TheOilDrum.com members are having thought-provoking discussions about the Fukushima nuclear disaster. Here are a few of the more interesting comments I came across.
Broken piping and/or vessel rupture has poured highly radioactive water into the turbine hall basements. This is infinitely worse than previous. I think it’s an urgent priority to make a seawall (sunken barges loaded with cement, infill with rock, scrap metal, debris from tsunami damage) and close/shut down the underground heat discharge loop.
Blow the roof off #2, air drop boron and shredded tin, repeat.
Destroy turbine halls and build 20-ft dike from concrete rubble of nearby outbuildings. Start serious water flooding of reactor buildings immediately to cool everything down. Add boron and shredded tin to absorb neutrons. Water will pour into contained seawall, evaporate. Add concrete, cement, sand. Cover the cold reactors first. Then the demolished turbine halls. Then the trapped lagoon.
I also have been thinking about a cofferdam or seawall of some sort around the plant to prevent runoff from entering the ocean. We’ll see.
The comment below notes that 3 weeks into the Chernobyl disaster, Russia had 10,000 men on the ground. TEPCO has how many, 500 or so, max?
User Idyl says (emphasis mine):
Looking at recent coverage, there appears to be a situation almost exactly mimicking the situation at Chernobyl. The first responders on the scene at Chernobyl were firefighters, who sprayed water throughout the whole site. This water pooled and evaporated as steam, and most significantly filled up the basement floors of the reactor building. Russian officials were very concerned that the corium would come into contact with this water, and explode in an equivalent of a 3-5 megaton bomb, obliterating Minsk (320 km away), and spreading a great deal of radiation throughout region (rendering an extensive part of Europe uninhabitable). So they sent in workers to remove this water (many later died), and then hired some 10,000 miners to tunnel under the plants and build a cooling system under the foundation of the plant (to be filled with liquid nitrogen gas).
If there’s water throughout the site at Fukushima, and a corium pile now on the concrete slab of the primary containment vessel (as suggested by this latest report), I’m a little bit at a mystery about the next steps, and why efforts appear to be so casual and modest to this point (involving only 50-100 people at the site). After three weeks at Chernobyl, the Russians had sent in tens of thousands of people at this point to work on clean-up and containment. And all they had to do was hide from them the dangerous nature of the work detail, pay an extra 100 rubbles as a bonus, and provide 150 grams of free vodka after each meal. I’m worried this situation is going to get much worse before it gets better.
Idyl links to a documentary (below) about Chernobyl at the end of his post. It is well-worth watching. At the one hour mark, the film documents hand-sewn lead suits worn by “bio-robots”, those on the front lines doing the most dangerous work.
User PVGuy thinks using barges to remove the radioactive water may be one of the better options available, for now:
I think the barges are the best bet (although my information is certainly incomplete). Distance counts as shielding too.
Fill the barges with isotope soup. Put another barge with seawater between the tug and the softly glowing barge, and push it out to sea. The question then is sink the barge (ick) or anchor it out several miles until you find enough ion exchange beads to try to clean up the water, and hope nothing more goes wrong in the mean time.
No good answers to be had. And you will need a lot of barges either way, unless you pump it out once you are far enough from the beach. That’s even worse. If you sank the barge intact at least the soup would stay put while the hull rusted out, by which time the short-lived stuff would be gone.
“Steve from virginia” casts doubt on PVguy’s barge plan (based on this layman’s reading), but he offers intriguing alternative ideas. Highlighting is mine:
Normal procedure with contaminated water @ a reactor is to filter contamination onsite. Right now there is too much water to process or to take to other reactors. (Other reactors is where the waste goes, too.)
The flow of water is cooling what is left of the cores, the ground is a heat sink and the water is the heat transfer mechanism.
There is little pressure in the cores and the large amounts of water being pumped into the reactors indicates leaking rather than boiling/venting as the cooling dynamic.
Any water that gets into the soil or basements will wind up in the ocean.
The Japanese management has been completely lost from the beginning. The operators cannot even conceive of the scale of effort needed to render these plants safe. (Hint: Chernobyl and the hundreds of thousands of ‘Liquidators’.)
The Wall Street Journal’s plan diagrams are wrong, so the information they carry is also wrong. A better diagram can be found here, originally from GE.
What the managers must do is fill the reactors and spent fuel pools with reactor poison such as boron w/ sand. They can create working areas by making walls of lead bricks and sheets and inch toward the cores so that concrete pumps can direct the boron onto the fuel. More leaded areas can be built so workers can use grouting pumps to seal cracks and leaks.
Liquid nitrogen can be piped via directional drilling under the reactors to prevent corium from reaching the water table. I don’t know why the Japanese aren’t doing this right now. It would solve the water leaking into the ocean along with cofferdams built into the turbine hall which is between the cores and the ocean.
They need lead pathways up the stairs onto the service decks so that debris can be cleared from the spent fuel pools and so more boron can be pumped into them along with sand. Sand melts and fuses with the uranium trapping it for a long enough period so that it can be dealt with later. Lead, sand and boron are also cheap: using it won’t bankrupt Japan, unlike the onrunning fiasco taking place right now where 50 men and wheelbarrows pretend to ‘fix’ the (irrelevant) ‘pumps’ while the hot fuel spews garbage everywhere.
Soon, the site will be too radioactive for the crews to work. I guess that is when the bosses will get serious. Then again, maybe not …
The cores have likely already melted down so ‘saving the cores’ is a farce.
OD member Ridgecritter on the “China Syndrome”, doubt over effectiveness of neutron-absorbers and flooding sans containment vessels:
Flooding the reactor buildings won’t help. The reactor cores are inside steel pressure vessels inside the buildings. Flooding the buildings, even if that were possible, won’t get water inside the pressure vessels so it can remove heat from the reactor fuel rods. And if the rods are not covered with continuously cooled (or continuously replaced, if open-loop) water, they will melt and burn. Melting and pooling of fuel elements could lead to renewed criticality (nuclear fission), which would generate additional heat, perhaps melting through the pressure vessels (the famed “China Syndrome”).
Neutron absorbers aren’t effective either. The reactors shut down when the earthquake happened, meaning that neutron-absorbing control rods were inserted into the cores to stop the neutron-driven chain reaction that occurs when the reactors are in operation. And crews have already introduced boron-containing water. What they’re fighting is residual decay heat – not heat driven by neutrons fissioning nuclei, but heat from radioactive materials created during normal operation that are fissioning on their own and liberating heat without needing external neutrons. Neutron absorbers don’t shut off residual decay processes.
If these pressure vessels were to be opened, the remaining water would immediately flash to steam and vanish. Fuel elements would rapidly (we’re talking minutes, not hours) heat to the point where zirconium combusion would start. This would expose the uranium (or in the case of one of the distressed reactors, the mixed uranium and plutonium) fuel and would disperse a lot this radioactive material into the air. The remainder would be available for a meltdown scenario.
I don’t think there’s a fix that doesn’t involve keeping the reactor cores and the adjacent spent fuel elements immersed in water. And if the suspicions of compromised structural integrity in at least one reactor pressure vessel are correct, it won’t be possible to keep the core submerged and cooled. The likely outcomes are becoming more and more ugly with time.
Note: I do not have the expertise to evaluate these claims/ideas from a physics/chemistry perspective. They are only meant to provoke discussion.