Nuclear experts told Congress Wednesday that spent-fuel pools at US nuclear power plants are fuller than safety suggests they should be. They say the entire US spent-fuel policy should be overhauled in light of the nuclear crisis at Japan's Fukushima plant.
An aerial view of the Fukushima Daiichi Nuclear Power Station is seen in Fukushima Prefecture in this photo taken by Air Photo Service on March 24, 2011. Air Photo Service/Reuters
By Mark Clayton, Staff writer / March 30, 2011
The travails of the Fukushima Daiichi nuclear power plant in Japan are highlighting a key question for the US: Why are America's nuclear power plants allowed to store tons of used but still highly radioactive fuel in pools for as many as 100 years – despite the fact that those pools are far more vulnerable to terrorist attack than the reactors themselves?
In Japan, a relatively small amount of used-up fuel was sitting in Fukushima's seven spent-fuel pools when disaster occurred. Yet after just days without a cooling system, most water in at least one pool had apparently boiled away, a fire was reported, and radiation levels soared.
By contrast, nuclear utilities in the US have over decades accumulated some 71,862 tons of spent fuel in more than 30 states – the vast majority of it sitting today in pools that are mostly full, according to a recent state-by-state tally by the Associated Press. It's a huge quantity of highly radioactive material equal to a great many Chernobyls' worth of radioactivity, nuclear experts say.
RELATED: How dangerous is nuclear power? Three lessons from Japan.
The reason is the lack of a national repository for spent fuel – meaning it must be stored on site – as well as the lack of a coherent nationwide policy, experts told Congress Wednesday.
"From the history of our nuclear power program, storage of spent fuel – between the reactor and the presumed repository – has been an afterthought," said Ernest Moniz, a nuclear expert at the Massachusetts Institute of Technology, at a Senate hearing. "It has not really been part of our serious policy discussion about fuel cycle design."
"What we need to do is to stand back and say: What is our whole integrated system?" he added. "We should really start thinking hard about that view."
Warnings years ago
The risks posed by spent fuel held in such pools are hardly new or unknown. A 2006 study by the National Academy of Sciences (NAS) warned Congress and the Nuclear Regulatory Commission (NRC) that spent fuel pools were vulnerable to terrorist attack, with some nuclear plant designs more than others. With water gone from the pools, the spent fuel could easily catch fire and see "the release of large quantities of radioactive materials to the environment," the study found.
The NAS report found that another method of storing spent fuel, called "dry cask" storage, did not require on complex power systems. Dry-cask storage involves putting older spent fuel into concrete- and steel-lined cylinders to allow natural air circulation for cooling. Dividing up spent fuel among a large number of such cylinders also makes "it more difficult to attack a large amount of spent fuel at one time" and also reduces "the consequences of such attacks," the report found.
RELATED: Five recent 'near miss' incidents at US nuclear power plants
Echoes of that report could be heard in Congress Wednesday, with several experts testifying that finding a new way to deal with spent fuel was a key takeaway from Fukushima.
For instance, the Fukushima General Electric Mark 1 Boiling Water Reactor design, which has a spent-fuel pool near the top of the building where it's easy for loading cranes to access, is one of the most vulnerable reactor designs, some experts say. At least 28 of America's 104 reactors are of that type.
The Fukushima problems of spent-fuel pools located on the same site with the reactors "will undoubtedly lead to a reevaluation of spent nuclear fuel management strategy," said Professor Moniz.
_____
Related Stories
Japan considers unusual fixes to contain radioactive leak
Meltdown 101: What are spent-fuel pools and why are they a threat?
Japan nuclear crisis: Why are the spent-fuel pools so hard to control?
No comments:
Post a Comment