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 ANS Annual Conference
May 31–June 3, 2026
Denver, CO|Sheraton Denver
Latest Magazine Issues
Mar 2026
Jul 2025
Latest Journal Issues
Nuclear Science and Engineering
March 2026
Nuclear Technology
February 2026
Fusion Science and Technology
April 2026
Latest News
NRC approves TerraPower construction permit
Today, the Nuclear Regulatory Commission announced that it has approved TerraPower’s construction permit application for Kemmerer Unit 1, the company’s first deployment of Natrium, its flagship sodium fast reactor.
This approval is a significant milestone on three fronts. For TerraPower, it represents another step forward in demonstrating its technology. For the Department of Energy, it reflects progress (despite delays) for the Advanced Reactor Demonstration Program (ARDP). For the NRC, it is the first approval granted to a commercial reactor in nearly a decade—and the first approval of a commercial non–light water reactor in more than 40 years.
Nisy E. Ipe
Nuclear Technology | Volume 168 | Number 2 | November 2009 | Pages 559-563
Shielding Materials | Special Issue on the 11th International Conference on Radiation Shielding and the 15th Topical Meeting of the Radiation Protection and Shielding Division (Part 2) / Radiation Protection | doi.org/10.13182/NT09-A9243
Articles are hosted by Taylor and Francis Online.
A typical particle therapy facility consists of an injector, a cyclotron or a synchrotron, a high-energy transport beam line, several treatment rooms including fixed-beam and gantry rooms, and even a research area. During the operation of these facilities, radiation is produced with neutrons being the dominant component outside the shielding. These facilities have large amounts of shielding with concrete thicknesses ranging up to [approximately]5 m or more. Space required for shielding can be minimized by using composite shielding or high-density material such as Ledite® (manufactured by Atomic International, Frederick, Pennsylvania). Transmission data for radiation from protons and carbon ions incident on tissue targets with energies in the therapeutic energy range of interest were derived using the Monte Carlo code FLUKA for three different compositions of Ledite. Use of Ledite® or composite shielding results in space savings when compared to concrete.