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.
Jungchung Jung
Nuclear Science and Engineering | Volume 65 | Number 1 | January 1978 | Pages 130-140
Technical Paper | doi.org/10.13182/NSE78-A27131
Articles are hosted by Taylor and Francis Online.
The neutron transport equation in toroidal geometry is numerically solved by making use of the discrete-ordinates SN method. The computer program developed for this computation is capable of treating a multigroup problem with anisotropic scattering. Numerical examples are given for the first wall and blanket system of a conceptual tokamak reactor design that has an aspect ratio of ∼3. To validate the present method, several numerical comparisons have been made with Monte Carlo results as well as with ANISN calculations in the case of an infinite major radius. The toroidal geometry calculation, with a uniform neutron source distribution throughout the plasma region, yields a neutron flux that, at the first wall, is maximum near the top and bottom of the torus. As one moves radially outward from the first wall, the position of the maximum flux rapidly shifts to the outermost point of each poloidal circle, and the flux decreases monotonically along the poloidal circumference until it reaches a minimum at the innermost point of the torus. At ∼10 cm from the first wall, for example, the variation becomes >20%. The one-dimensional infinite cylinder calculation shows an overestimate of flux within the first 1 cm of the first wall compared to the present calculation. In the rest of the first wall and blanket system, the one-dimensional model underestimates the fluxes in the outer region of the torus and overestimates the fluxes in the inner region.