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
Jul 2025
Jan 2025
Latest Journal Issues
Nuclear Science and Engineering
September 2025
Nuclear Technology
August 2025
Fusion Science and Technology
Latest News
Deep Space: The new frontier of radiation controls
In commercial nuclear power, there has always been a deliberate tension between the regulator and the utility owner. The regulator fundamentally exists to protect the worker, and the utility, to make a profit. It is a win-win balance.
From the U.S. nuclear industry has emerged a brilliantly successful occupational nuclear safety record—largely the result of an ALARA (as low as reasonably achievable) process that has driven exposure rates down to what only a decade ago would have been considered unthinkable. In the U.S. nuclear industry, the system has accomplished an excellent, nearly seamless process that succeeds to the benefit of both employee and utility owner.
Tsuyoshi Misawa, Seiji Shiroya, Keiji Kanda
Nuclear Technology | Volume 83 | Number 2 | November 1988 | Pages 162-170
Technical Paper | Fission Reactor | doi.org/10.13182/NT88-A34157
Articles are hosted by Taylor and Francis Online.
A criticality safety study on a light water moderated and reflected coupled core loaded with highly enriched uranium fuel was performed in the Kyoto University Critical Assembly. The critical mass and neutron flux distribution were measured systematically as a function of the separation distance between the two cores, varying the H/235U atomic ratio (i.e., the moderator-to-fuel volume ratio). These data were analyzed with the SRAC code system to assess the capability of diffusion theory to analyze the coupled-core system. It was found that the critical mass of the coupled core showed the minimum when the two cores were separated by a certain distance depending on the neutron spectrum in the core region. The neutron flux peak value at the water gap region reached the maximum when the separation distance was 5 to 6 cm. The results calculated with the diffusion code installed in the SRAC system agreed well with the experimental data.
