The Department of Energy (DOE) might not have enough heavy water to meet its long-term nuclear weapons and non-weapons activity needs, according to a newly released audit report from the DOE Inspector General’s Office.
Heavy water for the National Nuclear Security Administration’s (NNSA) weapons activities is stored primarily at the Y-12 National Security Complex in Tennessee and is used for the production of life-extension program parts and Lawrence Livermore National Laboratory National Ignition Facility (NIF) nuclear-weapon design and simulation.
The Department of Energy in 2009 completed an assessment that outlined options to ensure it has enough heavy water for its nuclear weapons life-extension programs and stockpile stewardship design and simulation requirements through fiscal 2031, the Dec. 23 report noted. In recent years, DOE obtained additional heavy water from the Defense Department; the NNSA established a reserve of heavy water for its own missions, no longer supplying it for non-weapons activities; and Y-12 moved to a direct material manufacturing process that recycles weapons parts and decreases demand for heavy water.
However, “management of the heavy water inventory may not ensure a sufficient supply for Weapons Activities” and some non-weapons work beyond fiscal 2031, the audit found. It attributed this problem to “the uncertainty of heavy water requirements beyond 2031, the long lead time to establish a production capability, and the estimated lead time to develop recycle or re-enrichment capabilities.”
Specifically, Y-12 plans to implement a new capability to produce weapons parts containing lithium deuteride that may require heavy water at amounts that are not yet forecast, in contrast with the direct material manufacturing process currently in place. Future requirements at the NIF also remain uncertain, the report said, “pending a decision on the reconfiguration of NIF’s laser using a Direct Drive technique that could significantly increase the demand for heavy water.”
The U.S. since 1996 has not had the capability to produce the material, and would need 10-15 years to establish this capability, the report said. It said that NIF officials noted no current plans to establish a recycle or re-enrichment capability, which would involve a three-to-four-year lead time.
In addition, because the NNSA no longer supplies heavy water for non-weapons activities, other DOE offices purchase it from U.S. suppliers that receive the material from foreign producers, putting future purchases at risk of price fluctuations and sales restrictions by foreign countries, the report said.
The audit recommended establishing “trigger points” at which management would develop a “more aggressive” plan for a capability to recycle the material or find other ways to acquire heavy water; and preparing feasibility and cost benefit analyses of alternatives to move forward with at these trigger points.
NNSA management agreed, noting that its current plans address these issues. The agency’s annual nuclear material forecasts have found it has enough heavy water to meet its needs for the next 15-20 years, the NNSA said. “NNSA also stated that the report overstated the risk regarding the lead time required to resume a production capability,” the audit said.
The NNSA said the heavy water it acquired from the Defense Department would be enough to meet manufacturing needs and that it would make plans for a recycle capability after using recycled heavy water for NIF. “NNSA stated that its planning and forecasting processes already accounted for the uncertainties highlighted in the report,” according to the report.
The IG said in response that the Defense Department’s heavy water would not meet NIF specifications for stockpile stewardship activities, and that it could not confirm the NNSA’s claim that it would use recycled heavy water for NIF applications in roughly five years. The National Ignition Facility, the world’s highest-energy laser, uses laser beams to create extreme temperatures and pressures similar to those inside nuclear weapons during detonation – work that is done in support of the NNSA’s stockpile stewardship program.
“Because NNSA committed to continuing to closely monitor and forecast heavy water requirements to ensure action can be taken in sufficient time to meet potential future long-term requirements, we considered NNSA’s response and planned actions responsive to our recommendations,” the IG said.
NNSA spokeswoman Francie Israeli said by email, “As stated in the Management Comments in the report, NNSA believes the Inspector General’s report overstates the risk associated with the lead-time required to resume a production capability.”
“Acquisition of heavy water from [the Defense Department] effectively eliminates the need for production in the foreseeable future, and NNSA would have sufficient time to react if additional demands are forecast,” Israeli said.
