Time: Was Fukushima a China Syndrome?

[villager]

Was Fukushima a China Syndrome?

The China Syndrome refers to a scenario in which a molten nuclear reactor core could could fission its way through its containment vessel, melt through the basement of the power plant and down into the earth. While a molten reactor core wouldn't burn "all the way through to China" it could enter the soil and water table and cause huge contamination in the crops and drinking water around the power plant. It's a nightmare scenario,the stuff of movies. And it might just have happened at Fukushima.

Last week, plant operator Tepco sent engineers in to recalibrate water level gauges in reactor number 1. They made an alarming discovery: virtually all the fuel in the core had melted down. That means that the zirconium alloy tubes that hold the uranium fuel and the fuel itself lies in a clump---either at the bottom of the pressure vessel, or in the basement below or possibly even outside the containment building. Engineers don't know for sure, though current temperature readings suggest that fission inside the reactor core has definitely ceased for good (i.e. there will be no further melting).

Anecdotal evidence doesn't bode well for how far the fuel melted: Tepco has been pumping thousands of tons of water onto reactor 1 to try to cool it—yet the water level in the containment vessel is too low to run an emergency cooling system. That means the water is escaping somewhere on a course cut by molten fuel--probably into the basement of the reactor building, though it's also possible it melted through everything into the earth.

<snip>

It's difficult to say for sure just how bad things are at the plant itself—high radioactive levels mean that engineers can't get close to the reactor cores themselves and can only make inferences, deductions and guesses about the extent of the damage. As Alexis Madrigal of the Atlantic has pointed out, we've faced this uncertainty—and troubling surprises— before. Eight months after the Three Mile Island accident, "an Oak Ridge National Laboratory scientist declared, 'Little, if any, fuel melting occurred, even though the reactor core was uncovered. The safety systems functioned reliably.' A few years later, robotic sorties into the area revealed that half the core -- not 'little, if any' -- had melted down."

<snip>



Read more: http://ecocentric.blogs.time.com/2011/05/16/was-fukushima-a-china-syndrome/#ixzz1MXjx7wtL

[damntexdem]

1. No, it was an America Syndrome -- look at the globe.

;-)

But, yes, a chain reaction in full rods in Unit 1 melted through the bottom of the containment vessel, allowing radioactivity to escape into the environment.

[Recursion]

3. Uruguay, roughly

A bit off the coast of it.

http://maps.google.com/maps?f=q&source=s_q&hl=en&geocode=&q=35S+41W&aq=&sll=37.0625,-95.677068&sspn=50.291089,89.736328&ie=UTF8&ll=-35.029996,-40.957031&spn=51.495451,89.736328&z=4

[nadinbrzezinski]

2. The fact that further evacs

Are happening tells me how bad things are. Neato Kan moving away from nuclear same thing.

[leveymg]

4. May not have melted through the lower concrete floor - most radiation leakage is likely due to

contaminated water runoff that cannot be contained inside the building, hundreds of tonnes of which each day that couldn't be transferred to storage ponds has simply spilled out into the Pacific Ocean. Releases of radioactive smoke, particles, and steam account for the contamination far from the site.

At least, that's what I believe has happened. But, no, this is not nearly as bad as if the a large molten mass had burned down into the soil and into water table. That would have created a highly radioactive plume of salt water, ash and silicate particles - extremely toxic for miles and miles around.

[flamingdem]

6. They don't know jack, they said there are holes caused by the corium

that caused water leaks ... all bets are off on all 3 reactors.

[leveymg]

8. Very useful article on the dynamics and interaction with concrete of corium here:

http://en.wikipedia.org/wiki/Corium_%28nuclear_reactor%29

[AndyTiedye]

5. How Can They Be So Sure of the Core's Temperature When They Don't Even Know Where the Core Is???

virtually all the fuel in the core had melted down. That means that the zirconium alloy tubes that hold the uranium fuel and the fuel itself lies in a clump---either at the bottom of the pressure vessel, or in the basement below or possibly even outside the containment building. Engineers don't know for sure, though current temperature readings suggest that fission inside the reactor core has definitely ceased for good (i.e. there will be no further melting).

If the core is somewhere "outside the containment building", then the temperature sensors are measuring something other than the temperature of the core.

They won't know until it hits groundwater. Then everybody will know real soon. :nuke:

and there are 2 more of them doing the same thing.

:nuke::nuke:

[flamingdem]

7. They can't get close enough to answer the Q: Where is the corium? nt