Written on May 7, 2019, this essay centers on the high praise Bill Gates and TerraPower gave to Toshiba’s next-generation reactor 4S, and discusses both the advanced nature of Japan’s nuclear technology and the danger posed by its stagnation after the Fukushima Daiichi accident.
Touching on fast breeder reactors, high-temperature gas reactors, the ASTRID project, and the rapid advances of China, Russia, and India, it argues that Japan must not allow the flame of next-generation reactor development to go out if it is to preserve its future energy security and international competitiveness.

2019-05-07
Mr. Gates and the other members of TerraPower lavished praise on it, saying, “Of all the nuclear technologies we have studied so far, Toshiba’s 4S was the most innovative.”

The following is a chapter I published on 2018/7/30.
…It is from a Sankei Shimbun article dated 201?/9/18.
It is an article I found by searching, thinking that voices of indignation must surely have arisen in Japan over what Bill Gates had done.
The Japanese next-generation reactor that excited Bill Gates, stalled by the nuclear accident, with China and others in hot pursuit, making it “fatal.”
“Wow!”
Those involved with Toshiba vividly remember the sight of Bill Gates, the excited founder of Microsoft in the United States.
On 2009/11/9, Mr. Gates paid a secret visit to the “Isogo Engineering Center” (Yokohama City), where nuclear plants are designed, among other places.
Mr. Gates visited to inspect Toshiba’s next-generation reactor “4S” as chairman of TerraPower, the venture company developing next-generation reactors in which he himself had invested.
4S is small, at 10,000 to 50,000 kilowatts, but its distinctive feature is that it can operate continuously for 10 to 30 years without refueling.
It is also said to have a high level of safety, in that even if power is suddenly lost, the reactor automatically shuts down and the core is cooled naturally.
Akira Ozaki, chief engineer in Toshiba Power Systems Company’s nuclear power division, says, “Even at present, construction of a practical reactor is technically possible.”
The next-generation reactor called the “traveling wave reactor (TWR),” which TerraPower is developing, also has a mechanism extremely similar to that of 4S.
In addition to being able to operate for up to 100 years without refueling, it requires almost no maintenance inside the reactor, and in emergencies the reactor stops naturally.
Mr. Gates and the other members of TerraPower lavished praise on it, saying, “Of all the nuclear technologies we have studied so far, Toshiba’s 4S was the most innovative.”
Toshiba and TerraPower have concluded a confidentiality agreement, and the details are unclear, but a Toshiba insider disclosed that “they are considering applying 4S technology to the TWR.”
At present, development plans for next-generation reactors known as the “fourth generation” are advancing around the world.
Nuclear power has continued to evolve in safety and other respects, from the “first generation” of the early development period, to the “second generation” built from the latter half of the 1960s to the first half of the 1990s, to the “third generation” that began operation from the latter half of the 1990s to around 2010.
The fourth generation is expected to be put to practical use from the 2030s onward.
Research and development are advancing on multiple next-generation reactors, beginning with TerraPower’s TWR.
What has been positioned in Japan as the “leading candidate” of the fourth generation is the “fast breeder reactor.”
The fast breeder reactor, which produces more nuclear fuel than it consumes, is a “dream reactor,” but the prototype reactor “Monju” (Fukui Prefecture), which is still in the research stage, has remained in long-term shutdown after one trouble after another.
After the Tokyo Electric Power Company’s Fukushima Daiichi nuclear accident, the future became unclear, and within the ruling party as well there remained strong opinions calling for a “complete withdrawal” from Monju.
With nuclear power facing headwinds, Japanese players are working to preserve the technology they cultivated through fast breeder reactor development.
The Japan Atomic Energy Agency and Mitsubishi Heavy Industries, among others, agreed with the major French nuclear company Areva and others to cooperate in the development of next-generation reactors.
They will participate in the development plan for “ASTRID,” France’s demonstration fast reactor for the next generation, and make use of the technology Japan possesses.
In addition, the government intends to restart as early as next fiscal year the research reactor for the next-generation reactor known as the “high-temperature gas reactor,” whose progress had stagnated since the Great East Japan Earthquake, and to intensify research and development in earnest.
A Mitsubishi Heavy Industries executive explained the significance, saying, “Domestic development of next-generation reactors is in an uncertain state.
We need to build up our strength for the future.”
Yutaka Sagayama, specially appointed advisor to the same organization, emphasized, “For us as well, it will lead to the maintenance of technology.”
However, with regard to next-generation reactors, Russia, China, India, and others are conducting research and development aimed at practical use.
According to Ministry of Economy, Trade and Industry materials, Russia is scheduled to begin operation of a commercial fast reactor in 2025, and China is scheduled to introduce a commercial reactor around 2030.
While Japan hesitates in developing next-generation reactors, there is also the danger that its technological superiority will be lost.
“A discontinuity of several years would be fatal.”
Nuclear researchers all say this in unison.
For Japan to maintain its international competitiveness, it is indispensable not to let the flame of technological development go out in pursuit of both stable energy supply and safety.
A senior METI official emphasized the significance that next-generation reactor development has for Japan’s energy policy.
“For Japan, having many choices available is indispensable for the future.”