ENVIRONMENT

Ionizing radiation and its doses

Emission of radiation during Fukishima Daichi accident

Although low radiation doses during normal nuclear power plant operation are not harmful for people, situation can change completely in few hours. Recent outage in Japanese Fukushima Daichi nuclear power plant have caused emission of radioactivity with maximum dose rate of 400 mSv per hour at the Fukushima plant gate [108],[110]. Moreover in the water from the trench inside the plant, radiation over 1000 mSv/h was detected. Due to this a few workers were transported to the hospital. Probably water came from the core of the reactor. In the plant site, highly radioactive plutonium was found [111]. It came from reactor no.3 due to MOX fuel disintegration and penetrated into the soil. Plutonium, recovered from spent nuclear fuel and used in MOX fuel production is one of the most dangerous particle on the Earth. It emits alpha radiation, which significantly increases cancer disease risk. It can continue to emit the radiation, after being inhaled or getting to the human body in a different way. Plutonium half-life time is around 24 000 years. [111],[112],[113]. Additionally seawater near Fukushima power plant has been contaminated. It has contained iodine 131, and radioactivity has been 4 385 times over standards [114]. In period from 11 March to 26 March 2011, 17 workers were irradiated with doses greater than 100 mSv. This value is maximum, allowable dose for nuclear facilities employees in Japan [113]. Estimating doses received by people outside power plant is difficult and there was no information concerning this matter.

  • Copyrights 2011 © Michal Wierzbowski