“A nuclear accident provokes [?] countless victims and leaves vast tracts of land uninhabitable for thousands of years. Is such risk morally permissible?”
Well, we’ve had quite a few nuclear accidents, from the steam explosion in a weapons-production reactor at Chernobyl to guys breaking their ankles falling down flights of stairs at plant sites, and only Chernobyl required any sort of permanent evacuation. The area around Chernobyl isn’t exactly uninhabitable, either–it’s lower than occupational radiation standards but higher than levels allowed for the general public, and the lack of major human interference in the area since 1986 has resulted in (of all things) a de facto wildlife refuge.
Chernobyl was by no means a good thing. Don’t get me wrong; it was terrible, but not the end of the world. Uninhabitable? Absolutely not.
We always hear this word ‘risk.’ Why?
In the 1950s, scientists calculating the impact of a nuclear accident had neither the operational experience nor the computers necessary to accurately determine the consequences of any one of a number of postulated accidents. So they simply gave what they thought was the probability of an accident, based on what they could figure out. Most of these ‘postulated accidents’ turned out to be physically impossible, for one reason or another, and the rest had universally lower impacts than previously estimated. The worst-case meltdown, for instance, was defined as an accident in which all the fuel melted, all the cladding broke open, all the melted fuel was released through some large break, and it all escaped the containment. Estimated consequences were an uninhabitable area the size of Pennsylvania and hundreds of billions of dollars in damage. It was assumed that nuclear power plants were inherently unsafe, and needed layers of backups (defense-in-depth).
Then came Three Mile Island. One of the defense-in-depth systems had failed; ironically, had this “safety system” been left out, the accident never would have happened. Large amounts of cooling water were lost through a malfunctioning valve, and an operator switched off the emergency coolant, thinking that there was no loss of coolant. Radioactive gas was mysteriously generated by the reactor and released to nil radiological impact but huge public protest. Finally, eventually, the reactor vessel was refilled with water, and public officials gave themselves a pat on the back for preventing a meltdown, which would certainly have caused widespread, unimaginable devastation. Efforts were redirected to restarting the reactor, and the reactor vessel head was removed to determine the condition of the reactor–which most people assumed was intact, since Pennsylvania was not uninhabitable.
It was destroyed. It had melted down, and TMI Unit 2 could never be restarted.
Some people started to rethink these previous impact studies, and by the early 1990s, enough advances were made in reactor physics and computers to allow nuclear engineers to design a reactor that was passively safe. Such a reactor could be abused to no end and not release radioisotopes. It wouldn’t matter if Homer Simpson and Osama bin Laden were operating the reactor–the laws of physics cannot change and need no backups. Unless, of course, aliens come down from the planet Zorkon with antigravity beams. But I somehow don’t think that’s a credible postulated accident.
Do we need to have a zero-risk reactor? No. We need to stop thinking in terms of a risk–to think in terms of the laws of physics, not probability. Current plants are probabilistically safe, and certainly safe enough, especially when compared to the alternatives. However, if pro-nuclear people got their way in regulatory reform, there would not be a single nuclear power plant currently in operation in this country that would meet standards–but, importantly, passive features of new reactors seen by the current regulatory system as added safety measures would be recognized as absolutely essential, and defense-in-depth discouraged and discontinued.
Filed under Anti-Nuclear Quote of the Day, Chernobyl, Health, International, Safety, Three Mile Island
Posted on July 28, 2006 by Stewart Peterson |
