Radiation at the Fukushima Daiichi power plant has now exceeded more than eight times the radiation limit set by the Japanese government – presenting new concerns for problems that many say are exacerbating. The largely government-owned Tokyo Electric Power Company (TEPCO) admitted that radiation levels had elevated to an estimated 8 millisieverts per year (mSv/y) outside of the Fukushima No. 1 nuclear plant in December.
This greatly eclipses the Japanese government-set limit of 1 mSv/y, put in place as part of the officially-sanctioned reactor decommissioning plan for the disaster-stricken nuclear plant as a safety measure to diminish the level of harmful effects on the surrounding areas so that the exclusion zone can eventually be lifted. According to NHK, Japan’s public broadcaster, the plant was measuring at below the required 1 mSv/y benchmark back in March 2013, but the increasing emission of beta-rays from the contaminated water, and particularly strontium-90, stored in above-ground tanks was spiking these levels. However, the Asahi Shimbun reported that a very high level of 7.8 mSv/y was recorded back in May 2013. Official media accounts blamed the approximately 1,000 above-ground storage tanks, explaining that the metal tank containers reportedly amplify the beta-rays to create stronger X-rays and, thus, higher readings. Asahi carried this account of the official explanation: “Beta rays released from radioactive strontium and other substances in the water reacted with iron and other elements in the storage tank containers to generate the X-rays, the officials said.” More