Because they lost power to the water cooling system, they needed to vent the pressure that's building up inside.My suspicion is that as the temperature inside the reactor was rising, some of the metal cans that surround the fuel may have burst and at high temperature, that fuel cladding can react with water to produce zirconium oxide and hydrogen.That hydrogen then will be part of the gases that need to be vented. That hydrogen then mixes with the surrounding air. Hydrogen and oxygen can then recombine explosively. So it seems while the explosion wasn't directly connected with the nuclear processes, it was indirectly connected, because the hydrogen was only present because of what was going on in the reactor core.
quote: 1000x greater radiation level in the control room
quote: aren't 'normal' radiation levels outside a nuke plant as close to zero as it is sitting at your desk reading this?
quote: When something goes wrong with gasoline production it does not affect people living a thousand miles away or more....Oil spills and fires at refineries can be bad but they are nothing compared to how bad Nuclear disasters can get so enough with the pro-Nuclear propaganda.
quote: what it boils down to is that an area contaminated by nuclear meltdown is uninhabitable for *much* longer than any other kind of power plant destroyed. That and the widespread effect on people and the wildlife is much longer lasting as well.
quote: If you find nuclear power plant so safe, are you living near one already?
quote: When you operate a coal plant, the harm is spread all around and avoidable
quote: Nuclear accident: 1 in 10,000,000 chance of dying Scalding: 1 in 5,000,000 Food poisoning: 1 in 3,000,000 Falling out of bed: 1 in 2,000,000 Drowning in bath: 1 in 685,000 Work accident: 1 in 43,500 Car crash: 1 in 8,000
quote: Also expecting the world to be rational is futile. Look at how much money is being spend on countering terrorism - if that money was instead spend fighting pollution and improving traffic safety the results would be much better.
quote: Heck, the money could be spend building schools, providing the most basic health care and thus making the whole world a better place (and likely make many wannabe terrorists into happy productive people).
quote: There will always be extremists and those who are angry at the world no matter what country they are in, but the idea is to minimize the number of ant hills we step on along the way.
quote: The new reactors need energy input to sustain fission so if the power is cut the reaction dies out automatically.
quote: There are simple and effective solutions in use today that guarantee a reactor shutdown if coolant power is lost. Simply suspending the control rods above their slots via electromagnets is probably the simplest. If the magnets lose power the control rods drop into the reactor and bring the nuclear reactions to a stop (or near enough anyway).
quote: The much worse being a total core meltdown and breach of the inner containment chamber resulting in a release of large amounts of highly radioactive material on a Chernobyl scale.
quote: The next step was to halt the reaction by cooling the power rods, composed of uranium-235.
quote: This reactor is NOT still running. The control rods did fully insert. But - since it was running at full power and had been for weeks or months, there is a lot of residual heat from nuclear decay that remains for hours and days. That is the heat that must be removed to avoid melting the fuel pellets.
quote: I strongly disagree. Ultimately, the Fukushima disaster illustrates the need to progress to modern reactor designs such as the German pebble bed AVR, the Chinese HTR-10 or Thorium reactors, as examples.
quote: Thorium designs are promising, but produce less power per gram of fuel than uranium designs making them a tough sell.
quote: As to the pebble bed design...
quote: Please explain.
quote: Why is it that you believe that it's more difficult to contain a pebble bed design than currently extant types of reactors? And given that the problems a pebble bed addresses are precisely the ones that threaten containment in the current Japanese situation, why would it be more dangerous in a case like this?
quote: What new safeguards on legacy reactors do you suggest would solve the problems the Japanese face?
quote: The reactor did not explode as your article says, the top of the building where the reactor is blown up, the reactor is intact.
quote: The disaster does illustrate that nuclear fission power is far from failsafe, particularly older reactors -- even if retrofitted with modern controls. Ultimately the international community needs to work towards fusion power, which should be much safer and cheaper
quote: Placing a fusion reactor (assuming we could build one) in the same ring of fire earthquake prone area would have resulted in a thermonuclear explosion
quote: You forgot another little detail about coal, the amount of radioactive elements it contains and the amounts of coal burned annually.
quote: ...this time the damage was far worst
quote: My thoughts and prayers go out to those affected.