RLUOB recategorization for pit mission in early ’23, Los Alamos says

December 9, 2022

By Dan Leone

A building slated to become a key cog in the Los Alamos National Laboratory’s plutonium pit-production complex is taking longer than expected to be authorized to hold enough plutonium for its new mission, a spokesperson said this week.

The Radiological Laboratory/Utility/Office Building (RLUOB) should be recategorized as a hazard category 3 nuclear facility by March 2023, a lab spokesperson said Tuesday in an email. If it took until the end of the first calendar quarter, that would be a rightward slide of almost a year compared with the April 2022 date the lab was shooting for as recently as last year.

RLUOB will eventually be rechristened as PF-400 and, once upgraded to hazard category 3, will be allowed to legally hold about 400 grams of plutonium at once — around 10 times as much as it can take now.

With the increased capacity and other modifications, Los Alamos technicians could perform analytical chemistry work at RLUOB associated with the manufacture of plutonium pits — fissile cores of nuclear-weapon primary stages — that’s supposed to start in 2024 in the nearby PF-4 Plutonium Facility.

The NNSA has said that RLUOB’s current categorization allows it to handle enough plutonium to support the early stages of pit making in PF-4.

However, PF-4 is supposed to crank its output up to at least 30 pits annually by the end of 2026 and RLUOB’s long-planned recategorization, floated publicly six years ago, is part of that plan.