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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
Dragonfly, a Pu-fueled drone heading to Titan, gets key NASA approval
Curiosity landed on Mars sporting a radioisotope thermoelectric generator (RTG) in 2012, and a second NASA rover, Perseverance, landed in 2021. Both are still rolling across the red planet in the name of science. Another exploratory craft with a similar plutonium-238–fueled RTG but a very different mission—to fly between multiple test sites on Titan, Saturn’s largest moon—recently got one step closer to deployment.
On April 25, NASA and the Johns Hopkins University Applied Physics Laboratory (APL) announced that the Dragonfly mission to Saturn’s icy moon passed its critical design review. “Passing this mission milestone means that Dragonfly’s mission design, fabrication, integration, and test plans are all approved, and the mission can now turn its attention to the construction of the spacecraft itself,” according to NASA.
Hesham R. Nasif, Atsushi Neyama, Hiroyuki Umeki, Atsuyuki Suzuki
Nuclear Technology | Volume 141 | Number 3 | March 2003 | Pages 275-300
Technical Paper | Radioactive Waste Management and Disposal | doi.org/10.13182/NT03-A3367
Articles are hosted by Taylor and Francis Online.
Radionuclides released from a vitrified waste package after overpack failure spread into the buffer material surrounding the waste package, then migrate through different pathways into the water-bearing fracture in the rock surrounding the high-level radioactive waste repository, and transport through the faults to the biosphere. The buffer material has low permeability and the solute is transported through the engineered barrier system by diffusion only. In the water-bearing fracture, the problem is of the convection diffusion type with highly varying parameters from one medium to the other due to the variability in length, transmissivity, and other transport-relevant properties of the transport paths. This complex geometry is modeled using the wavelet Galerkin approach. The Wavelet Integrated Repository System (WIRS) wavelet-based system is an integrated tool to calculate the transport of single or radionuclide chains in both near and far fields of the repository system. The model, which is a very coarsely discretized wavelet based, is devised to be very fast since the scaling functions, which are used as a basis function, are compactly supported. Only finite numbers of the connection coefficients are nonzero, and the resultant matrix has a block diagonal structure that can be inverted easily. One of the main problems encountered in solving the model for the radionuclide transport in the geospheric media is the treatment of the boundary and interface conditions. In order to maintain the integrity of the system, the boundaries of the wavelet series are shifted until the end is independent of any expansion coefficients of the scaling function that affect the solution within the real boundaries. WIRS agreed well with models using a very detailed discretization. Accuracy is gained with the proper selection of wavelet-dilation orders pair. WIRS has been applied to the Japanese high-level radioactive waste repository concept where the migration is through different barriers and pathways. Single and decay chain radionuclide release calculations have shown the capability of WIRS to handle different situations rapidly and easily.
