When it comes to investments—philanthropic, environmental, and technological—even the so-called “Oracle (News - Alert) of Omaha,” Warren Buffet, trusts Bill Gates with his money. And usually, Gates’ instincts are in the right place. But, in the case of the traveling wave reactor, the Microsoft (News - Alert) founder has gone astray, according to a new report just released this week.
The research study, produced by the nonprofit, Washington, DC-based think tank, the Institute for Energy and Environmental Research (IEER), finds that the traveling wave reactor (TWR) concept championed by TerraPower— a nuclear reactor design spin-off company of Intellectual Ventures that is headquartered in Bellevue, Wash., and in which Bill Gates (News - Alert) is a key investor—is likely to be a commercial failure.
According to the study—entitled “Traveling Wave Reactors: Sodium-Cooled Gold at the End of a Nuclear Rainbow?”—about $100 billion already has been invested by over half a dozen countries over more than six decades in an unsuccessful commercialization effort. Over that time, there has been essentially no demonstrable learning curve: The most recent sodium-cooled demonstration reactors in France and Japan have among the worst reliability records.
Unproven to Date
The “traveling wave reactor,” first conceived in 1958, has been intensively investigated only since about 2006. It represents a new—and unproven— type of nuclear reactor, called a sodium-cooled fast reactor, that does not use enriched uranium exclusively for fuel. Instead, TerraPower’s reactor uses the waste byproduct of the enrichment process (or waste uranium).
At the beginning of the process, the TerraPower-designed reactor requires a small amount of enriched uranium, but then it continues to operate on the waste product and can make and consume its own fuel. The benefits are that the reactor doesn’t have to be refueled or have its waste removed until the end of life of the reactor (a century or more). Using waste uranium reduces the amount of waste in the overall nuclear life cycle, and extends the available supply of the world’s uranium for nuclear by many times.
What’s more, using sodium as a coolant is theoretically an advantage, because the liquid metal coolant has a high heat capacity which provides thermal inertia against overheating. However, a disadvantage of sodium is its chemical reactivity, which requires special precautions to prevent and suppress fires. If sodium comes into contact with water, it explodes, and it burns when in contact with air.
This was the case at the Monju Nuclear Power Plant, a Japanese sodium-cooled fast reactor located in Tsuruga, Fukui Prefecture. The reactor went online in April 1994, but an accident in December 1995, in which a sodium leak caused a major fire, forced a shutdown. A subsequent scandal involving a cover-up of the scope of the accident delayed its restart until May 2010–however, three months later, another accident shut the plant down again.
Sodium handling at the now-shuttered Monju plant in Japan (courtesy Monju).
Thus, the new study, conducted and authored by Arjun Makhijani, Ph.D., nuclear engineer and president of the Institute for Energy and Environmental Research, concludes:
- The sodium-cooled reactor experience does not bode well for TWRs—Makhijani notes, “Sodium-cooled fast reactors have a checkered history. Some have operated well, while others have done poorly. The most recent commercial demonstration reactors belong in the latter category. The French demonstration reactor, Superphénix, operated at an average capacity factor of less than 7 percent over 11 years before being shut in 1996….The Japanese Monju reactor, commissioned in 1994, and connected to the grid in 1995, had a sodium leak and fire in 1995. It was closed until May 2010, when it was restarted for testing, but suffered another accident in August 2010. It has not been restarted since.”
- Power produced by TWRs would not be affordable or competitive—Again, the author points out, “Even apart from the poor reliability in many cases, sodium-cooled breeder reactor capital costs have been very variable and have not decreased over time. Fermi I, built in the 1960s, cost about $4,000 per kilowatt; while the Fast Flux Test Facility, operational in 1980, cost over $10,000 per kilowatt. Superphénix cost, commissioned in 1986, was priced at about $4,800 per kilowatt; but Monju, commissioned nearly a decade later, cost over $20,000 per kilowatt [all in 1996 dollars].”
Not Convincing, Even on Paper
Makhijani notes, “Given the reactor development that remains, it is highly unlikely that such reactors could help significantly alleviate the problem of fossil fuel generation in the next few decades, when it must be solved. TWRs are likely to be economically obsolete before there are commercialized.”
Report reviewer M.V. Ramana, Ph.D., Nuclear Futures Laboratory and Program on Science and Global Security, Woodrow Wilson School of Public and International Affairs, Princeton University, agreed: “Sodium cooled fast neutron reactors have been pursued by several countries around the world. The lesson from the many decades of such pursuit has been that these reactors are expensive, are prone to operational problems and sodium leaks, and are susceptible to severe accidents under some circumstances. There is no evidence that TWR will overcome any of these. It is not convincing even on paper.”
Edited by Alisen Downey