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Reality isn't like movies or tv, fusion reactors can't turn into bombs. For one, there simply isn't enough fuel in the device at any given time. For another, ma

Reality isn't like movies or tv, fusion reactors can't turn into bombs. For one, there simply isn't enough fuel in the device at any given time. For another, maintaining the conditions that allow fusion reactions to happen doesn't happen easily. If the equipment goes offline or haywire the worst case scenario is that the reactor stops. Fusion reactors are like balancing a pencil on its tip. If anything goes wrong it simply falls over. Fission reactors are different in two ways. One, it's possible for them to have a positive feedback in fission reaction rate due to lolss of coolant (this is called a "positive void coefficient"), but this can be changed in the design of the reactor and all modern reactors have a negative void coefficient. Two, fission byproducts are both extremely radiologically hazardous and continually producing heat from decay over long periods of time. This means that reactor fuel and used decomissioned fuel still needs to be actively cooled for a very long time, and if not then it can melt down which is very difficult to contain. These two problems are the genesis of the disasters at Chernobyl and Fukushima, respectively. In contrast, the products of fusion reactor operations don't get hot and as mentioned the reaction will just stop running if anything goes pear shaped. These factors alone are major reasons why fusion power is so desirable. It wouldn't use of fossil fuels nor produce CO2 and would be unimaginably safer than fission power.

AnthonyMouse 13y ago
> Two, fission byproducts are both extremely radiologically hazardous and continually producing heat from decay over long periods of time. It's probably worth pointing out that those two things are the inverse of each other. The elements that take the longest to decay are inherently the least radioactive, because that's what radioactivity is: The consequence of radioactive decay. Something with a half life of 24,000 years is barely radioactive at all. Something with a half life of 24 seconds will give you radiation poisoning very quickly if you encounter a lot of it but won't be anywhere to be found if you come back in an hour. The waste problem is also largely a political rather than scientific problem. The commonly-cited 24,000 year half life is for Plutonium-239 ("weapons grade plutonium"), which can be mixed at the outset with Plutonium-240 to make it unsuitable for bombs and impossible to separate, and then used as reactor fuel to destroy it entirely. The most radiologically dangerous fission byproducts (largely Sr-90 and Cs-137) are the ones with ~30 year half lives, making them radioactive enough to cause significant damage and also long-lived enough to persist for several decades, but they also have significant market value in nuclear medicine or radioisotope thermoelectric generators or scientific research. The massive political stupidity is in not removing the spent fuel from the reactor site and separating it into its constituent elements so that it can be put to productive use rather than sitting around waiting for disaster to strike. And the entire concept of burying it under a mountain for a million years is just ridiculous.

AnthonyMouse 13y ago

> Two, fission byproducts are both extremely radiologically hazardous and continually producing heat from decay over long periods of time. It's probably worth pointing out that those two things are the inverse of each other. The elements that take the longest to decay are inherently the least radioactive, because that's what radioactivity is: The consequence of radioactive decay. Something with a half life of 24,000 years is barely radioactive at all. Something with a half life of 24 seconds will give you radiation poisoning very quickly if you encounter a lot of it but won't be anywhere to be found if you come back in an hour. The waste problem is also largely a political rather than scientific problem. The commonly-cited 24,000 year half life is for Plutonium-239 ("weapons grade plutonium"), which can be mixed at the outset with Plutonium-240 to make it unsuitable for bombs and impossible to separate, and then used as reactor fuel to destroy it entirely. The most radiologically dangerous fission byproducts (largely Sr-90 and Cs-137) are the ones with ~30 year half lives, making them radioactive enough to cause significant damage and also long-lived enough to persist for several decades, but they also have significant market value in nuclear medicine or radioisotope thermoelectric generators or scientific research. The massive political stupidity is in not removing the spent fuel from the reactor site and separating it into its constituent elements so that it can be put to productive use rather than sitting around waiting for disaster to strike. And the entire concept of burying it under a mountain for a million years is just ridiculous.