共查询到18条相似文献,搜索用时 203 毫秒
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采用静态吸附容量法,测定了温度273~303K、压力0~1kPa范围内,CO和CO2在UO2表面的吸附等温线,研究了CO和CO2的吸附热力学性质。结果表明,Langmuir方程和Freundlich方程分别是描述CO和CO2吸附的最优模型方程。CO2的吸附强度明显高于CO的,实验条件下,CO和CO2的最大吸附量分别为0.36和1.25μmol/g。CO的吸附热为26kJ/mol,表明吸附为物理吸附;CO2的吸附热随吸附量增加而减小,当吸附量由0.3μmol/g增至0.8μmol/g时,吸附热由46kJ/mol降至37kJ/mol,表明吸附同时存在化学吸附和物理吸附。 相似文献
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大晶粒的UO2核芯可更有效地阻止反应堆运行时裂变气体的释放,实现反应堆燃耗的加深和延长反应堆燃料元件的运行寿命。采用溶胶凝胶工艺制备高温气冷堆燃料元件的UO2核芯,在胶液中加入含有Al的化合物Al(NO3)3•9H2O,以增大核芯晶粒尺寸。研究了添加剂对核芯晶粒尺寸的影响及烧结过程中分解的O离子与核芯U离子的扩散系数之间的关系。通过添加含有Al的化合物,UO2核芯的平均晶粒尺寸由18μm增加到30μm。对添加Al(NO3)3•9H2O的UO2核芯的烧结机理研究表明,UO2核芯晶粒的长大主要受空位扩散机制的影响。 相似文献
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采用循环伏安法和线性扫描法对模拟草酸钚沉淀母液中草酸和钚的电化学行为进行研究。研究结果表明,HNO3介质中的H2C2O4在Pt电极上的氧化为不可逆反应。在模拟的草酸钚沉淀母液中,因Pu(Ⅳ)被C2O2-4络合而未出现Pu(Ⅲ)/Pu(Ⅳ)的氧化还原峰,H2C2O4的氧化峰则清晰可见,H2C2O4的氧化反应仍为不可逆过程。对模拟草酸钚沉淀母液进行恒电流电解,考察了模拟母液中Pu(Ⅳ)初始浓度对草酸电解速率的影响以及电解过程中Pu价态的变化。结果表明,钚浓度为0.002~0.1g/L时,对H2C2O4的电解速率影响不大。恒电流密度下电解可将草酸钚沉淀母液中草酸的浓度破坏到0.001mol/L以下,可满足工艺要求。 相似文献
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动力转换单元是高温和超高温气冷堆的重要组成部分。本文对高温和超高温气冷堆的动力转换单元进行研究。从4个关键参数(反应堆出口温度、反应堆入口温度、压缩比和主蒸汽参数)入手,对5个循环方案进行比较分析。综合考虑各种工程因素,上位循环为简单氦气透平循环、下位循环为有再热的蒸汽轮机循环的联合循环方案是具有竞争力的,其中下位循环在高温气冷堆范围是亚临界参数循环,在超高温气冷堆范围是超临界参数循环。联合循环可实现高温和超高温气冷堆热量的高效率转化,且反应堆入口温度在反应堆压力壳材料允许的范围内,具有足够的安全性。 相似文献
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本工作对用于测量α粒子的BaF2探测器的时间分辨随温度变化情况进行了实验研究。实验选用退激γ射线能量较高的237Npα源,利用α粒子与退激γ射线的时间关联性得到时间谱,在不改变任何条件的情况下对BaF2晶体加热,加热到设定温度后保持恒温,在BaF2晶体达到热平衡后开始测量时间谱,由该时间谱上读出的半高宽与标准偏差的线性关系得出α粒子的时间分辨随温度变化的情况。测量结果显示,时间分辨随温度变化在目前实验条件下较为明显,这为未来快时间分辨α粒子探测器的选择和优化使用提供了依据。 相似文献
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熔盐堆(MSR)能实现在线填料和后处理,出口温度较高,应配备一种与之出口温度相匹配的创新型循环方式,且可达到较高的循环效率。本文基于中国科学院上海应用物理研究所设计的小型模块化熔盐堆(smTMSR-400)设计超临界二氧化碳(SCO2)布雷顿循环系统,使用控制变量法分析了分流比、压缩机/透平效率、主压缩机出口温度、低温换热器换热温差/阻力对SCO2布雷顿循环系统的影响。分析结果表明:①存在最佳分流比使低温换热器两侧温差相等;②相较于压缩机效率,等幅度的透平效率提升可使系统循环效率和?效率更高;③主压缩机出口压力增大为系统带来正面影响,但循环效率/?效率与其斜率都逐渐降低;④换热器换热温差和流动阻力都为系统循环带来了可量化的负担: 换热温差每增加10 K,循环效率降低1.85%,?效率降低2.70%;流动阻力每增加1 MPa,循环效率降低6.58%,?效率降低10.22%。最后根据分析结果和系统?流变化设计了5种物理参考方案。 相似文献
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Shintaro Ishiyama Yasushi Muto Yasuyoshi Kato Satoshi Nishio Takumi Hayashi Yasunobu Nomoto 《Progress in Nuclear Energy》2008,50(2-6):325-332
Power generation systems such as steam turbine cycle, helium turbine cycle and supercritical CO2 (S-CO2) turbine cycle are examined for the prototype nuclear fusion reactor. Their achievable cycle thermal efficiencies are revealed to be 40%, 34% and 42% levels for the heat source outlet coolant temperature of 480 °C, respectively, if no other restriction is imposed. In the current technology, however, low temperature divertor heat source is included. In this actual case, the steam turbine system and the S-CO2 turbine system were compared in the light of cycle efficiency and plant cost. The values of cycle efficiency were 37.7% and 36.4% for the steam cycle and S-CO2 cycle, respectively. The construction cost was estimated by means of component volume. The volume became 16,590 m3 and 7240 m3 for the steam turbine system and S-CO2 turbine system, respectively. In addition, separation of permeated tritium from the coolant is much easier in S-CO2 than in H2O. Therefore, the S-CO2 turbine system is recommended to the fusion reactor system than the steam turbine system. 相似文献
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为满足小型氟盐冷却高温堆(FHR)能量转换需求,开发与之匹配的高效、紧凑、无水冷却动力转换系统,本文对比了超临界二氧化碳(SCO2)、空气、氩气(Ar)、氮气(N2)、氙气(Xe)5种气体工质在不同布雷顿循环构型中的热电转换效率、?效率、?损失分布。研究发现,SCO2布雷顿循环相比其它工质循环具有最高的热电转换效率和?效率,且结构更为紧凑,易于小型化和模块化,与小型氟盐冷却高温堆耦合更具优势;进而对SCO2布雷顿循环进行构型优化,得出匹配小型氟盐冷却高温堆的最佳循环构型方式,构成固有安全模块化小型氟盐冷却高温堆热电转换系统,为西部能源利用提供新研究思路。 相似文献
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Medium temperature carbon dioxide gas turbine reactor 总被引:1,自引:0,他引:1
A carbon dioxide (CO2) gas turbine reactor with a partial pre-cooling cycle attains comparable cycle efficiencies of 45.8% at medium temperature of 650 °C and pressure of 7 MPa with a typical helium (He) gas turbine reactor of GT-MHR (47.7%) at high temperature of 850 °C. This higher efficiency is ascribed to: reduced compression work around the critical point of CO2; and consideration of variation in CO2 specific heat at constant pressure, Cp, with pressure and temperature into cycle configuration. Lowering temperature to 650 °C provides flexibility in choosing materials and eases maintenance through the lower diffusion leak rate of fission products from coated particle fuel by about two orders of magnitude. At medium temperature of 650 °C, less expensive corrosion resistant materials such as type 316 stainless steel are applicable and their performance in CO2 have been proven during extensive operation in AGRs. In the previous study, the CO2 cycle gas turbomachinery weight was estimated to be about one-fifth compared with He cycles. The proposed medium temperature CO2 gas turbine reactor is expected to be an alternative solution to current high-temperature He gas turbine reactors. 相似文献
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Qiao Wu DuWayne L. Schubring James J. Sienicki 《Nuclear Engineering and Design》2007,237(20-21):2114-2119
A two-phase MHD energy conversion unit is proposed to a liquid metal cooled fast reactor. Using supercritical CO2 as the working fluid in the gas cycle without considering friction and heat losses, the optimized cycles efficiency is obtained, which is about 5% higher than that of the gas turbine Brayton cycle with the same regenerator/compressor configurations. Based on a simple MHD power analysis and the two-phase homogeneous flow model, the important system operational conditions were estimated. The results suggest that a liquid lead pump of at least 20% of the MHD power output is needed in order to convert the 400 MW reactor heat into electricity at the specified thermal efficiency, unless a mixture foam flow of void fraction greater than 80% is achievable at very high mixture velocity. 相似文献
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Sodium cooled fast reactors (SFR) traditionally adopt the steam Rankine cycle for power conversion. The resulting potential for water–sodium reaction remains a continuing concern which at least partly delays the SFR technology commercialization and is a contributor to higher capital cost. Supercritical CO2 provides an alternative, but is also capable of sustaining energetic chemical reactions with sodium. Recent development of advanced inert-gas Brayton cycles could potentially solve this compatibility issue, increase thermal efficiency, and bring down the capital cost sufficiently to compete directly with light water reactors. In this paper, helium Brayton cycles with multiple reheat and intercooling states are presented for SFRs with reactor outlet temperatures in the range of 510–650 °C. The resulting thermal efficiencies range from 39% to 47%, which is comparable with supercritical recompression CO2 cycles (SCO2 cycle). A systematic comparison between the multiple reheat helium Brayton cycle and the SCO2 cycle is given, considering compatibility issues, plant site cooling temperature effect on plant efficiency, full plant cost optimization, and other important factors. The study indicates that the multiple reheat helium cycle is the preferred choice over SCO2 cycle for sodium cooled fast reactors. 相似文献
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高温气冷堆气体透平循环方式的技术评价 总被引:3,自引:2,他引:3
气体透平循环被认为是高温气冷堆发电的发展方向。循环方式包括直接循环,开式间接循环和闭式间接循环,工质包括氦气,空气和氮气,对于每一种循环都进行了热力学分析和优化计算,并对透平压气机进行了气动设计,研究结果表明,氦气直接循环是一个理想的选择,但是基于现有技术水平难度较大,氦气和氮气闭式间接循环是目前比较现实的方案,可以实现气体透平循环的设想并为将来的直接循环做技术积累。 相似文献
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Parametric evaluation of large-scale high-temperature electrolysis hydrogen production using different advanced nuclear reactor heat sources 总被引:1,自引:0,他引:1
Edwin A. Harvego 《Nuclear Engineering and Design》2009,239(9):1571-1386
High-temperature electrolysis (HTE), when coupled to an advanced nuclear reactor capable of operating at reactor outlet temperatures of 800-950 °C, has the potential to efficiently produce the large quantities of hydrogen needed to meet future energy and transportation needs. To evaluate the potential benefits of nuclear-driven hydrogen production, the UniSim process analysis software was used to evaluate different reactor concepts coupled to a reference HTE process design concept. The reference HTE concept included an intermediate heat exchanger and intermediate helium loop to separate the reactor primary system from the HTE process loops and additional heat exchangers to transfer reactor heat from the intermediate loop to the HTE process loops. The two process loops consisted of the water/steam loop feeding the cathode side of a HTE electrolysis stack, and the sweep gas loop used to remove oxygen from the anode side. The UniSim model of the process loops included pumps to circulate the working fluids and heat exchangers to recover heat from the oxygen and hydrogen product streams to improve the overall hydrogen production efficiencies.The reference HTE process loop model was coupled to separate UniSim models developed for three different advanced reactor concepts (a high-temperature helium cooled reactor concept and two different supercritical CO2 reactor concepts). Sensitivity studies were then performed with the objective of evaluating the affect of reactor outlet temperature on the power cycle efficiency and overall hydrogen production efficiency of the integrated plant design for each of the reactor power cycles. The results of these sensitivity studies showed that overall power cycle and hydrogen production efficiencies increased with reactor outlet temperature, but the power cycles producing the highest efficiencies varied depending on the temperature range considered. 相似文献