The Godiva I device, an unreflected 54-kg sphere of 93.7 percent pure uranium-235, before (left [in the scrammed state]), and after (right) the February 3, 1954, criticality excursion that released 5.6 × 1016 neutrons and warped or broke several support structures of the device. (Photos: DOE)
Fast burst reactors were the first fast-spectrum research reactors to reach criticality by using only prompt neutrons with high-enriched uranium as fuel, creating a pulse for microseconds. Among many achievements, fast burst reactors were the first research reactors to demonstrate the ability of thermal expansion to terminate a pulse and to show how this could aid in reactor safety. In addition, fast burst reactors were pivotal in early fission studies including critical mass determination, criticality safety, the study of prompt and delayed neutrons, and much more.
NNSA administrator Jill Hruby (left) holds up the signed MOU on HEU conversion during the agency’s virtual meeting with Japan’s MEXT. (Credit: NNSA)
The Department of Energy’s National Nuclear Security Administration (NNSA) has signed a memorandum of understanding with Japan’s Ministry of Education, Culture, Sports, Science, and Technology (MEXT). The MOU describes their commitment to convert the Kindai University Teaching and Research Reactor (UTR-KINKI) from high-enriched uranium fuel to low-enriched uranium fuel. The nuclear nonproliferation–related agreement also calls for the secure transport of all the HEU to the United States for either downblending to LEU or disposition.
NNSA administrator Jill Hruby (right) and Ken Nakajima, director of the Institute for Integrated Radiation and Nuclear Science at Kyoto University, in the KUCA control room. (Photo: NNSA)
As part of a nonproliferation agreement, Canada and the U.S. undertook a multi-year campaign to ship liquid high-enriched uranium material from Chalk River to Savannah River.
State troopers and first responders at a TRM roadshow stop in Virginia. The display LWT cask can be seen at the far right in its shipping container. (Photos courtesy of DOE/NNSA)
In March 2012, during the Nuclear Security Summit in Seoul, South Korea, the governments of Canada and the United States committed to work cooperatively to repatriate approximately 6,000 gallons of high-enriched uranyl nitrate liquid (HEUNL) target residue material (TRM) stored at the Chalk River Laboratories in Ontario to the U.S. Department of Energy’s Savannah River Site in South Carolina. The announcement was part of a larger agreement between the two countries to reduce proliferation risks by consolidating high-enriched uranium at a smaller number of secure locations.
