Until now I have been writing a post about what was going on in Fukushima. I reported the explosion in reactor 1 on Saturday (the tsunami took place on Friday, March 11th 2011), I reported the explosion on reactor 3 on Monday. And I have reported that this Tuesday there has been a fire in reactor 4 (it has not working when the tsunami took place but it kept the spent fuel rods) with some radiation leak. This Tuesday there has been also an explosion in reactor number 2 and in this case, and it seems that FOR THE FIRST TIME, the protection would have been damaged!
So now, I think that it is time not to speak about Fukushima but just about the radiation.
Some days ago I read books about that. The unit used is Sv o Sievert. In a natural way we receive about 3 mSv (3 milliSievert o 3000 microSievert) in a natural way in ayear.. As a natural way you can think about cosmic rays, etc. People on planes receive more radiation.
It seems that 5 mSv/year is the good limit for humans. 70 mSv in a life would be also a good limit. 1 Sv to 3 Sv would cause death. But it is not necessary to reach 1 Sv! If you get more that 5 mSv/year there can be problems like cancer, etc.
I just have read that these last hours at some point they reach 500 mSv/hour in the Fukushima plant! That’s crazy! It seems that can kill white cells on blood.
I imagine that in the next days we will read a lot about radiation. So with this post I just try to make myself familiar with the unity and the limits!: The unit is the Sievert (Sv) and we normally speak about milliSievert or microSievert. 1 Sv has 1000 milliSievert and 1000000 microSievert. A good limit for a human is a radiation of 5 mSv (milliSievert) for a year. Please be aware that in the news they may use micro or milli.
In some places instead of Sievert they use the unit rem. This is the conversion:
1 Sv (Sievert) = 100 rem 1 mrem = 0.00001 Sv = 0.01 mSv = 10 μSv 1 rem = 0.01 Sv = 10 mSv 1 μSv = 0.1 mrem 1 mSv = 100 mrem = 0.1 rem
I have found an article in THE GUARDIAN. It is a very useful RADIATION GUIDE with useful links too: http://www.guardian.co.uk/news/datablog/2011/mar/15/radiation-exposure-levels-guide
I find THE GUARDIAN is a very useful newspaper to follow live the Japan crisis.
- Radiation and risks (nextbigfuture.com)