Source: Knoxville News Sentinel | Brittany Crocker – USA Today Network | April 7, 2017
The Energy Department must take steps to secure a heavy water supply beyond the next 15 years, or research and defense programs may suffer.
A follow-up audit on the nation’s heavy water inventory has shown some strides toward securing a long-term supply, but the measures will not be sufficient beyond about 15 years, according to the Office of the Inspector General.
Heavy water, or deuterium oxide, is a form of water that contains a larger-than-normal amount of the hydrogen isotope deuterium. The water is called “heavy,” because the deuterium increases the chemical’s mass. It also gives the chemical different properties than regular water that make it more useful for nuclear research and weapons production.
The United States has not been able to produce heavy water since 1996 and the Department of Energy’s current supply is its only source for weapons programs. According to Y-12, it would take more than 10 years of lead time to establish a production capability.
The Office of the Inspector General first raised concerns about the DOE and National Nuclear Security Administration’s (NNSA) inventory in 2008, forecasting that the supply would dwindle by 2019.
Since then, DOE has been able to obtain some heavy water from the Department of Defense to be used for weapons activities only, along with a 32-metric-ton purchase from Iran that can not be used for any weapons related activities at all due to nonproliferation agreements.
Working properly, the plug should reflect neutrons back into the target and its moderators. The regular water that fills the plug now absorbs neutrons, but heavy water will maximize the target’s neutron output to as much as 20 percent, according to outgoing Oak Ridge National Laboratory Director Thom Mason.
The rest of the purchase from Iran will be sold to private industry.
The acquisitions have extended heavy water supply by about 12 years, but, the audit said, dependence on uncertain sources and inadequate planning by the NSSA, which maintains the nation’s nuclear stockpile, may endanger research and, especially, weapons activities beyond 2031.
The audit said the DOE does not expect to get more heavy water from the Department of Defense and that sales restrictions and fluctuating prices make the foreign market too unstable to rely upon. It cited the 2012 Nuclear Management Plan which said that Canada, a previously reliable supplier of heavy water, has restricted its sales to the U.S.
Policy analyst Andrea Stricker and founder Daniel Albright at the Institute for Science and International Security in Washington disputed that statement in a report last December. They wrote that the DOE terminated a heavy water procurement process with a Canadian company to purchase from Iran when the country’s inventory was found in excess of its 130-ton limit.
“We were in the process of going through a procurement process, basically at the same time that the Iranian deal was being made,” Mason said. “That afforded us this other alternative which happened to line up with the direction the administration wanted to go in at the time.”
Congressional proponents of the nuclear deal insisted the 32-ton purchase was a one-time event, but Stricker and Albright argued that selling the 26 tons of heavy water not used at ORNL would disrupt the global market in the future, especially if it is sold at the same rate the United States paid to Iran.
“The DOE purchase and sale of Iranian heavy water has threatened the prospects of avoiding a shortage in the future,” they wrote. “The sudden appearance of this heavy water disrupted needed investment in a reliable long-term production capability of heavy water for both the U.S. government and private industry.”
ORNL houses the business office for the DOE’s isotope program that will manage the heavy water sales. The shipment arrived last year, packaged in 600 beer kegs.
Mason said the office will factor work done to test and repackage the heavy water into its retail price so that the U.S. will recover any additional costs from heavy water purchasers.
“Essentially, it’s the difference between the wholesale and retail price,” he said. “So I don’t think there’s really any kind of market distortion that one needs to be concerned about.”
Once filled, the plug at the Spallation Neutron Source will last as long as the facility does, though ORNL will reserve a small amount to top off the plug in case of any incidental loss.
“At the moment there are no plans to buy any additional heavy water,” Mason said. “I think the reserves that are there will essentially last us for quite some time. Presumably, if additional need did arise, we would just go through a normal procurement process that would be open to any vendor that meets the requirements.”
Even so, heavy water produced by foreign countries can’t be used for U.S. defense programs, including the NNSA’s Stockpile Stewardship Program that maintains the reliability of nuclear weapons without the use of underground tests.
The inability to purchase from foreign entities led the NNSA to circle the wagons in 2006 when ORNL first requested heavy water for the cooling plug from NNSA’s Y-12 National Security Complex in Oak Ridge.
Y-12 turned the request down to preserve the reserves dedicated to weapons activities, so ORNL instead acquired about seven metric tons of depleted heavy water from the Savannah River Site, but the water wasn’t sufficient to fill the plug.
The Savannah River Site still houses a large supply of that depleted heavy water, according to the audit report, but the DOE determined that re-enriching it to make it usable again would be too costly and has made plans to dispose of it.
The NSSA said new technologies that could decrease heavy water demand for both weapons activities and nuclear research sectors could be available by 2031. Y-12 implemented a new production method for weapons parts in 2010 to reduce heavy water demand after a 2009 assessment of options to meet stockpile requirements. The newer, direct material manufacturing method uses less heavy water by recycling weapons parts.
But, it was never intended as a permanent process and has been less productive than expected, according to both the audit and a 2015 Government Accountability Office report. The auditors also said direct manufacturing has contributed to contamination build up.
Y-12 plans to reintroduce the original “wet chemistry” process that used more heavy water in 2028 and pair it with the direct manufacturing process.
Steven Wyatt, a Y-12 spokesperson declined to specify what kind of contamination has accumulated or whether pairing the wet chemistry method with direct manufacturing will require more or less heavy water than the wet chemistry method alone.
The auditors said the NNSA needs to establish a “trigger point,” at which it would begin to pursue other means of replenishing the heavy water supply, should such alternative technologies remain insufficient.
The NNSA asserted that the current inventory meets weapons manufacturing needs beyond “any conceivable horizon,” and that plans to recycle heavy water for use at the Lawrence Livermore Laboratory’s National Ignition Facility (NIF) would begin in about five years.
However, the Inspector General was unable to confirm that assertion, citing the 2016 Nuclear Materials Management Plan that said recycled heavy water would not be used at the NIF until after 2031.
NIF officials told the auditors that a private vendor might be able to recycle depleted heavy water, but that they have no plans to pursue that capability. They said the lead time on that project would be about four years, if the NNSA decides to pursue the capability in the future.
The DOE Office of Inspector General maintained the warning to the NNSA: uncertain heavy water requirements beyond 2031 and the long lead times to establish heavy water production, re-enrichment or recycling capabilities put the DOE “at risk of being unable to meet all of its weapons activities” in the long run.