Q1 - Tokuhiro's Entrance into Nuclear
Naomi Senehi: How did you get involved in the nuclear space?
Akira Tokuhiro: In his early years, Akira Tokuhiro was interested in racecar design, but found it very challenging to get a job in the industry. He was drawn to systems engineering and became interested in nuclear energy, receiving his PhD in nuclear engineering from Purdue. During his graduate program, he completed experimental work for heat transfer in a fusion reactor design. Tokuhiro’s thesis topic was centered on how the magnetic field of liquid metal cooling affects its heat transfer abilities. Tokuhiro started working in nuclear reactor design research and development, with the European Fast Reactor program, not starting his career in academia until 2000 at three different universities in the U.S. He joined on with NuScale Power, where he worked on development from 75% to 100% design completion for two and a half years. Akira Tokuhiro is currently the Dean and a Professor in the Engineering Systems and Nuclear Department at the Ontario Tech University. Before academia, Tokuhiro also worked on development of an integral test facility for General Electric’s simplified boiling water reactor (SBWR).
Q2 - Japanese Sodium Cooled Fast Reactor
Naomi Senehi: What did you go on to do after working on GE’s simplified boiling water reactor?
Akira Tokuhiro: After working on GE’s simplified boiling water reactor (SBWR), Akira Tokuhiro was invited to be an institute research fellow at what is now the Japan Atomic Energy Agency. He supported the development of the Japanese sodium cooled fast reactor between 1995 and 2000. A fast reactor is important for a closed nuclear fuel cycle and is very compact. Sodium is a very good coolant, but must be kept under a cover gas. Tokuhiro supported the ultrasonic doppler velocimetry measurements, which required development of new measurement methods since the material is opaque. Tokuhiro considers himself an innocent bystander for multiple incidents, such as the Kobe earthquake, the Tokyo sarin attack, a sodium leak at a fast reactor demonstration plant, which caused a major fire, and the criticality accident at Tokaimura which happened when workers didn’t know they were switching between low enrichment and high enrichment fuel.
Q3 - Tokuhiro's Debut in Academia
Naomi Senehi: Where did you go following your time in Japan?
Akira Tokuhiro: After ten years of research and development, Akira Tokuhiro started his career in academia at the University of Missouri in Rolla. He started submitting applications for Department of Energy grants for the university, receiving grants for research reactor instrumentation, application of polymer gels for radioactive waste processing, and testing the heat exchanger for supercritical CO2 loops. In 2001, Tokuhiro published a paper comparing risk as a spectrum and how safety culture is different for automobiles, commercial airline flights, and nuclear reactors. His order of magnitude analysis looks at the amplification factor that the mass media exercises for each industry, such as fatality statistics. The level of acceptance is the ratio of the perception of the benefit to the perception of the risk. Tokuhiro also was responsible for the University of Missouri - Rolla reactor, as the director and licensed operator for five years. In order to receive his license from the Nuclear Regulatory Commission, Tokuhiro was tested on knowledge of the facility, how fuel is moved, what the license entails, etc. When 9/11 happened, the university went on lockdown, the reactor was shut down, and Tokuhiro acted as the public liaison for the university’s reactor. As part of the aftermath, had to install additional biometric security measures at the university reactor, such as facial recognition and fingerprint scanning.
Q4 - Advanced Reactor Safety Design
Naomi Senehi: During your time working at the plant, what were some of your lessons learned?
Akira Tokuhiro: As the director and licensed operator for the experimental reactor at the University of Missouri in Rolla, Akira Tokuhiro was able to support a high school student interested in pursuing and receiving an operating license for the reactor. After Rolla, Tokuhiro spent two years at Kansas State University, then transitioned to the University of Idaho in Idaho Falls. Tokuhiro continued working in advanced reactor safety design and a project with Argonne National Labs analyzing air cooling and water cooling of decay heat. In the development of advanced reactors, such as the German-designed pebble-bed reactor, safety issues and challenges are identified. These tennis ball sized graphite sphere in a container move during online refueling. During movement, graphite dust is created and considerations needed to be taken for control and management of the dust due to its high flammability. Tokuhiro also worked on the very high temperature reactor (VHTR), a graphite-moderated nuclear reactor. On shutdown, decay heat cooling must be required due to the temperature limitations of the concrete vault; both air-cooled and water-cooled solutions were considered. While working in Idaho, Tokuhiro took an opportunity to work for NuScale Power in 2014.
Q5 - Involvement After Fukushima
Naomi Senehi: What was your involvement with the Fukushima incident?
Akira Tokuhiro: After the hydrogen explosion at Fukushima, which resulted of melting fuel or damaged cladding, Akira Tokuhiro received many phone calls from the media due to his role as a nuclear professor. Tokuhiro participated in a blog on LinkedIn started to share information about the accident between industry experts. The American Nuclear Society (ANS) selected Tokuhiro to be on the President’s committee for the accident. The committee addressed communication and management as it relates to both risks and crises. During his visit to Fukushima, Tokuhiro witnessed the destruction of the tsunami and some of the clean-up efforts. Approximately 40 years of work is needed to complete decommissioning. In subsequent trips, Tokuhiro studied the effects of the radiation cloud on the surrounding plant and animal life. One finding was that the radiation was strongest at the base of trees, due to the radiation cloud and rain.
Q6 - NuScale Power Development
Naomi Senehi: Tell me more about your experience at NuScale Power.
Akira Tokuhiro: NuScale Power was much further ahead in completion of design compared to other small modular reactors (SMR’s). Tokuhiro was on a team to establish the technical basis for the emergency planning zone (EPZ). Due to their size, SMR’s require a much small EPZ than traditional nuclear plants. The NuScale SMR design is a natural circulation design which doesn’t have a pump and much fewer valves and piping components. The steam generator is integrated into the reactor pressure vessel. One benefit of the small modular reactors is being able to tap into the mass manufacturing industry that typically manufacture large components. The SMR’s are small enough to be placed on a semi or a barge. The reactor vessel is inside a containment which sits inside a pool. The integration design, fewer components, and natural cooling all contribute to safety benefits of SMR’s. Akira Tokuhiro now runs the only nuclear engineering program in Canada at Ontario Tech University, with about 300 undergraduates studying at this time.
Q7 - Nuclear Education Opportunities
Naomi Senehi: What’s next for you and what do you see coming down the line for nuclear?
Akira Tokuhiro: Akira Tokuhiro is the Dean and Professor of the College of Energy Systems in Nuclear Science. Climate change and nuclear power has come to the forefront in terms of social license and public discussion. Tokuhiro is kicking off a new Bachelor of Technology program in Sustainable Energy Systems at the university. There is also a new degree to produce energy analysts and energy communications, both aimed at supporting the nuclear energy industry as a whole and widening the umbrella of nuclear power expertise.