高温气冷堆燃料元件固有循环安全特性的研究

介绍了高温气冷堆TRISO型的包覆燃料颗粒及球形燃料元件的结构特点及其安全原理.高温气冷堆具有低功率密度特点和负温度反应性特点,其与球形燃料元件有安全循环关系,实现了高温气冷堆固有循环安全特性.     

10MW高温气冷实验堆的堆体结构特点

模块式高温气冷堆是当今世界上公认的先进反应堆堆型之一。固有安全性是它的最突出的优点。本文对10MW高温气冷堆的堆体布置进行了详细描述,并对10MW高温气冷堆的结构设计特点进行了分析。根据10MW高温气冷堆的特点,本文对该堆的固有安全性、制造工艺等方面的优点进行了论述。     

我国高温气冷堆的发展

模块化高温气冷堆具有的固有安全特性、建造周期短和相处容量小等优势正好符合电力系统非管制化（Ｄｅｒｅｇｕｌａｔｉｏｎ）发展趋势对于发电厂的要求，清华大学核能设计研究院正在建造一座１０ＭＷ高温气冷实验堆。本文着重分析了高温气冷堆的安全特性和提高发电效率的氦循环方式。     

高温气冷堆产业推广及应用前景

高温气冷堆是我国具有完全自主知识产权的第四代先进核能技术,具有固有安全性、模块化设计及建造、发电效率高、用途广泛等特点。文章介绍了高温气冷堆产业化推广以及高温气冷堆在替代中小火电、制氢、石化和海水淡化等领域多功能综合利用的发展前景,分析了高温气冷堆产业化面临的挑战,指明了高温气冷堆产业化发展的重要意义。     

模块式高温气冷堆的技术背景及展望

模块式高温气冷堆具有固有安全性、发电效率高、用途广泛等特点,是第四代核能系统代表堆型之一,也是我国16个重大科技专项之一。本文介绍了高温气冷堆的发展历史,对高温气冷堆国际研究现状进行了阐述,说明了高温气冷堆在我国的发展情况。介绍了我国正处于调试期的模块式高温气冷堆示范电站的技术特点,从高效发电、工艺热应用、能源替代、分布式能源四个角度对模块式高温气冷堆的发展前景进行了分析,提出了我国模块式高温气冷堆后续工作建议。     

在冷却剂流量降低时高温气冷堆仍然安全

【日本原子能研究所网站新闻2003年10月21日报道】 目前,日本原子能研究所正在利用高温工程试验堆(HTTR)进行高温气冷堆固有安全性验证实验,这也是文部科学省革新性原子能系统技术开发的一部分。迄今为止,日本原子能研究所进行了几次降低冷却剂流量实验,验证了高温气冷堆的固有安全性。即,即使在急速降低堆芯冷却剂氦气流量的情况下,反应堆的功率会随着冷却剂流量的降低而降低,而不必使反应堆停堆,从而避免了堆芯温度的大幅上升。 堆芯冷却剂流量降低是典型的反应堆异常工况。而高温气冷堆具有以下特性,即在慢化剂石墨和燃料温度上升时,燃…     

HTR-10安全负压通风系统的设计

由于高温气冷堆具有固有安全性，因此在高温气冷堆的设计中采用通风式包容体替代了密封承压式安全壳，在供暖，通风与空调（HVAC）系统中相应采用了安全负压通风系统，以保证包容体在正常工况或事故工况下都能满足与安全相关的一切功能，本文介绍了10MW高温气冷实验堆（HTR－10）安全负压通风系统的设计与评价。     

模块式高温气冷堆非能动余热排出系统分析与研究

非能动的余热排出系统是高温气冷堆固有安全性的重要体现之一。本文介绍了模块式高温气冷堆余热排出系统热工水力计算方法,并给出了不同工况、不同环境温度下余热排出系统的运行参数,为余热排出系统的设计和运行提供了参考。对事故工况下舱室混凝土温度分布进行了数值分析,结果表明混凝土最高温度低于安全限值。     

高温气冷堆在我国的发展与应用前景

本文简要地介绍了高温气冷堆技术,特别是具有固有安全性的模块式高温堆技术在世芥的发展现状。该文还简要地介绍了清华大学核能技术研究所在研究和发展高温气冷堆技术上的主要成果及进展,包括若干高温堆方案设计研究及一系列高温堆部件、燃料元件及特种材料的实验研究,并介绍和探讨了高温堆供工艺蒸汽在我国重油开采及石油化工企业上的应用。     

球床模块式高温气冷堆失冷事故特性研究

利用高温气冷堆专用系统分析软件THERMIX程序,对球床模块式高温气冷堆(HTR-PM)失冷失压和失冷不失压事故的动态特性进行了研究,分析了堆芯功率、燃料最高温度及堆舱水冷壁余热载出功率等关键参数的变化过程,并对影响余热排出功率和燃料最高温度的不确定性进行了评价.研究结果表明,在失冷事故下,堆芯余热可通过热传导、辐射和自然对流等非能动方式传至最终热阱大气,燃料元件和压力容器等重要部件的最高温度均在设计限值内.这为HTR-PM保持模块式高温气冷堆固有安全性不变的同时实现单堆250 MW的功率方案奠定了基础,也为后续高温气冷堆电站示范工程进一步的深入设计研究提供了依据.     

HTGR plant safety design bases

The high temperature gas-cooled reactor (HTGR) has inherent and design safety features that are sifnificant and unique, requiring a number of safety criteria and approaches that differ markedly from other reactor types. This paper briefly reviews the design of HTGR plants that have been built and are being offered in the United States. It then reviews the safety considerations involved in the design of the plants being offered. The unique features, their development, and their effects on safety criteria are described. The design bases of the prestressed concrete reactor vessel (PCRV) are given particular attention. Operating characteristics of the HTGR and plant response to transient conditions are discussed. The design-basis depressurization accident evolution and related HTGR safety requirements are discussed. Characteristics of the HTGR with respect to technical specifications are discussed, with particular emphasis on the PCRV and the core safety limit.     

Possible design of PBR for passive decay heat removal

Conditions for design parameters of above-ground and underground, prismatic high-temperature gas-cooled reactor (HTGR)s for passive decay heat removal based on fundamental heat transfer mechanisms were obtained in the previous works. In the present study, analogous conditions were obtained for pebble bed reactors by performing the same procedure using the model for heat transfer in porous media of COMSOL 4.3a software, and the results were compared. For the power density profile, several approximated distributions together with original one throughout the 10-MWt high-temperature gas-cooled reactor-test module (HTR-10) were used, and it was found that an HTR-10 with a uniform power density profile has the higher safety margin than those with other profiles. In other words, the safety features of a PBR can be enhanced by flattening the power density profile. We also found that a prismatic HTGR with a uniform power density profile throughout the core has a greater safety margin than a PBR with the same design characteristics. However, when the power density profile is not flattened during the operation, the PBR with the linear power density profile has more safety margin than the prismatic HTGR with the same design parameters and with the power density profile by cosine and Bessel functions.     

安全经济高效的先进能源

具有第四代安全经济特性的核电应该是人们期待的先进的清洁低碳能源。高温气冷堆是当今研发的第四代核电堆型之一,但现有的设计还存在需要排除的严重的安全隐患。堆芯不熔化,不等于说不会有严重事故发生。需要吸取国外球床高温堆和柱状高温堆两种实验堆型运行的经验教训、扩展安全观念和应对安全低概率事件,确保反应堆不出现后果极其严重的放射性释放事故。当热电转换系统采用与燃气蒸汽联合循环耦合应用的技术以后,会发挥高温堆所长,更大地提升转换效率,形成一种高安全低投资和高效率的双燃料清洁能源,可用于大堆或小堆的应用环境,可满足电力系统基本负荷和调锋负荷的需要。在工程设计上采取一系列改进和创新措施,包括釆用规则床模块化及地下反应堆设计以后,可在提高反应堆核心部位安全防卫能力的同时,防范低概率事件,成为一种新的安全经济高效的先进能源。     

Safety design

JAERI established the safety design philosophy of the HTTR based on that of current reactors such as LWR in Japan, considering inherent safety features of the HTTR. The strategy of defense in depth was implemented so that the safety engineering functions such as control of reactivity, removal of residual heat and confinement of fission products shall be well performed to ensure safety. However, unlike the LWR, the inherent design features of the high-temperature gas-cooled reactor (HTGR) enables the HTTR meet stringent regulatory criteria without much dependence on active safety systems. On the other hand, the safety in an accident typical to the HTGR such as the depressurization accident initiated by a primary pipe rupture shall be ensured. The safety design philosophy of the HTTR considers these unique features appropriately and is expected to be the basis for future Japanese HTGRs.This paper describes the safety design philosophy and safety evaluation procedure of the HTTR especially focusing on unique considerations to the HTTR. Also, experiences obtained from an HTTR safety review and R&D needs for establishing the safety philosophy for the future HTGRs are reported.     

Numerical simulation of three-dimensional thermal-hydraulic behavior for HTTR (High Temperature Engineering Test Reactor)

Safety demonstration tests using the HTTR (High Temperature Engineering Test Reactor) are now in progress in order to verify the inherent safety features and to improve safety designing and analysis technologies for future HTGR (high temperature gas-cooled reactor). Coolant flow reduction test is one of the safety demonstration tests for the purpose of demonstration of inherent HTGR safety features in the case that coolant flow is reduced by tripping of helium gas circulators. If reactor core element temperature and core internal structure temperature during abnormal events are estimated by numerical simulation with high-accuracy, developed numerical simulation method can be applied to future HTGR designing efficiently. In the present research, three-dimensional in- and ex-vessel thermal-hydraulic calculations for the HTTR are performed with a commercially available thermal-hydraulic analysis code “STAR-CD^®” with finite volume method. The calculations are performed for normal operation and coolant flow reduction tests of the HTTR. Then calculated temperatures are compared with measured ones obtained in normal operation and coolant flow reduction test. As the result, calculated temperatures are good agreement with measured ones in normal operation and coolant flow reduction test.     

高温气冷堆核电站在我国的商业化前景

分析了发展高温气冷堆核电站的必要性,介绍了高温气冷堆发电技术的特点、现状和我国高温气冷堆核电站示范工程的建设情况,提出了充分发挥高温气冷堆发电技术特点、进一步开发高温气冷堆核电站的设想,认为条件成熟情况下,高温气冷堆核电站将有很大的商业推广价值。     

Future HTGR developments in China after the criticality of the HTR-10

Nuclear power has a great potential to develop in China because of China's fast economic increase. HTGR will be the most promising nuclear reactor to apply in the future Chinese market. After the initial criticality of the HTR-10, subsequent research and validation of the HTGR performance is by hot commissioning tests and power operation, safety demonstration experiments, R&D of gas turbine and process heat application technologies, and promotion of industrial application of HTGR technologies. The commercial prototype HTR-PM is under study and conceptual design has started. These activities will result in the safe and economic development of HTGR technologies in China.     

The design of 2300 MW(e) twin high temperature gas-cooled reactors for the philadelphia electric company

The basic design features of a 2300 MW(e) twin high temperature gas-cooled reactor (HTGR) power plant are described. The reactor core consists of vertical columns of hexagonal graphite fuel-moderator elements and graphite reflector blocks which are grouped into a cylindrical array and supported by a graphite core support structure. Reactivity control is accomplished by means of 146 control rods. The distribution of helium coolant flow through the core is controlled by variable orifice valves. Each of the six primary coolant loops is equipped with a helium circulator. The main steam/water section of each steam generator consists of a single helical tube bundle arranged in an annulus around the center duct. A core auxiliary cooling system is provided to furnish an independent means of removing reactor afterheat. The inherent safety characteristics and the design safety features of the large HTGR are discussed. Station arrangement, steam cycle and twin turbine generators, plant performance and control, containment and fuel handling, and environmental controls, are described.     

Achievement of Reactor-Outlet Coolant Temperature of 950°C in HTTR

A High Temperature Gas-cooled Reactor (HTGR) is particularly attractive due to its capability of producing high-temperature helium gas and to its inherent safety characteristics. The High Temperature Engineering Test Reactor (HTTR), which is the first HTGR in Japan, achieved its rated thermal power of 30 MW and reactor-outlet coolant temperature of 950°C on 19 April 2004. During the high-temperature test operation which is the final phase of the rise-to-power tests, reactor characteristics and reactor performance were confirmed, and reactor operations were monitored to demonstrate the safety and stability of operation. The reactor-outlet coolant temperature of 950°C makes it possible to extend high-temperature gas-cooled reactor use beyond the field of electric power. Also, highly effective power generation with a high-temperature gas turbine becomes possible, as does hydrogen production from water. The achievement of 950°C will be a major contribution to the actualization of producing hydrogen from water using the high-temperature gas-cooled reactors. This report describes the results of the high-temperature test operation of the HTTR.