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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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2024 ANS Annual Conference
June 16–19, 2024
Las Vegas, NV|Mandalay Bay Resort and Casino
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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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Glass strategy: Hanford’s enhanced waste glass program
The mission of the Department of Energy’s Office of River Protection (ORP) is to complete the safe cleanup of waste resulting from decades of nuclear weapons development. One of the most technologically challenging responsibilities is the safe disposition of approximately 56 million gallons of radioactive waste historically stored in 177 tanks at the Hanford Site in Washington state.
ORP has a clear incentive to reduce the overall mission duration and cost. One pathway is to develop and deploy innovative technical solutions that can advance baseline flow sheets toward higher efficiency operations while reducing identified risks without compromising safety. Vitrification is the baseline process that will convert both high-level and low-level radioactive waste at Hanford into a stable glass waste form for long-term storage and disposal.
Although vitrification is a mature technology, there are key areas where technology can further reduce operational risks, advance baseline processes to maximize waste throughput, and provide the underpinning to enhance operational flexibility; all steps in reducing mission duration and cost.
Tuomas Viitanen, Jaakko Leppänen
Nuclear Science and Engineering | Volume 177 | Number 1 | May 2014 | Pages 77-89
Technical Paper | doi.org/10.13182/NSE13-37
Articles are hosted by Taylor and Francis Online.
The target motion sampling (TMS) temperature treatment technique, previously known as “explicit treatment of target motion,” is a stochastic method for taking the effect of thermal motion on reaction rates into account on-the-fly during Monte Carlo neutron tracking. The method is based on sampling target velocities at each collision site and dealing with the collisions in the target-at-rest frame using cross sections below the actual temperature of the nuclide or, originally, 0 K. Previous results have shown that transport with the original implementation of the TMS method requires about two to four times more CPU time than conventional transport methods, depending on the case. In the present paper, it is observed that the overhead factor may increase even above 10 in cases involving burned fuel. To make the method more practical for everyday use, some optimization is required. This paper discusses a TMS optimization technique in which the temperatures of the basis cross sections are elevated above 0 K. Comparisons show that the TMS method is able to reproduce the NJOY-based reference results within statistical accuracy, both with and without the newly implemented optimization technique. In the specific test cases, the optimization saved 35% to 83% of the calculation time, depending on the case.