28,1988. When the dosimeters were frisked for removal from the radiological controlled area, the package they were in was found to be contaminated and was subsequently decontaminate The dosimetry devices remained overnight at the Main Control Point and were subsequently read the following day ( September 29,1988) at about 3:00 P The dose result indicated an apparent shallow dose of 10.8 rad to the extremit Note: The clerk who read the TLD reader printout made an error in transposing decimal points. The actual value was 108 rad The apparent value of dose wa~ entered into the licensee's dose controlling computer system at 9:30 AM on September 30, 198 Because the 10.8 rads was below the licensee's controlling limit for the extremity (80 % of the 10 CFR Part 20 limit of 18.75 rem), the individual was not prohibited from receiving additional exposur *
The contractor individual (individual B) wanted to terminate at the site and initiated action to obtain his dose records on October 2, 198 The Dosimetry Supervisor reviewed the individual's TLD results and approved the incorrect results at 11:15 AM on October 2, 198 On October 3, 1988, the licensee's inplant radiation protection personnel questioned the 10.8 rad value (because of the high value)
and met with dosimetry personnel to review the results. Subsequent review of the printouts indicated an apparent exposure of 108 rads to the shallow dose TLD worn by the individua The individual's allowable exposure was reset to zero on the licensee's dose controlling and access computer on October 3, 1988 thereby prohibiting his entry into the radiological controlled area pending performance of a dose evaluatio On October 5 and 6, 1988, the individual was directed by a Radiation Protection Supervisor to perform contamination surveys of articles being removed from the radiological controlled are Note: Although the individual could not sign in on the computer and thus sign in on an radiation work permit, the supervisor unknowingly directed the individual to enter the radiological controlled area because the supervisor did not correctly know where the RCA bega Licensee Administrative Procedure no. AP 24 Radiation Protection Program, section 6.1.3 states that personnel shall be denied access to the RCA unless they are entering under the provisions of a valid RW Failure to adhere to radiation protection procedures is considered a violation of Technical Specification 6.11 which requires such procedures to be adhered to. (50-311/88-25-01)
5.3 Licensee Corrective Actions The licensee initiated the following corrective actions The supervisor who authorized the improper entry into the RCA was counseled by managemen All appropriate personnel were notified regarding proper prohibition of personnel restricted from entering the RC *
Personnel were formally notified as to the exact location the RCA begin The licensee provided additional RCA boundary demarcation at th Control Point to enhance boundry definitio A memorandum was published by the Radiation Protection Services group to outline handling of dosimetry associated with radiological significant work and to provide flags regarding handling of anomalous dosimetry result.4 Dose Evaluation The inspector reviewed licensee exposure,evaluations. These included test irradiations of the TLD badge to determine its response and linearity and test irradiations of a TLD badge with a hot particle found in the individual's work locatio The licensee's evaluations were considered innovative and of good qualit The inspector concurred that the pattern of the irradiation of the TLD badge and other dosimetry supported licensee conclusions that the exposure was due to a hot particle on or very close to the TLD badg Since the individual was wearing multiple layers of protective clothing, the skin was shielded from a significant portion of the exposure measured by the badge which was located on the outside of the clothin Licensee dose estimates for the skin from the beta radiation ranged from 8 millirem to 1 square centimeter of the skin of the forearm to 8.14 rem to 1 square centimeter of the skin of the forearm depending on where the particle was located on the badg The licensee selected a value of 6.16 re The basis for selecting the 6.16 rem value was not clear to the inspecto Licensee personnel indicated that the basis would be reviewe The inspector concluded that the maximum apparent exposure (8.14 rem), if it is selected, is below the regulatory limit of 18.75 rem per calendar quarter and no apparent overexposure occurre The inspector noted that the individual with the high reading TLD had suffered apparent heat stress necessitating his quick removal from the RC The rapid collection of his dosimetry devices may have contributed to or resulted in the contamination of his dosimetry package when his badges were placed with those from within the steam generator waterbo Thus it is possible that no actual personnel exposure may have occurre Because it cannot be determined that the badges were contaminated by coming in contact with those from the steam generator, the licensee plans to conservatively assign a dose valu *
12 NRC Review and Conclusions Within the scope of this review the following program weaknesses were identified relative to this event:
Licensee controls to prevent contamination and thus potential exposure of personnel dosimetry may. need improvement and should be reviewe Personnel dosimetry devices worn by personnel performing radiologically significant work are not processed and reviewed on a priority basi Dosimetry readout results 'are not presented in a manner that is easy to interpret and are subject to interpretation errors:
Clerical personnel did not receive sufficient training in interpretation of print out results. Proper training to avoid mathematical errors was not give Dosimetry processing procedures contain inadequate "flags" for use in identifying apparent anomalous or significant readout results to ensure that supervision and management are notified in a timely fashion of apparent problem Dosimetry Supervisor review of dosimetry processing results was not adequate to identify errors in a timely fashio Licensee restriction and prohibition of personnel from re-entering the radiologically controlled area was inadequate due to misunderstanding of procedure requirements and understanding of exactly where the RCA begin Licensee personnel had independently recognized weaknesses in the above areas during their review of the even The licensee was in the process of initiating corrective actions for the above identified weaknesse Some_
interim corrective actions were in place; including interim dosimetry processing instructions and specific guidance regarding prohibition of personnel *entry into the RC.0 Exit Meeting The inspector met with licensee representatives denoted in section 1 of this report on December 2, 198 The inspector summarized the purpose, scope and findings of the inspection. The inspector also summarized the inspection findings during a January 26, 1989 telephone conversation with those individuals denoted in section No written material was provided to the licensee.