Tag Archives: Radioactive decay

Visualization and Explanation of Level 7, Fukushima and Chernobyl

Visualization -> Fukushima Nuclear Accident – Radiation Comparison

Explanation –> Fukushima moved to Level 7 by WNN (world nuclear news)

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Posted by on April 20, 2011 in Disaster, Science, Uncategorized


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From Chemical Side

Here, a university chemistry teacher writes some posts about the accident, of course about the chemical side. Mark Foreman’s Blog

Well, I am not an expert of nuclear technology in any meanings and English is my second language. On the other hand, he is chemist, even a chemistry teacher at a university, and British, so I think you can get more useful and understandable English information with him.

I believe it is always good to know someone else’s view as much as possible, from right and left, outside and inside, in particular or general, to make up your own opinion about something. If you have an opinion about something without knowing other’s opinion, then, I think it is not an opinion, it is prejudice.

I hope my posts will help you to have your own opinion, but not a prejudice….. Well, I should be careful!

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Posted by on April 20, 2011 in Disaster, Science, Uncategorized


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Get Information about Japan in English

I think following Daniel Kahl on twitter is a way. Daniel Kahl on twitter

He is an American man living in Japan more than 30 years, including years of experience as a English teacher in Yamagata, one of prefectures in Tohoku (By the disaster, the East part of Tohoku is suffered badly, and Yamagata is in the West part of Tohoku, not suffered so much.) He keep posting on twitter, videos on YouTube since the disaster.  Daniel Kahl on YouTube

He even visited the suffered area different from me, and reported what he found out.

I know you understand what is really going on here in Japan with your wisdom and understanding whatever the mass medias say, but I hope you have a look on his messages.

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Posted by on April 17, 2011 in Disaster, life in Japan, Uncategorized


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Why I decided to write about Radiation

Radioactive expose seems dangerous to me. I don’t like it. It is scary to imagine to be exposed. I have never given my support to nuclear power technology.

As a person who was born and grown up in Hiroshima, I have heard lots of lots of scary stories about radioactive expose, but at the same time, I know there are lots of lots of healthy seniors in Hiroshima who survived the attack.

I also know we humans use Radiation as a part of medication. We sometimes do X ray check even when we feel no health problem and it doesn’t seem to cause a problem on my health.

I think whatever the reason is or whatever the reason for, radioactive expose is radioactive expose. No difference.

Then, I thought, there might be a medical standard to find out whether one’s exposed level is in safe or danger.

That’s why I have tried to learn or understand what radiation is or what radiation expose is, why it is dangerous from what point, why it is medically OK to exposed someone at some level, etc. and wrote those posts about radiation or radioactive expose based on what I learned.

I hate all the nuclear technology, I want to see the world not to have it, but I won’t share any information which doesn’t make sense to me, even if they seem useful to say, “See, any nuclear is dangerous. Don’t you think it’s time to build a new world without nuclear technology?” I want the world including myself to be careful about radiation with clear and right knowledge.


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An Explanation about Radiation

Today, I found an interesting article explaining how to understand the risk of radiation, but unfortunately, it was in Japanese and I can’t find a translated post in English. I am going to translate it into English as much as possible. There is anything you found, my mistakes or anything you feel it difficult to understand, please let me know.

Qestion1) Radiation decreases inverse proportion  to square of the distance. (right) Then, does it become 1/4 you move from 10 km point to 20 km point?

Answer) Radiation decreases like that in a vacuum. If it is filled with air ,the space between 10 km point to 20 km point, it works like a wall to block the radiation. That’s why it is impossible to reach  the surface of Earth for Gamma ray from Space. About radiation in Tokyo right now, it is provided by radioactive materials flying from Fukushima Nuclear Power Plant. In this case, the amount of radioactive materials / a square will decrease in distance, but those materials keep providing radiation.

Question 2) It is 8 days a half-life of Iodine-131. Then, is it safe 8 days later?

Answer) Both yes and no. Iodine131 lost its half power in 8 days. That’s true. But, if there are 4 times of safe limits for Iodine-131, there are still twice of safe limits 8 days later. So, you need 16 days to have safe limits of Iodine-131 in this case. And, Iodine-131 changes to Xenon-131m while providing Beta ray, and Xenon-131m changes to Xenon-131 while providing Gamma ray. A half-life is 11.84 days. So, it is impossible to say something is safe 8 days later.

Question 3) Is it more dangerous to be exposed a little every day from inside of your body by a radioactive material which comes into your body than to be exposed to more radiation only once.

Answer) It depends on how much radiation you are exposed in a moment. It is similar to the risk of having salts. In Japan, it is OK with an adult to have 10 g of salt / a day. Then, it won’t cause a problem on your health if you had 10 g of salt / a day for 20 days, but it is not good for you if you had 200 g of salt at a time. About Radiation, it is less effective for your health to be exposed to 6 micro SV of radiation for 42 days (1000 hours) than to be exposed to 6000 micro SV of radiation by 1 time CT scan.

Question 4) Experts say, “it doesn’t mean to cause a problem to your health right now.” Does it mean it will be dangerous later?

Answer) It is again similar to the risk of salt. It is safe to have 10g / a day, and it won’t be dangerous to have 20g if it is once or so. But, it will be dangerous for your health if you keep having 20g of salts everyday for a long time. It is the same with those vegetables or tap water that show much radioactivity than the safe limit. If you ate those vegetables or drank such tap water once or so, it won’t be dangerous just like 20g of salts won’t be dangerous if it was once or so. It will be dangerous if you eat/drink much everyday for a long time, again just like the salts, then, Japanese government announced the warning not to eat/drink as much as possible.

Those questions and answers are very understandable and seems rational for me. I hope I translated well.


Posted by on April 7, 2011 in Disaster, Science, Uncategorized


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Short Note from Japan on April 4

Well, I think you want to know how dangerous it will be for you the radioactively contaminated water which was released from Fukushima Nuclear Power Plant into the pacific ocean yesterday.

TEPC said it would be 0.6 milli SV/year of expose if you eat fished or seaweeds everyday which is caught or  collected around there. Our policy is, I am not sure it is international policy or not, but at least Japanese policy is set safe limit to general people as 1 milli SV/year, and it is impossible to catch any fishes nor seaweed around there right now. So, TEPC said it won’t be so dangerous even for us Japanese.

I think it won’t be so dangerous at least to the world if it is only one time release.
The water included low level radiation. It is 100 times higher than usual safe limit, but you know, pacific ocean is very large and every radioactive materials lost its power in time and distance. It is very high in limited space and water, but it will be less high once it is mixed with seawater of pacific ocean. While the materials traveling from Japan to your county by the ocean, the materials will make distance among them loosing its power in time. It will be bit higher than usual the radiation level of seawater around your country, but I am sure it won’t be so high to cause a problem on your health.

But, what if TEPC needs to do again? How many times they will need?  That is the question.

Right now, many experts from all over the world come to support us. I hope they will find a way more safe way to the world.

Believe me, all of us Japanese feel very sorry for what is going on. Natural disaster is something we can’t control and there is no way other than to accept and rebuild. But, the nuclear accident is different. I am sure TEPC and Japanese government have been trying hard their best, but it seems not enough. I am so sad we failed to keep a nuclear plant in safe. It is our own fault not to have more reliable way to keep a nuclear power plant in safe even with such a huge earthquake and tsunami as we know they happened very often in Japan, and, we knew how dangerous radiation is since 1945. We should be more careful.

I apologize as a Japanese to the world about that our country bring great fear to the world on the Earth. I promise we will find better way to be a reliable county.

Well, I might be sound bit pessimistic, I guess, but actually not. I keep my trust to our technology and friendship with many countries. I don’t think all the experts all over the world can’t find even a way to make the situation a little better. It won’t be so soon, but I believe we will find a way, maybe a tough and difficult way, but find a way with hope.


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Radiation Effects Research Foundation

Radiation Effects Research Foundation

A Cooperative Japan-US Research Organization

You can get more information about radiation effects there.

I am now trying to write a post about what happened today, April 4, but it was too complicated to me to explain in English. Give me a time, please.


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