Japan’s new nuclear watchdog decided on Wednesday morning to declare a radioactive spill at the crippled Fukushima Daiichi nuclear plant a Level 3 — or “serious incident” — on the International Nuclear and Radiological Event Scale. That’s a scale, overseen by the International Atomic Energy Agency, that lets us compare, for instance, the 2011 meltdowns at Fukushima Daiichi (a “7”) with the 1986 nuclear disaster at Chernobyl (also a “7”) with the 1999 uranium-processing accident at Tokaimura, Japan, which caused two deaths but didn’t spread contamination widely beyond the accident site (a “4”).
Though there have been contaminated-water leaks at Fukushima Daiichi before, the reason this is a Level 3 is because there’s a lot of water (300 metric tons) and it’s very radioactive (measurements of more than 100 milliseiverts per hour — which is the level at which cancer risks are seen as rising, and equivalent to double the maximum dosage that workers at the plant are allowed in an entire year).
JRT readers may be wondering just what this all means for Fukushima Daiichi. Are conditions there getting worse?
The short answer is: To some extent, yes — although it’s not deemed a serious hazard yet to the surrounding environment.
For the nearly two and a half years since an earthquake and tsunami knocked out power at Fukushima Daiichi and sent the site’s three active reactors into meltdown, operator Tokyo Electric Power Co. has been struggling with the massive amounts of water — 400 metric tons — it’s needed to apply to the damaged fuel cores every day. Add to that an estimated 1,000 tons a day of groundwater that flows through the site — and is potentially contaminated as it goes — and that’s a lot of liquid to deal with.
Tepco has set up a series of water processing facilities that can remove much of the radioactive elements in the water. But since it’s not allowed to dump that water elsewhere, it’s largely been dealing with the accumulation by sticking it in storage tanks, about a thousand of which are on the compound now.
- Fukushima Watch: Draft Plan Sees Minimal Water Risks in 7 Years
- Fukushima Watch: IAEA Starts 2nd Review of Decommissioning
- Fukushima Watch: Some Power Companies in Black without Nuclear Restarts
- Fukushima Watch: Daiichi Plant Chief Assures Fuel Removal Safe
- Fukushima Watch: Letter to Emperor Draws Criticism
It was only a matter of time before that situation became unsustainable, and that time is now. Tepco is finding that groundwater in various places at the site is increasingly radioactive, and that it’s likely flowing into the sea. All sorts of tanks have sprung leaks this year, though the latest leak is the worst so far.
Tepco — and now the Japanese government — has said it’s working on fixing all this.
Still, so far Tepco says the water doesn’t seem to have gotten to the ocean — at least not through the easiest route, which is a nearby trench. And the levels of radioactivity measured in the ocean so far have been relatively low, particularly past the immediate Fukushima Daiichi harbor.
One heartening thing for Fukushima watchers is the speed at which the new regulator, the Japan Nuclear Regulation Authority, is responding. Tepco first disclosed news of the leak on Monday, and the NRA has been sending out bulletins several times a day on developments, as well as upgrading its assessment of the seriousness of the situation Wednesday morning, after it got more data on the situation.
“This is what we have been concerned about,” said Shunichi Tanaka, NRA chair, at the Wednesday morning meeting. “We cannot waste even a minute” to take action.
Follow Phred Dvorak on Twitter @Phred_Dvorak
For the latest news and analysis, follow @WSJAsia