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Conference Spotlight
Nuclear Energy Conference & Expo (NECX)
September 8–11, 2025
Atlanta, GA|Atlanta Marriott Marquis
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The Standards Committee is responsible for the development and maintenance of voluntary consensus standards that address the design, analysis, and operation of components, systems, and facilities related to the application of nuclear science and technology. Find out What’s New, check out the Standards Store, or Get Involved today!
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DOE issues new NEPA rule and procedures—and accelerates DOME reactor testing
Meeting a deadline set in President Trump’s May 23 executive order “Reforming Nuclear Reactor Testing at the Department of Energy,” the DOE on June 30 updated information on its National Environmental Policy Act (NEPA) rulemaking and implementation procedures and published on its website an interim final rule that rescinds existing regulations alongside new implementing procedures.
T. H. Newton, Jr., M. S. Kazimi, E. E. Pilat
Nuclear Science and Engineering | Volume 157 | Number 3 | November 2007 | Pages 264-279
Technical Paper | doi.org/10.13182/NSE07-A2727
Articles are hosted by Taylor and Francis Online.
The Massachusetts Institute of Technology (MIT) Reactor II (MITR-II) is a 5-MW research reactor presently fueled with highly enriched uranium (HEU) in uranium-aluminum plate-type elements. A low-enriched uranium (LEU)-fueled core has been designed using 20% enriched monolithic uranium-molybdenum fuel that maintains high experimental neutron flux and increases flexibility in meeting the needs of experiments. The configuration of the new plate fuel elements was selected using a full-core MCNP model, with which different in-core materials were evaluated to optimize the neutron fluxes, reactivity, and experimental neutron spectrum. In-core materials were chosen to meet experimental flux level and spectrum needs. Of the designs evaluated, the most promising consisted of half-width fuel elements with nine U-7Mo LEU fuel plates.Results from the MCNP/ORIGEN linkage code MCODE depletion calculations showed that the refueling interval of the chosen LEU core would be twice as long as the HEU core at the same power level. Thermal-hydraulic analysis using the MULtiCHannel analysis code II (MULCH-II) indicated that the peak channel will remain below the onset of nucleate boiling under normal and loss-of-flow conditions. A thermal-hydraulic evaluation of the limiting channel using point kinetics showed that the LEU core could withstand a step reactivity insertion of 3.92 $, increasing by 60% the allowable reactivity for an in-core experiment. Finally, preliminary analyses show that it may be feasible to use the proposed design to double the core power, if the fuel cycle length is to be kept at its present length.