Post-Fukushima:

Some New Directions?

One clear outcome of the accident at the Fukushima Nuclear Power Station is that it will focus technology development and regulatory requirements towards the systems that seemed to contribute to the situation at the Japanese plant.

A number of these systems are obvious, of course: spent fuel pools and emergency diesel generators, for example. Others are extensions of some of these, most prominently, the whole issue of spent fuel storage.

Among those taking an early look ahead are Ernest Moniz, former Undersecretary of the US Department of Energy, and now a professor at MIT and director of MIT's Energy Initiative. An article in the Wall Street Journal's blog by Russell Garland covers Moniz's views on why Japan's accident could change US energy policy assumptions. His four top predictions are 1) higher costs, 2) an end-to-end review of waste-storage practices, 3) a revisiting of the 20-year license extensions in the US, and 4) a shift of R&D from advanced fuel systems to issues associated with cladding and other safety-related matters. He points out that US models of energy supply and demand in the coming decades all assume most license renewal applications will be approved, so any delays (or even retractions of licenses already granted) could affect the presumed availability of tens of thousands of megawatts of clean energy.

A paper by Akira Tokuhiro of the University of Idaho, submitted as a short communication to Nuclear Exchange this month, outlines some 14 technical measures that he has identified as an initial set of lessons learned. They start with the issue of cladding, noting that the hydrogen generation that caused so much trouble was produced by the cladding. His other observations relate to the issues mentioned above (such as back-up power, spent fuel pool) as well as to other issues (an offsite control room, valves for emergency core cooling, backup water supply, and more). In addition to looking at the plant itself, he highlights other areas for possible changes, including establishing alternate routes for access to nuclear plants in emergency, and establishing international teams of emergency responders.

A final push may well be enhanced interest in non-traditional reactor technologies. It has already been observed that a pebble-bed design, for example, would not need water for cooling. It is likely, however, that any look at alternative technologies will now give greater scrutiny to other types of accident sequences and their consequences, such as the possibility of pebbles jamming in an earthquake.

While a lot more remains to be learned about the accident before any such measures are adopted and implemented and all these proposals will need further examination, there will clearly be needs in these areas, and it is useful to see a dialogue developing around the question of what we can learn from the recent events.

***