(Don’t miss part 1.)
Two evolving stories are the current focus of news from the ongoing Fukushima nuclear reactor disaster in Japan. The first story is about leaks, the second about leaks into the ocean. Both are full of uncertainties and ambiguities that the media is mostly missing.
There are two different stories of leaking water, but they are not always clearly distinguished. Radioactive water has leaked from a storage tank and, separately, there is also the issue of groundwater potentially picking up radiation and then flowing into the sea. Complicating the confusion is that the same number – 300 tons – appears in both stories.
In the weeks and months after the tsunami-triggered crisis began at the plant, the normal systems for cooling the reactors did not work. Instead, massive amounts of water had to be pumped into and over the cores, and as a result, this water was heavily contaminated with radioactivity. TEPCO, the company operating the reactors, built a huge collection of large tanks to store this water, and also built systems for removing Cesium-137, one of the more bothersome radioactive elements.
Last week it was discovered both that 300 tons of water had leaked out of one tank, and that this water was very radioactive indeed. Reports varied, but it seems that the level was high enough that four or five hours of continuous exposure at close range would have proven fatal.
However, this water was mostly contained inside the tank farm, and there are no reports as of yet that anyone was exposed to a significant amount of radiation.
This leak has sometimes been confused with a second problem: the normal flow of groundwater under the mainland, across the plant complex and into the ocean. Because of all the damage to the reactors, this groundwater flow, normally of no concern, now is a problem because this water is now picking up radioactivity.
TEPCO estimates – here is that number again – that some 300 tons of water a day are being contaminated and flowing into the ocean.
This water is not contaminated to anywhere near the level of the water leaking from the storage tank, but it still has raised concerns. Unfortunately, these concerns have involved the blurring of yet another two distinct issues.
Immediately after the crisis began, a significant amount of radioactive material ended up in the ocean around the reactors. This has certainly led to levels of radioactivity in local fish high enough to trigger health warnings, and they have been banned from sale ever since.
But the long-term groundwater flow is a different matter. Perhaps as a result of conflating these two issues, warnings are being screamed that “your days of eating Pacific Ocean fish are over,” followed by a slew of scary stories about animals dying and a reference to unusual mortality among sea lions in California. But there’s a problem: radiated water hasn’t had time to make it to California yet. Meanwhile, those investigating sea lion the die-off have a long list of possible causes to check out and don’t seem willing to pin the blame on radiation as of yet.
A 2012 study by scientists at the University of Hawaii found that actual concentrations of one radionuclide, Polonium 210, in Fukushima-affected marine life, were orders of magnitude less than various sources of radiation most humans are exposed to in their normal lives. Tests by Canada’s Food Inspection Agency did not reveal any contamination of food products imported from Japan, but they have yet to start a new round of tests on ocean fish.
So, just how contaminated is this water? And will it disperse in the ocean to be of no concern? This is hard to sort out. There is even confusion about whether the water has already hit the ocean (assumed by most of the media) or is simply about to get there, per the Washington Post.
To be sure, the contaminated water will make it to the ocean someday, if it hasn’t already. What happens then? There is at least one published study by scientists in Germany and at the National Oceanic and Atmospheric Administration. Using a detailed model of the Pacific Ocean, researchers simulated the movements of water from near the Fukushima reactor for a period of ten years into the future.
Such simulations have been done for decades with increasing levels of sophistication. The report makes comparisons to assessments of contamination from atmospheric nuclear tests.
Their conclusions? It will take five to six years for the contaminated water to reach the Pacific coast of North America. When it does, the radioactivity will be diluted by a factor anywhere from ten thousand to a hundred thousand of its initial level. Taking a reasonable guess as to the starting level of contamination just offshore at Fukushima, this means a radiation level at the U.S. coast of perhaps twice the background rate.
So, that would mean a measurable increase, but not a crisis and probably no real health impacts.
So that’s alright then?
So is everything fine? No, it’s not. The problem is not the present level of damage to the environment, it is rather that the margin of safety to prevent serious damage has been used up. Nuclear power plants and other endeavors with potential negative consequences employ a “defense in depth” concept. No one safety measure is assumed to be adequate by itself; there are backup system and layers of safety mechanisms that don’t depend on any one system to work.
At Fukushima, the crisis has eaten through most of the safety systems to the point where there may not be any major health crisis now, but the ability to withstand another shock has been significantly degraded.
Suppose there was another earthquake, one that cracked a large number of those storage tanks and overflowed the remaining protective barriers. Suppose another major power outage, for whatever reason, or a social crisis that disrupted ongoing maintenance of the reactors. These would have a significant chance of overwhelming the remaining safety checks in place.
Looking in the wrong place
This is the real safety issue; not theories of massive animal kills or mysterious radiation that no one has yet been able to detect. The Guardian, which ought to know better, totally missed the mark with a bizarre scare piece by Damian Carrington who brought out the old canard about a reactor being a slow atomic bomb and accused everyone of a “crass disregard for safety.” His rhetoric distracts attention from something he does mention, and which is a real problem: the cost of the cleanup.
(Part 1 of this series examined how the media plays on nuclear contamination fears, drowning out far more lethal consequences of Japan’s tsunami while exaggerating the dangers of nuclear power.)