Fukushima Nuclear Accident:Radiological Monitoring and Consequences.

Abstract

FUKUSHIMA NUCLEAR ACCIDENT: RADIOLOGICAL MONITORING & CONSEQUENCES. This seminar talks about the sequences of event that lead to the release of high radioactivity and contamination which are as follows: the major treat to nuclear reactor is power supply. High pressure build-up in the RPV as a result of steam production, dissociation of water molecules → hydrogen production in the RPV → dynamic loading RPV. Same situation in the spent fuel pool. To avoid reaching the rupture limit of the RPV → venting the RPV (steam&H2) + H2 & steam from SFP→ containment loading, direct containment heating (DCH) → deflagration or detonation.

It further more discussed deflagration and detonation in which deflagration is type of combustion which propagates through a gas or across the surface of an explosive at subsonic speeds, driven by the transfer of heat. While detonation is a type of combustion involving a supersonic exothermic front accelerating through a medium that eventually drives a shock front propagating directly in front of it.

It also talks about the environmental monitoring in fukushima perfection which says The Ministry of Health, Labor and Welfare reported results for thirty – three samples of food stuffs analyzed for Cs-134, Cs-137 and I-131. The samples came from the prefectures of Niigata, Ibaraki, Tochigi, Gunma, Yamagata and Fukushima which were collected between 25-26 March. The levels detected were all below the action limits. It is worth noting that some measurements (on 18 March) in Iitate village, about 40km NW from Daiichi site are high for leafy vegetables, dust and soil also display high radio isotope concentrations in this location.

The seminar concludes that as of August 2011, the crippled plant still leak slow level radiation, hence on 22nd August It was reported that the evacuated areas could be a forbidden zone for 20yrs for areas with current dose rate of 200mSv/a and a decade for areas with dose rate of 100mSv/a.

Seminar presented by Jonathan ORURU