Tracking load changes in a pressurized water reactor(PWR)with the help of an efficient core power control scheme in a nuclear power station is very important.The reason is that it is challenging to maintain a stable c...Tracking load changes in a pressurized water reactor(PWR)with the help of an efficient core power control scheme in a nuclear power station is very important.The reason is that it is challenging to maintain a stable core power according to the reference value within an acceptable tolerance for the safety of PWR.To overcome the uncertainties,a non-integer-based fractional order control method is demonstrated to control the core power of PWR.The available dynamic model of the reactor core is used in this analysis.Core power is controlled using a modified state feedback approach with a non-integer integral scheme through two different approximations,CRONE(Commande Robuste d’Ordre Non Entier,meaning Non-integer orderRobust Control)and FOMCON(non-integer order modeling and control).Simulation results are produced using MATLAB■program.Both non-integer results are compared with an integer order PI(Proportional Integral)algorithm to justify the effectiveness of the proposed scheme.Sate-spacemodel Core power control Non-integer control Pressurized water reactor PI controller CRONE FOMCON.展开更多
Control rod is used to change the power in nuclear reactor.?Certainly, the core at any moment can be made subcritical condition and shut downs when occurring?to emergency instance in the core. The rod is grouped based...Control rod is used to change the power in nuclear reactor.?Certainly, the core at any moment can be made subcritical condition and shut downs when occurring?to emergency instance in the core. The rod is grouped based?on their function and located at different places in the core where their feature is maximized.?Two methods of control rod calibration are the asymptotic period method and the rod-drop method, which were applied in this experiment. In the first method, the reactor is made supcritical by inserting the control rod to be calibrated a certain level. The rod drop method is to determine the subcritical;at the critical state, the rod to be calibrated is dropped into the core, and the resulting decay of neutron flux is observed and related to the reactivity. In this paper, the regulating rod will be calibrated according to the reactivity in OPR-1000 that corresponds to a certain control rod insert or withdraw, and the reactivity in power reactor depends?on the integral and differential control rod group too. The core simulator OPR1000 is used to test those methods.展开更多
背景中医药治疗脓毒症性急性肺损伤(ALI)/急性呼吸窘迫综合征(ARDS)的疗效确切,但大多数已发表的临床试验设计中缺乏标准、统一的结局指标,造成同类研究结果难以合并、对比,无法产生高质量的循证证据指导临床决策。目的分析2017—2022...背景中医药治疗脓毒症性急性肺损伤(ALI)/急性呼吸窘迫综合征(ARDS)的疗效确切,但大多数已发表的临床试验设计中缺乏标准、统一的结局指标,造成同类研究结果难以合并、对比,无法产生高质量的循证证据指导临床决策。目的分析2017—2022年中医药治疗脓毒症性ALI/ARDS临床试验结局指标的使用情况。方法检索中国知网(CNKI)、万方数据知识服务平台、中国生物医学文献服务系统、PubMed、Web of Science、Embase、Cochrane Library数据库中有关脓毒症性ALI或ARDS的随机对照试验,其中干预组措施为中医药联合其他药物或常规治疗方案,对照组不做限制。采用Cochrane研发的ROB.2工具进行文献质量评价并总结结局指标分类情况。结果经筛选后纳入39篇文献,其中文献偏倚风险评估为低风险1篇(2.56%),高风险3篇(7.69%),可能存在风险35篇(89.74%)。5篇(12.82%)文献结局指标报告质量评分≥5分,为结局指标报告完整。共报告106种结局指标,累计使用443次,包括理化检测(55种,51.89%)、中医症状/证候(2种,1.89%)、症状/体征(13种,12.26%)、远期预后(19种,17.92%)、生活质量(7种,6.60%)、安全性事件(8种,7.55%)和经济学评估(2种,1.89%)。使用率>50%的结局指标有4个,分别是氧合指数(82.05%)、急性生理与慢性健康状况评分系统Ⅱ(58.97%)、机械通气时间(51.28%)和白介素6(51.28%)。21篇文献使用有效率和/或中医证候疗效的复合结局指标,包括总有效率12次,中医证候积分8次和中医症状疗效6次。由于各结局指标差异较大,对106种指标进行合并和依次归类,最终总结出3个大类,分别为:整体评价指标(36种,33.96%)、共性指标(36种,33.96%)及不同关注重点指标(34种,32.08%)。结论目前中医药治疗脓毒症性ALI/ARDS临床试验结局指标的选择尚不规范,主要表现为主次结局指标区分不明确、复合结局指标标准不统一、轻视终点指标、缺少随访数据和中医特色指标等。未来应构建脓毒症性ALI/ARDS的中医药核心结局指标集,推动中医药的高质量发展。展开更多
小型棒控压水堆舍弃了可溶硼,并高度依赖控制棒与可燃毒物棒控制堆芯的反应性。为研究控制棒对堆芯关键性能的影响,本文以核动力破冰船用KLT-40模型为对象,以轴向功率偏移、堆芯寿期、燃料利用率与径向功率峰因子为指标,开展长寿期小型...小型棒控压水堆舍弃了可溶硼,并高度依赖控制棒与可燃毒物棒控制堆芯的反应性。为研究控制棒对堆芯关键性能的影响,本文以核动力破冰船用KLT-40模型为对象,以轴向功率偏移、堆芯寿期、燃料利用率与径向功率峰因子为指标,开展长寿期小型棒控压水堆控制棒布置与动作策略设计分析。首先,基于OpenMC程序开发带棒燃耗程序;其次,比较堆芯带控制棒与无控制棒运行时的堆芯寿期等指标;最后,分析不同动作策略对轴向功率偏移等指标的影响。结果表明:控制棒将堆芯寿期从590 EFPDs(等效满功率天,Effective full power days)延长至650~698 EFPDs;低价值棒组优先动作策略使轴向功率偏移程度由−0.69与+0.80分别下降至−0.29与+0.52。因此,要准确计算长寿期压水堆寿期必须采用带控制棒燃耗计算策略,并且通过合理的动作策略能够有效减小控制棒带来的轴向功率偏移。展开更多
基金This project was funded by the Deanship of Scientific Research(DSR),King Abdulaziz University,Jeddah,Saudi Arabia under grant no.(KEP-Msc-36-135-38).
文摘Tracking load changes in a pressurized water reactor(PWR)with the help of an efficient core power control scheme in a nuclear power station is very important.The reason is that it is challenging to maintain a stable core power according to the reference value within an acceptable tolerance for the safety of PWR.To overcome the uncertainties,a non-integer-based fractional order control method is demonstrated to control the core power of PWR.The available dynamic model of the reactor core is used in this analysis.Core power is controlled using a modified state feedback approach with a non-integer integral scheme through two different approximations,CRONE(Commande Robuste d’Ordre Non Entier,meaning Non-integer orderRobust Control)and FOMCON(non-integer order modeling and control).Simulation results are produced using MATLAB■program.Both non-integer results are compared with an integer order PI(Proportional Integral)algorithm to justify the effectiveness of the proposed scheme.Sate-spacemodel Core power control Non-integer control Pressurized water reactor PI controller CRONE FOMCON.
文摘Control rod is used to change the power in nuclear reactor.?Certainly, the core at any moment can be made subcritical condition and shut downs when occurring?to emergency instance in the core. The rod is grouped based?on their function and located at different places in the core where their feature is maximized.?Two methods of control rod calibration are the asymptotic period method and the rod-drop method, which were applied in this experiment. In the first method, the reactor is made supcritical by inserting the control rod to be calibrated a certain level. The rod drop method is to determine the subcritical;at the critical state, the rod to be calibrated is dropped into the core, and the resulting decay of neutron flux is observed and related to the reactivity. In this paper, the regulating rod will be calibrated according to the reactivity in OPR-1000 that corresponds to a certain control rod insert or withdraw, and the reactivity in power reactor depends?on the integral and differential control rod group too. The core simulator OPR1000 is used to test those methods.
文摘背景中医药治疗脓毒症性急性肺损伤(ALI)/急性呼吸窘迫综合征(ARDS)的疗效确切,但大多数已发表的临床试验设计中缺乏标准、统一的结局指标,造成同类研究结果难以合并、对比,无法产生高质量的循证证据指导临床决策。目的分析2017—2022年中医药治疗脓毒症性ALI/ARDS临床试验结局指标的使用情况。方法检索中国知网(CNKI)、万方数据知识服务平台、中国生物医学文献服务系统、PubMed、Web of Science、Embase、Cochrane Library数据库中有关脓毒症性ALI或ARDS的随机对照试验,其中干预组措施为中医药联合其他药物或常规治疗方案,对照组不做限制。采用Cochrane研发的ROB.2工具进行文献质量评价并总结结局指标分类情况。结果经筛选后纳入39篇文献,其中文献偏倚风险评估为低风险1篇(2.56%),高风险3篇(7.69%),可能存在风险35篇(89.74%)。5篇(12.82%)文献结局指标报告质量评分≥5分,为结局指标报告完整。共报告106种结局指标,累计使用443次,包括理化检测(55种,51.89%)、中医症状/证候(2种,1.89%)、症状/体征(13种,12.26%)、远期预后(19种,17.92%)、生活质量(7种,6.60%)、安全性事件(8种,7.55%)和经济学评估(2种,1.89%)。使用率>50%的结局指标有4个,分别是氧合指数(82.05%)、急性生理与慢性健康状况评分系统Ⅱ(58.97%)、机械通气时间(51.28%)和白介素6(51.28%)。21篇文献使用有效率和/或中医证候疗效的复合结局指标,包括总有效率12次,中医证候积分8次和中医症状疗效6次。由于各结局指标差异较大,对106种指标进行合并和依次归类,最终总结出3个大类,分别为:整体评价指标(36种,33.96%)、共性指标(36种,33.96%)及不同关注重点指标(34种,32.08%)。结论目前中医药治疗脓毒症性ALI/ARDS临床试验结局指标的选择尚不规范,主要表现为主次结局指标区分不明确、复合结局指标标准不统一、轻视终点指标、缺少随访数据和中医特色指标等。未来应构建脓毒症性ALI/ARDS的中医药核心结局指标集,推动中医药的高质量发展。
文摘小型棒控压水堆舍弃了可溶硼,并高度依赖控制棒与可燃毒物棒控制堆芯的反应性。为研究控制棒对堆芯关键性能的影响,本文以核动力破冰船用KLT-40模型为对象,以轴向功率偏移、堆芯寿期、燃料利用率与径向功率峰因子为指标,开展长寿期小型棒控压水堆控制棒布置与动作策略设计分析。首先,基于OpenMC程序开发带棒燃耗程序;其次,比较堆芯带控制棒与无控制棒运行时的堆芯寿期等指标;最后,分析不同动作策略对轴向功率偏移等指标的影响。结果表明:控制棒将堆芯寿期从590 EFPDs(等效满功率天,Effective full power days)延长至650~698 EFPDs;低价值棒组优先动作策略使轴向功率偏移程度由−0.69与+0.80分别下降至−0.29与+0.52。因此,要准确计算长寿期压水堆寿期必须采用带控制棒燃耗计算策略,并且通过合理的动作策略能够有效减小控制棒带来的轴向功率偏移。
