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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
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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Latest News
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.
Qicang Shen, Brendan Kochunas, Yunlin Xu, Sooyoung Choi, Thomas Downar
Nuclear Science and Engineering | Volume 195 | Number 7 | July 2021 | Pages 741-765
Technical Paper | doi.org/10.1080/00295639.2020.1866388
Articles are hosted by Taylor and Francis Online.
The Transient Multilevel (TML) scheme in the MPACT code has reduced the computational burden for three-dimensional, full-core, time-dependent reactor simulations with pin-resolved detail. However, the total computational cost is still large for practical applications. In this paper, we present a new method that uses a one-group coarse mesh finite difference (1GCMFD) approach to further accelerate the TML scheme. Since multigroup coarse mesh finite difference (MGCMFD) calculations in TML dominate the simulation run time, the 1GCMFD method developed here is shown to reduce the overall computational time by as much as 50% for some large-scale applications. The 1GCMFD method accelerated the calculation primarily by accelerating the convergence of the source for MGCMFD calculations through 1G/MGCMFD iteration. A new 1GCMFD level was implemented in the TML scheme (TML-4) assuming that the energy distribution of the scalar flux shape varies more slowly than the energy-integrated amplitude of the scalar flux. Various numerical cases were used to investigate the practicality of the 1G/MGCMFD iteration and TML-4 scheme. Numerical results show that using the 1G/MGCMFD iteration with a dynamic iteration strategy alone does better capture the evolution of the amplitude function when the scalar flux distribution in energy space varies rapidly and thus provides more accurate results. However, TML-4 is more efficient in capturing the variation of the energy-integrated amplitude when cross-section changes are small and feedback dominates the change of the reactivity. For smaller problems, the 1G/MGCMFD iteration and the new TML-4 scheme can reduce the run time of the coarse mesh finite difference (CMFD) solver by 50% and the total run time by at least 16%. For large-scale, full-core problems, the run time of the CMFD solver can be reduced by 78% and the total run time by as much as 47%.