碩士 / 國立臺灣海洋大學 / 食品科學系 / 103 / BC March 11, 2011, occurred in nine magnitude strong earthquake in northeastern Japan, shortly after the earthquake, the tsunami flooded with seawater the power plant backup diesel generator room, the cooling system has no power to pump cooling water into the reactor, resulting in four reactor of overheating and meltdown. It was caused by radiation leakage. April 2011 total emissions of six days of the Fukushima nuclear power plant reached 18 x 1014Bq of 134 + 137Cs. From June 2011, the Japanese government collected once a month the samples of the surface seawater and seabed soil (sediment) from Fukushima important harbor, fishing port, fishing grounds. Test results, 131I mostly not detected. The other concentration of radiactive contaminated seawater was below the Japanese regulatory limits of which the 131I , 134Cs and 137Cs to per liter of seawater are 40Bq , 60Bq and 90Bq , respectively. Food irradiation concentration limits are 100 Bq / kg. Fukushima offshore fishery products caught by four survey, from April to June 2011, there are 57.7% catch radiation exceeded. Catch the first quarter of 2012 the amount of radiation has exceeded 25.1%. To catch the last quarter of 2013 the amount of radiation exceeded by 1.7%. Catch the first quarter of 2015 exceeded the amount of radiation is 0.2%. Japan the other Prefectures the proportion exceeded after 2012, from July to September is less than 1%, 2013 10 to 12 months continued to decrease to 0.1%.
Sewage radiation Fukushima nuclear power plant accident emissions, with the ocean currents will spread throughout the North Pacific. Scientific research boat of the Coast Guard in Canada in June 2012, in Canada, bordering the Pacific Ocean 1,500 kilometers of water samples collected in coastal waters, sewage radiation to be detected by the research team. From the Fukushima nuclear power plant accident for about 1.3 years. In June 2013, radiation sewage reach the North American continental shelf. Shallow water radiation levels are within 150 meters of 2 Bq / m3. Between 2015 to 2016, the value of the North American West Coast waters radiation will reach 3-5 Bq / m3. Fukushima nuclear power plant accident before 2008 year of detecting radiation content captured off the coast of California, Pacific bluefin tuna, 134Cs is not detected, 137Cs concentration of about 1 Bq / kg, and the same background value. In August 2011, California collected 15 captured off the coast of the Pacific bluefin tuna, these fish have been tested radiation content, 134Cs average concentration was 4.0 ± 1.4 Bq / kg, 137Cs average concentration was 6.3 ± 1.5 Bq / kg. These data suggest that Pacific bluefin tuna can rapidly transmit radiation was the Fukushima nuclear power plant emissions to the distant east coast of the North Pacific. Also it shows that migratory fish is the North Pacific radiation was spread carrier.
After the fish was mostly accumulated radiation through the food chain relations, but also a direct result of drinking the water, absorbed by the digestive tract. After the study, known radiation 90Sr more gathered in the fish bones and scales. Multi 137Cs accumulation in fish flesh. 137Cs harm is higher scallops, followed by clams, oysters less risk. Algae cumulative radiation concentration in surface waters are hundreds to thousands of times more concentration.
When the nuclear power plant accident, radiation was leaked, rain may suffer radiation contamination, and contamination of surface water. To remove contaminated rainy water, Some scholars use water filter bottle decontamination, decontamination rates were: iodine (131I) can be removed 94.2~97.8%. Cesium (137Cs, 134Cs) can be removed 84.2~91.5%. And water filter bottles by 2-3 times a filter can be divisible radiation contaminants. Some scholars also use zeolite decontamination. After verification, zeolite modified electron radiation than the natural zeolite alone have the ability to further enhance radiation sewage purification. In addition, at a distance of 78 kilometers Fukushima Daiichi nuclear power plant at a wastewater treatment plant sludge alive, found covered with green algae. Algae in bright light (2000 lux) can absorb water, iodine radioisotopes, not when there is no light absorption. Such algae concentrations in 100 mg / ml (24 hours), iodine (131I) adsorption rate was 38.7 ± 3.1%. Adsorption rate of strontium (85Sr) was 75.9 ± 4.2%. Of cesium (137Cs) adsorption rate is 41.0 ± 4.8%. This new species of algae with resistance against high temperature, high pH, high salinity and other characteristics, it is suitable for the future development and application as the decontamination system.
RMC (RADIATION MONITORING CENTER, ATOMIC ENERGY COUNCIL, EXECUTIVE YUAN) publishes a semi-annual report - Taiwan radioactive fallout and Food Survey, which can be found in seawater samples of 137Cs concentration collected from the Keelung and Kaohsiung coast are at the lowest value measurable activity. The same can be found in Taiwan 137Cs concentration of coastal fish are less than 1 Bq/ kg-wet, indicating that Fukushima-derived radionuclides in Taiwan's coastal waters and marine influence is minimal.
Keywords：131I, 134Cs, 137Cs, 85Sr , FDNPP disasters, nuclear reactor meltdown.
| Identifer | oai:union.ndltd.org:TW/103NTOU5253047 |
| Date | January 2015 |
| Creators | Hsieh, Ming-hung, 謝明鴻 |
| Contributors | Sen-shyong Jeng, 鄭森雄 |
| Source Sets | National Digital Library of Theses and Dissertations in Taiwan |
| Language | zh-TW |
| Detected Language | English |
| Type | 學位論文 ; thesis |
| Format | 94 |
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