多样化非能动衰变热排出方法研究

事故情况下的衰变热排出是涉及核安全的重要方面。采用非能动方法来排出衰变热对于提高核反应堆的安全性非常有益。在目前一些先进反应堆中通过设置非能动余热排出系统、非能动安注系统、非能动安全壳冷却系统等安全子系统,形成多样化的从堆芯到最终热阱的非能动衰变热排出渠道。论文对多种非能动衰变热排出方法和系统设计方案进行了归纳总结,比较分析了这些非能动衰变热排出方法的共性特征和区别,探讨了非能动衰变热排出系统的设计原理。通过对传热过程分解,将这些衰变热排出方法表达为一些基本传热形式的不同组合方式,根据不同的组合可获得多样化的非能动衰变热排出方法和新的系统设计方案。

实验快堆自然循环和衰变热排出系统计算程序DHRSC

一、前言实验快堆设计必须具有非能动安全特征,这是近几年来快堆设计中一种明显的新进展。所谓非能动安全,指的是不依赖外界机械或电力而依靠自然规律和材料特性完成其功能的安全特征。非能动衰变热排出功能是十分重要的快堆安全特征之一。

热污染与人类健康

随着科技和工农业生产的迅速发展,热污染已成为一个日益严重的社会问题。 热污染是指日益现代化的工业生产和现代化生活中排放出的大量废热所造成的环境污染。热污染能严重污染周围环境,特别是污染大气和水体。火力发电厂、核电站和钢铁厂的冷却系统排出的热水,石油、化工、造纸和纺织等工业排出的生产废水中均含有大量的废热,排入地面水体后,使水温升高。

AP1000启动给水在非LOCA事故下的衰变热排出性能分析

为验证三代核电AP1000核电厂在非LOCA事故工况下,启动给水补给性能是否满足衰变热排出的纵深防御准则,保守认为事故发生后,反应堆停堆,厂用电及外电网丧失,主给水丧失,凝汽器热阱丧失,蒸汽发生器背压为安全阀最低整定压力,蒸汽发生器与启动给水泵均为单列可用。首先,验证凝结水储箱处于最低液位时,启动给水的最低补给能力能否满足不小于118.1 m3/h的准则要求;其次,论证事故后由于备用交流电源加载滞后而导致启动给水延后140 s投运,蒸汽发生器依靠自身缓冲水装量能否带走衰变热而不触发专设安全系统;再次,论证140 s后启动给水最低补给流量,能否稳定蒸汽发生器液位并使其回升;最后,验证凝结水储箱纵深防御水装量能否满足启动给水24 h连续补给的准则要求。本文通过对启动给水最低补给流量、蒸汽发生器缓冲水装量、启动给水液位控制,以及凝结水储箱水装量的保守计算分析,验证了AP1000启动给水在非失水事故(Non-LOCA)事故下衰变热排出功能设计的可靠性以及与纵深防御准则的一致性。

低流速下涡流二极管单向性实验研究

为研究氟盐冷却高温堆(Fluoride-salt-cooled High temperature Reactor,FHR)非能动余热排出系统的控流装置——涡流二极管在低流速下的性能参数,建立了实验装置,测试了在水工质下由3D打印尼龙材料涡流二极管的单向特性,并由实验结果得到相同结构尺寸的涡流二极管在FliBe工质下的压降值。研究结果表明,本文实验流量范围内测得的涡流二极管单向性随雷诺数的增加不断升高,最大值为23。正向流动阻力系数随雷诺数的升高不断降低,反向流动阻力系数随雷诺数的增大先增大后降低。研究结果还表明本文研究的涡流二极管结构不适用于小功率氟盐冷却高温堆非能动余热排出系统的设计。

法BETHSY试验装置自然循环实验研究

１前言ＢＥＴＨＳＹ整体效应试验装置（图１）是一座用于ＰＷＲ核电站热工水力安全研究的大型试验装置，由ＣＥＡ、ＥＤＦ和Ｆｒａｍａｔｏｎｅ３家共同投资，建于法国Ｇｒｅｎｏｂｌｅ核研究中心的ＢＥＴＨＳＹ实验室。作者９０年代初曾在该室进修了一年，有幸参加了试验...

超吸水纤维工业化试验装置中纺丝甬道的改造

在超吸水纤维项目工业化试验研究中,针对出现的丝束拉伸不足、纤维强度偏低等问题,对关键设备进行了改造,即在甬道入丝口处加装湿热气流排出装置,创建流变态拉伸区域,有效地解决了纺丝中出现的问题。

An Experimental Research of Natural Circulation Heat Transfer for PRHR Heat Exchanger in AP1000

The heat transfer characteristics of the PRHR （passive residual heat removal） HX （heat exchanger） are very important to reactor design and safety assessment of AP1000. The purpose of the present experiment was to obtain the natural circulation data in HX to research the heat transfer behavior. The PRHR HX was simulated by three C-type tubes with prototype sizes immerged in a cooling tank. Separate-effect tests of natural circulation in HX tubes have been performed within wide conditions which could cover the operation conditions in AP1000. The experiment provided lots of important data to indicate heat transfer phenomena of PRHR HX. The test conditions were calculated by RELAP5/MOD3.3. The calculation results agreed well with the experiment. RELAP5 could be applied with proper correlations to analyze the heat transfer in PRHR HX under the test conditions.

Validation of the TASS/SMR-S Code for the Core Heat Transfer Model on the Steady Experimental Conditions

The SMART （System-integrated Modular Advanced ReacTor） which is a 330 MWt advanced integral PWR was developed by the KAERI （Korea Atomic Energy Institute） for electricity generation and seawater desalination. To enhance its safety, the various design concepts were adopted such as the most containing of the RCS （reactor coolant system） components and a PRHRS （passive residual heat removal system）. To ensure the safety and performance of the SMART, a thermal hydraulic evaluation and safety analysis are performed by the TASS/SMR-S code. It uses a one dimensional node/path modeling and point kinetics for the core power simulation. The code also has specific models reflecting the design features of the SMART such as a helical tube and PRHRS heat transfer models. In this study, the validation of the core heat transfer model in the TASS/SMR-S code on the steady conditions was performed with the Bennett＇s heated tube tests and THTF （thermal hydraulic test facility） experiment. From the results of the TASS/SMR-S code calculation, the CHF （critical heat flux） point and the fuel rod surface temperature were predicted conservatively compared to the test results.

Analysis of the Presence of Vapor in Residual Heat Removal System in Modes 314 Loss-of-Coolant Accident Conditions Using RELAP5

The Westinghouse Nuclear Safety Advisory Letter NSAL-09-8 investigated the possibility of presence of vapor in RHR （residual heat removal） system in modes 3/4 LOCA （loss-of-coolant accident） conditions. This concerns the Westinghouse standard three-loops plant for which the RHR is the low pressure part of the St （safety injection）. In some cases one or both RHR trains may become inoperable for SI function. As a response to this letter, Westinghouse Electric Belgium is providing RELAP5 analyzes for Westinghouse NSSS （nuclear steam supply system） European plants to assess the thermal hydraulic behavior of the RHR suction piping system for ECCS （emergency core cooling system） initiation events postulated to occur during startup/shutdown operations. Several concerns including condensation induced water hammer and voiding at the RHR pump have been investigated. As a conclusion, the analysis allowed to define the bounding hot leg temperature conditions under which both RHR trains remain safely operable. These bounding conditions are then implemented by the customer in their OPs （operating procedures） to achieve safe operations and successful accident management.

酷暑盛夏话空调

眼下正值北京的盛夏,气候湿热,加之大都市所特有的“热效应”,令人暑热难耐。因此,许多家的窗户上都装上了窗式、分体式空调器。怎样看待这些空调器呢? 居住在装有空调器的房间内,令人感到凉爽、舒适、心旷神怡。但是,事情总有利弊。