Little to fear from Japan Nuclear problems, more from fear mongerers
There have been some fear and worries about the on-going nuclear emergency in Japan brought about by the recent magnitude 8.9 earthquake and the tsunami that it triggered last March 11. Being worried and having some fears are valid, but what’s annoying is when false rumors about doomsday scenarios are spread so fast it doesn’t [...]
There have been some fear and worries about the on-going nuclear emergency in Japan brought about by the recent magnitude 8.9 earthquake and the tsunami that it triggered last March 11.
Being worried and having some fears are valid, but what’s annoying is when false rumors about doomsday scenarios are spread so fast it doesn’t really help at all.
Just as I was writing this, I received an SMS message that we in the Philippines should stay indoors and avoid getting caught in a rainfall because it could be contaminated with radioactive material that leaked from Japan.
I say to each and all, please verify the facts in whatever message you’ve received before forwarding it to someone else. It will save us all the unnecessary worries and fears. It will also save you from being thought of as another mindless drone in the spread of false information.
Fact check
The nuclear power plants in trouble were reactors 1 and 3 at the Fukushima Dai-Ichi Nuclear Power Station, some 220 km north of Tokyo. The nuclear power facility itself is on the coast which placed it right on the path of the tsunami triggered by the 8.9 magnitude earthquake that struck last March 11, off the northeast coast of Japan.
The earthquake and tsunami didn’t damage the nuclear reactors, which is a testament to the facility’s design and Japan’s reputation for efficient and safe management of nuclear power plants, it was the subsequent loss of electricity that crippled the systems that kept the nuclear reactors from overheating that is now the problem.
It was made worse when the backup on-site diesel generators were also damaged by the tsunami which followed within hours after the strong earthquake.
An excellent explanation by US nuclear experts on what the problems are at Fukushima Nuclear Power Plant is available at Scientific American. Physicist Ken Bergeron, who did research on nuclear reactor accident simulation at Sandia National Laboratory in New Mexico explains:
Reactor analysts like to categorize potential reactor accidents into groups. And the type of accident that is occurring in Japan is known as a station blackout. It means loss of offsite AC power—power lines are down—and then a subsequent failure of emergency power on site—the diesel generators. It is considered to be extremely unlikely, but the station blackout has been one of the great concerns for decades.The problem then, boils down, so to speak, to overheating problems that would lead to what is called a fuel core meltdown. This is the core of the nuclear reactor, which is an assembly of radioactive fuel rods and their casings literally melting down because of excessive heat which cannot be removed from the reactor. Again, Scientific American has an educational piece on how to cool a nuclear reactor.
The probability of this occurring is hard to calculate primarily because of the possibility of what are called common-cause accidents, where the loss of offsite power and of onsite power are caused by the same thing. In this case, it was the earthquake and tsunami. So we’re in uncharted territory, we’re in a land where probability says we shouldn’t be. And we’re hoping that all of the barriers to release of radioactivity will not fail.
This is what basically happened in the Three Mile Island accident in the US in 1979 and the Chernobyl explosion in 1986. Thanks to the lessons learned from those accidents, the Fukushima nuclear power plant withstood the strong earthquake and successfully contained radioactive materials from leaking to the environment.
What about the explosions at the reactors? The radioactive fallout from Japan?
The March 12 explosion at reactor No 1 at Fukushima Power Plant was not nuclear. It was caused by hydrogen contained in the steam vented from the reactor in order to remove excess pressure. Dr Josef Oehmen, a research scientist at MIT, in Boston, explains why there’s little to fear from the on-going nuclear emergency at Japan. He likened nuclear reactors to pressure cookers sealed inside an airtight box of steel and concrete, designed to contain radioactive material inside.
So imagine our pressure cooker on the stove, heat on low, but on. The operators use whatever cooling system capacity they have to get rid of as much heat as possible, but the pressure starts building up. The priority now is to maintain integrity of the first containment (keep temperature of the fuel rods below 2200°C), as well as the second containment, the pressure cooker. In order to maintain integrity of the pressure cooker (the second containment), the pressure has to be released from time to time. Because the ability to do that in an emergency is so important, the reactor has 11 pressure release valves. The operators now started venting steam from time to time to control the pressure. The temperature at this stage was about 550°C.Chances of radioactive or acid rain from Japan falling over the Philippines is very, very remote.
This is when the reports about “radiation leakage” starting coming in. I believe I explained above why venting the steam is theoretically the same as releasing radiation into the environment, but why it was and is not dangerous. The radioactive nitrogen as well as the noble gases do not pose a threat to human health.
At some stage during this venting, the explosion occurred. The explosion took place outside of the third containment (our “last line of defense”), and the reactor building. Remember that the reactor building has no function in keeping the radioactivity contained. It is not entirely clear yet what has happened, but this is the likely scenario: The operators decided to vent the steam from the pressure vessel not directly into the environment, but into the space between the third containment and the reactor building (to give the radioactivity in the steam more time to subside). The problem is that at the high temperatures that the core had reached at this stage, water molecules can “disassociate” into oxygen and hydrogen – an explosive mixture. And it did explode, outside the third containment, damaging the reactor building around. It was that sort of explosion, but inside the pressure vessel (because it was badly designed and not managed properly by the operators) that lead to the explosion of Chernobyl. This was never a risk at Fukushima. The problem of hydrogen-oxygen formation is one of the biggies when you design a power plant (if you are not Soviet, that is), so the reactor is build and operated in a way it cannot happen inside the containment. It happened outside, which was not intended but a possible scenario and OK, because it did not pose a risk for the containment.
Very little radioactive material leaked from the Fukushima nuclear reactors. Weather patterns are against the scenario that a radioactive cloud would float from Japan, head towards the Philippines and fall as acid rain.
Various government agencies have confirmed this:
“‘Yong hangin galing sa Japan papalayo kaya ‘di makakarating sa atin. Hindi totoo ang ulan may kasamang acid,” PAGASA forecaster Aldczar Aurelio told radio dzBB today. (“The winds from Japan are moving away from us. It’s not true that these winds contain acid rain.”)Nuclear fallout is a serious threat to public health and safety. Surely, the government would not mess around with information regarding this matter. So should the public too.
Department of Science and Technology (DOST) Secretary Mario Montejo told radio dwIZ today, “There is no immediate threat to the Philippines … (We are) very optimistic in a few days puwede na natin bitawan ‘yan (We are very optimistic in a few days we can declare no threat to the country).”
Spreading false information is not only stupid, it helps no one at all.
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Originally Posted by Pete/London
