Vol. 19 No. 36 • Sep 25, 2015

DNFSB Identifies Alternative Storage Options for MAR at PF-4

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.