IR 05000352/1992014

Insp Repts 50-352/92-14 & 50-353/92-14 on 920420-24. Violations Noted.Major Areas Inspected:Review of Status of Radioactive Material,Staffing & Qualifications of Contractor Technicians,Alara & Tours of Radiological Controls Area

ML20198D604
Person / Time
Site:	Limerick
Issue date:	05/06/1992
From:	Pasciak W, Sherbini S NRC OFFICE OF INSPECTION & ENFORCEMENT (IE REGION I)
To:
Shared Package
ML20198D503	List: IR 05000352/1992014 ML20198D499 ML20198D568
References
50-352-92-14, 50-353-92-14, NUDOCS 9205210092
Download: ML20198D604 (9)

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U. S. NUCLEAR REGULATORY COMMISSION REGION 1 Report N /92-14 and 50-353/92-14 Docket N and 50-353 License N NPF-39 and NPF-8h Licensee: Philadelphia Electric Company Corresoondence Control Desk P. O. Box 195 Wayne. Pennsylvania 19087-0195 Facility Name: Limerick Generating Shtion. Units 1 and 2 Inspection At: Litterick. Pennsylvania inspection Conducted: April 20 - 24.1992 Q .f f ,

Inspector: < s' A IL-C '

S. Sherbini, Senior Radiation Specialist date Facilities Radiation Protection Section

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Approved by: A _ C / G< c W. Pasciak, Chief, Facilities Radiation h[dZ.date Protection Section Areas inspected: An announced inspection of the radiological controls program on site. Areas inspected included a review of the status of the recent incident involving an intake of radioactive material, staffing and qualifications of contractor technicians, survey procedures for contamination and airborne radioactivity, ALARA, and tours of the radiological controls area and observation of outage activities in Unit Results: Progress was made in assessing the intake of radioactive material in connection with the intake incident, as well as in identifying root causes. Tours of the radiological controls areas indicated adequate control of activities, btn some weaknesses in contamination control and housekeeping. Weaknesses were also identi0ed in the alpha contamination monitoring and survey programs, as well as in some of the procedures controlling these activities, and in outage planning and scheduling. Within the scope of this inspection, no safety concerns or

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violations of regulatory reqirements were identifie $$00 kSo$ o

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l DETAILS 1.0 Personnel Contacted 1.1 Licensee Personnel

• J. Doering, Plant Manager

• R. Dubiel, Superintendent, Plant Services

• J. Fongheiser, Senior Health Physicist

• D. J. Horne, Nuclear Maintenance

• G. M. Leitch, Vice President, Limerick J. Mallon, Dosimetry Physicist T. Mscisz, Assistant Senior Health Physicist

• D. C. Shutt, Licensing, Limerick

• W. A. Texter, Superintendent, Reactor Services 1.2 NRC Personnel T. Kenny, Senior Resident Inspector

• L. Scholl, Resident Inspector

• Denotes attendance at the exit meeting on April 24,199 .0 Status of Previous 1v identified IteIm 2.1 Assessment Of Intake An incident involving an intake cf radioactive material by a radiation work:r was described in a previous NRC Inspection R#prt (50-352/92-13 & 50-353-92/13). The incident occurred on March 25,1992 in the Unit I reactor cavity, during preparations for flooding the cavity. At the time of the previous inspection, excreta bioassay samples had been taken and sent to a vendor laboratory for analysis, but the results ,

were not available for revie .

The vendor laboratory completed the excreta analyses and provided the licensee with a preliminary report of the results. These results indicated the presence of significant quantities of alpha emitting radionuclides, approximately 50 nCi, but the identity of the radionucliv s not known at the time. The licensee reported these findiigs to the NRC but a .aat they could not explain the presence of the alpha emitting radionuclices ;ince their site sutveys before and since the incident had indicated that there was no significant alpha contamination on site. The licensee contracted an expert

! in the field to investigate these findings and also to perform an independent assessment of the intake. As a result of the expert's investigations, the licensee has concluded that the vendor's bicassay results were in error and that there had not been an intake of alpha emitting radionuclides. This conclusion was based on a review of the vendor's methods of analysis, as well as a visit to the vendor's laboratory by the

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expert and licensee representatives. The licensee stated that they believed the apparent alpha activity reported by the vendor was caused by an effect known as cross-talk between the alpha and l' eta channels of the radiation detection system. Cross-talk is caused by a phenonenon known as pulse pileup, which resulu from the presence of a relatively high beta activity in the sample, and leads to some of the beta radiation being improperly counted as alpha :diation. The licensee stated that their bioassay samples contained a significant amout of beta-emitting radionuclides and that this intense beta field caused the apparent alpha coimts. The licensee also stated that the vendor had overlooked this phenomenon when analyzing their sampics and had failed to compensate for the effect. To evaluate this hypothesis, the vendor ran several tests during the licensee's visit to their facility. One test involved counting a calibration beta source of comparable activity to that present in the samples; the source was found to produce alpha counts. In another test, the bicassay samples were counted on a different, more sophisticatul, system that is much less susceptible to cross-talk; the samples did not show any alpha activity on that system. Preliminary results of analyses to identify the alpha emiiters in tiie sampics also showed that, although some alpha emitting radionuclides were identified, they were present in very lw concentrations. Based on these consideration, it appears that the licensee's conclusion that there was negligible alpha activity in the worker's intate b vali An NRC assessment of the intake based on the most recent bicassay data asailable during this inspection suggests that the intake was smaller than had initially been estimated. Ir,it:al estimates had suggested an intake of about 100 MPCH (Maximum Permissible Concentration Hours). However, the recent bioassay data suggest that the particle sizes. inhaled may have been larger than those assumed m the standard lung model used in the initial assessments. This means that the initial retention of inhaled dust was higher than originally assumed, with a lower fraction of that dust being deposited in the pulmonary region. This in turn leads to a smaller estimate of intake based on measurements of retained activity. The best current estimate of intake, taking these factors into consideration, is about 70 MPCH of beta / gamma-emitting i radionuclides with negligible alpha emitting activity. The final report from the vendor's laboratory, as well as the reports from the independent consultant and the licensee's staff, will be reviewed during a future inspectio .2 Eat Jause Analysis The licensee developed an Event and Causal Factors chart and an Event Investigation Report to summarize the incident described above and to identify the immediate and root causes. The prelirainary drafts of these reports were reviewed during this inspectiw and.were found to be well written and thorough. The event was clearly summarized and the immediate and contributing causes were clearly identifie Recommended corrective actions were not provided in the draft reports, but the licensee stated that these will be added to the report when woik on root causes is complete . .

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7 4 Although the report clearly identified the immediate and contributing causes of the I

~ incident, it apparently did not attempt to determine if these causes reflected any

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weaknesses in the radiological controls program in general. For example, the report notes _that the health physics technician (HPT) v/as alerted at the tima of the incident that a dustpan and brush were being used in a comaminated area. 'te+ ever, he made only a quick check and concluded that there was no dustpan in u 4 a H : specified area. The_ report implies that this failure was due to poor judgemeN < a the part of the HPT, but it did not investigate the possibility that the HP staffing level on the refuel fioor may have been too low for the amount of work at the time, leading to a disinclination of the HPT to spend too much time on any single item of concer Other possible program weaknesses not considered in the report included the adequacy

of the HPT's experience and understanding of reactor cavity work and cavity

- flooding, as well as the adequacy of pre-job briefing practices on site. The licensee stated that part of the reason for not addressing these issues was that they base their Tassessment of program weaknesses on a review of trends indicated by many incidents over a period of time and not on s single incident. The licensee also stated that they have a system that classifies incidents into groups by root cause and that such a system allows identification of common elements that may point to program weaknesses. The inspector stated that, although such a system is necessary, failure to pursue the possibility of program weaknesses following a significant incident such as

- this one suggests a weakness in the self-identification and correction part of thei ,

program. The licensee stated that they will review this matter and will make changes in their reporu as necessar .0 Alpha Monitoring Program

- The intake incident discussed above, as well as the report of possible alpha

contamination in the bioassay samples taken in ' connection with that incident, raised

- questions regarding the licensee's program to monitor for alpha contamination on sit This area of the program was therefore reviewed during this inspection. The routine surveillance prograni is described in Procedure HP-200, " Routine Surveillance '

Program". According to this procedure, a weekly alpha contamination survey is conducted by taking at least one sample from the reactor water sampling sinks in the Reactor B tilding, the Turbine Building, and the Radwaste Enclosure. The survey results an reviewed by a HP supervisor and any alpha results greater than 20 dpm/100 sq. cm. are reported to HP supervision.

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The results of these weekly surveys for the months of March and part of April were reviewed during this inspection. The surveys consisted of smears taken from the ledges of the various sample sinks in the plant. Most of the surveys showed no alpha activity, and those that did show some activity showed very low count rate However, almost none of the samples were counted for beta activity, and the few that

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' ere counted showed very low contamination levels. The inspector stated that since L

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5 most of the samples showed no alpha activity and were not counted for contaminati level, these samples may not have contained sufficient activity to provide the necessary information to conclude that there was no alpha contamination problem in the plant. In addition, the inspector stated that it was not clear why the licensee. was using a level of 20 dpm as an indicator of an alpha contamination problem. The licensee stated that 20 dpm/100 sq. em. is the alpha contamination level at which an area is posted as a contamination area. However, a level of 20 dpm alpha activity on the weekly smears could represent a considerable alpha problem on site, depending on the level of beta activity also present on the saraple. A review of the surveillance procedure, as well a= Wr HP procedures giving guidance on sample counting, showed that there werv ao established limits for the counting sensitivity (such as the lower level of detection, LLD) necessag to allow detection of alpha activity at levels sufficiently low to alert the licensee of an alpha proble The licensee performs annual waste stream analyses on samples taken from various sample points in the plant for use in radwaste clastmcation and shipping. The results of these analyses, performed by a vendor laboratory, are also used by :Se licensee as an indicator of a possible alpha contamination problem in the plant. The inspector reviewed the results of these analyses for the period from 1989 to the present. Most of the analyses showed no detectable alpha activity or very low levals of such activit However, one sample, the dry active waste (DAW) sample wnt for analysis in September 1990 showed considerable gross alpha activity in comparison with the gross beta activity detected. The licensee's radwaste personnel stated that the sample was based on a composite of smears taken from various areas in the plant and that it was the first time that DAW samples were based on such smears. 'I hey also stated that they did not know why the alpha activity was high, and that apparently this result had not been investigated further. It should be noted that the analysis report in which this gross alpha activity was reported also showed less than detectable activity for l

individual alpha-emitting radionuclides in the sample. The significance of these results l is_not apparent from the analysis sheet 'xcause the sensitivity for the detection of individual radionuclides appears to be far higher than the reported gross alpha activity. For example, the gross alpha activity was reported as 1.79E-4 uCiigm of sample, whereas the individual radionuclides are reported as being less than activities of the order of IE-5 uCi/gm or lowe The licensee stated that they supplement their routine surveillance program with smear samples taken from various areas of the plant. However, the details of this l

supplemental program are not documented. The licensee stated that they will review l their a'pha sampling program and procedures and take action as appropriate.

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6 Oualifications of Vendor Technicians The qualifudons of vendor senior HP technicians hired for work during the cunent Unit 1 otage were reviewed during this inspection. The review showed that most of the technicians had more than the minimum required experience, with the majority showing over four years experience and many with over eight years of experience. No technicians with insufficient experience were identifie The minimum experience requirements for senior HP technicians is specified in the station's Technical Specifications, which refer to ANSI /ANS-3,1-1978, " Selection, qualificadon and training of personnel f:r nuclear power plants". According to this standard, technicians "shall have three years of working experience in their specialty of which one year should be related technical training". These requirements are implementad in Procedure HP-105, Tualification Review for vendor Senior Health Physics Technicians". A review of this procedure showed that it was clearly written and gives explicit guidance. However, the procedure does not provide a clear description of the manner in which the ANSI standard requirements are to be implemented on site. Specifically, the procedure does not explicitly state the minimum requirements for qualification as a senior tsnician but gives the ANSI standard as e reference. The procedure also does not provide guidance on the correspondence between hours, months, and years used in the various guidance documents. For example, the experierce in the resumes is specified in terms of months of work, whereas NRC guidance on the maximum acceptable rate of crediting experience is specified as 2000 hours0.0231 days <br />0.556 hours <br />0.00331 weeks <br />7.61e-4 months <br /> in a minimum of 10 months. On the other hand, the ANSI standard specifies minimum experience and training requirements in numbers of yeart. The procedure also does not specify the licensee's position regarding the recommendation in the standard for one year of related technical training. The procedure also permits Navy ELT (Engineering Laboratory Technician) time to be credited on a one for one basis, which is contrary to NRC guidance. The question of the appropriate method to credit ELT experience was discussed in a previous NRC Inspection Report (50-352/92-08 & 50-353/92-07). The licensee's position at the Sme was that, since they allow a maximum of two years credit for ELT experience, and the ELT program usually extends over a period of six years, their method of crediting experience is equivaler.t to or more conservative than the NRC guidance which specifies one year credit for each two years in the program. However, a review of the resumes during this inspection showed that several technicians were credited ELT experience on a one for one basis even though they had stayed in the ELT program for a total of only two to three years. The licensee stated that there must be an error in these resumes and that they will investigate these cases. The procedure also

. specifies that the maximum creditable experience outside of normal nuclear power plant health physics experience shall not exceed two years. However, some resumes were found in which over two years were credited for non-power plant health physics experience. The inspector stated that, in addition to the lack of explicit guidance in the procedure regarding some of the important selection criteria, it appeared that

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crediting of experience was in some cases apparently not in accordance with the guidance that is provided in the procedure. The inspector also stated that these observations do not imply that some of the technicians were unqualified, which was not found to be the case. However, they do indicate some weakness in the process itself that may lead to the hiring of unqualified technicians. The licensee stated that they will review this area and take corrective action as appropriat .0 Tours and Observation of Work Activiti Several tours of the radiological controls areas (RCA) were conducted during this inspection. Work activities in the RCA were also observed. The tours indicated good posting in most areas of the RCA, and random verification of the radiation fields in posted areas showed these areas to have been appropriately posted. However, several examples of poor contamination controls practices were ne% mainly in the Turbine Building. These poor practices included articles and tools phiui on the floor across contamination control boundaries, as well as unsecured air hoses, electrical wires, wood planks, and other objects placed over radiological ropes marking the boundaries of contaminated areas. The licensee stated that they were aware of these deficiencies and were attempting to correct them. The licensee also stated that many radiation workers engaged in work activi in the Turbine Building are not used to working in nuclear power plants and are havh.g difficultly observing contamination controls practices even though they were given the radiation worker training. The total number of personnel contaminations for 19o2 to date at the time of this inspection was -

approximately 75, and the number that occurred during the outage was 54. These

numbers are higher than estimated for these periods, but a significant number of these L

occurred during an airborne contamination incident on the refueling floor, in which airborne radioactivity from the drywell was inadvertently blown by a misaligned ventilation system into the refueling floor, contaminating a number of people who were working there at that tim Controls within the Reactor Building were much more effective than in the Turbine Building, and postings were found to be observed by all workers. Access control to the drywell was good, and work within the drywell appeared to be well controlled, l

although some examples of workers not engaged in work activities and standing in fields of 5-15 mR/hr were observed. Housekeeping in general was not very good, and it varied in different parts of the RCA, being poorest in the Turbine Building and quite good on the refuel floo .0 Outage Work and ALARA At the time of this inspection, the fourth refueling outage in Unit I was in its fifth week of an estimated total outage duration of about ten weeks. However, the estimated cumulative radiation exposure of about 140 person-rem for the outage had

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already been exceeded at the time of the inspection, the outage was behind schedule, and the work scope was being increased. Discussions with licensee personnel indicated that the high exposure to date was due to several factors, some attributabic to poor licensee performance and some to unforeseen circumstances. One of the unforeseen circumstances was an unusually high failure rate on snubber tests. This required a larger fraction of the snubbers to be tested, and it appeared that all the snubbers may have to be tested during this outage. This will result in additional unexpected exposure because most of these snubbers are located in the drywell, where the radiation fields are relatively high. Another unforeseen circumstance was a higher than expected valve work scope. Poor planning also contributed to the high doses. It appears that, as a result of scheduling difficulties, some jobs were not started in the proper sequence to maintain exposure ALARA. For example, some scaffolding was erected in areas with relatively high radiation fields before temporary shielding was installed over the radiation sources (mostly pipes), it also appeared that there was a conflict between the demands of industrial safety, which called for the crection of extensive scaffolding, and ALARA, which called for minimizing scaffolding and for balancing the risks between these conflicting requirements. it seems that more scaffolding was erected than warranted considering the radiation fields at these scaffolds. The licensee stated that a contributing factor in the planning and scheduling difficulties was the use of a new computer-based scheduling system. The licensee also stated that much difficulty was encountered during the initial phases of using that system, and that some of the difficulties persis A review of the exposure data showed that many of the major jobs were below their estimated exposures at the time of this inspection. For example, exposure on the refuel floor was below expected at the current phase of work, as was LPRM (Local Power Range Monitor) work, control rod drive work, reactor vessel and nozzle inspections, pipe and hanger inspections, and main steam isolation valve wor Although many of these jobs had not been completed at the time of the inspection, the exposure trend indicated that the exposures in these cases will probably stay within he estimate or exceed it by a slight amount. The licensee stated that they believed most of the higher than expected exposures resulted from poor performance on the smaller jobs. The licensee stated that during the early phases of the outage, there were apparently excessive numbers of workers allowed into the RCA, but this problem is being addresse Outage data presentation and dissemination on site was found to be quite poo Although many curves were produced showing exposures for various jobs, most of these curves were poorly designed and difficult to understand. Also, much of the information was not readily available in a suitable format for site personnel and management to review. For example, there were no daily reports showiag the status of each outage-related work permit and its person-hour and dose status and its stage of completion, although such data were available internally within the HP organization. It appears that the absence of such data in proper format contributed to

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the difficulties that the licensee appeared to have aeountered in tracking exposures and understanding in a timely manner the causes for the observed higher than expected cumulative dose trends. The licensee stated that much of the difficulty with data presentation stemmed from the same computer software mentioned above in connection with planning and scheduling, because the same software is used to generate the outage-related data and graphic It should be pointed out that, despite the above problems, the cumulative exposure to date still remains below industry averages for this type of plant. The licensee's efforts to maintain low dose rates within the plant and to keep contamination levels also at very low levels has minimized the radiological impact of the poor planning and performance observed in some aspects of this outag .0 liut Mechng The inspector met with licensee representatives at the end of the inspection on April 24,1992. The inspector reviewed the purpose and scope of the inspection and discussed the inspection findings.

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