japanese government officials have been busy recovering from a severe natural disaster, and there are areas in their country that still have not been visited by search and relief groups.
they’ve also been busy denying that japan is experiencing the greatest environmental disaster human beings have ever created.
several nuclear reactors have gone offline, and an entire facility – fukushima – has suffered explosions in three of its six reactors, and partial meltdowns in at least three, one of which hasn’t yet blown up.
so far, this incident is listed as a category 6 nuclear incident by the international atomic energy agency. to put that into perspective, the three mile island incident in the u.s. was a category 5 incident, while the worst incident in the past – the explosion of a facility in the former soviet union, at chernobyl in the ukraine – was a category 6 incident.
however, as the joke goes – this one (the fukushima incident) goes to 11!
When the Fukushima Meltdown Hits Groundwater – by dr. tom burnett, Ph.D. Earth Sciences and Physics.
Fukushima is going to dwarf Chenobyl. The Japanese government has had a level 7 nuclear disaster going for almost a week but won’t admit it.
The disaster is occurring the opposite way than Chernobyl, which exploded and stopped the reaction. At Fukushima, the reactions are getting worse. I suspect three nuclear piles are in meltdown and we will probably get some of it. (he means radioactive fallout from the damaged reactors…ed.)
If reactor 3 is in meltdown, the concrete under the containment looks like lava. But Fukushima is not far off the water table. When that molten mass of self-sustaining nuclear material gets to the water table it won’t simply cool down. It will explode – not a nuclear explosion, but probably enough to involve the rest of the reactors and fuel rods at the facility.
Pouring concrete on a critical reactor makes no sense – it will simply explode and release more radioactive particulate matter. The concrete will melt and the problem will get worse. Chernobyl was different – a critical reactor exploded and stopped the reaction. At Fukushima, the reactor cores are still melting down. The ONLY way to stop that is to detonate a 10 kiloton fission device inside each reactor containment vessel and hope to vaporize the cores. That’s probably a bad solution.
A nuclear meltdown is a self-sustaining reaction. Nothing can stop it except stopping the reaction. And that would require a nuclear weapon. In fact, it would require one in each containment vessel to merely stop what is going on now. But it will be messy.
Anyway, here is the information that the US doesn’t seem to want released:
Potential dispersion of the radioactive cloud over The Northern Hemisphere
This animation displays a potential dispersion of the radioactive cloud (Caesium 137 Isotope) after a nuclear accident in reactor Fukushima I. The continuous release rate is very uncertain, thus the calculations have to be interpreted qualitatively. Dispersion in the near surface level (Level 1), in appr. 2500 m height (Level 12) and in appr. 5000 m height (Level 16). (click on the link above to see how much radiation will fall where you live.)
And here is a chart that might help with perspective:
radiation dose chart -
a chart that explains the system used to measure radiation and exposure to radioactivity.
Making matters worse is the MOX in reactor 3. MOX is the street name for ‘mixed oxide fuel‘ which uses ~9% plutonium along with a uranium compound to fuel reactors. Here’s why it is used:
Mixed Oxide Nuclear Fuel Raises Safety Questions
Ordinary low-enriched uranium fuel contains primarily uranium 238, the most common natural isotope of the element, along with about 5 percent uranium 235, a rarer isotope that splits, or fissions, more readily. MOX fuel, on the other hand, substitutes plutonium 239 as the fissionable component, reducing the need for uranium 235.
But Robert Alvarez, a senior scholar at the Institute for Policy Studies, a Washington, D.C., think tank, says that MOX is not the best way to irreversibly render plutonium unsuitable for weapons use. “If you really want to pursue the path of irreversibility, there are probably cheaper, easier ways to do it,” he says. One way would be to blend the plutonium down to a low concentration and put it in the DoE’s Waste Isolation Pilot Plant in the New Mexico desert. With the price tag attached to the MFFF, “it’s certainly not something you’d think you could make money off,” Alvarez says. “I kind of see it as a nuclear equivalent to a bridge to nowhere.”
And Edwin Lyman, senior scientist for global security at the Union of Concerned Scientists in Washington, D.C., argues that MOX is more likely to cause nuclear accidents than ordinary uranium fuel and is liable to release more harmful material in the event of an accident. “Plutonium has different properties than uranium 235 that generally tend to degrade some of the safety systems in nuclear plants,” Lyman says. For instance, because weapons-grade plutonium fissions more readily than uranium 235, reactors may need more robust control rods—neutron absorbers that shut down the nuclear chain reaction when inserted into a reactor’s core. “You never get quite as much margin even after doing all that as you do with uranium,” Lyman says.
Lyman authored a study in 2001 in Science & Global Security showing that radioactive leakage from a meltdown with MOX fuel, which in addition to plutonium has higher levels of radioactive isotopes such as americium 241 and curium 242, would be deadlier than a low-enriched uranium meltdown. “Because plutonium is so much more radiotoxic than many of the other radionuclides, even if it’s released in relatively small concentrations it can have an impact on the effects,” Lyman says. He adds that it is not possible at the moment to identify how much the MOX fuel in Fukushima reactor No. 3 has contributed to the radioactive plumes emanating from the plant.
The problem is that you don’t want to play with this stuff. A nuclear reactor means bring fissile material to a point at which it is hot enough to boil water (in a light-water reactor) and not enough to melt and go supercritical (China syndrome or a Chernobyl incident). You simply cannot let it get away from you because if it does, you can’t stop it.
The Japanese are still talking about days or weeks to clean this up. That’s not true. They cannot clean it up. And no one will live in that area again for dozens or maybe hundreds of years.
IAEA Data Appear to Show Increased Ground Contamination. Why Doesn’t the IAEA Just Say So?
It’s difficult to make any sense of the data being reported from various quarters regarding dose rates and contamination levels at varying distances from the Fukushima Dai-Ichi nuclear plant.
The International Atomic Energy Agency (IAEA) could do a public service by establishing a consistent reporting framework so the public can assess whether radionuclide release rates are changing, and in what direction. However, its daily updates are only adding to the confusion.
It would also be helpful if the IAEA provided some insight to the relationship between measured beta-gamma levels and the much lower reported I-131 and Cs-137 deposition rates. Many short-lived isotopes have already decayed away. However, the reported beta-gamma rates were significantly lower than 3.1 MBq/sq. m even on March 21. This indicates continued high levels of deposition that cannot be explained by the reported deposition rates of I-131 and Cs-137.
The IAEA data would be much more useful if it also provided enough detail to allow apples-to-apples comparisons from one day to the next.
UPDATE: March 27, 8 PM
On March 24, the IAEA reported beta-gamma measurements of 3.8 to 4.9 MBq/sq m. in a northwesterly direction from the Fukushima site, which is in the direction of the highly contaminated plume that DOE identified a few days earlier. The much lower readings of 0.4 MBq/sq. m or below reported on March 26 were taken in a southerly or southwesterly direction. So it is likely that the high reading of 3.1 MBq/sq m. reported on March 27 was taken from the northwesterly direction again, although IAEA did not say so.
Where Did the Water in the Spent Fuel Pools Go?
One cause of low water levels may have been that water splashed from the pools during the earthquake. I haven’t seen reports suggesting significant water loss by splashing or that the water levels in the pools were low shortly after the earthquake. Also, as noted above, the reported rate of heating of the pools at Units 4, 5, and 6 suggests that the water level was not significantly reduced early on.
Moreover, except in the case of the Unit 4 pool, even if the water levels in the pools had dropped by several meters during the earthquake—corresponding to hundreds of tons of water being spilled—the heating and boiling times to expose the fuel would still be too long to account for very low water levels in the pools.
A second possible cause of the low water levels is that the pools at Units 2, 3, and 4 all developed significant leaks. Some reports said that a leak was suspected in the pool of Unit 4 and possibly in Unit 3. This analysis suggests that all three pools may be developed leaks.
also of interest:
Fukushima nuclear power plant update: get all the data
Japan is racing to gain control of the crisis at the Fukushima nuclear power plan. Where does the most detailed data come from? Updated daily.