ANS is committed to advancing, fostering, and promoting the development and application of nuclear sciences and technologies to benefit society.
Explore the many uses for nuclear science and its impact on energy, the environment, healthcare, food, and more.
Division Spotlight
Fuel Cycle & Waste Management
Devoted to all aspects of the nuclear fuel cycle including waste management, worldwide. Division specific areas of interest and involvement include uranium conversion and enrichment; fuel fabrication, management (in-core and ex-core) and recycle; transportation; safeguards; high-level, low-level and mixed waste management and disposal; public policy and program management; decontamination and decommissioning environmental restoration; and excess weapons materials disposition.
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!
Latest Magazine Issues
Apr 2025
Jan 2025
Latest Journal Issues
Nuclear Science and Engineering
June 2025
Nuclear Technology
Fusion Science and Technology
May 2025
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.
Janez Perko, Eef Weetjens
Nuclear Technology | Volume 174 | Number 3 | June 2011 | Pages 401-410
Technical Paper | TOUGH2 Symposium / Radioactive Waste Management and Disposal | doi.org/10.13182/NT11-A11748
Articles are hosted by Taylor and Francis Online.
Assessment of gas generation and transport is inevitable for evaluation of the safety of nuclear waste disposal in deep geological formations. The long-term safety of the geological disposal facility is guaranteed by several engineered and natural barriers. The reference disposal concept in Belgium consists of a concrete-based repository situated in Boom Clay, which is a low-permeability plastic clay. Hence, the mobility of gas and liquid within these barriers is very small and may lead, in combination with increased temperatures due to decay heat of the waste, to pressure buildup and the potential structural failure of barriers. The focus of this study is on coupling two-phase water and gas flow with a heat source, originating from the heat dissipating waste. The main gas production mechanism within the considered geological repository system is (anaerobic) corrosion of metal barriers, generating H2 gas. The corrosion process itself and therefore the intensity of the gas source is temperature dependent. Furthermore, the heat source is time dependent due to the decaying nature of the radioactive material. This property, in turn, makes the gas generation rate time dependent as well. The cases presented in this work couple variable gas generation with a time-variable heat source and are modeled with TOUGH2. Because of large uncertainties associated with the yet-uncharacterized engineered materials (e.g., concrete), two bounding material permeabilities with a span of two orders of magnitude are chosen for comparison. Results demonstrate that the peak pressures for the isothermal and nonisothermal cases do not differ considerably in the case of high-permeability buffer material. On the contrary, the peak pressures differ considerably for low-permeability material, which hinders the flow of water induced by thermal expansion of water with temperature increase. This peak pressure is not related to the gas-generation process and occurs a little earlier than the gas pressure peak, which is in this case comparable to the high-permeability case. Overall, this near-field analysis showed that the effect of pressure increase remains relatively localized and should not affect the structural integrity of the host formation. The behavior of the system is additionally refined by the implementation of temperature-dependent hydrogen solubility within the numerical code, which slightly modifies the transition to H2 gas phase.
