Alissa Tabirian
NS&D Monitor
9/25/2015
The Los Alamos National Laboratory (LANL) should use alternative storage locations at its Plutonium Facility (PF-4) to facilitate nuclear material-at-risk (MAR) minimization and protection from hazards associated with earthquakes or fires, according to a Defense Nuclear Facilities Safety Board (DNFSB) letter sent to the National Nuclear Security Administration (NNSA) and made public this week.
The Sept. 21 letter and accompanying report identify issues with life-cycle planning and inefficient MAR use at the lab and a lack of NNSA waste disposition funding as factors exacerbating MAR accumulation on the first floor of the PF-4 facility. Moreover, funding uncertainties related to upgrades of the facility’s fire suppression and active confinement ventilation systems could leave the site and surrounding public vulnerable in the short term to the risk of accidents, the report says.
The report notes that glove boxes and the floor – locations most vulnerable to earthquakes and fires – “hold nearly 80 percent of the MAR,” the amount of radioactive material vulnerable to release in an accident. Meanwhile, safes on the first floor largely contain less-hazardous MAR, which suggests this material can be moved elsewhere to make room in the safes for higher-hazard MAR. The study found idle material – stored material no longer in active use – on the first floor of PF-4, including several items that had remained there over a decade. Less than 1 percent of the first floor’s MAR limit corresponds with material that must remain there due to “long-term programmatic activities,” the report says, meaning “more than 300 kg of Pu-239 equivalent could be moved off the first floor to more robust storage locations.” The study also notes that material handlers are not required to document the type of container that holds MAR. Because certain containers are certified “as capable of protecting MAR from fire and drop insults,” the DNFSB said, “maintaining an accurate database and transitioning away from the use of non-certified containers” could help reduce the MAR inventory.
The study says “the ideal location in PF-4 for the storage of MAR is the vault,” which offers several hundred available storage locations, because it can withstand a design basis earthquake. The letter also points to 50 safes in PF-4 that could be used for storage pending nuclear criticality safety evaluations, including “six large, robust safes that were acquired in the past few years” that could “accommodate more than 200 kg of material, but are presently empty.” The report further identifies a project under the Material Recycle and Recovery program meant to recycle or dispose of nuclear materials and transuranic waste that “will free up storage space and greatly improve safety and efficiency for vault users.” However, the project is stalled by “resource conflicts associated with the ongoing PF-4 restart effort” and safety basis issues at LANL’s transuranic waste facilities. The letter notes that LANL personnel “have not made much progress because of the high priority placed on the PF-4 restart effort.” The laboratory aims to resume operations at PF-4 by the end of fiscal 2016 following the shutdown of some of the facility’s operations in 2013 due to criticality safety issues.
The letter says LANL has “accomplished a significant reduction in MAR in the last decade” but needs better life-cycle planning of nuclear materials “at the activity level” by tracking certified containers and completing the waste disposal process. It also recommends making Material Recycle and Recovery program implementation a priority to free up vault space and remove MAR from the facility. The NNSA did not respond to requests for comment by press time.
