Question about Fukushima in 2016
Posted: Mon Mar 21, 2016 11:18 pm
Is there a fission physicist in the house?
I realize Chernobyl (graphite pile) and Fukushima (boiling water with metal containment vessel) are different technologies, but both had meltdowns, and both contain tons of melted nuclear fuel that no one knows how to remove (let alone "clean up").
Chernobyl avoided the "China Syndrome" by luck. Sand placed around the plant when it was constructed slipped into the basement as a result of an explosion. As the fuel melted down, it mixed with the sand, which vitrified it, and diluted it out of criticality. It's still very hot (in a radioactive sense) but it's no longer molten. An ice tunnel (to create a barrier between the core and ground water) was started, but not completed.
In Fukushima there are three molten cores -- and no sand. Apparently they are kept from melting into ground water (or from further melting into ground water) by being constantly cooled by water hosed in. The result is a lot of contaminated water being stored in an ever-growing number of tanks. Fukushima also plans an ice tunnel.
Which to me raises a lot of questions:
1. The cores are still "hot" enough (radioactively) to fry purpose-built robots (as of March 2016). Doesn't that imply ongoing criticality? What is the status of short-life daughter products (iodine, Xenon) that signify criticality?
2. Doesn't the plan for the ice tunnel also signify ongoing criticality?
3. Is the purpose of the water cooling to draw away heat to prevent the China Syndrome? Presumably the water does not "cool" the chain reaction. Could the water even be acting as a moderator that increases the amount of fission?
4. The BBC recently ran a story claiming the abandonment of the Fukushima area did more harm than the low levels of ambient radiation would have done if people stayed. But:
-- the radiation is low because a lot of weeds and surface soil were removed. Might not hot spots remain?
-- If no longer cooled with water couldn't the cores melt into the ground (potentially releasing radioactive steam), or generate hydrogen that might cause another radiation-spreading explosion?
Fukushima is a classic "Cat in the Hat" problem. Try to rub out a pink stain, and you just spread it. I don't like some of the alarmist stuff written about Fukushima (like blaming it for USA West Coast starfish die-offs, which appears to be pure speculation); but the situation does seems justifiably terrifying -- and not being discussed hardly anywhere.
I realize Chernobyl (graphite pile) and Fukushima (boiling water with metal containment vessel) are different technologies, but both had meltdowns, and both contain tons of melted nuclear fuel that no one knows how to remove (let alone "clean up").
Chernobyl avoided the "China Syndrome" by luck. Sand placed around the plant when it was constructed slipped into the basement as a result of an explosion. As the fuel melted down, it mixed with the sand, which vitrified it, and diluted it out of criticality. It's still very hot (in a radioactive sense) but it's no longer molten. An ice tunnel (to create a barrier between the core and ground water) was started, but not completed.
In Fukushima there are three molten cores -- and no sand. Apparently they are kept from melting into ground water (or from further melting into ground water) by being constantly cooled by water hosed in. The result is a lot of contaminated water being stored in an ever-growing number of tanks. Fukushima also plans an ice tunnel.
Which to me raises a lot of questions:
1. The cores are still "hot" enough (radioactively) to fry purpose-built robots (as of March 2016). Doesn't that imply ongoing criticality? What is the status of short-life daughter products (iodine, Xenon) that signify criticality?
2. Doesn't the plan for the ice tunnel also signify ongoing criticality?
3. Is the purpose of the water cooling to draw away heat to prevent the China Syndrome? Presumably the water does not "cool" the chain reaction. Could the water even be acting as a moderator that increases the amount of fission?
4. The BBC recently ran a story claiming the abandonment of the Fukushima area did more harm than the low levels of ambient radiation would have done if people stayed. But:
-- the radiation is low because a lot of weeds and surface soil were removed. Might not hot spots remain?
-- If no longer cooled with water couldn't the cores melt into the ground (potentially releasing radioactive steam), or generate hydrogen that might cause another radiation-spreading explosion?
Fukushima is a classic "Cat in the Hat" problem. Try to rub out a pink stain, and you just spread it. I don't like some of the alarmist stuff written about Fukushima (like blaming it for USA West Coast starfish die-offs, which appears to be pure speculation); but the situation does seems justifiably terrifying -- and not being discussed hardly anywhere.