http://www.fairewinds.com/...
Arnie Gunderson argues that Fukushima Rac 3 may have had a prompt criticality
event.
http://en.wikipedia.org/...
A supercritical assembly is said to be prompt-critical if it is supercritical even without the contribution of the delayed neutrons. In this case the time between successive generations of the reaction, T, is only limited by the lifetime of the prompt neutrons, and the increase in the reaction will be extremely rapid, causing a rapid release of energy and a potential explosion within a few milliseconds. With the exception of specially designed research experiments, prompt-critical assemblies are only used in nuclear weapons. Their inadvertent creation is the cause of many criticality accident
that's a nuclear flash.
In the design of nuclear weapons, on the other hand, achieving prompt criticality is essential. Indeed, one of the design problems to overcome in constructing a plutonium-fueled bomb is to contract the fissile materials and achieve prompt criticality before the chain reaction has a chance to force the core to expand. A good bomb design must therefore win the race to a dense, prompt critical core before a less-powerful chain reaction (known as a fizzle) disassembles the core without allowing a significant amount of fuel to fission.
in prior diaries i had argued that Reactor 4 may have had a criticality event,
http://www.dailykos.com/...
http://www.dailykos.com/...
I think Rac 4 may have had a slow critical set of flashes, and Gunderson thinks
Rac 3 may have gone prompt critical.
Now I'm sure the Apologists, will be arguing, but, Gunderson says the proof is
in the Xenon Isotope readings.
Lets see if we can get Xenon data from the Rac 3 explosion and aftermath
and settle out what happened in Rac 3.