Looking for "safer" type of reactors?

November 28, 2014

JAEA seeks to resume research on new type of nuke reactor it says is safer

http://ajw.asahi.com/article/sci_tech/technology/AJ201411280055

November 28, 2014

By TERUHIKO NOSE/ Staff Writer

The Japan Atomic Energy Agency is seeking to resume research and development of a new type of nuclear reactor that it claims is safer, even as experts raise doubts about such efforts in the wake of the March 2011 Fukushima nuclear accident.

"While we do not expect everyone to support us, it would serve as one option for a future energy source," said Satoru Kondo, director-general of the JAEA's Oarai Research and Development Center in Oarai, Ibaraki Prefecture, where the experimental reactor is located. "We would like to proceed with research."

The experimental high-temperature gas reactor halted operations in the wake of the Fukushima nuclear accident, but the JAEA, an independent research institute, submitted an application on Nov. 26 to the Nuclear Regulation Authority for a screening of the reactor based on new safety standards.

The JAEA said the experimental reactor is safer than the light water reactors that have been in use at Japanese nuclear plants.

JAEA officials explained that the structure of the new experimental reactor guards against core meltdowns. The nuclear fuel is encased in highly heat-resistant ceramic and then placed in a graphite vessel container that can withstand temperatures up to 2,500 degrees.

The agency plans to conduct experiments to heighten the capabilities of the reactor and confirm its safety. Researchers will also seek to use the technology to manufacture hydrogen by applying the high temperatures generated to break down water. Helium gas, rather than water, is used to transfer heat and the gas can be heated to temperatures as high as 950 degrees. That is much higher than the steam that reaches temperatures of about 300 degrees in light water reactors.

Research on the high-temperature gas reactor began in the late 1960s. It was envisioned as a multipurpose reactor that could manufacture hydrogen in addition to generating electricity. Experimenting at the reactor in Oarai began from 1998. However, the reactor received little attention because the commercialization costs were considered too high. For one thing, the reactor had to be kept small because in larger dimensions it would be much more difficult to cool the core due to the higher temperatures generated.

The situation changed in April 2014 when the Abe Cabinet approved a basic energy plan that included a provision calling for the promotion of research and development.

Rather than power generation, the production of hydrogen is attracting attention because of its increase in value as a fuel source with the development of fuel cells.

A panel of experts under the science ministry compiled a report in the summer detailing how research and development should proceed. The ministry included a request of 1.6 billion yen ($13.6 million) for research in the fiscal 2015 budget, much higher than the 600 million yen included in the fiscal 2013 budget.

According to Koji Okamoto, a professor of nuclear engineering at the University of Tokyo who has been involved in the research on the high-temperature gas reactor, research on such reactors has proceeded in China and Indonesia, and there are plans to go commercial.

"In order to take advantage of research results from the past, the reactor should resume operations as soon as possible," Okamoto said.

However, other experts are casting doubts on the resumption of operations, even for experimentation.

In October, questions were raised at a meeting of the science ministry's nuclear power science and technology committee about the excessive emphasis on safety and the possibility of actually producing hydrogen.

One committee member, Yoko Wake, a professor emeritus of business at Keio University, said about the science ministry's report, "From the standpoint of the sensitivity toward safety that Japan faces in the wake of 3/11, I cannot but feel a sense of discomfort."