Monday, July 13, 2009

The LFTR: Is it safe?

Mothers worry about nuclear power. They have heard the stories about the dangers of radiation, and words like Chernobyl and "Three Mile Island" can bring a shudder of fear. But is nuclear power in general, and the LFTR in particular really that unsafe? Ralph Nader says so, but then what does Ralph Nader know about nuclear safety?

Nader tells stories about himself, in which he claims to be a saint of knowledge. For example, Nader claims that in 1964 he attended a conference at the Oak Ridge National Laboratory. Over lunch Nader claims that he began asking nuclear engineers some questions. "They couldn't answer them, or the answers weren't satisfactory," Nader claims. "'What could happen if a system goes wrong?' Nader asked. They avoided any such descriptions or said, 'we've got defense in depth' -- and other jargon." "Defense in Depth" is of course an effective operational concept, that was proven to be effective at Three Mile Island. By describing a discussion of things things that he did not understand as jargon, Nader revealed his lack of understanding of and indeed interest in nuclear safety. As Gomer Pyle use to say, "surprise, surprise surprise." There were of course, other people at ORNL who could have the answered Nader's 1964 questions, or at least would have known the answers within the state of knowledge. If Ralph Nader wanted people who could answer his questions about what could go wrong in reactors and under what conditions, he could have talked to George Parker, or he could have talked to my father. Needless to say, Nader did not seek out nuclear safety experts to answers to his questions. Certainly Alvin Weinberg would and could have answered Nader's questions about nuclear safety, and indeed Weinberg made himself available to Ralph and his sister Claire. It is quite possible that Nader talked to someone in Oak Ridge who did not answer his question, or alternatively gave Nader an answer that Nader did not understand. Had Nader sought out answers about nuclear safety in 1964, he would have found them, but Nader wanted answers that made nuclear scientist look bad, not the truth. There is not the slightest evidence that Ralph Nader ever investigated the possibility that reactors could be made safe, despite his family connection with Oak Ridge National Laboratory, where so much nuclear safety research was conducted in the 1960's.

The truth is that the worst nuclear accidents, those signified by the words Chernobyl and Three Mile Island, were far from the worst industrial accidents of the 2oth century. In terms of loss of life Three Mile Island would not count among the ten thousand worst industrial accidents of the 20th century, and the Chernobyl probably would not have counted among the hundred worst energy related accidents in the last 50 years. Chernobyl simply was not an accident of the same rank as the Bhopal disaster. At Bhopal 500,000 people were exposed to toxic gas, and as many as 10,000 died within 72 hours since their exposure. Estimates of the eventual death total run as high as 100,000, yet no one shudders at the thought of a chemical factory in their town. In contrast there have been 56 deaths attributed to the Chernobyl accident. In contrast to the Bhopal and Chernobyl, there have been no deaths deaths that can be attributed to Three Mile Island.

New reactor designs are far safer than the Three Mile Island Reactor. The Westinghouse AP-1000 will have an estimated mean time between core meltdowns of five million years. But several more very bad, and unlikely things would have to happen before an AP-1000 meltdown would lead to a single civilian casualty. It is far more likely that a natural disaster, say the eruption of the Yellowstone super-volcano, would kill a million people than a nuclear accident involving the AP-1000 would produce on single casualty. By all rational standards the AP-1000
is safe.

How safe then is the LFTR? Probably safer than the AP-1000. Even if there were a major structural failure in the LFTR core, there would be several lines of defence between the core and a civilian population. Breach of any one of those defenses would be very improbable. Again, when compaired with the probability of mass casualties produced by a natural disaster, the LFTR proves far safer. Safer even than the AP-1000.


P.M.Lawrence said...

"Estimates of the eventual death total run as high as 100,000, yet no one shudders at the thought of a chemical factory in their town".

Oh? I don't know who you've been talking to, but certainly that is not the general view here in Australia. Memories of the accident at the Coode Island plant are still quite strong.

friend2all said...

LFTR technology will gradually begin to get scrutiny from decision makers and regulators that are deeply familiar with and invested in current Light Water Reactor technology.

The ORNL MSRs were research reactors and while highly successful may not have been built the way we would require commercial power generating reactors to be built.

Regulators and decision makers are use to seeing included in a nuclear reactor the following design safety features that are expensive and perhaps unnecessary with LFTR.

Protective Forged Steel Reactor Containment Vessel - Light Water Reactor Technology typically uses an enormously heavy (~600 ton) forged steel vessel to enclose the reactor core for safety reasons. LFTR molten salt reactors will not produce high pressure events and cannot suffer core melt downs.

Heavy above Ground cement and steel containment building needed by LWRs can suffer high pressure and loss of primary coolant failures. Dr. Teller suggested underground installation of LFTR in his final paper. Underground mounting of LFTR would seem to have many advantages both economic and in terms of security.

It seems to me both of these expensive traditional LWR design features are unnecessary with LFTR. Would you agree?


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