ML20211K360
| ML20211K360 | |
| Person / Time | |
|---|---|
| Site: | University of Missouri-Columbia |
| Issue date: | 11/03/1986 |
| From: | Gill C, Greger L, Slawinski W NRC OFFICE OF INSPECTION & ENFORCEMENT (IE REGION III) |
| To: | |
| Shared Package | |
| ML20211K330 | List: |
| References | |
| 50-186-86-03, 50-186-86-3, NUDOCS 8611170142 | |
| Download: ML20211K360 (23) | |
See also: IR 05000186/1986003
Text
{{#Wiki_filter:F . . . U.S. NUCLEAR REGULATORY COMMISSION REGION III Report No. 50-186/86003(DRSS) , Docket No. 50-186 License No. R-103 Licensee: University of Missouri Research Park Columbia, M0 65201 ! j Facility Name: Research Reactor Facility ! Inspection At: Research Reactor Facility, Columbia, M0 t Inspection Conducted: August 26-29, September 18, and October 3, 1986 Inspectors: W. J. Slawinski // .
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/ Date' ' C. F. Gill /8 *'-84> Date l un - Approved'By: L. R. Greger, hief & 3/- 4 Facilities Radiation Protection Section Date Inspection Summary Inspection on August 26-29, September 18, and October 3, 1986 (Report No. 50-186/86003(DRSS)) Areas Inspected: Routine, unannounced inspection of radiation protection and radwaste management programs including: qualifications; audits; training; radiation protection procedures; exposure controls; posting, labeling, and area controls; radiological surveys; instruments and equipment; coolant chemistry effluent releases; receipt and transfer of radioactive materials; and notifications and reports; and special inspection of a reported exposure exceeding 10 CFR 20.101(a) limits. Results: Four violations were identified (failure to adequately evaluate potential personnel exposures associated with handling curie quantities of thulium-170 - Section 8; failure to maintain survey records - Section 8; failure to include correct activity on shipping paper - Section 16; overexposure report did not include all required information - Section 17). Nk" DON [[ O Q
. DETAILS 1. Persons Contacted
- D. Alger, Associate Director, Research Reactor Facility
R. Brugger, Director, Research Reactor Facility R. Dobey, Health Physics Technician J. Ernst, Health Physics Technician S. Gunn, Reactor Services Manager P. Lee, Director, Health Physics Services 0. Olson, Manager, Reactor Health Physics
- L. Pitchford, Associate Director, Office of Research Safety
- R. Stevens, Senior Health Physics Technician
- J. Tolan, Director and Radiation Safety Officer, Office of
Research Safety C. Yoder, Technology Manager, Radiation Dosimetry, R. S. Landauer Jr. and Company The inspectors also interviewed other licensee employees, including licensed operators, reactor services personnel, and facility researchers.
- Denotes those present at the exit interview on August 29, 1986.
Denotes those present at the enforcement conference on October 3, 1986. 2. _ General This inspection, which began with visual observation of facilities, equipment, posting, labeling, and access controls at 3:00 p.m. on August 26, 1986, was conducted to examine the routine, operational radiation protection and radwaste management programs. Areas visited during tours of the facility included the hot cell area, all levels of the containment building, and various laboratories located throughout the research reactor facility. The special September 18, 1986 inspection was conducted to review the licensee's evaluation of an apparent extremity overexposure and witness a reenactment of the event. 3. Organization The current Health Physics staff for the reactor facility consists of a Health Physics Manager, three full-time Health Physics Technicians, and up to three part-time student technicians. Independent oversight of the reactor health physics program is provided by the University's Office of Research Safety. This oversight includes all NRC licensed activities conducted as part of the University program. Since the previous NRC radiation protection inspection in April 1985, one additional health physics technician has been hired. The inspectors reviewed the new technician's qualifications. This individual has a Bachelor of Science degree in Health Physics, successfully completed 2 . __ _ _ . _ _ _ . - . _ _ _ _ _ _
' . a 10 week Oak Ridge Health Physics course, has experience at an operating power reactor while working for a consulting firm as a health physics / chemistry technician, and has five years experience as a Radiation Control Inspector for the State of Kansas. This technician appears to meet the selection criteria of ANSI N18.1-1971. No violations or deviations were identified. 4. Internal Audit Program The licensee's Reactor Advisory Committee reviews changes to equipment, procedures, and operations involving safety significance, and license modifications and/or technical specifications changes. This committee currently consists of fourteen members of various disciplines who together with their appointed Isotope Use Subcommittee are the governing body for the Research Reactor facility. The Reactor Advisory Committee typically meets on at least a quarterly basis, as required by technical specification. The inspectors reviewed the minutes of the Reactor Advisory Committee meetings conducted since December 1985. No problems were noted in the radiation safety matters discussed. The inspectors reviewed audits of the research reactor's radiation protection and radwaste management programs conducted from September 1985 to date including extent of audits and adequacy of corrective actions. The University's Office of Research Safety last conducted an audit of the reactor health physics program in April 1986. A previous audit was ' conducted in January 1985. The April 1986 audit did not identify any significant findings relevant to radiation safety; minor recommendations were made concerning overall documentation of training and the need for increased health physics training. In response to the recommendations, in June 1986, the licensee began implementation of a more formalized and better documented training program for reactor services personnel and also plans to expand health physics tecnnician training in the near future. Training / documentation for reactor services personnel and health physics technicians will be reviewed during a future inspection (50-186/86003-01). An internal audit of the research reactor facility's transportation quality assurance program was last conducted by a health physics staff member in September 1985. The purpose of the audit was to verify compliance with subpart H of 10 CFR Part 71, and with the licensee's internal quality assurance program. No significant problems were identified; however, some procedural deficiencies with the internal quality assurance program were identified. Timely corrective actions have been taken for all but one identified deficiency; the exception concerns a lack of documented / approved training procedures for individuals involved in handling radioactive material shipments. The licensee anticipates such procedures should be completed by approximately mid-1987. The procedures and their implementation will be reviewed during a future inspection (50-186/86003-02). No violations or deviations were identified. 3
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5. Training The Reactor Health Physics Group provides orientation instruction for individuals new to the facility, including administrative and housekeeping personnel. All personnel who are part of the facilities' work force, temporary or permanent, are so instructed before unescorted access is i allowed. The instruction consists of a 30-minute videotape with topics devoted to security, emergency response, and health physics. The videotape was viewed by an inspector; no problems were noted. The following handouts are provided to the trainee to supplement the instruction: Research Reactor Safety and Safeguards Policy Reminders
Regulatory Guide 8.29, " Instruction Concerning Risks from
Occupational Radiation Exposure" Regulatory Guide 8.13, " Instruction Concerning Prenatal Radiation
Exposure" Annual reinstruction is provided in written form, basically reiterating
the information provided by the videotape. Individuals who complete ' reinstruction sign a form indicating they have read and understand the information provided in the reinstruction. The inspectors selectively reviewed records of orientation instruction /reinstruction conducted in 1986 to date; no problems were identified. It appears the requirements of 10 CFR 19.12 were met. Since the previous NRC inspection in April 1985, the licensee initiated , ! a topical training program geared toward specific work groups within their facility. Thus far, two such training sessions were held for which documentation exists: " Introduction to Shielding," April 30, 1985. Provided to reactor
services by health physics personnel. " Emergency Breathing Apparatus," April 21, 1986. Provided to
health physics and operations by the Columbia Fire Department.
Reportedly other topical training has been given; however, the licensee could not recall specifics. Weaknesses in training documentation were previously identified by the licensee's audit program (Section 4); . corrective actions have been implemented. , No violations or deviations were identified.
6. Procedures Thus far, the licensee has developed thirty Health Physics Standard Operating Procedures (SOP-HP), which are incorporated into the license by Technical Specification 6.1. The inspectors reviewed several of these procedures including a new procedure, SOP-HP-10, " Radiation Work Permits." No problems were noted. No violations or deviations were identified. 4 _ - _ . _ _ _ _ _ . _ _ _ _ _ _ _ _ _ _ . _ _ _ _ _ _ _ _ _ _ . - _ _ _ _ _ ._ _ _ _ - . - . _ _ _ _
. 7. Exposure Controls a. External The personnel monitoring services of R. S. Landauer, Jr. , and Company are utilized by the licensee on a monthly exchange basis. All permanent employees are provided with whole body film badges capable of detecting X-ray, beta, gamma, fast and thermal neutrons. Single chip TLD (TLD-100) extremity monitors (finger rings) are provided when extremity exposures are suspected. Self-reading dosimeters are provided to visitors, temporary workers, and other personnel as warranted. Self-reading dosimeters are checked on a semiannual basis for drift and response to a known cesium-137 radiation field. Dosimeters exceeding 110% variance with the known radiation field or which exhibit greater than 2% full scale drift per day are discarded. The vendor's dosimetry reports were reviewed for the period January 1986 through July 1986. Other than the exposures discussed in Section 8, the highest whole body and extremity quarterly exposures recorded were 750 mrems and 5,880 mrems, respectively. 50P-HP-22, " Review of Unplanned, Unusual Radiation Exposures," requires an investigation if a personnel exposure exceeds 1/3 of applicable 10 CFR 20.101 limits. The inspectors reviewed two whole body exposures exceeding this administrative action level; the licensee's review and recommended corrective actions appeared adequate. Four instances of personnel contamination occurred since the last radiation protection inspection. The inspectors reviewed one such event involving hand contamination resulting from a punctured glove while handling irradiated materials from the pneumatic tube system. No problems were noted; the event was handled in accordance with 50P-HP-20, " Report of Personnel Contamination." b. Internal The licensee performs tritium analyses of urine samples which are collected monthly from at least one individual in each group employed at the facility. In addition, the licensee attempts to obtain/ analyze a urine sample from each employee every six months. Sample results for 1986 through July were reviewed; no problems were noted. Continuous air samples are currently taken in the three areas where airborne effluents are considered most possible; filters are changed weekly or as needed. Daily grab air samples are taken in the reactor containment building and analyzed for tritium and argon-41. Records < of the results of the continuous and grab air samples were reviewed for 1986 through June. Maximum concentrations of tritium and argon-41 were 9.5% and 17.5%, respectively, of applicable 10 CFR 20, Appendix B, Table I, Column 1 values. 5 - _ _ _ - _ .
_. ~ . The licensee does not take allowance for respirator usage as detailed in 10 CFR 20.103(c). Numerous full and half-face respirators are maintained for general use by the Health Physics Group, as are four self-contained breathing (SCBA) units and a few forced air hood-type respirators. In addition, two emergency cabinets contain SCBAs (1/2), full face respirators (2/3), and half-face respirators (3/5). Other than for the SCBAs, no routine maintenance or quality control program is exercised for this equipment. This matter was discussed at the August 29 exit meeting and will be reviewed further during a future inspection (50-186/86003-03). No violations or deviations were identified 8. Review of Reported Exposure Exceeding 10 CFR 20.101 Limits . a. Summary On July 29, 1986, the dosimetry vendor notified the licensee that a researcher's TLD ring received a shallow dose of 23,560 mrem (extremity) and the researcher's film badge received a 1,710 mrem ' beta dose (whole body); the extremity dose was subsequently revised to 115,400 mrem by the dosimetry vendor. The researcher was involved in a thulium-170 handling operation in June 1986. Similar thulium handling ope.ations had been performed by the researcher on three previous occasions in 1985. These earlier operations resulted in significantly lower exposures than reported for the June 1986 operation. The June 1986 operation involved ten thulium pellets contained in a high purity aluminum container which had been activated in the licensee's reactor flux trap from February through April 1986. Thulium-170 is produced by neutron activation of thulium-169. After removal from the reactor, the pellets were stored for about one month to allow short lived activation products to decay. The pellets are barrel shaped, approximately 0.09 inches in diameter and nearly 0.1 inches long; nominal pellet activity is 1.5 curies thulium-170. 4 ' On June 9 and 10, 1986, a researcher with experience in handling radioactive materials was packaging these pellets for eventual shipment to another NRC licensee. During the packaging operation, the researcher transferred six pellets from the activated aluminum , container into a similar unactivated container for the subsequent ' shipment. The remaining four pellets were transferred into a brass cylinder and placed in storage. Personnel exposures were monitored with whole body film and TLD finger ring badges. The licensee's health physics staff monitored the entire operation, which was said to have run smoothly; no problems were identified by the licensee. _ _ . -. - _. - . .- -- - . - _-
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. After notification by the dosimetry vendor, the licensee banned all future thulium packaging operations and on July 30, 1986, formed a committee to review the apparent extremity overexposure. b. Operation The researcher's June 9, 1986 pellet handling operation generally consisted of the following manipulations: Using a hacksaw blade, saw open the activated aluminum container
housing the ten thulium-170 pellets (approximately a two-minute operation). Due to shielding provided by the aluminum cylinder and a lead shield block housing the activated aluminum cylinder, little exposure to the researcher should have occurred during . this operation. ' Pick up the aluminum container using 12-inch long tweezers and
dump the pellets into a petri dish (approximately a five-second operation). Due to the presence of the ten unshielded pellets as they were being dumped from the activated aluminum container, this manipulation had a high personal exposure potential. Actual exposure to the researcher, however, should have been limited by the use of the 12-inch long tweezers and - the short exposure time. Using a 12-inch long suction tool, transfer six pellets into
an unactivated aluminum container and the four remaining pellets 4 into a brass storage container (approximately a two and one-half minute operation). Figures 1 and 2 of Attachment I show portions of the sawing and suction operations and the portable shielding used. This manipulation had a high personal exposure potential due to the presence of the ten unshielded pellets until they were transferred into the unactivated aluminum cylinder or the brass storage container. Actual exposure, however, should have been limited because the researcher's hands were reportedly maintained i behind a lead-acrylic shield during the entire manipulation. By hand, screw a cap onto the brass cylinder (approximately a
five-second operation). This manipulation had a high personal exposure potential directly over the open end of the brass cylinder. Proper hand positioning during the capping manipulation should have limited the actual exposure. 4 To accomplish the transfer (suction) operation, the pellets to be packaged for shipment were withdrawn from the petri dish, one by one, and placed into the aluminum container alternating with beryllium pellets which reduce bremsstrahlung. During this process, the aluminum container sat inside a large tungsten cylinder which is machined out to accept the container. After the pellets were transferred, another individual carted the tungsten shielded pellets to the licensee's welding shop, where a cap was welded onto the aluminum container. The initial weld of the aluminum container was
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__ . L inadequate and the operation, minus the brass cylinder transfer, was repeated on June 10, 1986. The second weld was adequate and the six pellets were shipped to another NRC licensee later that day. Receipt and transfer of the shipment are described further in Section 16. Those pellets not destined for shipment were removed from the pertri dish using similar methods, and placed into a lead shielded brass cylinder. After applying a screw-cap to the brass cylinder, the lead shielded brass cylinder was placed in locked storage. Similar thulium operations were performed by the same researcher on three previous occasions (July 16, August 5, and October 8, 1985). i Four pellets were handled during each of these operations rather than ten and the brass storage cylinder was not used. Other operational , differences existed also but those differences should have resulted in less potential for exposure as the operation was refined. The licensee's health physics staff reportedly provided coverage for all evolutions, including the June 1986 operations, c. Surveys and Radiological Controls Health physics preplanning for the initial 1985 operations consisted primarily of survey instrument measurements of the pellet work area using various ionization chamber detectors. These surveys were performed prior to and during pellet handling. Personnel exposure estimates for actual operations were based on the survey results. Exposure rate calculations and dry runs were not performed prior to actual operations; however, the licensee's health physics staff indicated this was the first time they worked with high purity sources i of this activity, and therefore were very careful. All initial work was performed in a fume hood using brick and leaded-acrylic shielding. , TLD finger rings and whole body film badges were provided to those involved. $ Radiation levels measured during the initial (July 1985) operation could not be specifically recalled by the licensee. The July 1985 Radiation Work Permit used to document survey results could not be > located. The Radiation Work Permit (RWP) for the August 5, 1985 , operation documented radiation levels of 4 rem /hr (assumed to be ' . beta gamma) in close proximity to the unshielded pellets and 2 rem /hr ! further away. Survey distances were not specified. The general work area behind the leaded-acrylic shield (between shield and researcher) , was recorded as 10 mrem /hr. The RWP for October 8, 1985, indicated ' 2.2 rem /hr beta and 1.33 mrem /hr gamma about 2 inches above the pellet work area, and 150 mrem beta and 30 mrem gamma to the researchers' 2 eyes. The general work area behind the leaded-acrylic shield was recorded as 20 mrem /hr. However, the licensee could not recall either the exact survey locations or the survey instruments used for the August and October operations. , !
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. The licensee's health physics staff monitored the June 1986 operations i but did not use an RWP to record their results. Health physics survey results were not recorded in any manner on June 9; June 10 results were informally recorded but subsequently discarded according to licensee personnel. Survey results, recalled by health physics personnel, were later recorded in signed statements dated August 6 and 7, 1986. These statements indicated radiation levels of 40 rem /hr (beta gamma) about 2-3 inches above the area where six unshielded pellets were located and 20 rem /hr (gamma) at this same location. Radiation levels behind the leaded-acrylic shield were recalled to be 5-10 mrem /hr. The survey instrument said to be used for these surveys was a Victoreen Model 450 ionization chamber. June 1986 operations were performed on a laboratory table using the same shielding employed in the previous operation. i These survey results are confusing in that calculated beta dose rates from a single 1.5 curie Tm-170 pellet are approximately 16,000 rads /hr at 2 inches, 1800 rads /hr at 6 inches, and 450 rads /hr at 1 foot. Use of multiple pellets, as was the case in all the handling operations, would further increase the radiation levels proportionately. The licensee's survey results were three to four orders of magnitude lower than the calculated dose rates. The calculated dose rates were generally confirmed by measurements made by licensee personnel recently (322 rads /hr at 12 inches from a single pellet). The licensee could not explain the low survey results for the thulium pellet handling operations. Survey records for those operations were unsatisfactory in that no survey data was available for the July 1985 operation, survey distances for the August 1985 operation were not available, the survey results for the June 1986 operation were recorded from memory in August 1986, and the survey instruments utilized in the 1985 operations were not specified. - The failure to maintain proper records of these surveys is a violation ' of 10 CFR 20.401(b). The inspector noted that the survey instrument used for the June 1986 operation (Victoreen Model 450) had a maximum range of 50 rem /hr and was therefore most likely at full-scale when, as reported by the licnesee, it read 40 rems /hr at two to three inches from six Tm-170 pellets. - d. Dosimetry ' Personnel monitoring devices worn by the researcher during the initial three operations were processed on a priority basis by the dosimetry vendor. Film badges, used to monitor whole body exposures, were worn on the left breast pocket. TLD finger badges were worn on left and right hand ring fingers. The processing showed maximum shallow whole body and right hand exposures of 110 mrem and 250 mrem, respectively, for the first three operations. The October 8 RWP indicated predicted whole body and right hand exposures of 133 mrem and 5.4 rads, respectively. l
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- - __ " . These predications were made by health physics personnel based on radiological surveys performed during the operation and estimated handling times. Licensee personnel indicated they were not surprised that their predicated extremity exposure was significantly higher than that determined by the TLD because theirs was a worst-case estimate. Because of the close working proximity to the Tm-170 pellets and the predominance of the beta hazard associated with Tm-170, placement and orientation of the extremity dosimetry is very important in these operations. It is important to ensure that the dosimetry is representative of the part of the extremity which is closest to the source (s) and that the dosimetry is not shielded from the 0.97 MeV betas characteristic of Tm-170. TLD chip orientations (towards or away from the palm with fist clenched) for the initial three operations could not be recalled by licensee personnel; however, a notation in the October 8 RWP stated that the TLD chip for that operation was facing towards the palm of the hand. (The researcher's fingers could attenuate the beta particles prior to reaching the TLD chip in this TLD orientation.) The TLD chip orientation for the June 1986 operation was said to be facing outward; however, due to the TLD location on the ring finger, significant attenuation could again have ' occurred due to shielding by other portions of the hand. It was also noted in the reenactment that the ring finger was not the part of the extremity closest to the source (s). Licensee personnel indicated that they had not measured or calculated exposure to other portions of the researcher's hand. According to licensee personnel, since recorded personnel exposures for the first three handling operations were not significant, the personnel monitoring devices worn during the June 1986 operation were not sent to the dosimetry vendor for priority processing. Instead,
the devices were mailed to the vendor on July 2, 1986, packaged together with the other dosimetry devices used at the research i reactor. Approximately 75 individuals are routinely film badged at this facility. The package containing the June dosimetry, i mailed to the dosimetry vendor thru the licensee's university mail system, took a circuitous route and was returned to the licensee on July 14. Apparently the package was found in St. Paul, Minnesota's dead letter area, was partially opened, and returned to the licensee because it lacked postage. (R. S. Landauer is located in Glenwood, Illinois, near Chicago.) The package was reshipped and arrived at Landauer on July 16. On July 29, Landauer notified the licensee that the researcher's TLD ring received a shallow dose of 23,550 mrem and the film badge a 1710 mrem beta, 100 mrem deep gamma, and 110 mrem shallow gamma dose. Landauer later revised the TLD extremity dose to 115.44 rem, due to application of a calculated thulium-170 beta correction factor. The researcher typically receives monthly whole body exposures less than 100 mrem. Extremity badges are issued to the researcher only as needed; exposures are highly dependent on the particular job but typically in the hundreds of mrem range. Dosimetry 10 -- . ___ .__ .. . -- -- - _ _ __ --- . _ _ _ _ - _ - _ - _ - - _-. -
. worn by other personnel in June 1986 did not receive significant or unusual exposures. Control dosimeters received 60 mrem; they typically receive minimal doses. There is no convincing reason, therefore, to attribute the high extremity TLD reading on exposure during mailing since other dosimetry in the same mailing did not reflect unusually high exposures. In late September, the licensee performed an exposure study to verify Landauer's ability to measure beta doses in the 100 rem range and to compare reported film to TLD beta exposure ratios. In this study, the licensee exposed three Landauer TLD ring and film badges to a single 1.2 curie thulium pellet at distances of six, twelve, and twenty-four inches. Badges were attached to small pieces of wood to reduce bremsstrahlung and beta back scatter. Exposure times were nearly one-half hour and produced exposures ranging from a few rem up to one thousand rem. The dosimetry was analyzed by Landauer and resulted in film to TLD beta exposure ratios of approximately 2.9. No beta correction factors were applied to reported TLD or film values. As a result of this study, the licensee contends that Landauer's calculated TLD beta correction factor of 4.9, which increased the reported extremity dose from 23.56 to 115.44 rem, is erroneous. However, this conclusion ignores any needed correction to the film values. The inspector was informed by the dosimetry vendor's Radiation Dosimetry Technology Manager that a 1.45 correction factor (calculated) must be applied to the recorded film value to correct for the Tm-170 beta. When this correction is applied to the licensee's empirical results, the TLD correction factor becomes 4.2, which is reasonably close to the dosimetry vendor's calculated value of 4.9. The licensee's empirically determined TLD correction factor therefore predicts an extremity dose of approximately 100 rems compared to the dosimetry vendor's reported 115 rems. e. NRC Inspection During the August 26-29, 1986 inspection, a Region III Radiation Specialist was onsite to review the apparent overexposure and perform a routine radiation safety inspection of the licensee's research reactor program. As a result of this inspection, the inspector determined that the licensee had not adequately investigated the high TLD reading to be able to determine its validity. The inspector informed the licensee that the matter would be considered unresolved pending further investigation by the licensee. One early development in the followup investigation was the upward revision of the TLD exposure due to a necessary correction for beta particles. (The dosimetry vendor's default assumption is low energy gamma exposure when reading extremity TLDs.) . 11
. On September 18, 1986, an NRC inspector was dispatched to the licensee's facility to witness a reenactment of the thulium pellet handling operation. The reenactment included all manipulations performed by the researcher on June 9, 1986, except placing the four remaining pellets into the brass storage cylinder. At the time of the reenactment, the inspector was unaware that a brass cylinder, with a screw-cap, was utilized in this operation. The manipulations observed in the reenactment did not identify an obvious overexposure scenario. Based on the distances and times measured by the inspector during the reenactment and NRC calculated in-air radiation levels (assume 300 rad /hr/ curie at twelve inches), a beta extremity exposure of approximately 5 rem is predicted and a corresponding whole body beta exposure of less than 500 mrem. Thulium-170's comparatively small gamma component is not significant in this case. This exposure estimate assumes the actual operations were identical to the reenactment and that the brass cylinder / screw cap manipulation was performed as verbally described by the health physics manager. It is possible that something unknowingly occurred in the actual event that was not repeated in the reenactment. This later point is important considering the potential for a significant exposure in a very short time existed from the unshielded pellets. Specifically, radiation levels of approximately 50 rads /second are calculated to exist at two inches from ten unshielded pellets. The exposure recorded by the TLD could have occurred in a few seconds had the researcher's hand been close to the unshielded sources. f. Licensee Investigation On July 30 and again on August 6, 1986, a committee was convened by the licensee to review the apparent extremity overexposure. No conclusive scenario was identified which would have caused the overexposure. Minutes of the committee's second and final. meeting stated that the exposure may not have been real. "The film badges may have been exposed to a radiation source after their use and prior to their evaluation due to the circuitous path they took to Landauer before being processed." (This possibility is contradicted, however, by the lack of unusually high exposure of any other dosimetry device in the same shipment.) The licensee reported the apparent overexposure to the NRC's Region III office in a letter dated August 20, 1986, which was received in the Region III office on August 25, 1986 (see Attachment II). On September 15, the licensee notified Region III that Landauer's reevaluation of the e:<tremity exposure, due to calculated thulium beta correction factors for the TLD, resulted in an increase from the initially reported 23.56 rem to 115.44 rem. I 12
3 . In September 1986, the licensee conducted a series of exposure studies using microcurie (up to 130 uCi) quantities of thulium-170. The study consisted of comparisons of licensee survey instrument response to TLD analysis results. Survey instrument readings were found to be consistent with the dosimetry vendor's reported TLD results for these small sources. The licensee has stated that they do not consider the extremity exposure to be valid for the following reasons: The June 1986 operation ran smoother / quicker then previous ~ evolutions, and previous similar operations did not result in significant exposures to the personnel dosimetry that was used. Based on reenactments with simulated sources, an extremity - exposure of the magnitude detennined by the dosimetry contractor is not expected. The licensee's extremity exposure estimate, resulting from their investigations to date, is 14.5 rem (5 rem times their empirically derived TLD correction factor of2.9). The vendor's dosimetry analysis, including the derivation _ of a TLD correction factor, is not accurate. g. NRC Conclusions The licensee has indicated that the lack of significant exposures recorded by personal dosimetry in the first three thulium pellet handling operations support their conclusion that an extremity ' overexposure did not occur, especially since the June 1986 operation ran more smoothly than the previous operations. This conclusion, however, does not recognize significant differences between the June 1986 operation and the previous operations (ten Tm-170 pellets versus four, handling operation essentially conducted twice due to bad weld on aluminum shi with screw-cap)pping cylinder, and use of the brass storage cylinder More importantly, the licensee's conclusion assumes . that the dosimetry devices accurately recorded the extremity exposures during the three 1985 handling operations, which as noted below may not have been the case, and the licensee's conclusion does not recognize that due to the large exposure rates involved a slight deviation from the prescribed procedures could have easily caused the large recorded extremity exposure in the June 1986 operation. The licensee also indicated that the lack of a conclusive exposure scenario when the handling operation was reenacted supports their conclusion that the researcher received at most a 14.5 rem extremity dose. This conclusion ag61n doesn't recognize that due to the large exposure potential involved, a slight deviation from the reenacted procedure, either knowingly or unknowingly, could have easily caused the large recorded exposure. Also, as noted earlier, the brass cylinder loading and screw-cap replacement operatior, was omitted from the reenactment and therefore introduces an additional uncertainty factor into their evaluation. \\ 13
,
. The licensee contends that the dosimetry vendor's TLD readout is erroneous but does not support this conclusion with substantive evidence. As noted in Section 8.d, the licensee's own empirical results reasonably support the dosimetry vendor's calculated TLD correction factor (4.2 versus 4.9), when the dosimetry vendor's calculated Tm-170 beta correction factor is applied to the film badge reading. The lack of other unusually high TLD readouts for the same dosimetry shipment from the licensee does not support an in-transit exposure or a systematic dosimetry vendor error. The dosimetry vendor is accredited by the National Voluntary Laboratory Accreditation Program for Personnel Dosimetry Processors of the National Bureau of Standards, again tending not to support a conclusion that the dosimetry vendor's reported TLD reading was erroneous. Further, the significantly higher than normal beta reading to the researcher's film badge (chest) supports a conclusion that the researcher may have incurred an abnormally high exposure during the June 1986 thulium pellet handling operation. While the licensee's arguments in support of their conclusion that the recorded (TLD) extremity exposure for the researcher was not valid are flawed as noted above, it is also not possible, based on the information available, to conclusively snow that the exposure was valid. An extremity exposure in the 25 to 100 rem range was quite possible during the June 1986 operation since a several second exposure at a distance of a few inches from the sources would have yielded such an exposure. However, such an exposure was not predicted by the reenactment or by discussions with the licensee personnel involved. Nevertheless, it is apparent that the licensee had not adequately evaluated the radiological hazards surrounding the thulium pellet handling operations. As noted in Section 8.c, the licensee was apparently unaware of the actual beta dose rates associated with the thulium pellets, no calculation of radiation exposure rates had been made by the licensee to support the thulium handling operation, and surveys were haphazardly conducted and documented. Also, extremity dosimetry placement does not appear to have been satisfactorily evaluated to ensure that the researcher's extremity exposure was adequately monitored. TLD ring chip (single chip TLD used) orientations on the researcher's hand varied and may have been directed toward the palm during the 1985 thulium pellet operations. This can be significant, especially when beta emitters are involved. When working with beta emitters, it is neutsary to ensure that extremity dosimetry is not shielded. In the 1985 operations, significant attenuation could have occurred due to shielding afforded by the finger (s), and extremity exposures recorded by dosimetry used in these previous thulium pellet operations may not have been representative of maximum extremity exposures actually received. Also, reenactments showed that the ring finger may not have been the portion of the extremity in closest proximity to the sources during the thulium pellet handling operations. 14
1 . . The failure to adequately evaluate the radiological hazards surrounding the thulium pellet handling operations is in violation of 10 CFR 20.201(b) which requires such evaluations to ensure, among others, that the extremity dose limits of 10 CFR 20.101(a) are not exceeded. Although it has not been conclusively shown that such an o/erexposure occurred, there was clearly a substantial potentia 7 for such an overexposure due to the extremely high beta rates preser.t and the licensee's lack of awareness of these dose rates. Also, the licensee had not adequately investigated the high TLD reading prior to the inspector's onsite inspection. The actual exposure to the researcher's extremities has not been, and probably will not be, conclusively determined. , Two violations were identified. 9. Posting, Labeling and Control During facility tours, the inspectors performed radiological surveys using an NRC Xetex Model 305B, smeared various laboratory and containment areas for removable contamination, and observed the licensee's compliance with posting and labeling requirements specified in 10 CFR 19.11 and 10 CFR 20.203. Measured area and container beta / gamma exposure rates were consistent with applicable 10 CFR 20.203 requirements. Smear tests were analyzed by the licensee. No problems were noted. No violations or deviations were identified. 10. Surveys The licensee's Health Physics Group routinely conducts external radiation and contamination surveys in various facility restricted and unrestricted areas. Cursory surveys are performed on a daily basis in areas where potential for fluctuation exists. More comprehensive surveys are performed on a monthly or quarterly basis, depending on the location. The latest survey results are posted at the entrance to the specific area. The inspectors randomly reviewed survey results for 1986 to date; no problems were noted. No violations or deviations were identified. 11. Gemstone Irradiation Since approximately 1984, the Research Reactor Facility has been irradiating , l gemstones (topaz) for distribution to non-licensees. Neutron flux irradiation produces color changes in the stones which enhance their value. (Report No. 50-186/86001(DRP)). The gemstone release criteria previously used by the licensee was 2400 dpm/ gram. < 15 - . - _ . . . . . _ . _ _ _ _ - , _ _ _ _ -
.. . . On June 4,1986, a meeting was held with University of Missouri representatives in the NRC Region III office to discuss this matter. (Memorandum from J. A. Hind to R. Cunningham, June 7, 1986.) As a result of the meeting, the NRC staff concluded the licensee was in violation of 10 CFR 30.14(d). Irradiated gemstone distribution ceased on June 6, 1986, except for those stones which do not exhibit levels of radioactivity above background. The licensee plans to apply for an NRC license pursuant to 10 CFR Part 32 to distribute gemstones which contain low levels of radiation. Until final action is taken on the license application, the licensee committed to not distribute irradiated stones which exhibit radiation levels distinguishable from background radiation. No violations or deviations were identified. ' 12. Instruments and Equipment a. Portable Survey Instruments Numerous portable radiation survey instruments are maintained by the licensee's Health Physics Office. All such instruments are calibrated annually or removed from sarvice until repairs / calibrations can be performed. Calibrations are performed by the instrument manufacturer or the licensee. Calibrations performed by the licensee are conducted using equipment and procedures referenced in the University's Material License No. 24-00513-32. Records of instrument calibrations since June 1975 were selectively reviewed; no problems were noted. b. Hand and Foot Monitors Hand and foot monitors are utilized for detection of personnel contamination; an external probe is connected to each monitor for survey of hand carried items. One monitor is located near the main entrance to the facility and another is located at the top of the stairs leading to the hot cell area. Personnel are instructed to use the monitors prior to eating or leaving the facility. Every six months, the monitors are electronically pulse checked and source checked using a strontium-90 source. The monitors are set to alarm at 600 counts per minute and have a strontium-90 efficiency of about 7%. The monitors were operability checked by the inspectors; no problems were noted. c. Area Radiation Monitoring System (ARMS) The facility has seven area radiation monitors which continuously monitor the reactor bridge area, various other containment areas, the fuel storage vault, and the vital equipment room. These monitors are calibrated semiannually and source checked for operability and alarm response prior to reactor startup. Calibration records for 1986 were reviewed; no problems were noted. i 16 __, _ . - .. -.. - -
, _.
. d. Stack Monitoring System Particulate, gaseous (argon-41) and iodine monitors in the stack monitoring system were last calibrated in February 1986. The licensee is currently in the process of recalibrating this system. February 1986 calibration data including supporting calculations were reviewed; no problems were noted. The particulate and iodine filters on the stack monitoring system are changed and analyzed weekly. The results of these analyses were reviewed for February and March 1986; no problems were noted. No violations or deviations were identified. 13. Primary Coolant Iodine Activity Records of primary cooiant water sampling and iodine analyses were reviewed from May 1985 to date. The technical specification requirements for sampling frequency and maximum permissible concentrations were met. Records indicated iodine-131 concentrations less than the minimum detectable activity of 4E-7 uCi/ml. No violations or deviations were identified. 14. Containment Building Integrity The containment building's leak rate was last determined by the licensee in May 1986. A makeup flow rate method was used, maintaining a pressure differential of at least one psig between outside and containment building atmospheres. The leak rate was measured to be 11.2 cfm, which is 69% of the technical specification limit. No violations or deviations were identified. 15. Radwaste Management a. Liquid Radwaste The facility contains three liquid radwaste holdup tanks, each with an approximate 4600 gallon capacity. Isotopic analysis is performed on a one liter sample of liquid radwaste prior to each discharge to either the sanitary sewer or the cooling tower basin. Records of liquid releases to the sanitary sewer made between July 1985 through June 1986 were reviewed. During this period, 1.49 curies of tritium were released to the sanitary sewer. The gross quantity of all other radioactive materials released was less than one curie. The alternate release pathway to the cooling tower was not utilized. 17 .- - - -- _ ._ - - - - --
. A partially uncontrolled release of liquid radwaste was made on November 21, 1985, when a bolt jammed the diaphragm of the drain valve in holdup tank no. 1, coincident with a planned release from tank no. 2. The known quantities of radionuclides for tank no. 2 were added to the assumed activity of tank no. 1. A conservative approach was used to calculate the activity of tank no. 1 by using reactor pool water analysis data obtained just prior to the release. Based on reactor operations records,17,425 liters of liquid were released (both tanks) with a gross activity of 978 millicuries of tritium. This is 65% of the 10 CFR 20.203 limits, using the sum of the fractions relationship in the footnotes to 10 CFR Part 20, Appendix B. The licensee's calculations and assumptions were reviewed; no problems were noted. b. Gaseous Radwaste Daily grab samples taken from the stack are analyzed for argon-41. The licensee's method to determine gaseous releases consists of multiplying the average daily argon-41 concentration by the total volume of air discharged from the facility (based on measured flow rates and hours of reactor operation). Graphs of daily sample results were reviewed for 1986 through June. The concentration of argon-41 discharged to the environment for that period ranged from 1.5 to 5.1E-6 uCi/ml, which is 36% of the technical specification limit (350 MPC annual average). The graphs also indicated that the technical specification instantaneous maximum concentration limit (3500 MPC) had not been exceeded. c. Solid Radwaste All radwaste generated at the reactor facility is collected, packaged, and prepared for shipment by the Health Physics Office. A segregation and volume reduction / compaction program for these wastes is continuing. The reactor facility has made three shipments of solid radwaste since the previous inspection in April 1985. The shipments were made to the Barnwell Disposal Site and totaled 116 packages of primarily low specific activity material. The inspectors reviewed the records of these shipments; no problems were noted. The licensee currently has approximately 60 packages (55 gallon drums) of solid radwaste accumulated in a storage area near their hot cell. No reactor facility waste is currently stored under the Universities' broad license at Sinclair Farm. No violations or deviations were identified. 16. Receipt and Transfer of Radioactive Material The Reactor Services Group is responsible for all packaging and transportation of radioactive materials, except radwaste, from the facility. Radwaste and incoming shipments of radioactive materials - are monitored by the Health Physics Group. 18
. .- - _ _ - - - - -
. The inspectors selectively reviewed the licensee's records of transfer of licensed byproduct material for 1986. Material is transferred to both on and off-campus users at a rate of about two or three shipments per day. A large portion of the off-campus shipments consists of iridium-192 and gold-98 seeds transferred to medical product distributors for eventual hospital therapeutic uses. Also, the inspectors reviewed the licensee's 10 CFR 30.41(c) verification process; no problems were noted with the verification process. In addition, the inspectors reviewed the licensee's actions concerning previous problems associated with a shipment of sodium-24 (Report No. 50-186/85001(DRSS)). The current practice, without exception, is to send an empty cask containing identical hardware to the transferee about one month prior to the actual sodium shipment. This allows the recipient to observe how the material will arrive and perform dry runs of unpackaging and handling operations. The use of instruction booklets describing safe package receipt and handling procedures is still under consideration. The licensee is also considering altering the form of the sodium to a powder rather than a liquid. The licensee indicated that no further problems have occurred with such shipments. On June 10, 1986, the licensee shipped six thulium-170 pellets to Lixi, Inc., located in Dewners Grove, Illinois. Lixi, Inc. is authorized to receive sealed sources of thulium-170 under NRC Materials License No. 12-18215-01. The licensee's Material Transfer Form (shipping paper) for this shipment documented the total thulium-170 activity as 4.0 curies; shipped as radioactive material, N.0.S. , physical form - solid, UN2982. Recalculations performed by the licensee subsequent to the shipment showed the correct activity per thulium pellet to be 1.5 curies 125%. Calculations were based on revised reactor flux levels, activation times, and neutron absorption crcss sections. Therefore, the correct activity for the six pellets shipped to Lixi, Inc. should have been 9.0 1 2.25 curies. 10 CFR 71.5(a) requires each licensee who transports licensed material outside the confines of its plant or other place of use, or who delivers licensed material to a carrier for transport, to comply with the applicable requirements of the regulations appropriate to the mode of transport of 00T in 49 CFR Parts 170 through 189. 49 CFR 172.203(d)(iii) requires the description for a shipment of radioactive material to include the activity contained in each package in terms of curies, millicuries, or microcuries. Contrary to these requirements, the licensee failed to include the correct activity of thulium pellets contained in a shipment to Lixi, Incorporated on June 10, 1986. Specifically, the shipping paper listed the cumulative thulium activity as 4.0 curies, the correct activity was later determined to be 9.0 curies (125%). No other violations of regulatory requirements occurred because of the erroneous activity calculations. One violation was identified. i 19 - - -. --.
_ _ - _ _ - _ _ _ _ _ _ _ _
. 17. Notification and Reports a. In a letter dated August 20, 1986, received in the NRC Region III office on August 25, 1986, the licensee reported an apparent extremity exposure in excess of 10 CFR 20.101(a) limits. (See Section E). The letter indicated that an investigation into the matter was still active. 10 CFR 20.405(a)(2)(iii) and (iv) require that each report under 20.405(a)(1) describe the cause of the exposure and corrective steps taken or planned to prevent recurrence, respectively. Contrary to the requirement, the licensee's extremity exposure report dated August 20, 1986, submitted in accordance with 20.405(a)(1), did not describe the cause of the exposure or corrective steps taken or planned to prevent recurrence. 10 CFR 20.405(b) requires that any report filed with the Commission pursuant to 20.405(a) include certain specified information for each individual exposed. Contrary to this requirement, the licensee's extremity exposure report dated August 20, 1986, submitted in accordance with 20.405(a), did not include the social security number or date of birth for the individual exposed. b. Annual reports for the period July 1, 1985 through June 30, 1986 were submitted by the licensee as required by technical specifications. These reports include summaries of radiation exposures to facility personnel and radioactive effluents released to the environs, as well as a report describing their environmental survey program. Violations were identified. 18. Independent Measurements On August 28 and 29, the inspectors performed direct radiation and contamination surveys of various areas in the containment building, the hot cell area, and laboratories throughout the facility. Direct surveys were performed with an NRC Xetex Model 305B. Smear samples were counted on the licensee's equipment. Survey results were found to be consistent l with posted licensee survey results and area postings. t No violations or deviations were identified. i ! ' 19. Exit Meeting The inspectors met with licensee representatives (denoted in Section 1) at the conclusion of the site inspection on August 29, 1986. The inspectors summarized the scope and findings of the inspection, and discussed the likely content of the inspection report. The licensee did i not indicate that any of the information disclosed during the inspection l were proprietary in nature. ! 20 , l
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. The licensee acknowledged the inspectors comments concerning the following: a. Thenextremity TLD reading which indicated an exposure apparently in excess of 10 CFR 20.101(a) limits required further evaluation by the licensee (Section 8). b. The need to consider a respirator maintenance / quality control program (Section 7). ' c. The need to improve training documentation (Section 4). On September 18, 1986, an inspector met with licensee representatives (denoted in Section 1) to discuss the licensees evaluation of the apparent extremity overexposure, the reenactment of the thulium handling operation, and the NRC Enforcement Policy described in 10 CFR Part 2. 20. Enforcement Conference An enforcement conference was held in the NRC Region III office on October 3, 1986, between Mr. A. B. Davis and other members of the NRC Region III staff and the licensee representatives denoted in Section 1. During the conference, the licensee reiterated their prior position that they did not consider the exposure reported by Landauer to be a valid personal exposure. In addition, the licensee provided the following information for NRC consideration: A knowledgeable and informed person was doing the operation.
Radiation safety personnel were present during the entire operation
and had no operation responsibility, only surveillance responsibility. The operator had proper dosimetry, shielding, and tools.
Past experience with similar operations indicated that the exposure
1 to the hand would be less than 2 R. ' j Reconstruction of the procedure indicated that the only way the
reported dose could have been obtained would be through a compromise of all protective measures: time, distance, and shielding. The finger dose of the researcher was calculated to be less than
2 to 6 rem, times a 2.9 TLD correction factor = 5.8 to 17.4 rem. l The conversion factor of Landauer was not judged to be correct.
The radiation safety program at the Research Reactor is a very
good one. l l 21 _____. __.
_ _ _ _ _ _ _ _ _ _ _ _ _ .
i The licensee comitted to postpone further thulium packaging operations until the following corrective actions are taken: a. Design and make a wafer (or pellet) holder for the transfer operation which prevents significant emission of beta in any direction except up through an opening for the wafer transfer tool, b. Provide equipment such that multiple shielding barriers exist for the operator when the wafers are handled. c. Complete a study to determine specific monitoring instruments best suited for monitoring Tm-170 operations. d. Develop a Health Physics monitoring procedure which provides for use of the selected instrument (s), e. Provide the operator with multiple beta monitoring devices, f. Provide radiation exposure information and process procedure infonration to radiation monitors and operators before they are assigned to the thulium wafer transfer procedure for the first time. The licensee was informed that escalated enforcement action is being considered based on the inadequate evaluation of the radiological hazards associated with the thulium pellet handling operation and the possibility that the reported extremity exposure was valid. Attachments: As stated r f f 22 _ _ . _ . _ _ _ _ _ _ _ _ . _ _ _ _ _ _ _ _ _ _ _ - _ _ _ _ . _ _ _ _ - - _ _ _ _ __
_ - . - - _ . Attachment 1 - Ali , l -:A % - , \\ .,
/>g ~ ~ \\ . . - i ' o/ .. ed J ( FIGURE 1 FIGURE 2 (Sawing Operation) (Suction Operation) . - - . . - - - -.--- -
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