【作者】 魏巍；

【导师】 齐克林；

【作者基本信息】 哈尔滨工程大学 ， 核科学与技术， 2018， 博士

【摘要】 日本福岛核事故后,核电厂严重事故的研究再次成为核工业界关注的焦点,一方面在设计上有针对性的推动实施严重事故预防和缓解措施,另一方面在核电厂运行上推行“状态导向的事故规程”以及“严重事故管理导则”的开发和应用。在设计上的研究主要通过理论和实验相结合的方法,其直接的工具是“严重事故分析软件”。在运行管理上,事故规程和管理导则的开发及验证不仅基于软件分析的结果,还要求经过专门的“严重事故模拟机”的验证,确保规程和导则的全面合理可行。“严重事故模拟机”的核心软件是“严重事故仿真软件”。因此严重事故软件工具的研究开发是核工业进行严重事故相关设计和运行管理的基础。目前我国的严重事故软件主要依靠从欧美引进。在我国从核电大国迈向核电强国的征途上,特别是我国实施核电“走出去”战略后,包括严重事故软件在内的基础软件的自主化成为我们必须解决的问题。中国核工业集团公司“核电软件自主化专项”正是在这个背景下开展的。本论文研究的课题作为“核电软件自主化专项”的组成部分,其目的首先是解决严重事故模拟机的关键基础软件即“严重事故仿真软件”,其次是通过严重事故仿真软件的研究,为后续“严重事故分析软件”奠定基础。“严重事故仿真软件”和“严重事故分析软件”相比,均要求模型的真实可信,要求能够描述严重事故进程中的主要物理过程。不同之处在于,严重事故分析软件是通过不断的理论研究和实验研究开发和改进的,而严重事故仿真软件的开发方法主要偏重于理论研究,同时允许在不违背基本物理原理前提下,可以通过借鉴、简化“分析软件”模型的方法进行开发。严重事故仿真软件的应用对象是严重事故模拟机,还必须解决严重事故软件与模拟机中原有堆芯物理物理软件、热工水力软件以及安全壳软件的实时耦合计算问题。本文研究开发的严重事故仿真软件SimSA就是通过关键理论模型的研究,并通过借鉴国际上先进的严重事故分析软件的物理模型进行开发的,同时重点解决了严重事故仿真软件与其它软件的耦合问题。首先,对严重事故仿真系统的实施方案进行了研究,对比分析了国际上两种常用方案的优劣,提出了基于实际使用效果及技术自主研发方面考虑,应该采用开发严重事故仿真软件的方案。随后对严重事故仿真软件的架构进行了设计,并确定了其开发范围。其次,参考国际上成熟的严重事故分析软件(MAAP及SCDAP)的理论模型,考虑模拟机实时计算的要求,重点对模型数值算法进行了研究。结合算法研究给出了各控制模型的数值求解方法,开发了一套的描述轻水堆严重事故关键过程的仿真模型,包括堆内过程:1)锆-水反应模型;2)二氧化铀与锆的共晶作用模型;3)堆芯熔化损毁过程模型;4)熔融物再定位及支撑板失效过程模型;5)下封头熔池行为模型。堆外过程:堆芯熔融物与混凝土相互作用过程模型。并参考相关实验数据或其它公认的成熟模型对仿真模型进行了对比验证。再次,对程序集成及耦合技术进行了深入研究,给出了堆芯行为模型与主系统热工水力模型耦合计算的解决方案,解决了严重事故阶段热工水力过程计算与堆芯行为计算的耦合问题,完成了对堆内严重事故过程的完整模拟。再通过研究变步长多程序同步计算技术,提出了基于时域控制技术的同步计算解决方案,使得SimSA各程序模块在不牺牲计算精度的情况下,完成了多模块的同步协同计算。最终形成了能够模拟堆内、堆外完整严重事故过程的严重事故仿真计算程序SimSA。然后,在SimSA程序的整体验证环节,考虑SimSA并不是一个独立运行的程序,其运行环境高度依赖与模拟机的集成,为了确保验证环境的一致性,对MAAP5与模拟机集成技术进行了研究,开发了一套基于MAAP5与模拟机集成的严重事故验证环境。该验证环境的开发得到了MAAP软件所有者美国电力科学研究院(EPRI)的技术支持,相关集成技术得到广泛验证,验证系统准确可靠。最后,以中核集团二代改进型核电机组CP1000为研究对象,收集相关数据分别基于SimSA及MAAP5建立了CP1000核电机组的电厂模型,通过对比计算,验证SimSA的整体性能。验证结果表明SimSA能够模拟严重事故的主要过程,其模拟范围及计算性能可以满足严重事故仿真的要求。目前,SimSA程序已经应用到福清、方家山以及海南昌江等多台全范围模拟机严重事故仿真功能升级项目以及中国核电工程公司华龙一号设计验证平台开发项目中,负责严重事故过程的实时模拟,协助进行严重事故管理导则的培训、演练及验证工作。更多还原

【Abstract】 After the Fukushima nuclear accident in Japan,the study of severe accidents in nuclear power plants has once again become the focus of nuclear industry.On the one hand,measures to promote the prevention and mitigation of severe accidents are targeted,and on the other hand,state-oriented accident procedures and severe accident management guidelines are developed and applied in the operation of nuclear power plants.The research in design is mainly based on the combination of theory and experiment.The direct tool is severe accident analysis software.In operation management,the development and verification of accident procedures and management guidelines are not only based on the results of software analysis,but also require the verification of a special severe accident simulator to ensure that the procedures and guidelines are reasonable and feasible.The core software of the severe accident simulator is the severe accident simulation software.Therefore,the research and development of severe accident software tools are the basis for the nuclear industry to carry out design and operation management related to severe accident.At present,China’s severe accident software mainly relies on the introduction from Europe and the United States.In the journey of China from a nuclear country to a nuclear power,especially after China implementing the "going out" strategy for nuclear power,the autonomy of basic software including severe accident software has become a problem we must solve.The Nuclear Power Software Autonomy Project is launched by China National Nuclear Corporation in this context.The research topic of this thesis is part of the Nuclear Power Software Autonomy Project.Its purpose is firstly to analyze the severe accident simulation software,which is the key basic software for severe accident simulators,and secondly,to lay the foundation for the subsequent study of severe accident analysis software through the research of severe accident simulation software.The severe accident simulation software and the severe accident analysis software both require the model to be authentic and credible,and require the ability to describe the main physical processes in severe accidents.The difference lies in the fact that severe accident analysis software is developed and improved through continuous theoretical research and experimental research,while the severe accident simulation software mainly focuses on theoretical research,and at the same time,can be developed by learning from and simplifying the analysis software model without violating the basic physics principles.The application object of severe accident simulation software is a severe accident simulator.It must solve the problem of real-time coupling calculation between the severe accident software and the original core physical software,thermal hydraulic software,and containment software in the simulator.Firstly,through the extensive investigation of the latest foreign severe accident research results(including experimental data,research reports,and mature software),a complete physical model describing the process of severe accidents in LWRs is developed,including the core heating,melting,and damage processes,lower head melt pool behavior and failure process,MCCI process within the containment.Combining with the algorithm research,the calculation flow of each control model is achieved.The key model is validated with reference to the relevant experimental data and other recognized mature models.The verification results show that the correlation model is in good agreement with experimental data or other mature models.Secondly,referring to the theoretical models of MAAP and SCDAP which are mature in the world,the numerical algorithm of the model is studied,considering the real-time calculation requirements of the simulator.Combining with the algorithm research,the numerical solution methods of each control model are given,and a set of simulation models describing the key processes of severe accidents in light water reactors is developed.It includes the in-reactor process: 1)zirconium-water reaction model;2)the eutectic model of uranium dioxide and zirconium;3)the core melt destruction process model;4)the melt repositioning and support plate failure process model;5)the lower head bath pool behavior model.It also includes the out-of-core process: the interaction process between core melt and concrete.The simulation models are verified referring to relevant experimental data or other recognized mature models.Thirdly,with in-depth study of model coupling technology and program integration technology,the solution to coupled calculation of the in-reactor behavior model and main system thermal hydraulic model is presented,which solves the coupling problem of thermal hydraulic process calculation and core behavior calculation based on physical process in severe accident phase,and achieves a complete simulation of the severe accident process within the reactor.By studying the variable-step multi-program synchronous computing technology,a synchronous computing solution based on the time domain control technology is proposed,which makes each program module of SimSA completes synchronous multimodule calculations without sacrificing the calculation accuracy.Finally a severe accident simulation calculation program SimSA capable of simulating the complete severe accident process inside and outside the reactor is formed.Fourthly,in the overall verification of the SimSA program,its operation is highly dependent on the integration with the simulator,for SimSA is not a separate program.In order to ensure the consistency of the verification environment,the integration technology of MAAP5 and the simulator is studied,and a set of severe accident verification environment based on integration of MAAP5 and simulators is developed.The development of the verification environment gets technical support from the American Electric Power Research Institute(EPRI),the owner of the MAAP5 software.The relevant integration technology has been widely verified and the verification system is accurate and reliable.Finally,the second generation of improved nuclear power unit CP1000 of CNNC is selected as the research object and relevant data is collected.The power plant model of CP1000 nuclear power unit is established based on SimSA and MAAP5.The overall performance of SimSA is verified through comparative calculation.The verification results show that SimSA can simulate the main process of severe accidents,and its simulation scope and calculation performance can meet the requirements of severe accident simulation.At present,the SimSA program has been applied to multiple FSS with severe accidents simulation function such as Fuqing,Fangjiashan and Changjiang,as well as Hualong One design verification platform development project of China Nuclear Power Engineering Corporation.It is responsible for the real-time simulation of severe accident processes,and assists in the training,drills,and verification of severe incident management guidelines.更多还原