Published on July 13, 2019.
Based on an article from the Sankei Shimbun, this piece examines Toshiba’s next-generation 4S reactor, which attracted the attention of Bill Gates, and its relationship with TerraPower’s Traveling Wave Reactor, or TWR.
It highlights the reality that Japan’s innovative reactor technology, capable of long-term operation without fuel replacement, stagnated after the Fukushima Daiichi nuclear accident while China and others rapidly caught up.

July 13, 2019.
Toshiba and TerraPower have concluded a confidentiality agreement, so the details are unknown, but a Toshiba source revealed that “we are considering applying 4S technology to the TWR.”
The following is from an article in the Sankei Shimbun dated 201/9/18.
I found this article after searching, thinking that voices of indignation must have risen from Japan in response to Bill Gates’s actions.
The Japanese next-generation reactor that excited Bill Gates stagnated after the nuclear accident, while China and others rapidly caught up, making it a “fatal blow.”
“Wow!”
A Toshiba official vividly remembers the excited figure of Bill Gates, the founder of Microsoft.
On November 9, 2009, Gates secretly visited the Isogo Engineering Center in Yokohama, where nuclear power plants are designed, among other sites.
Gates visited as chairman of TerraPower, a venture company developing next-generation nuclear reactors in which he himself had invested, to inspect Toshiba’s next-generation reactor, the “4S.”
The 4S is small, with an output of 10,000 to 50,000 kilowatts, but its distinguishing feature is that it can operate continuously for 10 to 30 years without fuel replacement.
Even if power suddenly becomes unavailable, the reactor automatically shuts down and the core is cooled naturally, giving it a high level of safety.
Akira Ozaki, Chief Engineer of the Nuclear Energy Systems & Services Division of Toshiba’s Power Systems Company, says, “Even at this point, construction of a practical reactor is technically possible.”
The next-generation reactor called the “Traveling Wave Reactor,” or TWR, being developed by TerraPower, also has a mechanism extremely similar to that of the 4S.
It can operate for up to 100 years without fuel replacement, requires almost no maintenance inside the reactor, and in an emergency the reactor stops naturally.
Gates and the other TerraPower members praised it highly, saying, “Among everything we have studied about nuclear power so far, the most innovative was Toshiba’s 4S.”
Toshiba and TerraPower have concluded a confidentiality agreement, so the details are unknown, but a Toshiba source revealed that “we are considering applying 4S technology to the TWR.”
This article continues.