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Type B Investigation of the Am-241 Contamination Accident At the Sigma Facility, LANL, July 14, 2005

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Type B Investigation of the Am-241 Contamination Accident At the Sigma Facility, LANL, July 14, 2005

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    1. Type B Investigation of the Am-241 Contamination Accident At the Sigma Facility, LANL, July 14, 2005 Doug Minnema, PhD, CHP Type B Investigation Board Chair National Nuclear Security Administration

    2. May 2006 Am-241 Contamination at Sigma 2 Type B AI Board Members: Milton Chilton, CHP, NNSA Service Center Ronald Fontana, Facility Representative, LASO David Hall, NNSA Service Center Advisors: William McQuiston, Idaho Operations Office M. Bradford Graves, CHP, BWXT Y-12 Frederick Bell, LASO Laboratory Observer: Matthew Hardy, PS-7 Administration: Sandra Robinson, SAIC

    3. May 2006 Am-241 Contamination at Sigma 3 Precursor Event On July 7, 18 UN fuel pellets, produced at PF-4, were sealed into Swagelok® couplings in G138 for transport to Sigma. The work in G138 was done next to a furnace where Pu-239/Am-241 pellets had been baked for a separate program. The Am-241 had a high volatilization rate in the furnace, 20 – 30% by mass. The Swageloks® were inadvertently contaminated by residual dust from the furnace, predominantly Am-241. The Swageloks® were not monitored for contamination before being packaged for shipping.

    4. May 2006 Am-241 Contamination at Sigma 4 Initiating Event On July 14, the Swageloks® were shipped to Sigma and placed in a laser-welding glovebox, where the packaging was opened. Potential for contamination had not been communicated to receiver by shipper. Packaging material (plastic bags) and a knife were removed from glovebox without being checked for contamination, because none was expected. The knife was returned to its belt-sheath and packaging material was placed on a table in the room. The packaging was later discarded in a trashcan.

    5. May 2006 Am-241 Contamination at Sigma 5 Discovery On July 25, an RCT Supervisor discovered that package was opened, and conducted a swipe survey. High contamination levels were found near glovebox. Initial counts indicated that contamination was different than that normally found in Sigma. Lab determined it was Am-241. Further surveys found the worker, his office, and his work areas to be contaminated. A DOE RAP team verified the presence of contamination at the worker’s home. LANL formed an ad hoc management team to direct the recovery activities. Dose to worker estimated to be about 500 mrem, no other intakes were detected.

    6. May 2006 Am-241 Contamination at Sigma 6 Consequences Contamination was spread to the worker’s and other offices and work areas in Sigma and other onsite areas 3 workers’ homes or personal vehicles were contaminated Primary worker spread contamination to relatives’ homes in Colorado and Kansas and to a hotel in Kansas Multiple RAP Team deployments to NM, CO, and KS Contaminated package shipped to Bettis in Pittsburgh, PA Sigma was evacuated for about 2 days for cleanup, some work areas restricted for longer times Some work areas in PF-4 were also shutdown pending the investigation High degree of public and media interest resulted

    7. May 2006 Am-241 Contamination at Sigma 7 Direct Cause The direct cause of this accident was the repeated handling of highly contaminated components with no radiological controls in place. Package was not surveyed when accepted at Sigma. Package was opened in a positive pressure laser-welding glovebox. Contaminated material and a tool removed from glovebox resulted in initial release to ambient environment. Work conducted in glovebox the following week, including introduction and removal of other material, resulted in additional releases. Contaminated material was also taken to other areas, transferring contamination to those areas. The work room was not in a radiologically controlled area. No personnel or workplace contamination monitoring systems directly covered the area.

    8. May 2006 Am-241 Contamination at Sigma 8 Significance of the Accident Levels of Am-241 contamination on the Swageloks® were very high (Board’s measurements showed average of 7.4x108 dpm/100-cm2). Total Am-241 involved was ~4 millicuries, or ~4000 smoke detectors. Smoke detectors are safe because, by design, the Am-241 is not dispersible, not because it is small amount. Dose from inhaling amount in one smoke detector is about 100 rem CEDE. Fortuitously, material was very reactive; when exposed to room air it adhered to surfaces and sweaty hands. Did not readily spread once deposited on a surface. Could have resulted in more and higher doses, and much greater impacts to facility and the public. This was a significant event.

    9. May 2006 Am-241 Contamination at Sigma 9 Missed Opportunities for Avoidance NMT-11 knew contamination was likely, but did not discuss issue with MST-6 in multiple project meetings. NMT-11 assumed that since material was going into another glovebox it was adequately controlled, but did not verify the assumption. The Swageloks® were bagged inside the PF-4 glovebox and were never surveyed for contamination. The preparations for shipping the material to Sigma did not follow procedures that required evaluation or estimation of the contamination levels. MST-6 assumed that the parts would be decontaminated before transfer, but did not verify the assumption.

    10. May 2006 Am-241 Contamination at Sigma 10 Missed Opportunities for Detection An individual involved in event alarmed a hand-and-foot monitor on July 14, but washed hands and passed on retest. Incident was not reported to Sigma RCTs. The primary worker claimed to have frisked himself and found nothing. Instruments would have detected contamination if present. The Board found 3 possible explanations, but could not draw a firm conclusion. Sigma RCTs were not informed of incoming package, therefore there was no receipt inspection. Removal of package’s TIDs was not done properly; if done correctly it would have increased facility awareness of the opening of the package.

    11. May 2006 Am-241 Contamination at Sigma 11 Accepted Practices It was accepted practice at Sigma to wash hands and retest if they alarmed a frisker. Opening shipments without IWDs was accepted practice at Sigma. Failure to adhere to LANL’s requirements for preparing radiological shipments was accepted practice at PF-4. Failure to notify the Sigma RCTs of incoming radioactive shipments was accepted practice. Inadequate adherence to controls was accepted practice at Sigma.  Failure to conduct receipt inspections was accepted practice at Sigma. Opening packages and using radiological materials without RCT support was accepted practice at Sigma.

    12. May 2006 Am-241 Contamination at Sigma 12 Assumed Requirements Although it may be a good practice, the assumption that an IWD is automatically required for work involving radioactive material is an assumed requirement. The assumption that Sigma could only receive and work with uranium was an assumed requirement. In reality Sigma was authorized for any isotope as long as the aggregate inventory stayed below STD-1027 hazard category-3 thresholds. This “uranium only” assumption was the basis for the radiation protection program at the facility. The expectation that an RCT be present when radioactive material shipments are opened at Sigma did not exist as a formal requirement, and therefore it was an assumed requirement.

    13. May 2006 Am-241 Contamination at Sigma 13 Implied Assumptions Both NMT-11 and MST-6 made implied assumptions regarding the potential for contamination on the parts that were transferred to MST-6; those implied assumptions were in direct conflict with each other; and neither group attempted to communicate or verify those assumptions with the other group. The assumption that MST was exempted from all institutional IWM training was an implied assumption. Therefore, the worker was not properly trained on the integrated work document process. The belief at PF-4 that the recipient would know that the material being shipped was contaminated and that the material would be handled appropriately was an implied assumption. Therefore, the PF-4 staff did not take care to notify recipient of potential for contamination.

    14. May 2006 Am-241 Contamination at Sigma 14 Latent and Immediate Conditions All of the causal factors responsible for this accident were latent conditions that existed in the facilities prior to the onset of the events leading to this accident. There were no abnormal conditions immediately preceding this accident that contributed to the accident. These latent conditions could have been detected and corrected by adequate oversight. In fact, some had been detected prior to this accident but had not been corrected. The failure to detect and correct these latent conditions was in itself a latent condition and a causal factor for the accident.

    15. May 2006 Am-241 Contamination at Sigma 15 Root Causes RC1: NMT-11 failed to evaluate the radiological contamination on the components, and failed to inform MST-6 of the potential for contamination, even though NMT-11 recognized that the possibility of contamination existed. The Board concluded that this was due to a latent condition. RC2: MST-6 failed to ensure that the radiological condition of the components was fully evaluated, and that proper radiological controls were in place, before accepting the components and commencing work with them. The Board concluded that this was due to a latent condition.

    16. May 2006 Am-241 Contamination at Sigma 16 Root Causes (cont.) RC3: LANL and LASO failed to adequately oversee NMT, MST, and HSR, allowing the latent conditions that were the root causes of this accident to become established without detection and correction. RC4: NNSA failed to ensure that LASO had adequate guidance and direction to accomplish its oversight responsibilities, and failed to adequately oversee LASO’s implementation of its oversight program to ensure that there was an adequate balance between NNSA expectations and LASO’s available resources.

    17. May 2006 Am-241 Contamination at Sigma 17 Judgments of Need (JONs) The Board established 9 JONs for LANL in the areas of work processes, assessment processes, radiation protection program implementation, and conduct of operations The Board established 3 JONs for LASO concerning their oversight and issues management processes, and the need to verify the LANL CAS The Board established 1 JON for NNSA HQ dealing with the needs to promulgate expectations for LASO, balance resources against expectations, and oversee LASO’s performance The Board also established 4 JONs, one each for LANL, LASO, NA-10, and NA-40, for addressing lessons learned from the onsite and offsite response activities

    18. May 2006 Am-241 Contamination at Sigma 18 Lessons Learned from Accident Response Emergency management programs should ensure that adequate plans and preparations exist for a large-scale loss of control of hazardous material event such as this one. Site Offices should ensure that resource requirements for mitigating offsite impacts from emergency operations, and their role in coordinating command, control, and communication functions are clearly defined and understood. PSOs should ensure that they are coordinated with NA-40 when a NA-40 emergency response asset is responding to a request involving their facility or site. NA-40 should incorporate lessons learned from this accident into its RAP plans, and should provide “default” radiological release criteria to the RAP program for when there is no other authority having jurisdiction.

    19. May 2006 Am-241 Contamination at Sigma 19 Closing Remarks The clear communication and understanding of expectations, requirements, assumptions, and potential risks is vital to maintaining a safe and healthy work environment. The development of complacency and “bad habits” in the workforce is a natural outcome of the knowledge and confidence built from experience in the workplace. It is a normal consequence and should be anticipated. The checks and balances provided by routine oversight need to be designed and used in a manner that detects the “bad habits” and helps workers maintain the knowledge and confidence without becoming complacent. Oversight should not be used as a disciplinary tool.

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