Update: March 22. I’m glad to say that the situation at Fukushima Daiichi is gradually improving. However I would like to turn your attention to this. Even though there is no (or very low) radioactive particles in the air, and as long as you don’t live in the 30 km quarantine zone, you can feel save to walk the streets. However if enough radioactive particles enter your systems, they may have long term effects and/or cause cancer. Unfortunately I can’t give you any specific number, but the less exposure the better.
I myself will refrain from drinking tap water and fresh vegetables, fruits, fish and milk that are made in Japan. I will concentrate on frozen goods, cans, meat and Chinese vegetables, I will also take some Iodine rich food supplements until the radiation levels have returned back to normal.
Tokyo radiation levels hourly data.
Update: March 18 14:05. The radiation levels reported by NHK were WRONG. The latest value is 271 μSv (microSieverts) not milli~. Here is a screenshot of the report. This is very good news. It means that the radiation is 1000 lower then we previously thought. Also the radiation levels are dropping after the cooling operations, which still continue.
Update: March 18 05:00. Radiation levels at the power plant continue to fall down, to 279 mSv. Source NHK.
Update: March 17 23:00. Radiation levels at the power plant have lowered after the water spraying operations, to 289 mSv/h. Source NHK.
Update March 17 13:00. Maximum radiation levels 30 km from the Fukushima Daiichi is 0.17 mSv/h. 60 km away the levels drop down to 0.0011 mSv/h. Still no danger for your health. Source NHK.
Update: March 17 10:00. Radiation levels in Ibaraki prefecture are detected to be 5.8 millisieverts/hour. This is a relatively big increase, but still bellow the danger zone. Source:NHK
Update: March 16. The radiations levels at 30 km from the Fukushima Daiichi Plant are around 0.33 millisieverts/hour – this is an extremely low value, not dangerous for your health. Source
There has been a huge misunderstanding about the radiation measured around Japan after the Fukushima Nuclear Accident. I will try to explain to the best of my abilities why you shouldn’t worry.
The reactors in Fukushima are of the second most popular type in the world: Boiling Water Reactor. You must understand that there is no more Nuclear Chain Reaction taking place inside the reactors. However a nuclear reactor is not an electric appliance that you can just unplug. After the chain reaction stops, some elements inside the reactor start decaying, some decay fast (like seconds), others – slower. It is important to note that many of these fission products produce heat while decaying. This means that gradually they will cool down after the stop decaying. For more information on reactor physics, read here.
The radiation measured around Fukushima is those slowly decaying elements, like cesium and iodine.
Iodine
Or Iodine-131 is a major fission product. It decays with a half-life of 8.02 days. This means that8 days after its produced, 50% of it has decayed; 16 days: 75% decay: 24 days 88%, etc.
The most dangerous aspect of Iodine is that the thyroid gland, actively accumulates iodine, which it uses to produce thyroid hormones required for normal body function.
A common treatment method for preventing iodine-131 exposure is by saturating the thyroid with regular, non-radioactive iodine-127. This prevents the thyroid from absorbing the radioactive iodine-131, thereby avoiding the damage caused by radiation to the body. This treatment method is most commonly accomplished by administering potassium iodide to those at risk.
In such cases the advised daily dosage for a grown up is 130mg Potassium Iodide. For more information on dosages see here.
Please don’t make the mistake of taking regular Iodide (aka Tincture of iodine). This is a disinfectant that is moderately toxic when ingested in amounts larger than those required to disinfect water. Tincture of iodine is sold labeled “for external use only,” and used primarily as a disinfectant.
Let’s summarize everything until now. The radiation detected is mainly Iodine-131 which decays in several days. Its effects can be countered by taking Potassium Iodide.
Radiation Levels
There has been a lot of talk about the radiation levels across Japan. This is what you should know:
It is measured in sievert (micro or millisieverts) or sieverts per hour (or year). Just sitting in your home on a sunny weekend, exposes you to 0.01 mSv a day. Which is several times bellow the danger zone. Here is a Symptom Benchmarks:
Effects to humans of acute radiation (within one day):
- 0–0.25 Sv: None
- 0.25–1 Sv: Some people feel nausea and loss of appetite; bone marrow, lymph nodes, spleen damaged.
- 1–3 Sv: Mild to severe nausea, loss of appetite, infection; more severe bone marrow, lymph node, spleen damage; recovery probable, not assured.
- 3–6 Sv: Severe nausea, loss of appetite; hemorrhaging, infection, diarrhea, skin peels, sterility; death if untreated.
- 6–10 Sv: Above symptoms plus central nervous system impairment; death expected.
- Above 10 Sv: Incapacitation and death.
read more here
!NOTE: The values above are in sievert (Sv). The values they mention on TV are in mSv (millisieverts). 1 Sv = 1000 mSv (millisieverts) = 1,000,000 μSv (microsieverts).
Let’s do some math. The radiation in Tokyo (as of 15 March) is 0.8μSv which is around 19μSv per day, which is equal to taking an X-ray. People get freaked out because they heard that it is several times larger than the normal, but people fail to understand that there is a huge gap between normal and dangerous. And the size of that gap is more than 2500 times.
The radiation (as of 15 March) between the No. 2 and the number-three reactors is about 30 millisieverts, 400 millisieverts near No. 3 and 100 millisieverts near No. 4. So you can see that the radiation levels change a lot in the Fukushima Daiichi plant. This means that the dangerous levels are at the plant itself. The only people in slight danger are those still working there. So there is no reason for worry at this point.
In the unlikely event of high radiation levels, like those in the 20/30 km radius around the Fukushima Daiichi Plant this is what you must do:
Radiation Safety
Even though the sources of the radiation are relatively fast decaying elements, it is still best to avoid exposure. If the radiation in your area starts to increase:
- Stay indoors and don’t go outside. Have plenty of food.
- Close and seal all windows, doors, air vents, etc. Limit the air flow as much as possible. Turn off the AC too.
- You can use wet towels to block air from coming in from small openings in doors and windows.
If you go go outside during high radiation levels:
- Cover your skin as much as possible. Wear cloves, hat and mask.
- Tie a wet towel around your face, so that you don’t inhale any radioactive particles.
- Limit your exposure as much as possible.
After going back inside:
- Take off ALL of your clothes and put them in a plastic bag and seal the bag.
- Take a shower and rub yourself with soap.
Also stay informed and calm. If you try to escape there is a high probability that you will get stranded in an open area (traffic jam, train station) and you will be exposed to several times more radiation in comparison to staying indoors. The best thing to do is to stay home and wait for the radiation to decipitate.
Watch this video
If wish you can read this. It’s a big long but explains a lot of things.
Please don’t be scared by what is written here. I strongly believe that such precautions will not be necessary. I have written what I have be thought in school. Back home we used to have disaster prevention classes every 5 years or so. This is a knowledge that you MUST know and hope that you never have to use.
“Hope for the best and prepare for the worst”
Conclusion
Keep watching the news. Pay attention to the radiation levels in the areas near you. Make preparations. Have an emergency bag with food, clothes, etc.
And most importantly: BE CALM! The situation is not so bad. If you live in Nagoya (like me) or somewhere further form Fukushima, there is even less to be worried about. Nagoya is about 450 km away from the Fukushima Plant and in the very unlikely event of something bad happening, we will have enough time to react. I am personally more worried about the economical consequences that this disasters have brought to Japan.
I hope this article helped you to better understand the problem and that you will remain calm.
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