It looks like some developing nations might do the work that Western countries never completed. South Africa, partnering with Westinghouse, apparently plans to make a high temperature reactor variant called the pebble bed modular reactor (PBMR) a cornerstone of its economy, testing it locally then exporting it worldwide.
I visited South Africa last year and spoke with some executives from Eskom, the state utility. For years, Eskom has been running on over 90 percent coal energy, but its coal plants are falling into disrepair. The PBMR came up during our conversation, along with another idea, development of solar thermal power for use in South Africa's deserts.
At the time, my thought was that it was odd for Eskom to attempt solar thermal on its own, with a number of players like Abengoa, BrightSource and eSolar all well ahead in the game. But focusing on the PBMR makes sense; it takes a national government to foster a new type of nuclear power, so there's inherently a better market opportunity, since few countries have gotten serious about nuclear to date.
That doesn't mean there won't be any competition, though. High temperature reactors are also being developed in China, where the Huaneng Group and China Nuclear Engineering and Construction are working with government support to get a set of test reactors completed.
The story in both South Africa and China is that HTRs are safer than any reactor ever built. Although they're built with cooling (from helium, in the case of the PBMR), graphite interspersed with the fuel will cause the reaction to end safely even if the cooling systems break down.
But there is some uncertainty about that point. Next Big Future has a play-by-play of some scientific catfighting over whether PBMRs are safe, suggesting that there's at least enough controversy to keep an argument going. Given the risk averseness toward nuclear of populations in rich countries, it may be that HTRs not only grow up in developing nations, but stay there, too.