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Division Spotlight
Reactor Physics
The division's objectives are to promote the advancement of knowledge and understanding of the fundamental physical phenomena characterizing nuclear reactors and other nuclear systems. The division encourages research and disseminates information through meetings and publications. Areas of technical interest include nuclear data, particle interactions and transport, reactor and nuclear systems analysis, methods, design, validation and operating experience and standards. The Wigner Award heads the awards program.
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!
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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.
James R. Powell, Hans Ludewig, Michael Todosow, Morris Reich
Nuclear Technology | Volume 125 | Number 1 | January 1999 | Pages 104-115
Technical Paper | Accelerators | doi.org/10.13182/NT99-A2936
Articles are hosted by Taylor and Francis Online.
Two new accelerator target and neutron filter concepts are proposed for boron neutron capture therapy (BNCT) to enable production efficiencies for epithermal neutrons (i.e., neutrons leaving the treatment port and neutrons generated in the target) of ~5 to 10%. These efficiencies are much greater than in previous designs and allow BNCT facilities to use near-term, low-current (~5 mA) proton accelerators. Two target/filter designs are described and their neutronic performance analyzed. In NIFTI-1, epithermal neutrons (maximum energy of ~100 keV) are generated by a proton beam that is maintained slightly above the 1.889-MeV threshold for the 7Li(p,n)7Be reaction. As the proton beam passes through the DISCOS target, which consists of a sequential series (e.g., total of 80) of very thin (several microns) liquid-lithium films on ultrathin rotating beryllium metal foils, the protons are reaccelerated by an applied direct-current field between the foils. This reacceleration enables a high total neutron yield, ~10-4 neutrons/proton. The NIFTI-1 neutron filter, a highly scattering cross-section layer of iron-magnesium, located between the target and the treatment port, impedes neutron transmission for energies >24 keV, but it has a deep window in the scattering cross section at 24 keV. Scattering in the filter and an accompanying thin (~1 cm) hydrogenous neutron "downshifter" yield a neutron output beam with an average energy of ~10 to 20 keV. In the NIFTI-2 design, a single thick lithium target is used, with a proton beam energy (~2.5 MeV) well above the (p,n) threshold. Although the neutron yield from the target is high, ~10-4 neutrons/proton, their energy is much greater (maximum of ~800 keV) than in NIFTI-1. The high-energy neutrons inelastically scatter in a fluorine-containing material (BeF2/PbF2) placed between the target and the NIFTI filter. The neutron beam out of the treatment port has an average energy of ~30 keV. The effectiveness of the two designs for BNCT treatment is analyzed. Both exhibit good penetration in tissue (advantage depth) and tumor/healthy tissue dose (relative biological effectiveness advantage ratio) performance.
