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压水堆核电站蒸汽发生器传热面管子的腐蚀破损是核电站经常发生的事故,极大地影响核电站的可靠性和经济性。本文仅从蒸汽发生器的热工水力特性出发,提出了结构设计上的改进措施,介绍了蒸汽发生器中的沸腾传热和两相流,着重分析了某些区域内的热工水力特性。 相似文献
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压水堆核电站已更换和计划更换的蒸汽发生器在逐渐增加,本文介绍美国西屋公司.法国法马通公司,联邦德国的KWU和加拿大的B&W公司为更换蒸汽发生器而新设计的蒸汽发生器.其设计瞩的在于解决过去发生过的各种传热管破损问题. 相似文献
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近些年来,压水堆蒸汽发生器经常发生传热管破损事故,严重地影响压水堆核电站运行的安全性,可靠性和经济性,并成为这类核电站事故关闭的重要原因之一。经验表明,在引起管子破损诸因素中最主要的因素是金属材料腐蚀破坏,本文将重点分析论述传热管腐蚀破损的现状、腐蚀类型、易发部位和解决方法。 相似文献
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由美国西屋公司设计全面国产化制造的第一台秦山核电二期工程600 MW核电蒸汽发生器结构复杂,技术要求严格.简要介绍了蒸汽发生器的结构特点、功能、以及蒸汽发生器所使用的本体材料和焊接材料的成分和性能,重点介绍了蒸汽发生器关键接头的焊接及热处理的技术要点及相应的焊接工艺措施.通过对产品所涉及的焊接及热处理技术的介绍,为核电设备制造提供了一些工艺技术资料. 相似文献
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蒸汽发生器是核电厂的主要设备之一,被称为核电厂一、二回路的枢纽。据压水堆核电厂事故统计表明,蒸汽发生器在核电厂事故中居重要地位,因而蒸汽发生器能否安全、可靠地运行对核电厂的经济性和安全可靠性有着十分重要的影响。本文主要针对蒸汽发生器役前检查时,对波纹板定位块脱落的处理进行了介绍。 相似文献
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由凝结水泵出口引出部分凝结水进入再生热交换器,吸收蒸汽发生器排污热量,是目前蒸汽发生器排污利用较普遍的回收热量方式。以某990MW核电机组为例,在蒸汽发生器排污量和排污参数一定的情况下,分别计算凝结水抽取份额、排污热量回收利用方式的不同对循环热效率、二回路管道热效率和全厂热效率的影响。结果表明,随着凝结水抽取份额的增加,循环热效率降低,而二回路管道热效率提高,当二者的相对变化量相等时,全厂热效率达到峰值;同时,考虑到排污水化学处理系统的安全性要求,确定蒸汽发生器排污热量回收利用的最佳方案:凝结水抽取份额为2.5%,且排污热量回收到除氧器。 相似文献
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Han Zhang Yabing Li Jianjun Xiao Thomas Jordan 《International Journal of Hydrogen Energy》2018,43(29):13659-13675
During the severe accident in nuclear power plants (NPPs), hydrogen is generated due to the zirconium-water reaction and released from the breaks in coolant pipe forming a locally high concentration hydrogen cloud in the steam generator (SG) compartment, which plays a key role for hydrogen safety analysis in NPPs. Accurate prediction of the turbulent dispersion process of hydrogen-steam gas mixture is a critical topic for a successful simulation of the flammable cloud distribution in SG compartment. In this study, the high-fidelity temporal evolution of the hydrogen turbulent dispersion in a SG compartment is performed using the Detached Eddy Simulation (DES) based on the parallel CFD code GASFLOW-MPI to capture more detailed unsteady turbulent information. Firstly, the newly developed DES turbulence model is validated using two turbulent benchmarks, a backward-facing step turbulent flow and a hydrogen turbulent jet. The simulation results are consistent well with the experimental data. Then a SG compartment model including one steam generator, two coolant pumps, a hot leg and two cold legs is built using the specialized auto-mesh generation module. There are two modes of turbulent dispersion behavior due to the turbulent driven force in the containment, i.e. jet dominated by initial monument and plume dominated by buoyancy. The simulation result shows that the decay rate for centerline velocity obeys law as well as hydrogen volume fraction, indicating a turbulent jet during the steam dominated phase. There is also a relatively long potential core region which could impinge on the bottom concrete floor for the downwards jet. While the hydrogen release transfers from a turbulent jet to a turbulent plume outside the region near the inlet during the hydrogen dominated phase. Different from the turbulent jet, the centerline velocity at the plume region decays with the slope , and the decay rate for the centerline hydrogen volume fraction is during this phase. Compared with the jet flow, the potential core region of the plume flow is relatively short, forming a hydrogen cloud near the inlet. The combustibility evaluation shows that the combustion clouds can be generated in the source compartment at the hydrogen dominated phase. However, they will be diluted by the following persistent steam injection from the break. This can provide technical support for the design of hydrogen mitigation system. 相似文献
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压水堆核电厂二回路系统管道热效率的影响因素分析 总被引:1,自引:0,他引:1
在压水堆核电厂热经济性分析中,管道热效率的分析往往不被研究者所重视。首先从管道热效率的定义出发,给出了管道热效率的计算表达式,以及各种管道损失的计算方法。然后针对某些影响管道热效率的因素,同时也对蒸汽动力转换系统循环热效率产生影响的问题,分析了影响管道热效率的因素变化对蒸汽动力转换系统循环热效率和压水堆核电厂全厂热效率的影响。最后,以某990MW核电机组为例,通过计算分析了如主蒸汽管道疏水门泄漏蒸汽、厂用蒸汽、主蒸汽管道散热、蒸汽发生器排污等对管道热效率、蒸汽动力转换系统循环热效率及全厂热效率的影响。结果表明,上述因素变化均导致管道热效率降低和全厂热效率的降低,但不同因素变化对全厂热效率的影响机理却存在较大的差别。 相似文献
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汽轮机超速事故是对电厂中发电设备破坏性最大的事故,所以发电企业对汽轮机超速的事故都尤为关注。2011年我厂#1、2机组由于发电机保护动作信号出现,机组ETS保护动作,在调阅SOE(事故追忆时)发现各抽汽逆止门关闭时间过长。后来通过对4台机组抽汽逆止门逻辑的整改,使抽汽逆止门关闭时间大大缩短。 相似文献
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During the generation of steam, most water impurities are not evaporated with the steam and thus concentrate in the boiler water. The concentration of the impurities is usually regulated by the adjustment of the continuous blowdown valve, which controls the amount of water (and concentrated impurities) purged from the steam drum. Since a certain amount of continuous blowdown must be maintained for satisfactory boiler performance, a significant quantity of heat is removed from the boiler. It is necessary to provide a simple-to-use method to calculate the total amount of heat that is recoverable using this system. In the present work, a simple-to-use predictive tool, which is easier than existing approaches, less complicated with fewer computations and minimize the complex and time-consuming calculation steps, is formulated to arrive at an appropriate estimation of the percent of blowdown that is flashed to steam as a function of flash drum pressure and operating boiler drum pressure followed by the calculation of the amount of heat recoverable from the condensate. Since all of the heat in the flashed steam is recoverable, the total percent of heat recoverable from the flash tank and heat-exchanger system is calculated in the final step. Results show that the proposed predictive tool has a very good agreement with the reported data wherein the average absolute deviation percent was observed to be around 1.47%. 相似文献