LANL: No risk of radioactive ‘criticality’ accident in recent incident

By Mark Oswald / Journal Staff Writer
Published: Monday, September 25th, 2017 at 6:08pm
Updated: Monday, September 25th, 2017 at 6:13pm

Plutonium 'pits,' the triggers for nuclear weapons, are cast at Los Alamos National Laboratory in 2011. None have been made since then but the lab is under orders to make about 80 a year by 2020. (COURTESY LANL)

SANTA FE – Los Alamos National Laboratory says there was no risk of an accidental nuclear reaction in a recent safety violation where plutonium limits were exceeded during casting work at the lab.

“The incident on August 18, 2017 was not a criticality accident,” a lab spokesman said in a statement.

“Our workers self-reported the fact that certain administrative limits were exceeded. There was never any risk of a criticality accident.

“However, because of the Laboratory’s focus on adhering to our safety rules, we suspended the workers’ qualifications until they completed the appropriate re-training.”

A criticality accident is an uncontrolled nuclear fission chain reaction that produces a potentially fatal blast of radiation. The lab spokesman said Monday there has not been an actual criticality accident at Los Alamos in more than 60 years.

But a longtime lab observer and critic says the error reported publicly by the Defense Nuclear Facilities Safety Board this month was not trivial, considering the lab’s history of safety issues and a federal mandate that LANL ramp up production of plutonium “pits,” the triggers for nuclear weapons.

“It’s hard to assess how serious it was,” said Greg Mello of the Albuquerque-based Los Alamos Study Group. “We don’t have enough information.

“But given the scrutiny and the lab’s repeated problems with criticality and the impact on the (lab’s) mission, it’s a serious screw up.” No pits have been produced since 2011 and the lab is supposed to make 80 a year by about 2030.

Mello said the lab’s casting work on the “shell” of a pit – the focus of the Defense Nuclear Facilities Safety Board’s recent report – was “a showcase operation” and focus of “a great deal of management attention and expectation.”

“They really have struggled to get this right,” he said.

In 2016, LANL was the only one of the Department of Energy’s nuclear facilities to receive a failing “red,” or does not meet safety expectations, safety rating for criticality.

No comment has been available from the DOE’s National Nuclear Security Administration, of which the Los Alamos lab is part.

The DNSFB’s recent report says that on Aug. 18, the crew that had cast the pit shell moved it “into a location that already contained plutonium metal,” exceeding plutonium limits. When too much plutonium is put in close quarters, a criticality reaction can take place. In this case, the violation was discovered three days later when the shell was moved again.

The DNFSB report said “this was the first shell cast in the facility in about four years and the second time that a restarted operation encountered conduct of operations issues related to the criticality safety of material movements shortly after resuming nuclear work.”

At a June DNFSB hearing in Santa Fe, a top NNSA official said a study was considering whether plutonium work should be continued at Los Alamos or moved elsewhere by adding capabilities at other weapons complex sites. The same official said criticality safety at Los Alamos is making progress but “not where we need to be.”

But New Mexico’s two Democratic U.S. senators — Martin Heinrich and Tom Udall — recently amended the latest defense budget bill to require the Trump administration to meet a number of necessary requirements, including certification from the Secretary of Defense, before it moves pit production away from Los Alamos.