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
Nuclear Energy Conference & Expo (NECX)
September 8–11, 2025
Atlanta, GA|Atlanta Marriott Marquis
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
Aug 2025
Jan 2025
Latest Journal Issues
Nuclear Science and Engineering
September 2025
Nuclear Technology
August 2025
Fusion Science and Technology
Latest News
Chris Wagner: The role of Eden Radioisotopes in the future of nuclear medicine
Chris Wagner has more than 40 years of experience in nuclear medicine, beginning as a clinical practitioner before moving into leadership roles at companies like Mallinckrodt (now Curium) and Nordion. His knowledge of both the clinical and the manufacturing sides of nuclear medicine laid the groundwork for helping to found Eden Radioisotopes, a start-up venture that intends to make diagnostic and therapeutic raw material medical isotopes like molybdenum-99 and lutetium-177.
Rene Sanchez, William Myers, David Hayes, Robert Kimpland, Peter Jaegers, Richard Paternoster, Stephen Rojas, Richard Anderson, William Stratton
Nuclear Science and Engineering | Volume 129 | Number 2 | June 1998 | Pages 187-194
Technical Paper | doi.org/10.13182/NSE98-A1973
Articles are hosted by Taylor and Francis Online.
The parameters that determine when critical mixtures of 239Pu, SiO2, and water and mixtures of 239Pu, Nevada tuff, and water are capable of sustaining an increasing neutron chain reaction as may be caused by a positive void coefficient at constant temperature are established. A single canister is considered that is loaded with up to 75 kg of 239Pu. A survey of critical spherical mixtures of plutonium, SiO2, tuff, and water at constant temperature is created and these results are examined to determine the mixtures that might be autocatalytic. Regions of criticality instability are identified that have the possibility of autocatalytic power behavior. A positive void coefficient is possible for a very limited range of wet systems.