Day by day, it seems, emergency workers are moving closer to bringing the Fukushima nuclear crisis under control. On Monday, IAEA director-general Yukiya Amano said he had “no doubt that this crisis will be effectively overcome”.
But each day, too, seems to carry a reminder of how serious the situation remains: on Monday, workers were temporarily evacuated from the complex after smoke was seen rising from the No 3 reactor, apparently from a pool where the reactor’s spent fuel rods are kept. Smoke was also reported to be rising from the No 2 reactor.
There was no immediate indication of what was causing the smoke, but the IAEA and Japan’s nuclear safety agency both reported that radiation levels had not risen after the smoke had been reported—an encouraging indication that it was not caused by overheating of dry spent fuel, which would cause radioactive fumes.
The best news on Monday was that the cooling system had been restored to reactors 5 and 6, and, according to Amano, they “are no longer an immediate concern.” That should allow emergency crews to focus their efforts on the other stricken reactors. The U.S. Nuclear Regulatory Commission also confirmed on Monday that reactors 1, 2 and 3 had some core damage (read: partial meltdown) but their containment was not currently breached: Good news because it means that radiation probably had not leaked from those reactors.
Workers also seem to have had some success refilling the cooling tank for spent fuel of reactor 4; according to a Tokyo Electrical Power Company press release, made available on the blog ArmsControlWonk, ten fire trucks managed to shoot over 80 tons of water into the tank. Most spent fuel tanks require an injection of 50 tons to remain safely cooled, industry spokespeople have said.
“I would say optimistically that things appear to be on the verge of stabilizing,” said Bill Borchardt, the NRC’s executive director for operations, according to the Associated Press.
But while emergency workers battle a serious, but improving, situation at the Fukushima plant, health officials are still attempting to grasp the full implications of what’s already occurred. The government started testing fish and shellfish on Monday after traces of radiation had been found to have tainted vegetables and crops, causing the government to ban sale of raw milk, spinach and canola from prefectures around the Fukushima plant. China, Japan’s biggest trading partner, ordered testing of Japanese food imports for radiation contamination, according to the Associated Press.
In another worrying development, high levels of radioactive iodine were detected in the tap water at Iitake village in the Fukushima prefecture, Japan’s Health Ministry said. Village authorities urged residents not to drink the tap water, CNN reported, citing a statement from the ministry. Measurements showed 965 becquerels per kilogram of radioactive iodine in the water, which is well above the 300 becquerels per kilogram maximum standard, according to CNN.
Health officials have gone to great lengths in Japan to say that so far radiation has not posed any threat to human health; they are probably aware, from research out of Chernobyl, that one of the most lasting health effects following radiation release is to mental health. Radiation–an invisible and uncertain threat–causes stress as well as cellular damage. But knowing that health officials will understandably want to protect against panic and unneeded worry poses another dilemma: can we actually trust them to give us the whole truth? Writing in The Bulletin of Atomic Scientists, Barbara Rose Johnston, an environmental anthropologist at the Center for Political Ecology in Santa Cruz, California, notes how in the initial hours following the tsunami, Tokyo Electrical Power Company reported only minor damage to the plant and, in the following days, government and industry officials said the venting of hydrogen gas posed no threat to health. Obviously, a power outage followed by the destruction of back-up diesel generators is hardly “minor damage.” And regarding the vented hydrogen gas, Johnston writes:
In fact, the hydrogen released is tritium water vapor, a low-level emitter that can be absorbed in a human body through simply breathing, or by drinking contaminated water. Tritium decays by beta emission and has a radioactive half-life of about 12.3 years. As it undergoes radioactive decay, this isotope emits a very low-energy beta particle and transforms to stable, nonradioactive helium. Once tritium enters the body, it disperses quickly, is uniformly distributed, and is excreted through urine within a month or so after ingestion. It produces a low-level exposure and may result in toxic effects to the kidney. As with all ionizing radiation, exposure to tritium increases the risk of developing cancer.
So, then, why no mention of tritium in the government or industry statements? Relatively speaking, the health effects of a low-level emitter like tritium are minor when compared to the other radiogenic and toxic hazards in this nuclear catastrophe. Such omission is a standard industry practice, designed to reassure the public that the normal operating procedures of a nuclear power plant represent no significant threat to human health.
In the U.S., the Nuclear Regulatory Commission is the industry watchdog, and is tasked with preventing such shenanigans. But as the Union of Concerned Scientists reported this week, the NRC isn’t always up to the task of keeping nuclear operators in line. The entire safety system surrounding nuclear power will likely come under review in the wake of Fukushima.
In the short-term, the NRC announced on Monday that it will undertake a 90-day review of the country’s 104 nuclear reactors. It will look at the U.S.’s nuclear industry’s ability to cope with severe accidents such as loss of power, flooding, and natural disasters. That will allow NRC officials to look for any gaping holes in security practices. But as the full cause of the Fukushima catastrophe won’t be known for some time, a more comprehensive review, as ordered up by Obama last week, will follow the 90-day spot check.
“The idea is to just get a quick snapshot of the regulatory response and the condition of the U.S. fleet based on whatever information we have available,” Borchardt said, according to Reuters.