ANS is committed to advancing, fostering, and promoting the development and application of nuclear sciences and technologies to benefit society.
Explore the many uses for nuclear science and its impact on energy, the environment, healthcare, food, and more.
Division Spotlight
Nuclear Installations Safety
Devoted specifically to the safety of nuclear installations and the health and safety of the public, this division seeks a better understanding of the role of safety in the design, construction and operation of nuclear installation facilities. The division also promotes engineering and scientific technology advancement associated with the safety of such facilities.
Meeting Spotlight
International Conference on Mathematics and Computational Methods Applied to Nuclear Science and Engineering (M&C 2025)
April 27–30, 2025
Denver, CO|The Westin Denver Downtown
Standards Program
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!
Latest Magazine Issues
Apr 2025
Jan 2025
Latest Journal Issues
Nuclear Science and Engineering
May 2025
Nuclear Technology
Fusion Science and Technology
Latest News
TerraPower begins U.K. regulatory approval process
Seattle-based TerraPower signaled its interest this week in building its Natrium small modular reactor in the United Kingdom, the company announced.
TerraPower sent a letter to the U.K.’s Department for Energy Security and Net Zero, formally establishing its intention to enter the U.K. generic design assessment (GDA) process. This is TerraPower’s first step in deployment of its Natrium technology—a 345-MW sodium fast reactor coupled with a molten salt energy storage unit—on the international stage.
Won S. Park, Yong H. Kim, Chang K. Park, Jong S. Chung, Chang H. Kim
Nuclear Science and Engineering | Volume 143 | Number 2 | February 2003 | Pages 188-201
Technical Paper | doi.org/10.13182/NSE03-A2329
Articles are hosted by Taylor and Francis Online.
A design study for the fission product (FP) target was performed to maximize the transmutation of 99Tc and 129I in the Hybrid Power Extraction Reactor (HYPER) system without causing any core safety concerns. Localized thermal flux is obtained by inserting moderators such as CaH2. Many types of target design concepts have been investigated. The concept where 99Tc is loaded as a plate type in the outermost region and 129I is loaded as NaI rods mixed with CaH2 rods in the inner region is concluded to be the most effective in terms of transmutation rate and core power peaking. The proposed FP target is estimated to have a net transmutation rate of 5.53%/effective full-power year (EFPY) and 11.41%/EFPY for 99Tc and 129I, respectively, which are much higher compared to the transmutation rates in other fast neutron systems. In addition, the support ratios of the HYPER system for 99Tc and 129I are 5.7 and 4.0, respectively, very similar to the support ratio of TRU. The maximum pin power peaking with the loading of the FP target is 1.232, which is within the acceptable range. The loading of the FP target increases the inventory of TRU and makes the core coolant void coefficient more negative but the Doppler coefficient less negative. The proposed FP target configuration causes no safety problems in terms of core neutronics.
