There is a great deal of buzz coursing through the “pipes” on the Internet regarding talks between Toshiba and Bill Gates’s TerraPower, the company that is developing the Traveling Wave Reactor (TWR). That is not terribly surprising – when Bill Gates talks, the web (and the business press) listens. Here are some links to example stories:
- China Post – Gates, Toshiba in early talks on nuclear reactor
- Fox News – Bill Gates Wants a Nuclear Reactor
- BBC – Bill Gates and Toshiba discuss nuclear power venture
- Fast Company – Bill Gates Goes Nuclear With Toshiba’s 4S Reactor
- The Register – Bill Gates goes (mini) nuclear
- Environmental Leader – Bill Gates, Toshiba May Develop Clean Nuclear Technology
- The Independent – Bill Gates company to go nuclear with Toshiba
- Taipai Times – Gates, Toshiba in talks on reactor
There is certainly some truth to what you might have been reading about the Toshiba-Gates discussions. Gates and TerraPower are definitely interested in developing reactors that can burn depleted uranium and used nuclear fuel for a very long time before they need to be refueled. Toshiba definitely is interesting in designing and building reactors of all sizes – from their 1358 MWe ABWR’s to their 1154 MWe Westinghouse AP1000’s (Toshiba owns 70% of Westinghouse), to their 10 MWe sodium cooled 4S reactors that might end up powering small villages in Alaska.
However, many of the versions of the stories linked above have combined information from several different projects to provide an inaccurate description of the TerraPower Traveling Wave Reactor as something that is quite small – some stories have even described it as being small enough to fit into a hot tub. I have it from a very good source that the physics associated with initiating and sustaining a fission wave that can convert depleted uranium or used nuclear fuel into fissile material so that the reaction can continue for decades requires a reactor that will produce at least 700 MWth (300 MWe) and is better with a reactor that will produce at least 1000 MW of thermal energy (430 MWe).
Those numbers indicate that the Traveling Wave Reactors will be 10-20 times as large as the “hot tub sized” Hyperion Power Modules. They can still be significantly smaller than the 1200-1600 MWe reactors that many people who discuss nuclear matters think of as “standard”.
Gates and his TerraPower team will need to work with a power plant designer and equipment vendors that can build the physical machinery that their computer programs design and simulate. Toshiba would be a great choice for helping to find materials that can withstand a long exposure to an intense neutron flux. However, it is important to understand that TWR’s that last for decades will not be “hot tub” sized systems. Systems in that size range will have characteristics more like the Hyperion Power Modules that use a liquid metal coolant, fast neutrons, and last for 5-8 years before needing to be refueled or replaced.
The world needs a full spectrum of nuclear fission power plant sizes that can fit a variety of customer needs; the concept should be understandable to anyone who recognizes that combustion power plants come in sizes ranging from leaf blowers to low speed diesel engines that power ships like the Queen Elizabeth.