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.
Explore membership for yourself or for your organization.
Conference Spotlight
2026 Nuclear Energy Conference & Expo (NECX)
August 24–27, 2026
Dallas, TX|Hilton Anatole
Latest Magazine Issues
Jul 2026
Jan 2026
2026
Latest Journal Issues
Nuclear Science and Engineering
September 2026
Nuclear Technology
August 2026
Fusion Science and Technology
Latest News
In transition: Commercializing fusion power
Commercial fusion power is closer than ever. There are now around 30 U.S. fusion companies, several of which claim to be on track to connect to the grid as early as the 2030s.
Tokamak and laser inertial confinement approaches benefit from decades of research at facilities such as the National Ignition Facility (NIF) at Lawrence Livermore National Laboratory and ITER, with alternative concepts including stellarator, magnetic mirror, and Z-pinch confinement also making notable progress as private and government funding for fusion increases.
M. Ishii, W. L. Chen, M. A. Grolmes
Nuclear Science and Engineering | Volume 60 | Number 4 | August 1976 | Pages 435-451
Technical Paper | doi.org/10.13182/NSE76-3
Articles are hosted by Taylor and Francis Online.
The motion and location of the molten clad during an unprotected loss-of-flow accident in liquid-metal fast breeder reactors are very important because of their effect on the reactivity and the subsequent fuel motion. The present study analyzes the clad relocation problem based on a single-channel film flow model and a simple thermal transient model for fuel pins. The motion of molten clad induced by sodium vapor streaming undergoes initial rapid upward acceleration, slowing down, flow reversal, and eventual slumping down into liquid sodium at the lower end of the heated section. A possibility for freezing of the molten clad at the unheated upper plenum region as well as bottom freezing and blockage formation were also included in the analysis. A sample calculation has been made for the case of R-series 7-pin tests in the Transient Reactor Test Facility. The agreement of the overall physical behavior of the clad motion with the post-test observations is quite satisfactory.