共查询到19条相似文献,搜索用时 203 毫秒
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彭军 《核标准计量与质量》2019,(3)
热工水力程序RELAP5/MOD3具有比较广泛的应用,文章基于RELAP5/MOD3.2与RELAP5/MOD3.3两个程序版本,对某反应堆冷段3.5in小破口失水事故进行计算分析,初步探讨不同临界流模型对计算结果的影响,相关结果可为分析类似小破口失水事故提供一定的参考。 相似文献
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AP1000核电厂采用非能动堆芯冷却系统来缓解小破口失水事故(SBLOCA),缓解事故的理念是流动冷却。RELAP5/MOD3.3程序适用于传统核电厂SBLOCA研究,对于非能动电厂SBLOCA研究的适用性需重新研究与评估。本工作基于非能动电厂小破口失水事故的分析,结合RELAP5/MOD3.3的结构与模型,对其进行评估和改进。为验证改进后的RELAP5/MOD3.3的适用性,以AP1000小破口失水事故的验证试验台架APEX-1000为模拟对象,分析模拟DBA-02、NRC-05事故工况。分析结果表明,改进后的RELAP5/MOD3.3的计算结果与试验数据符合较好。 相似文献
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大破口失水事故是压水堆核电厂最重要的设计基准事故,对该事故的准确模拟可为提升反应堆功率提供重要支撑。本文采用最佳估算程序RELAP5对压水堆失水事故试验(LOFT)的实验工况FP-LP-2进行了模拟计算,并应用德国反应堆安全研究所(GRS)不确定性分析方法对计算结果进行不确定性量化和敏感性分析;给出了关键输出参数95%置信度的不确定性包络带,并分析了计算结果的不确定性变化趋势及原因。分析结果表明,对包壳峰值温度影响较大的重要现象包括堆芯衰变热、完整环路破口临界流喷放系数和燃料棒的热导率。本文研究确认了GRS方法的有效性,为改进现有核电站安全分析方法具有积极作用。 相似文献
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用RELAP5分析RD-14装置的破口实验 总被引:1,自引:0,他引:1
用RELAP5 /MOD3 .2程序模拟了在RD 1 4实验装置上进行的两个CANDU反应堆临界破口实验。对破口出现以后 ,冷却剂系统压力、堆芯压降和元件包壳温度的变化趋势进行了研究 ,计算结果和实验数据符合较好 ,表明用RELAP5程序模拟CANDU反应堆在LOCA事故后系统瞬变是可行的 相似文献
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再淹没是压水堆大破口失水事故后的重要阶段,为评估系统程序在该阶段的计算能力,需要选择多种传热模型对失水事故进行复现并分析参数的敏感性响应。本文对压水堆失水事故实验(LOFT)台架进行建模,将COSINE程序中不同传热模型的计算结果与实验数据比较,验证了传热模型精确度;同时进行再淹没阶段的参数敏感性计算,识别出了对第二包壳峰值温度(PCT)影响最大的参数。计算表明:COSINE程序的传热模型能较好地预测再淹没现象;对计算结果影响较大的敏感性参数包括:UO2体积热容、液滴直径、液滴相间传热系数和膜态沸腾壁面对汽相的传热系数。 相似文献
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根据组成气液两相流基本场方程数量所反映的流动与传热特性的不同,两相流方程分为三方程、四方程、五方程和六方程模型,结合流动压降模型、传热模型、两相相互作用模型以及流动工质的状态参数和结构材料热物性等辅助关系式,可很好地对蒸汽产生系统进行设计和研究分析。本文分析了不同数量的两相流场方程的特点和局限性,结合直管式直流蒸汽发生器实验装置,分别选取最佳估算程序中4种不同的两相流场方程计算模型进行流动传热计算分析,重点比较了强制流动的单相过冷水被加热至单相过热蒸汽过程中的压力与传热特性,从而给出不同场方程的两相流模型在分析具有较大相变过程中的差异性,验证了RELAP5程序和RETRAN-3D程序计算分析直流蒸汽发生器的能力。结果表明,RELAP5程序的六方程模型更适合模拟直流蒸汽发生器。 相似文献
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Heng Xie 《Journal of Nuclear Science and Technology》2017,54(9):969-976
The risk of large-break loss of coolant accident (LBLOCA) is that core will be exposed once the accident occurs, and may cause core damages. New phenomena may occur in LBLOCA due to passive safety injection adopted by AP1000. This paper used SCDAP/RELAP5 4.0 to build the numerical model of AP1000 and double-end guillotine of cold leg is simulated. Reactor coolant system and passive core cooling system were modeled by RELAP5 modular. HEAT STRUCTURE component of RELAP5 was used to simulate the fuel rod. The reflood option in RELAP5 was chosen to be activated or not to study the effect of axial heat conduction. Results show that the axial heat conduction plays an important role in the reflooding phase and can effectively shorten reflood process. An alternative core model is built by SCDAP modular. It is found that the SCDAP model predicts higher maximum peak cladding temperature and longer reflood process than RELAP5 model. Analysis shows that clad oxidation heat plays a key role in the reflood. From the simulation results, it can be concluded that the cladding will keep intact and fission product will not be released from fuel to coolant in LBLOCA. 相似文献
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采取堆腔注水策略冷却熔融池对缓解严重事故后果、降低安全壳的失效概率具有十分重要的作用。本文采用SCDAP/RELAP5程序,首先以韩国APR1400相关实验结果对堆腔外部注水自然对流冷却能力进行比对分析,然后建立了耦合堆腔注水措施的融熔池冷却的核电厂模型,以非能动压水堆为研究对象,针对冷段大破口失水事故(LBLOCA)始发严重事故序列,分析堆芯熔融进展过程中实施堆腔注水策略后融熔池的冷却特性及堆腔外部注水的自然循环能力。分析结果表明,LBLOCA下,当堆芯出口温度达到923K时,实施堆腔注水后能有效冷却下封头内的熔融池,从而保持压力容器的完整性。 相似文献
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采用非能动余热排出系统实验数据对RELAP5程序的评价 总被引:2,自引:1,他引:1
利用非能动余热排出系统1∶10原理性实验台架的稳态实验与启动实验数据,对RELAP5/MOD3.2程序进行评估。结果表明:对于本原理性实验系统,RELAP5/MOD3.2程序过低估算了蒸汽流速对蒸汽凝结换热系数的影响,因而,程序中垂直管内的蒸汽凝结换热系数偏小,计算结果与实验结果偏差大。对RELAP5/MOD3.2程序垂直管内蒸汽凝结换热模型进行了修正,修正后的计算结果与实验值基本吻合。评价结果表明:采用RELAP5/MOD3.2程序对该类型的非能动余热排出系统进行计算,需对程序中垂直管内的蒸汽凝结换热模型进行修正。 相似文献
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Sweepout model implementation in RELAP5/MOD3.3 to improve RCS coolant inventory calculation during a LBLOCA 总被引:1,自引:1,他引:0
According to the experiments of the Upper Plenum Test Facility (UPTF) and advanced power reactor 1400 MWe (APR1400), the sweepout in the downcomer has been identified to play an important role in depleting the core coolant inventory during a Large-Break Loss-of-Coolant Accident (LBLOCA). In order to identify the sweepout mechanism and to estimate the amount of coolant discharged by sweepout, the separate-effect test was carried out in the plate type test apparatus, which was scaled down to 1/5 of the size of the APR1400 downcomer. In addition, the sweepout model was developed by correlating the experimental data on the critical void height and the discharge flow rate at the break to the values of analytically derived non-dimensional parameters. This model was implemented in RELAP5/MOD3.3 to improve its calculation of coolant inventory loss during a LBLOCA. To validate the modified RELAP5/MOD3.3 by implementing the sweepout model, the sweepout separate-effect test was simulated by both the original and the modified RELAP5/MOD3.3. The original one predicted the different discharge flow rates according to the node size of the donor volume, and these flow rates were larger than those of the experiment. On the other hand, the modified one calculated the discharge flow rate and the critical void height much more similar to those of the experiment than the original model did. In the future, the improved RELAP5/MOD3.3 adopted in an integrated analysis system will support a more realistic thermal hydraulic analysis. 相似文献
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This study investigates experimentally and analytically the thermal hydraulic phenomena during the transition from design basis accident (DBA) to beyond-DBA, particularly, the depletion of core coolant inventory. To investigate the overall thermal hydraulic behavior after safety injection (SI) failure during a large-break loss-of-coolant accident (LBLOCA) in a cold leg, an integral loop test was performed at the Seoul National University Integral Test Facility (SNUF), which was scaled down to 1/6.4 in length and 1/178 in area from the advanced power reactor 1400 MWe (APR1400) according to the three-level scaling method. The plant condition at 200.0 s as the base case and those at 625.0 and 1950.0 s as test cases after the initiation of LBLOCA were applied as initial conditions in the experiments, respectively. The experimental results showed that the sweepout increased the coolant flow discharged to the break depending on the steam flow rate in intact cold legs and the initial downcomer coolant level and expedited the depletion of the core coolant inventory.In the meantime, since RELAP5/MOD3.3 uses the average properties of donor volume as those of its connected junction, this scheme causes the mass and the energy flux in a junction to be calculated incorrectly if significant phase separation occurs in the donor volume such as in the downcomer during the LBLOCA. The sweepout model was developed and implemented in RELAP5/MOD3.3 to improve its calculation of coolant inventory during the LBLOCA. To assess the applicability of the modified RELAP5/MOD3.3 to the actual system, the experiments in SNUF were simulated by both the original and the modified RELAP5/MOD3.3. The original one predicted the discharge flow rate at the break larger than that of the experiment. On the other hand, the modified one calculated the discharge flow rate more similar to that of the experiment than the original one did. As a result, the modified RELAP5/MOD3.3 reduced the coolant flow discharged to the break to delay the initiation time of heater heat-up after SI failure during LBLOCA in a cold leg. This improved RELAP5/MOD3.3 will support a more realistic thermal hydraulic analysis in an integrated analysis system. 相似文献
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