Safety problems for the past five years prevented Los Alamos National Laboratory from using an important building built to temporarily store and load drums of radioactive waste. But officials on Friday said the structure, known as the Radioassay and Nondestructive Testing Shipping Facility, or RANT, has reopened.

The building passed safety inspections earlier this year following upgrades — including a new concrete roof and walls and steel reinforcement panels — to safeguard it from seismic events.

Laboratory Director Thom Mason said in a news release that reopening the facility “puts Los Alamos in a stronger position to fulfill its national security mission.”

Mason added the reopening is particularly important as the lab ramps up its work with plutonium. At the direction of the National Nuclear Security Administration, LANL is tasked with building dozens of plutonium pits — the grapefruit-sized cores used to trigger nuclear weapons — over the next few years as part of the nation’s nuclear modernization goals.

Workers loaded and delivered 42 55-gallon drums of nuclear waste to the Waste Isolation Pilot Plant in Carlsbad on April 11, the lab said in a news release Friday.

The type of nuclear waste sent to the plant is known as transuranic waste and includes items such as gloves, tools, clothing or soil that have been contaminated with plutonium or other highly radioactive material. The lab already generates more of this waste than anywhere else in the nation’s nuclear weapons complex, the lab said.

Before reopening the RANT building, waste had been loaded in a more high-risk environment — at an outdoor area near the lab’s plutonium facility.

The lab said using the indoor facility will decrease overall risk at Los Alamos.

Kelly Beierschmitt, deputy laboratory director for operations, said in a statement the reopened facility will “provide a better level of efficiency as we continue to improve our waste operations.”

Concerns that an accident could cause serious radiation exposure to workers and the public first closed the RANT facility in 2014.

In a report that year by the Defense Nuclear Facilities Safety Board, independent advisers to the Department of Energy secretary found managers at the lab had underestimated the seriousness of potential accidents at a high-level nuclear building. As a result, the advisers said, safety measures in place at the facility would not protect workers, or the public living around the lab, from serious radiation exposure in the event of an accident.

An earthquake, a significant storm involving intense wind and snow, a crane accident or a vehicle colliding with the building could cause the building to collapse or a fire to ignite among drums of waste, the report said.

The problems were identified just months after the lab caused a significant nuclear waste accident at WIPP.

The safety board noted last year that the lab declined to implement all the safety measures originally recommended. Instead, the lab agreed to reduce how much nuclear material would be kept at the building. Meeting original federal safety objectives is not expected to occur until 2024.

Infrastructure and building safety has been an ongoing issue at LANL. The plutonium facility, known as PF-4, has been plagued by problems, and safety board advisers say lab managers have been slow to make crucial upgrades to ensure it meets federal nuclear safety standards, particularly related to the building’s ability to withstand an earthquake without serious consequences.

For decades, LANL also has struggled to deal with the waste created during the Manhattan Project and Cold War, much of which remains buried in deep and shallow pits throughout the laboratory. Following the 2014 WIPP accident, shipments of waste stalled and moved more slowly off the lab property — and at nuclear sites throughout the nation.

The RANT facility is situated at Technical Area 54, also shared by Area G, the lab’s largest nuclear waste disposal sites.

Reporter

Rebecca Moss has covered the environment and Los Alamos National Laboratory for the Santa Fe New Mexican since j2015. In 2018, she was selected to participate in the ProPublica Local Reporting Network.