One of the possible negative environmental effects of hydropower stations is the supersaturation of total dissolved gas (TDG) downstream of high-dams,which can lead to gas bubble disease or even death of fish. By taki...One of the possible negative environmental effects of hydropower stations is the supersaturation of total dissolved gas (TDG) downstream of high-dams,which can lead to gas bubble disease or even death of fish. By taking the TDG as the main study object,the paper launched the TDG field observations on Zipingpu,Three Gorges,Ertan,Manwan,Dachaoshan,Gongzui and Ertan dams in China. The factors affecting TDG generation and dissipation were explored. Energy dissipation structures,spill rates and operation patterns were the main factors causing TDG supersaturation. TDG saturations are essentially the same in the hydro-electric tail water and in the upper reaches,so hydro-electric tail water can be less TDG supersaturated through mixing downstream. The main factors affecting the dissipation process of the supersaturated TDG were tributary convergence,water depth and turbulence. TDG supersaturation was unevenly distributed in both the vertical and transverse directions. This study is important because it adds to the accumulating experience of TDG field observations of dam projects in China,and because it objectively and impartially evaluates the impacts of supersaturated TDG. The study also provides field data and references for future studies of TDG supersaturation caused by high-dams.展开更多
After the damage of Fukushima Daiichi Nuclear Power Plant, a great number of radioactive materials were released into the Pacific Ocean. Therefore, it is necessary to research on the temporal and spatial distribution ...After the damage of Fukushima Daiichi Nuclear Power Plant, a great number of radioactive materials were released into the Pacific Ocean. Therefore, it is necessary to research on the temporal and spatial distribution of these radionuclides. We use Princeton Ocean Model to simulate the circulation of the coast water of Fukushima NPP and obtain the concentration of caesium-137 by solving the diffusion equations. We employ the Monte Carlo N-particle(MCNP) code to assess the external doses caused by these contaminated sea water. To improve the efficiency and effectiveness of volume source in MCNP code, we establish a transformation method between spot source and volume source, and determine an appropriate range of volume source. Finally, we calculate the absorbed doses of every organ/tissue and the effective dose of a human body.展开更多
基金supported by the National Natural Science Foundation of China (Grant No.50979063)
文摘One of the possible negative environmental effects of hydropower stations is the supersaturation of total dissolved gas (TDG) downstream of high-dams,which can lead to gas bubble disease or even death of fish. By taking the TDG as the main study object,the paper launched the TDG field observations on Zipingpu,Three Gorges,Ertan,Manwan,Dachaoshan,Gongzui and Ertan dams in China. The factors affecting TDG generation and dissipation were explored. Energy dissipation structures,spill rates and operation patterns were the main factors causing TDG supersaturation. TDG saturations are essentially the same in the hydro-electric tail water and in the upper reaches,so hydro-electric tail water can be less TDG supersaturated through mixing downstream. The main factors affecting the dissipation process of the supersaturated TDG were tributary convergence,water depth and turbulence. TDG supersaturation was unevenly distributed in both the vertical and transverse directions. This study is important because it adds to the accumulating experience of TDG field observations of dam projects in China,and because it objectively and impartially evaluates the impacts of supersaturated TDG. The study also provides field data and references for future studies of TDG supersaturation caused by high-dams.
基金supported by the National Natural Science Foundation of China(Grant No.71373140)the State Key Laboratory of NBC Protection for Civilian(Grant No.SKLNBC0308)Tsinghua University Initiative Scientific Research Program(Grant Nos.2012Z10137,2012THZ0124)
文摘After the damage of Fukushima Daiichi Nuclear Power Plant, a great number of radioactive materials were released into the Pacific Ocean. Therefore, it is necessary to research on the temporal and spatial distribution of these radionuclides. We use Princeton Ocean Model to simulate the circulation of the coast water of Fukushima NPP and obtain the concentration of caesium-137 by solving the diffusion equations. We employ the Monte Carlo N-particle(MCNP) code to assess the external doses caused by these contaminated sea water. To improve the efficiency and effectiveness of volume source in MCNP code, we establish a transformation method between spot source and volume source, and determine an appropriate range of volume source. Finally, we calculate the absorbed doses of every organ/tissue and the effective dose of a human body.
