發(fā)布時(shí)間：2020-12-13 05:53

　　在發(fā)生失水事故(LOCA)或主蒸汽管道破裂事故(MSLB)時(shí),在破口處由于水流噴射和隨后高溫高壓蒸汽的泄漏可能會(huì)產(chǎn)生大量不同類型的碎片,如顆粒碎片,潛在的纖維碎片和化學(xué)碎片。這些碎片會(huì)流向堆芯應(yīng)急冷卻系統(tǒng)(ECCS)或安全殼再循環(huán)系統(tǒng)(CRS),可能會(huì)附著在地坑濾網(wǎng)上并造成一定的壓頭損失。其中有部分顆粒碎片可旁通地坑濾網(wǎng)進(jìn)入一回路系統(tǒng),影響堆芯冷卻劑流道并引起燃料組件壓降增加。這些顆粒碎片堆積在燃料組件內(nèi),可能會(huì)阻礙核電廠堆芯長(zhǎng)期冷卻(LTCC)的能力。美國(guó)核管會(huì)(U.S.NRC)規(guī)定在運(yùn)行的商用核電廠必須能夠證明其LOCA后能保證堆芯長(zhǎng)期冷卻。綜上所述,研究不同工況下燃料組件內(nèi)的顆粒碎片對(duì)于分析碎片在組件內(nèi)的分布情況并得到壓頭損失這一關(guān)鍵參數(shù)從而避免發(fā)生堆芯熔毀事故具有必要性。針對(duì)壓水堆AP1000燃料組件(全尺寸組件)由華北電力大學(xué)核科學(xué)與工程學(xué)院搭建了試驗(yàn)測(cè)試回路,用于分析不同量的顆粒,纖維,化學(xué)沉淀物添加至試驗(yàn)回路后對(duì)燃料組件造成的壓降影響。本論文的研究目的是記錄試驗(yàn)獲得的數(shù)據(jù)并處理,建立CFD模型用于研究導(dǎo)致LTCC失效的堆積在燃料組件內(nèi)碎片的關(guān)鍵參量。 

【文章來源】：華北電力大學(xué)(北京)北京市 211工程院校 教育部直屬院校

【文章頁數(shù)】：76 頁

【學(xué)位級(jí)別】：碩士

【文章目錄】：
摘要
Abstract
Nomenclature
Chapter 1. Introduction
    1.1 Background
    1.2 Significance
    1.3 Literature Review
    1.4 Research Plan
        1.4.1 Critical Issues
        1.4.2 Methodology
        1.4.3 Outline of work
    1.5 Thesis Outline
Chapter 2. Loss of Coolant Accident （LOCA）, Emergency Core CoolingSystem （ECCS） & Debris Generation
    2.1 Emergency Core Cooling System
        2.1.1 Requirements for an ECCS
    2.2 Debris Generation and Transport
Chapter 3. Theory of CFD
    3.1 Computational Fluid Dynamics
    3.2 Advantages of CFD
    3.3 Concept of CFD
    3.4 Performing a CFD Analysis
    3.5 Multiphase Modeling
        3.5.1 Eulerian Model
    3.6 Turbulence Modelling
    3.7 Standard,RNG,and Realizable k-ε Models
        3.7.1 Transport Equations for the Standard k-ε Model
    3.8 Discrete Phase Model
        3.8.1 Limitations of Discrete Phase Model
Chapter 4. Experimentation & Ressults
    4.1 Theory
    4.2 Experimental facility
    4.3 Debris preparation and Test procedure
    4.4 Uncertainty in the Experimental Measurements
    4.5 RESULTS AND DISCUSSION
        4.5.1 Initial Data of Test Loop
        4.5.2 Debris Addition Method
        4.5.3 The Effect of Concurrent Addition
        4.5.4 Effect of Sequential Debris Addition
        4.5.5 Comparison and Discussion
        4.5.6 Fiber Debris Sensitivity
        4.5.7 Flow rate
Chapter 5. CFD Analysis & Results
    5.1 Geometry
    5.2 Meshing
    5.3 Discrete Phase Model （Case 1）
        5.3.1 Single Injection
        5.3.2 Batch Injection
        5.3.3 Single and Dual Particle Type Injection
    5.4 Porous Medium Model （Case 2）
        5.4.1 Porous Medium Bed Thickness vs Pressure Drop
        5.4.2 Inlet Flow-rate vs Pressure Drop
        5.4.3 Void Fraction vs Pressure drop
        5.4.4 Realizable and Observed Trend
Chapter 6. Conclusions and Discussion
    6.1 Conclusions
    6.2 Discussion
References
Acknowledgement



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