典型海洋摇摆对压水堆堆芯的热工水力特性有显著影响,从而导致一回路腐蚀产物的沉积生长规律发生变化。本文基于数据交换方法,通过多尺度耦合建立反应堆一回路系统模型,将摇摆条件下的冷却剂流动数学模型和腐蚀产物沉积生长模型加入模拟...典型海洋摇摆对压水堆堆芯的热工水力特性有显著影响,从而导致一回路腐蚀产物的沉积生长规律发生变化。本文基于数据交换方法,通过多尺度耦合建立反应堆一回路系统模型,将摇摆条件下的冷却剂流动数学模型和腐蚀产物沉积生长模型加入模拟中,对摇摆条件下3×3棒束上腐蚀产物的生长过程进行了研究。结果表明,摇摆会导致冷却剂流速和棒外壁温发生周期性变化,流量脉动和温度波动会加剧摇摆切线方向上的剥蚀作用,削弱沉积过程。在轴向高度较低的通道截面上,靠近外围绝热壁面的棒表面上生长的多孔介质沉积层(Chalk River Unidentified Deposit,CRUD)最厚;在轴向高度较高的通道截面上,所有位置的棒上的CRUD分布规律趋于一致,并且在燃料棒周向的分布体现在极坐标系中呈现出趋近于椭圆形的规律。展开更多
EVA was widely used as the pour point depressant for waxy oil.In order to improve its effect,some graft copolymerization methods should be used to modify EVA's property.EVA has long side chains and nitrogen polar ...EVA was widely used as the pour point depressant for waxy oil.In order to improve its effect,some graft copolymerization methods should be used to modify EVA's property.EVA has long side chains and nitrogen polar groups to enforce its adaptability and effect of waxy oil.The pure amine,maleicanhydride and their reaction product were tested using infrared spectra and the NMR spectral.The results show that when the modified EVA is added into oil,the wax deposits not only on the main chain but also on the side chains.And the polar groups have the function to avoid and resist the wax crystals connection each other to form the net.Using the reaction product of maleicanhydride and high carbonic amine(C12,C16,C18 amine) as the graft component,the toluene as the solvent and BPO as the initiator,the series of new EVA graft copolymer with special side chains are prepared under controlled condition.A series of cylmaleimide exist indeed in modified EVA and the highest grafted percentage is 18.8%.EVA-16,the new graft copolymer,is better than EVA about 3 ℃ more in depressant the pour-point of Daqing waxy crude oil.展开更多
The influences of solid particles in leach solution on the formation of the third phase crud during solvent extraction of copper were studied. Analyzed from the point of view of pH value and surface tension, the study...The influences of solid particles in leach solution on the formation of the third phase crud during solvent extraction of copper were studied. Analyzed from the point of view of pH value and surface tension, the study results showed that the solid particle is one of the most important contributors for the formation of the third phase crud. During solvent extraction, if the pH value was greater than 2.30, the number of solid particles in the mother solution increased, in which case the possibility of forming the third phase crud could also increase, and the interface tension value might grow in pace with the quantity of the third phase crud.展开更多
Under normal water chemistry conditions, the oxygen and hydrogen peroxide produced by water radiolysis in the coolant of boiling water reactors(BWRs) can lead to intergranular stress corrosion cracking in the constitu...Under normal water chemistry conditions, the oxygen and hydrogen peroxide produced by water radiolysis in the coolant of boiling water reactors(BWRs) can lead to intergranular stress corrosion cracking in the constituent materials of plant components. This fact has led to the wide-scale adoption of hydrogen water chemistry(HWC) in the nuclear industry to counteract these effects.This study seeks to characterize the metallic composition and the surface properties of the constituent materials of plant components in order to determine their effects on the accumulation of chalk river unidentified deposits(crud) on fuel rods in the BWR Unit-1 of the Kuosheng Nuclear Power Plant in Taiwan. Inductively coupled plasma-atomic emission spectroscopy was used to calculate the concentrations of surface crud and gamma spectrometry was used to determine the radioactivity of the corrosion products, as well as their axial distribution across the surface of the fuel rods. X-ray diffraction analysis and scanning electron microscopy/energy-dispersive X-ray spectroscopy were used to identify the crystalline phase and morphology of the crud as irregular shapes and flakes. The amount of crud deposited during the fourth fuel cycle exceeded that of the third fuel cycle due to extended burn-up time. Our analytical results indicate that the implementation of HWC had no significant effect on the characteristics of subsequent crud.展开更多
The authors investigated the mechanism of crud formation in copper solvent extraction. It is indicated that pH value of solution and the phase ratio (O/A) are the main factors affecting crud formation in solvent extra...The authors investigated the mechanism of crud formation in copper solvent extraction. It is indicated that pH value of solution and the phase ratio (O/A) are the main factors affecting crud formation in solvent extraction. The amount of crud extraction increases with aqueous pH value increase, and reduces with the increase of the phase ratio. Fe 3+ , Mg 2+ , fine air bubble and suspended particulates in leaching solution contribute to crud formation. One case is that a series of reactions of hydrolization and polymerization occurs for Fe 3+ , while pH>2.5, polyhydric complex or Fe SO 4 complex are formed. Then the complex ions of FeOH 2+ , Fe 2(OH) 4+ 2 cause poly reaction, which is likely to lead emulsion. The study on Zeta potential indicates the repulsion between electriferous droplets in solvent extraction prevents phase coalescence, which is one of the major reasons for emulsion.展开更多
压水堆(Pressurized Water Reactor,PWR)功率运行期间一回路中的腐蚀产物会生成反应堆污垢(Chalk Rivers Unidentified Deposit,CRUD),引起硼在CRUD中析出,增大垢致轴向功率偏移(Crud Induced Power Shift,CIPS)的风险。延伸运行(Stretc...压水堆(Pressurized Water Reactor,PWR)功率运行期间一回路中的腐蚀产物会生成反应堆污垢(Chalk Rivers Unidentified Deposit,CRUD),引起硼在CRUD中析出,增大垢致轴向功率偏移(Crud Induced Power Shift,CIPS)的风险。延伸运行(Stretch-Out,SO)是反应堆的一种灵活运行方式,能够提高反应堆的经济性。本文介绍了PWR硼析出分析模型,并研究了SO工况对CRUD和硼析出量的影响,最终对其CIPS风险做出评估。计算结果表明,SO工况可以减少PWR的CRUD总量和厚度,并且有利于降低下一燃料循环初期的硼析出量,进而降低CIPS风险。研究成果为PWR在SO期间的CRUD和CIPS风险控制提供了理论依据和数据参考。展开更多
为提升核电站的经济效益,越来越多的机构开始研发更加高效的先进核燃料组件。当堆芯引入一种新型燃料组件时,堆芯中的两种组件就会形成混合堆芯。垢致轴向功率偏移(Crud Induced Power Shift,CIPS)作为影响核电安全运行的关键因素之一,...为提升核电站的经济效益,越来越多的机构开始研发更加高效的先进核燃料组件。当堆芯引入一种新型燃料组件时,堆芯中的两种组件就会形成混合堆芯。垢致轴向功率偏移(Crud Induced Power Shift,CIPS)作为影响核电安全运行的关键因素之一,其在混合堆芯中的研究也有着重要意义。本文针对某压水堆不同混合堆芯方案下的CIPS风险进行了分析评估,计算结果表明,当混合堆芯引入新型燃料组件较少时,CIPS风险变化较小;当引入较多新型燃料组件时,CIPS风险有所降低。研究结果为新型燃料组件入堆的安全评估提供了数据支撑,同时也为混合堆芯中CIPS风险评估提供了思路和参考。展开更多
文摘典型海洋摇摆对压水堆堆芯的热工水力特性有显著影响,从而导致一回路腐蚀产物的沉积生长规律发生变化。本文基于数据交换方法,通过多尺度耦合建立反应堆一回路系统模型,将摇摆条件下的冷却剂流动数学模型和腐蚀产物沉积生长模型加入模拟中,对摇摆条件下3×3棒束上腐蚀产物的生长过程进行了研究。结果表明,摇摆会导致冷却剂流速和棒外壁温发生周期性变化,流量脉动和温度波动会加剧摇摆切线方向上的剥蚀作用,削弱沉积过程。在轴向高度较低的通道截面上,靠近外围绝热壁面的棒表面上生长的多孔介质沉积层(Chalk River Unidentified Deposit,CRUD)最厚;在轴向高度较高的通道截面上,所有位置的棒上的CRUD分布规律趋于一致,并且在燃料棒周向的分布体现在极坐标系中呈现出趋近于椭圆形的规律。
文摘EVA was widely used as the pour point depressant for waxy oil.In order to improve its effect,some graft copolymerization methods should be used to modify EVA's property.EVA has long side chains and nitrogen polar groups to enforce its adaptability and effect of waxy oil.The pure amine,maleicanhydride and their reaction product were tested using infrared spectra and the NMR spectral.The results show that when the modified EVA is added into oil,the wax deposits not only on the main chain but also on the side chains.And the polar groups have the function to avoid and resist the wax crystals connection each other to form the net.Using the reaction product of maleicanhydride and high carbonic amine(C12,C16,C18 amine) as the graft component,the toluene as the solvent and BPO as the initiator,the series of new EVA graft copolymer with special side chains are prepared under controlled condition.A series of cylmaleimide exist indeed in modified EVA and the highest grafted percentage is 18.8%.EVA-16,the new graft copolymer,is better than EVA about 3 ℃ more in depressant the pour-point of Daqing waxy crude oil.
基金This study is financially supported by the "973" National Basic Research of China (No. 2004CB619206).
文摘The influences of solid particles in leach solution on the formation of the third phase crud during solvent extraction of copper were studied. Analyzed from the point of view of pH value and surface tension, the study results showed that the solid particle is one of the most important contributors for the formation of the third phase crud. During solvent extraction, if the pH value was greater than 2.30, the number of solid particles in the mother solution increased, in which case the possibility of forming the third phase crud could also increase, and the interface tension value might grow in pace with the quantity of the third phase crud.
文摘Under normal water chemistry conditions, the oxygen and hydrogen peroxide produced by water radiolysis in the coolant of boiling water reactors(BWRs) can lead to intergranular stress corrosion cracking in the constituent materials of plant components. This fact has led to the wide-scale adoption of hydrogen water chemistry(HWC) in the nuclear industry to counteract these effects.This study seeks to characterize the metallic composition and the surface properties of the constituent materials of plant components in order to determine their effects on the accumulation of chalk river unidentified deposits(crud) on fuel rods in the BWR Unit-1 of the Kuosheng Nuclear Power Plant in Taiwan. Inductively coupled plasma-atomic emission spectroscopy was used to calculate the concentrations of surface crud and gamma spectrometry was used to determine the radioactivity of the corrosion products, as well as their axial distribution across the surface of the fuel rods. X-ray diffraction analysis and scanning electron microscopy/energy-dispersive X-ray spectroscopy were used to identify the crystalline phase and morphology of the crud as irregular shapes and flakes. The amount of crud deposited during the fourth fuel cycle exceeded that of the third fuel cycle due to extended burn-up time. Our analytical results indicate that the implementation of HWC had no significant effect on the characteristics of subsequent crud.
文摘The authors investigated the mechanism of crud formation in copper solvent extraction. It is indicated that pH value of solution and the phase ratio (O/A) are the main factors affecting crud formation in solvent extraction. The amount of crud extraction increases with aqueous pH value increase, and reduces with the increase of the phase ratio. Fe 3+ , Mg 2+ , fine air bubble and suspended particulates in leaching solution contribute to crud formation. One case is that a series of reactions of hydrolization and polymerization occurs for Fe 3+ , while pH>2.5, polyhydric complex or Fe SO 4 complex are formed. Then the complex ions of FeOH 2+ , Fe 2(OH) 4+ 2 cause poly reaction, which is likely to lead emulsion. The study on Zeta potential indicates the repulsion between electriferous droplets in solvent extraction prevents phase coalescence, which is one of the major reasons for emulsion.
文摘压水堆(Pressurized Water Reactor,PWR)功率运行期间一回路中的腐蚀产物会生成反应堆污垢(Chalk Rivers Unidentified Deposit,CRUD),引起硼在CRUD中析出,增大垢致轴向功率偏移(Crud Induced Power Shift,CIPS)的风险。延伸运行(Stretch-Out,SO)是反应堆的一种灵活运行方式,能够提高反应堆的经济性。本文介绍了PWR硼析出分析模型,并研究了SO工况对CRUD和硼析出量的影响,最终对其CIPS风险做出评估。计算结果表明,SO工况可以减少PWR的CRUD总量和厚度,并且有利于降低下一燃料循环初期的硼析出量,进而降低CIPS风险。研究成果为PWR在SO期间的CRUD和CIPS风险控制提供了理论依据和数据参考。
文摘为提升核电站的经济效益,越来越多的机构开始研发更加高效的先进核燃料组件。当堆芯引入一种新型燃料组件时,堆芯中的两种组件就会形成混合堆芯。垢致轴向功率偏移(Crud Induced Power Shift,CIPS)作为影响核电安全运行的关键因素之一,其在混合堆芯中的研究也有着重要意义。本文针对某压水堆不同混合堆芯方案下的CIPS风险进行了分析评估,计算结果表明,当混合堆芯引入新型燃料组件较少时,CIPS风险变化较小;当引入较多新型燃料组件时,CIPS风险有所降低。研究结果为新型燃料组件入堆的安全评估提供了数据支撑,同时也为混合堆芯中CIPS风险评估提供了思路和参考。
