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The accident occurring at the Fukushima Daiichi nuclear power plant on March 11, 2011 resulted in leakage of a large amount of radionuclides, contaminating farmlands, including rice field, in Fukushima and its neighboring prefectures. Potential contamination of the rice growing these areas by the radionuclides has thus attracted public attention. The objective of this paper is to analyze rice contamination in this region and its remediation. Literature review showed that the radionuclide that was most potential to contaminate the rice is the radioactive cesium. Among all available methods to detect radioactive cesium in rice grain, belt conveyor testers is quicker in measurement but is less accurate, while germanium semiconductor detectors is more accurate but is tedious. Rice contamination by cesium accumulation is modulated by a multitude of factors, one of which is fertilization. For example, potassium fertilizer (potassium chloride is more effective than potassium metasilicate) can reduce the absorption of the radioactive cesium in rice, while nitrogen fertilizer works in the opposite. The movement and transfer of radioactive cesium in soil was affected by its concentration, potassium content, immobilization of the cesium by soil, and the thickness of the topsoil. Apart from these, rice cultivars also affect cesium accumulation. Different methods for ameliorating rice contamination by radionuclides had been developed and tested. In paddy fields, rice contamination by cesium can be reduced by amending the soil or planting. The radioactive cesium is sportive to soil and cyanobacteria can be used to facilitate the exfoliation of top soil. Also, rice is a shallow-rooted plant and deep ploughing could bury the contaminated topsoil beyond the reach of roots so as to reduce its uptake by rice. Secondary contamination can be avoided by controlling fertilization and irrigation, and the transformation of the radioactive cesium from soil to rice can be inhibited by amending the soil with schwertmannite, zeolite and vermiculite, or by controlling fertilizer application rate and the secondary contamination. Implementation of above mitigating methods over the past few years reduced the radioactive cesium content in rice in Fukushima Prefecture to 25 Bq/kg in 2014 (the radiation level set by the Food Sanitation Act of Japan in 2012 was 100 Bq/kg). This paper has implications for constructing a database for mitigating and remediating crop contamination by radionuclides which is also relevant to food production in China. [ABSTRACT FROM AUTHOR]

Nuclear energy is indispensable and important energy to human society. Fukushima nuclear accident produced great harm and will seriously affect the development of nuclear energy. In this paper, the importance and necessity of the development of nuclear energy are introduced based on the development of world nuclear energy and the energy demand in China. The basic situation of Fukushima nuclear accident is introduced and the reasons of the accident are also analyzed. The influence of Fukushima nuclear accident on the development of world nuclear power, the nuclear power development plan of China, the nuclear power plant siting, the design and operation of nuclear power plant, and the research of nuclear power technology, nuclear safety culture and personnel training of nuclear major are analyzed and discussed. Nuclear safety is the most important thing in the development of nuclear power. [ABSTRACT FROM AUTHOR]