Volume 11: Mitigation Strategies for Beyond Design Basis Events最新文献_第2页

The Research and Simulation of Beyond Design Basis Accidents in PWR Nuclear Power Plant 压水堆核电站超设计基础事故的研究与仿真

Volume 11: Mitigation Strategies for Beyond Design Basis Events Pub Date : 2022-08-08 DOI: 10.1115/icone29-90267

Guo Cheng

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Research on Behavior of Migration for Molten Material in U-Al Alloy Fuels Under Severe Accident 严重事故下铀铝合金燃料中熔融物质的迁移行为研究

Volume 11: Mitigation Strategies for Beyond Design Basis Events Pub Date : 2022-08-08 DOI: 10.1115/icone29-93467

Yuejian Luo, Jian Deng, Dahuan Zhu, Hong-Ping Sun, Ming Zhang, Xiaoli Wu, Youyou Xu, Lili Liu, Wenzhen Hu, Qingan Xiang

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An Experimental Study on the Retention of Graphite Dust Aerosol in Pool Scrubbing and the Possible Application in HTGRs 石墨粉尘气溶胶在池擦洗中的滞留实验研究及其在htgr中的应用前景

Volume 11: Mitigation Strategies for Beyond Design Basis Events Pub Date : 2022-08-08 DOI: 10.1115/icone29-92561

Yating Wang, Yiyang Zhang, Zhu Fang, Xin-xin Wu

{"title":"An Experimental Study on the Retention of Graphite Dust Aerosol in Pool Scrubbing and the Possible Application in HTGRs","authors":"Yating Wang, Yiyang Zhang, Zhu Fang, Xin-xin Wu","doi":"10.1115/icone29-92561","DOIUrl":"https://doi.org/10.1115/icone29-92561","url":null,"abstract":"\u0000 Owing to the inherent safety, the modular high-temperature gas-cooled reactor (HTGR) eliminates the possibility of severe accidents in principle. Therefore, the source term is the main concern for HTGR accidents. Especially, the graphite dust problem, arising from the abrasion of fuel pebbles, complicates the evaluation of source terms. In the water ingress accidents, the graphite dust may be released to the containment during the overpressure discharge, which not only contributes to the source term but also makes trouble for post-accident measures. In this work, we consider the possibility to develop a pool scrubbing measure to retain graphite dust and fission products for the overpressure discharge of HTGR. A scrubber is set up with aerosol particle concentration measurement at both the inlet and outlet, which enables us to determine the decontamination factor (DF). By conducting a series of experiments for different submergence depth and particle size, it is demonstrated the DF value increases with the increase of submergence depth. When the submergence depth is 105 cm, the retention efficiency of graphite particles larger than 2 μm exceeds 96%. Our previous study has shown due to a fragmentation effect, most of the graphite particles released during the overpressure discharge are below 2 μm, while the DFs for these small particles fall below 20. The experimental results show that the pool scrubbing technology can efficiently retain the graphite particles for the overpressure discharge in HTRGs. More efforts are still needed to effectively improve the DF for graphite particles below 2 μm.","PeriodicalId":284948,"journal":{"name":"Volume 11: Mitigation Strategies for Beyond Design Basis Events","volume":"78 1","pages":"0"},"PeriodicalIF":0.0,"publicationDate":"2022-08-08","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"116066126","PeriodicalName":null,"FirstCategoryId":null,"ListUrlMain":null,"RegionNum":0,"RegionCategory":"","ArticlePicture":[],"TitleCN":null,"AbstractTextCN":null,"PMCID":"","EPubDate":null,"PubModel":null,"JCR":null,"JCRName":null,"Score":null,"Total":0}

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Assessment on Accident and Mitigation of Spent Fuel Pool in a Typical PWR 典型压水堆乏燃料池事故评价及缓解措施

Volume 11: Mitigation Strategies for Beyond Design Basis Events Pub Date : 2022-08-08 DOI: 10.1115/icone29-91550

Chao Guo, Zhenzhen Ge, Feiye Liao, Peng Chen, Dongyu He

{"title":"Assessment on Accident and Mitigation of Spent Fuel Pool in a Typical PWR","authors":"Chao Guo, Zhenzhen Ge, Feiye Liao, Peng Chen, Dongyu He","doi":"10.1115/icone29-91550","DOIUrl":"https://doi.org/10.1115/icone29-91550","url":null,"abstract":"\u0000 In consideration of low power rate and large water inventory in spent fuel pool (SFP), the accident progression may be very slow and the fuel melt accident was considered to be very unlikely in SFP. However, the accident in Fukushima Dai-ichi Nuclear Power Plant implies the possibility of severe accident in SFP and highlights the importance of accident management of SFP. As the fuel building has no three-barriers containing radioactive products like the reactor building and SFP has significantly larger fuel inventory, the potential consequences of severe accident (radioactive materials release and hydrogen production) could be far beyond the capability of practical mitigation measures in design. Since Fukushima accident, lots of efforts related to SFP simulation are made by developers of several severe accident simulation codes. For ASTEC code, models about radiative heat transfer and Zircaloy oxidation are added in V2.1 which makes it possible to have a better prediction of severe accident in SFP. In this paper, representative scenarios (loss of coolant, loss of cooling) in SFP of a typical pressurized water reactor (PWR) design are simulated with ASTEC code. Accident progression and phenomena are presented. The influence of potential mitigation measures is studied. Suggestions to the design of SFP and accident mitigation strategies are provided according to the analysis results.","PeriodicalId":284948,"journal":{"name":"Volume 11: Mitigation Strategies for Beyond Design Basis Events","volume":"28 1","pages":"0"},"PeriodicalIF":0.0,"publicationDate":"2022-08-08","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"125332915","PeriodicalName":null,"FirstCategoryId":null,"ListUrlMain":null,"RegionNum":0,"RegionCategory":"","ArticlePicture":[],"TitleCN":null,"AbstractTextCN":null,"PMCID":"","EPubDate":null,"PubModel":null,"JCR":null,"JCRName":null,"Score":null,"Total":0}

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Simulation on the Process of Core Molten Pool Formation and Corium Relocation in the Core Region 堆芯熔池形成过程及堆芯在堆芯区的迁移模拟

Volume 11: Mitigation Strategies for Beyond Design Basis Events Pub Date : 2022-08-08 DOI: 10.1115/icone29-92717

Xinhai Zhao, Peng Chen, Dongyu He, Ruhao Zhong

{"title":"Simulation on the Process of Core Molten Pool Formation and Corium Relocation in the Core Region","authors":"Xinhai Zhao, Peng Chen, Dongyu He, Ruhao Zhong","doi":"10.1115/icone29-92717","DOIUrl":"https://doi.org/10.1115/icone29-92717","url":null,"abstract":"Accurately estimating the moment on which the core melt relocates to the lower head in severe accidents is crucial for evaluating the effectiveness of the In-Vessel Retention (IVR) strategy. However, the collapse and fragmentation of the fuel rods as well as the melting and re-solidification of the core material during the core degradation process lead to complex changes in the core geometry, making it difficult to accurately simulate the relocation process of the melt in the core. Based on TMI-2 and Phebus FPT series experiments, a porous media model with transient flow and heat transfer both in the rod bundle region and debris bed region was established in this paper. The VOF and LEVEL SET methods were used to track the movement front of the corium in the core, as well as the coalescence process of local separate molten pools to form a large-scale core molten pool. Moreover, the efficient and stable IDEAL segregated algorithm was adopted to deal with the coupling problem of flow and heat transfer. The VOF and LEVEL SET methods were verified by the dam break problem, and the deviation of the results is within 10%. Using the above methods, the formation of a large-scale molten pool in the core and the relocation process of corium in the core region were simulated.","PeriodicalId":284948,"journal":{"name":"Volume 11: Mitigation Strategies for Beyond Design Basis Events","volume":"12 1","pages":"0"},"PeriodicalIF":0.0,"publicationDate":"2022-08-08","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"131826582","PeriodicalName":null,"FirstCategoryId":null,"ListUrlMain":null,"RegionNum":0,"RegionCategory":"","ArticlePicture":[],"TitleCN":null,"AbstractTextCN":null,"PMCID":"","EPubDate":null,"PubModel":null,"JCR":null,"JCRName":null,"Score":null,"Total":0}

引用次数: 0

Study on the Fallback Time Analysis Method for Loss of Ultimate Heat Sink Under Normal Power Operation of Nuclear Power Unit 核电机组正常动力运行下极限散热器损耗回退时间分析方法研究

Volume 11: Mitigation Strategies for Beyond Design Basis Events Pub Date : 2022-08-08 DOI: 10.1115/icone29-92687

Zhao Zhang, Jun Yan, Gen Li, D. Chong, Ming Liu, Zihua Wang, Rong-Fa Shen

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Mixing and Stratification Phenomena Under Natural Convection in the Multi-Openings Compartment 多开口舱室自然对流下的混合和分层现象

Volume 11: Mitigation Strategies for Beyond Design Basis Events Pub Date : 2022-08-08 DOI: 10.1115/icone29-90143

Jinghua Jiang, Ying Li, Tianlin Wang, L. Tong, Xuewu Cao

{"title":"Mixing and Stratification Phenomena Under Natural Convection in the Multi-Openings Compartment","authors":"Jinghua Jiang, Ying Li, Tianlin Wang, L. Tong, Xuewu Cao","doi":"10.1115/icone29-90143","DOIUrl":"https://doi.org/10.1115/icone29-90143","url":null,"abstract":"\u0000 The mixing and stratification of hydrogen-vapor-air in the compartment is extensively studied under inertia jets and turbulent buoyant jets. The characteristics of buoyancy-driven flows during fission and fusion reactor accidents need to be further studied to provide a benchmark for the validation of computational procedures. In this paper, a large-scale facility of a vessel with multiple openings is established to study the mixing and stratification of the mixture driven by buoyancy under natural convection. The test is carried out with well-controlled boundary conditions, in which, a mixture of helium and vapor with a volume fraction of 1:10 is injected in the compartment filled with air. As the injection begins, the gas mixture is driven by the injection source and the buoyancy of the light gas. The gas is released through the top and bottom openings with the flow velocity of 5 m/s and 7.5 m/s, respectively. When the injection is stopped at 4600s, the density gradient induces the natural convection, air enters the vessel through the bottom opening with a relatively low velocity, and the low-density mixture is discharged through the top opening at the same time. During this period, the velocity of the mixture at the opening decreases due to the reduction of the drive force of natural convection.","PeriodicalId":284948,"journal":{"name":"Volume 11: Mitigation Strategies for Beyond Design Basis Events","volume":"39 1","pages":"0"},"PeriodicalIF":0.0,"publicationDate":"2022-08-08","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"131410378","PeriodicalName":null,"FirstCategoryId":null,"ListUrlMain":null,"RegionNum":0,"RegionCategory":"","ArticlePicture":[],"TitleCN":null,"AbstractTextCN":null,"PMCID":"","EPubDate":null,"PubModel":null,"JCR":null,"JCRName":null,"Score":null,"Total":0}

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A Numerical Study of the Spray Cooling Effect on Improving the IVR Safety Margin 喷雾冷却提高IVR安全余量效果的数值研究

Volume 11: Mitigation Strategies for Beyond Design Basis Events Pub Date : 2022-08-08 DOI: 10.1115/icone29-89870

Pengkun Yu, Ningxi Jia, Qiang Guo, Zhuo Liu, Yu Jin, Yidan Yuan

{"title":"A Numerical Study of the Spray Cooling Effect on Improving the IVR Safety Margin","authors":"Pengkun Yu, Ningxi Jia, Qiang Guo, Zhuo Liu, Yu Jin, Yidan Yuan","doi":"10.1115/icone29-89870","DOIUrl":"https://doi.org/10.1115/icone29-89870","url":null,"abstract":"\u0000 In-vessel retention (IVR) is a widely adopted severe accident mitigation strategy in the advanced commercial PWRs. External water cooling on the outer surface of the reactor pressure vessel (RPV) is designed to efficiently remove the decay heat from the in-vessel corium, such that the RPV integrity can be kept and the radioactive corium retained inside. The effectiveness of the IVR strategy requires that the maximum heat flux along the RPV lower than the critical heat flux (the switch point from nucleate boiling to film boiling). In existing engineering design, water cooling is realized by flooding the RPV outer surface. Spray cooling on the outer vessel surface is considered to be a potential method to increase the safety margin. In this paper, we investigate the effect of spray cooling in the IVR applications with respect to the influences on the heat transfer and cooling capacity (limit). Molten pool heat transfer analysis is performed to analysis its influence on the thermal behavior of the melt pool and RPV. The cooling capability (limit) is also analyzed between the spray cooling and conventional cooling measurements. Results indicate that the spray cooling does not show significant influence on heat removal as the changes of the heat flux profile and the wall thickness (that are of interest in safety analysis) are insignificant; the main contribution to the enhancement of the safety margin by spray cooling would be from the expected significant improvement of critical heat flux (CHF).","PeriodicalId":284948,"journal":{"name":"Volume 11: Mitigation Strategies for Beyond Design Basis Events","volume":"6 1","pages":"0"},"PeriodicalIF":0.0,"publicationDate":"2022-08-08","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"127396987","PeriodicalName":null,"FirstCategoryId":null,"ListUrlMain":null,"RegionNum":0,"RegionCategory":"","ArticlePicture":[],"TitleCN":null,"AbstractTextCN":null,"PMCID":"","EPubDate":null,"PubModel":null,"JCR":null,"JCRName":null,"Score":null,"Total":0}

引用次数: 0

Evaluation of Effect of Depressurization Timing on the Thermal Load To Primary Containment Vessel During Severe Accident at BWR 沸水堆重大事故降压时机对主安全壳热负荷影响的评价

Volume 11: Mitigation Strategies for Beyond Design Basis Events Pub Date : 2022-08-08 DOI: 10.1115/icone29-90648

Taisei Matsumoto, A. Yamaji, D. Fujiwara

{"title":"Evaluation of Effect of Depressurization Timing on the Thermal Load To Primary Containment Vessel During Severe Accident at BWR","authors":"Taisei Matsumoto, A. Yamaji, D. Fujiwara","doi":"10.1115/icone29-90648","DOIUrl":"https://doi.org/10.1115/icone29-90648","url":null,"abstract":"\u0000 According to accident of a Boiling Water Reactor (BWR), the operators generally do not depressurize the Reactor Pressure Vessel (RPV) until low-pressure core injection systems are recovered. However, when the core water level decreases below a certain limit, the RPV is depressurized to prevent the RPV failure at high pressure, which may lead to failure of the Primary Containment Vessel (PCV) by direct heating of the ejected melt. In such a case, if recovery of the core cooling cannot be expected, earlier depressurization may be preferable from the viewpoint of reducing thermal load on PCV, because it may effectively reduce the amount of fission product (FP) aerosol deposition on the RPV dome and reduce the risk of PCV top head heating via convective and radiative heat transfers from the RPV dome. However, significance of such risk is not evident as the steam dryer and separator may hinder direct aerosol deposition on the RPV dome and the RPV dome is thermally insulated. Moreover, the narrow space between the RPV dome and the PCV top head may hinder convective heat transfer. In this study, sensitivity analyses have been carried out using MELCOR-2.2 to support such understanding.","PeriodicalId":284948,"journal":{"name":"Volume 11: Mitigation Strategies for Beyond Design Basis Events","volume":"34 1","pages":"0"},"PeriodicalIF":0.0,"publicationDate":"2022-08-08","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"128125137","PeriodicalName":null,"FirstCategoryId":null,"ListUrlMain":null,"RegionNum":0,"RegionCategory":"","ArticlePicture":[],"TitleCN":null,"AbstractTextCN":null,"PMCID":"","EPubDate":null,"PubModel":null,"JCR":null,"JCRName":null,"Score":null,"Total":0}

引用次数: 0

Sensitivity and Uncertainty Analysis of Molten Corium-Concrete Interaction (MCCI) for ALWR During Severe Accident 轻水堆严重事故中熔芯-混凝土相互作用(MCCI)的敏感性和不确定性分析

Volume 11: Mitigation Strategies for Beyond Design Basis Events Pub Date : 2022-08-08 DOI: 10.1115/icone29-89217

Zijie Wu, Peng Chen, Xinhao Zhao, Chao Guo, D. Zhan, Shaoxiong Xia

{"title":"Sensitivity and Uncertainty Analysis of Molten Corium-Concrete Interaction (MCCI) for ALWR During Severe Accident","authors":"Zijie Wu, Peng Chen, Xinhao Zhao, Chao Guo, D. Zhan, Shaoxiong Xia","doi":"10.1115/icone29-89217","DOIUrl":"https://doi.org/10.1115/icone29-89217","url":null,"abstract":"\u0000 Molten corium-concrete interaction is an important phenomenon in the late phase of severe accident, threatening the integrity of containment and might causing potential large release of radioactivity. A sensitivity and uncertainty analysis of MCCI under severe accident of a 1000 MW advanced light water reactor (ALWR) was performed with ASTEC (MEDICIS) [1], a lumped parametric integral severe accident code developed by IRSN. Several representative phenomena were screened out referenced by EURSAFE severe accident Phenomena Identification and Ranking Table (PIRT) [2], including debris bed formation, layer configuration, heat sources, and convective heat transfer correlation. Related input parameters, sensitivity coefficients, and modeling options in ASTEC code were selected, such as convective correlations, layer stratifications, initial layer compositions, and the potential ranges of these parameters were identified. A simple sampling method was used to analyze the independent effect of each parameter/model. Key parameters were chosen to evaluate the impact of sensitivity parameters to the MCCI process. A large break loss of coolant accident scenario, where in-vessel melt retention is invalid is simulated as an initial event. The results emphasize the importance of layer configuration and fission product partition. However, it should be emphasized that analysis results may be quite uncertain due to the limitation of the physical models and the adequacy or validity of the selected range of input variables.","PeriodicalId":284948,"journal":{"name":"Volume 11: Mitigation Strategies for Beyond Design Basis Events","volume":"17 1","pages":"0"},"PeriodicalIF":0.0,"publicationDate":"2022-08-08","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"131979380","PeriodicalName":null,"FirstCategoryId":null,"ListUrlMain":null,"RegionNum":0,"RegionCategory":"","ArticlePicture":[],"TitleCN":null,"AbstractTextCN":null,"PMCID":"","EPubDate":null,"PubModel":null,"JCR":null,"JCRName":null,"Score":null,"Total":0}

引用次数: 0