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
Apr 2026
Jan 2026
Latest Journal Issues
Nuclear Science and Engineering
May 2026
Nuclear Technology
March 2026
Fusion Science and Technology
Latest News
Mark your calendar for the 2026 ANS Annual Conference
The American Nuclear Society’s 2026 Annual Conference is coming up fast. From May 31 to June 3, leaders from across the nuclear industry will gather in Denver, Colo., to discuss the state of the industry and emerging opportunities.
To register for the conference, make hotel reservations, and explore the full program, visit ans.org/meetings/ac2026/.
Nuclear Criticality Safety Division 2025 Conference
Japan Atomic Energy Agency (JAEA)
Group Leader in the Criticality Safety Research Group of the Nuclear Safety Research Center
Dr. Satoshi Gunji completed his PhD in Engineering at Tohoku University before joining the Power and Industrial Systems Research and Development Center of Toshiba Corporation in 2007 as a researcher in the Nuclear Reactor System Analysis Group. Before the accident at the Tokyo Electric Power Company's Fukushima Daiichi Nuclear Power Plant, his main work was on criticality safety of next-generation light water reactor fuel. He was also an experimenter and an operator of the Toshiba Nuclear Critical Assembly.
After Toshiba decided to decommission the NCA, he moved to the Criticality Safety Research Group at the Japan Atomic Energy Agency (JAEA), where he currently works. At the time, JAEA was proceeding with plans to modify the criticality assembly STACY to conduct criticality assessments of the fuel debris generated by the FDNPP accident. He participated in this project as a criticality safety expert and planned the criticality experiment plans. STACY achieved first criticality in 2024, and he has been directing subsequent experiments.
Last modified August 26, 2025, 10:54am CDT
