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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.
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Utility Working Conference and Vendor Technology Expo (UWC 2024)
August 4–7, 2024
Marco Island, FL|JW Marriott Marco Island
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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ARPA-E announces $40 million to develop transmutation technologies for UNF
The Department of Energy’s Advanced Research Projects Agency–Energy (ARPA-E) announced $40 million in funding to develop cutting-edge technologies to enable the transmutation of used nuclear fuel into less-radioactive substances. According to ARPA-E, the new initiative addresses one of the agency’s core goals as outlined by Congress: to provide transformative solutions to improve the management, cleanup, and disposal of radioactive waste and spent nuclear fuel.
Paul Goldhagen
Nuclear Technology | Volume 175 | Number 1 | July 2011 | Pages 81-88
Technical Paper | Special Issue on the 16th Biennial Topical Meeting of the Radiation Protection and Shielding Division / Radiation Measurements and General Instrumentation | doi.org/10.13182/NT11-A12274
Articles are hosted by Taylor and Francis Online.
This paper describes the design and construction of an extended-range multisphere neutron spectrometer (ERMNS), also called a Bonner sphere spectrometer, created to measure the spectrum of cosmic-ray-induced neutrons on container ships. Such measurements require a highly sensitive neutron spectrometer and can benefit from improved energy resolution. To obtain high sensitivity, spherical 3 He gas proportional counters with a diameter of 152 mm (6 in.) were developed and used. The goal for designing the moderator assemblies of the new ERMNS was to optimize its energy resolution where it is typically worst for such spectrometers - at high and medium-low energies. Absorber shells containing boron carbide were used to improve resolution at medium-low energies. The response functions of various sizes and designs of plain and modified spheres were calculated using the radiation transport code MCNPX 2.6b. The resolution of combinations of 16 spheres of candidate designs was then determined using Reginatto's RESPOW code, and the sphere designs that gave the smallest standard deviations of the RESPOW averaging kernels were selected. Compared to an ERMNS used earlier for similar measurements, resolution improved by 7 to 17% from 10 eV to 0.1 MeV and 24 to 39% from 10 MeV to 10 GeV. Bayesian parameter estimation was also used to characterize the uncertainties in spectra measured with the old and new spectrometers. The uncertainties in the fluence rates and peak energies of a typical terrestrial cosmic-ray neutron spectrum improved by 15 to 85% and 56 to 400%, respectively. These results demonstrate the utility of RESPOW and Bayesian parameter estimation for designing ERMNSs.