Some experts believe Japan's nuclear disaster could become worse than Chernobyl.
Japan's Fukushima Daiichi nuclear power plant that was heavily damaged by the tsunami from the massive March 11 magnitude 9.0 earthquake continues to spread extremely high levels of radiation into the ocean, ground, and air.
Tokyo Electric Power (Tepco), the company that operates the plant, said on April 5 that radioactive iodine-131 readings taken from seawater near the water intake of the No. 2 reactor reached 7.5 million times the legal limit. The sample that yielded this reading was taken just before Tepco began releasing more than 11,000 tonnes of radioactive water into the sea.
The radioactive water discharged into the Pacific has prompted experts to sound the alarm, as cesium, which has a much longer half-life than iodine, is expected to concentrate in the upper food chain.
"The situation is very concerning," Dr MV Ramana, a physicist specialising in issues of nuclear safety with the Programme on Science and Global Security at Princeton University told Al Jazeera, "They are finding it very difficult to stabilize the situation."
Operators of the plant are no closer to regaining control of damaged reactors, as fuel rods remain overheated and high levels of radiation are being released.
Until the plant's internal cooling system is reconnected, radiation will flow from the plant.
Nuclear safety agency spokesman Hidehiko Nishiyama on April 3 offered the first sense of how long it might take to bring an end to the nuclear crisis.
"It would take a few months until we finally get things under control and have a better idea about the future," said Nishiyama, "We'll face a crucial turning point within the next few months, but that is not the end."
Ramana explained to Al Jazeera that he sees the current situation as being the "best case scenario," because "the wind has been largely over the ocean, there haven’t been any more major explosions, and none of the spent fuel areas have had a major fire."
Worst case scenario
"There could be a core that gets molten, and we could have an explosion," Ramana said of what he believes would be a worst-case scenario, "This isn't likely, but it is possible."
Mary Olson is the director of the Southeast Office of the Nuclear Information and Resource Service (NIRS), a group that describes itself as the information and networking center for citizens and environmental organisations concerned about nuclear power, radioactive waste, and radiation.
Olson shares Ramana's concerns about the worst-case scenario.
"The worst-case scenario is still out there, it could happen," Olson told Al Jazeera, "And that would be some kind of explosive force that mobilizes the fissile material on the site into a wider sphere."
Olson, who is also an evolutionary biologist with a double major in Biology and History of Science, including studies of chemistry and biochemistry at Purdue University, expressed concern over the fact that in the aftermath of the Three Mile Island nuclear disaster in the United States, "All the contaminated material generated from that was released to our environment in a planned and 'regulated' way. It was dumped in rivers or boiled off into the atmosphere."
Olson sees the same thing already happening now with the Fukushima disaster, and thinks the situation could eventually be worse than even the Chernobyl nuclear disaster that left some 200,000 people dead, according to a study from the environmental group Greenpeace.
"All of those [Fukushima] reactors have been in a catastrophic level of radioactive release that exceeds Chernobyl," she said,."Two of these have exploded, No. 2 is in meltdown, and we believe it has gone back into criticality and that there is a nuclear chain reaction coming and going."
She also pointed out that the fuel core in reactor No. 4 was offloaded for refueling at the time of the earthquake and tsunami, "So none of the fuel was in containment and was all in the pool and that's why it's gotten hotter faster and there has been very little attention to this. All of these are catastrophic in themselves. Having them in one place in one month is truly catastrophic."
Dr Ramana warned that it would likely take several months without any more setbacks before the crisis can be declared stable.
"What we're seeing is a lot of the systems were taken out during the tsunami and explosions," he added, "The lack of power to circulate the water is a problem, so there aren’t going to be any quick fixes for these things."
Olson also fears that if the core meltdowns get to the groundwater under the plant, "You have an explosive force that is like putting dynamite under the site. The problem is if you get this molten fuel into that water it could cause a steam explosion."
"Since unit two is showing signs of fission happening, the chances of something more catastrophic happening at that site are increasing," Olson added, "People are acting like the worst is over, and that is just not understanding the real issues here as far as the radiological impacts."
She also pointed out that the fuel pool in reactor No. 3 "is gone, according to recent photos. There is no fuel there. The reactor fuel pool in No. 3 is gone. Where did it go?"
On Thursday, Japan's chief cabinet secretary Yukio Edano said the current 20-kilometer evacuation zone around the plant may need to be enlarged due to the original parameters having been established in relation to short-term exposure.
"Current evacuation orders apply to areas where people are in danger of having received 50 millisieverts [of cumulative exposure]. We are now looking into what to do with other areas where, with prolonged exposure, people may receive that amount," Edano said.
A 50-millisievert amount is the exposure limit for a nuclear-plant worker for a full year.
"The regions the Japanese government has evacuated have been declared to be long-term, and these are regions of several hundred square kilometers and they are finding local hotspots that are further out," Ramana told Al Jazeera, "There is going to be an area around Fukushima that is going to be off-limits for human habitation for decades. The same thing happened with Chernobyl."
Olson agrees, and believes the mandatory evacuation area needs to be increased.
"Two hundred thousand people are now out of their homes," she said, "But the government needs to enlarge the evacuation area. Much of that area, to the north and west will become permanent interdiction, meaning nobody will be going home. There will be a fairly large area where nobody will be going home."
Taking 'safety' with a grain of salt
Recently disclosed documents show US regulators doubt that some of the nation's nuclear power plants can withstand a disaster akin to Fukushima's.
Nuclear Regulatory Commission (NRC) members have questioned back-up plans to maintain cooling systems in case main power sources fail, and a July 2010 memo assessing Exelon Corporation's Peach Bottom nuclear plant in Delta, Pennsylvania, concludes that contingency plans, "have really not been reviewed to ensure that they will work to mitigate severe accidents".
A Union of Concerned Scientists statement by nuclear expert Edwin Lyman said, "While [regulators] and the nuclear industry have been reassuring Americans that there is nothing to worry about … it turns out that privately NRC senior analysts are not so sure."
Possibly answering Olson's question about the missing fuel pool in Fukushima reactor No. 3, the document suggests that fragments of nuclear fuel from spent fuel pools above the reactors were blown "up to one mile from the units" during one of the plants earlier hydrogen explosions.
This ejection of radioactive material could indicate far more extensive damage to the radioactive pools than has been previously disclosed.
Ramana, the Princeton University physicist, is clear in what he believes needs to happen within the nuclear industry to correct these myriad and potentially catastrophic problems.
"At the minimum you probably want to stop all nuclear construction until we get a much better understanding of what happened at Fukushima and what problems occurred," he said. "Even though the reactors shut down as they are designed to do, the problem was cooling water. In Chernobyl, it took years to really get a better understanding of what happened. Until that happens, all construction should be put on hold."
Ramana points to another problem - that of building several reactors on the same site.
"There are six reactors on the same site at Fukushima, and what happened was that all of them were affected by one common cause, the tsunami. We also saw that when there were hydrogen explosions in one reactor, that affected the spent fuel at another reactor, so we have cross-effecting problems. Then when one started getting out of control, it impeded emergency steps that needed to be taken at other reactors. So building multiple reactors at one site is a bad idea, and should be stopped."
He said that previous accidents like Chernobyl and Three Mile Island have been dismissed by the nuclear industry. "Chernobyl was explained away due to Soviet operator errors and operators who had bad training, etc." he said, "So the argument for many years is that as long as we are using western built light water reactors we are perfectly safe."
"Now, however," he added, "Fukushima blows that idea out of the water. We are going to be told that new reactors are safer and that has to be taken with a grain of salt."
A nuclear Obama
The Obama administration has proposed $36bn in federal loan guarantees to jump-start the construction of nuclear power plants in the US
Nuclear operator Exelon Corporation has been among Barack Obama's biggest campaign donors, and is one of the largest employers in Illinois where Obama was Senator. The company has donated over $269,000 to his political campaigns.
Obama also appointed Exelon CEO John Rowe to his Blue Ribbon Commission on America's Energy Future.
Illinois, where Obama began his political career, gets approximately half of its electricity from nuclear power, more than any other state.
It currently has 10 operable reactors at six sites. The Quad-cities Nuclear Power Plant, located on the banks of the Mississippi River, is a GE Mark One plant, with the identical design and nearly the same age as the Fukushima reactors.
Olson said that even with Japanese and US government so-called acceptable limits of radiation exposure, "we’re still getting excess cancer".
She says it's too soon to say if the fallout from Fukushima will compare to cancers borne of the Chernobyl disaster, where two thirds of the excess cancers occurred outside of the Belorussia area.
"We are creating radioactive sacrifice zones on our planet," she said, "And these zones will persists for hundreds of thousands of years, and our genetics will be effected. Ionising radiation, especially when it is internalised in our bodies, randomizes DNA…so when cells are damaged, that is when cancer starts. And every single time radiation exposure occurs, there will be additional cancers."
Olson also pointed out that there is likely little Tepco can do to prevent the Fukushima plant's radiation from being released into the environment.
"All of that radioactive water they are holding will be diluted and released or evaporated into the air. The water is going off as radioactive steam or runoff, and all of that will end up in our environment because there is no place to put it. They treat it like dilution is the solution, but the more you spread it out the more human and animal tissue is exposed and the more cancer there is."