The Oak Ridge National Laboratory in Tennessee is replacing an inner reflector plug at its neutron source with a new one, filled with about 6 metric tons of heavy water purchased from Iran.
The Energy Department’s lab Spallation Neutron Source (SNS) produces neutrons for experiments to support scientific disciplines including physics, chemistry, materials science, and biology.
The facility is the world’s most powerful neutron source, but light water in the reflector plug that keeps its mercury target cool has caused cadmium in the plug to absorb neutrons.
The new, heavy water-filled plug should reflect back as much as 20 percent more neutrons once it is installed. More neutrons allow for more complex sample environments, greater measurement sensitivity, higher speed, and higher resolution imaging for experiments at the user facility, according to the ORNL website.
An ORNL spokeswoman said installation should wrap up in June. The facility has been on a routine maintenance outage since December.
The laboratory received the heavy water to fill the new plug as part of the 2015 nuclear deal with Iran after DOE failed to acquire heavy water from other sources, including its semiautonomous National Nuclear Security Administration.
The NNSA got some heavy water from the Department of Defense but has circled the wagons in the face of limited inventory. The agency’s Y-12 National Security Complex at Oak Ridge denied a 2006 request from ORNL for some heavy water to fill the reflector plug with, according to a 2016 report from the Office of Inspector General.
The NNSA uses the heavy water to produce parts for weapons life-extension programs and to support weapon design and simulation at the National Ignition Facility at the Lawrence Livermore National Laboratory in California.
The United States has not produced heavy water since 1996. The NNSA has said resuming production might take at least 10 years of lead time. To maintain scientific and weapons research, DOE has turned to the international market.
Former ORNL Director Thom Mason said the department was going through a procurement process with Canada when the Obama administration signaled its intent to purchase heavy water from Iran via the 2015 Joint Comprehensive Plan of Action (JCPOA).
Under the JCPOA, world powers agreed to lift economic sanctions on Iran if would stop pursuing nuclear weapons and allow its nuclear programs to be monitored. The agreement says Iran can’t have more than 130 metric tons of heavy water. The country’s heavy-water holding exceeded that amount, so the United States purchased 32 tons.
At the time, DOE said it was a one-time deal and hoped the purchase would encourage other countries to buy Iran’s excess inventory in the future. The future of the JCPOA now is in doubt, with President Donald Trump broadly believed to be preparing to withdraw the United States later this month.
Heavy water produced by foreign countries cannot be used for nuclear defense programs in the United States.
Six tons of the 32-ton purchase are being used to fill the new plug at the Spallation Neutron Source. The lab is keeping a bit extra to top off the plug in case of any “incidental loss,” Mason has said.
The Energy Department is repackaging the rest of the heavy water from the 600 beer kegs it arrived in for resale. A DOE spokesperson did not respond to inquiries regarding the amount of heavy water repackaged or resold so far.
