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1.
充分考虑反应堆堆芯中子学物理、热工水力、燃料等专业的相互耦合过程,将先进节块法堆芯中子学计算软件NACK V1.0、热工水力子通道软件CORTH V2.0、燃料棒性能分析软件FUPAC V1.1进行集成耦合,得到稳态堆芯多物理耦合模拟设计分析系统CSSS V1.0,可计算典型压水堆的稳态运行物理、热工、燃料等专业参数。通过NEACRP-L-335压水堆基准问题验证计算,CSSS V1.0系统的计算结果与国际基准PARCS程序总体符合较好。  相似文献   

2.
充分考虑反应堆堆芯中子学物理、热工水力、燃料等专业的相互耦合过程,将先进节块法堆芯中子学计算软件NACK V1.0、热工水力子通道软件CORTH V2.0、燃料棒性能分析软件FUPAC V1.1进行集成耦合,得到稳态堆芯多物理耦合模拟设计分析系统CSSS V1.0,可计算典型压水堆的稳态运行物理、热工、燃料等专业参数。通过NEACRP-L-335压水堆基准问题验证计算,CSSS V1.0系统的计算结果与国际基准PARCS程序总体符合较好。  相似文献   

3.
瞬态堆芯耦合模拟软件CTSS V1.0是以节块法堆芯中子学计算软件NACK V1.0、热工水力子通道软件CORTH V2.0、燃料元件性能分析软件FUPAC V1.1为模块的耦合软件,用于模拟典型压水堆堆芯性能,计算瞬态运行物理、热工、燃料等专业参数。堆芯三维时空中子动力学软件NACK V1.0采用粗网节块法进行堆芯扩散计算,为子通道模块和燃料性能分析模块提供堆芯精细功率。CORTH V2.0用于计算反应堆堆芯冷却剂的温度和密度。FUPAC V1.1用于模拟燃料棒在堆内的热力学行为以及计算燃料棒有效温度。NEACRP-L-335压水堆基准问题验证计算结果表明,CTSS V1.0的计算结果与国际基准程序PARCS总体符合较好。  相似文献   

4.
堆芯是核动力系统的核心部件,其完整性是反应堆安全运行的重要前提。传统核反应堆堆芯热工水力分析方法无法满足未来先进核动力系统的高精度模拟需求。本文依托开源CFD平台OpenFOAM,针对压水堆堆芯棒束结构特点建立了冷却剂流动换热模型、燃料棒导热模型和耦合换热模型,开发了一套基于有限体积法的压水堆全堆芯通道级热工水力特性分析程序CorTAF。选取GE3×3、Weiss和PNL2×6燃料组件流动换热实验开展模型验证,计算结果与实验数据基本符合,表明该程序适用于棒束燃料组件内冷却剂流动换热特性预测。本工作对压水堆堆芯安全分析工具开发具有参考和借鉴意义。  相似文献   

5.
相对于传统堆型,大型非能动先进压水堆堆芯设计具有重大改变,这些改变对弹棒事故分析具有重要影响,进而影响反应堆的安全性。通过选取典型的四类工况(寿期初满功率、寿期初零功率、寿期末满功率和寿期末零功率),利用中子动力学软件和燃料性能分析程序开展大型先进压水堆CAP1400的弹棒事故模拟计算,验证大型先进压水堆弹棒事故工况下的安全性,并针对弹棒事故分析关键输入参数开展敏感性分析。计算分析结果表明:大型先进压水堆发生弹棒事故时,其结果能够满足验收准则的要求,反应堆处于安全可控状态;弹棒事故分析中功率峰值对弹棒价值最敏感,事故分析结果对停堆反应性敏感性较小。  相似文献   

6.
针对超临界水堆堆芯内流体物性分布非均匀性显著、核热反馈强烈的特点,建立了适用于超临界水堆运行环境的、基于燃料棒层面的精细化堆芯中子学/热工水力耦合方法,开发了子通道程序NCEDSCWR、节块扩散计算程序MRAPS、多功能程序COUPLE,结合西屋公司组件能谱计算程序PARAGON,构建了堆芯中子学/热工耦合分析程序系统SCAP。以具有121盒燃料组件的超临界水堆堆芯进行模拟分析,研究了堆芯三维功率分布和流体物性分布的特点以及反应性参数与重要同位素密度等随燃耗的变化规律。结果表明,本文提出的精细化核热耦合方法和开发的程序系统可以应用于超临界水堆堆芯的研究与分析,相关研究结果对超临界水堆堆芯设计具有一定的指导意义。  相似文献   

7.
《核动力工程》2015,(1):124-126
为进一步深化核安全审评工作,国家核安全局从美国核管制委员会(NRC)引进了大型热工水力最佳估算程序TRACE程序。本文利用TRACE程序以及辅助建模工具SNAP程序,建立了秦山核电厂二期两环路压水堆热工水力模型,进行了大破口失水事故模拟计算,得出了合理的计算结果。  相似文献   

8.
在超临界水冷堆预概念设计中,组件设计是十分重要的,将影响堆芯性能。超临界水冷堆中水密度变化剧烈的特性要求必须进行核热耦合分析。从中子学及热工性能角度,使用三维核热耦合程序对环形燃料组件进行了优化设计。应用中子学计算程序FENNEL-N对环形燃料组件进行三维扩散计算,可得到组件内单棒功率分布,应用热工计算程序SUBSC对组件进行子通道分析。在计算过程中,分析了燃料棒间距及燃料棒与组件壁盒之间的间隙对组件性能的影响。计算结果显示,增大棒间距和棒壁间隙能提高组件kinf,但会增大组件内功率峰因子;子通道受热不均匀性对组件热工性能影响较大,通过加入定位格架的方式能展平冷却剂出口温度,降低最大包壳温度。对环形燃料组件的安全分析表明,从中子学角度该组件是安全的。  相似文献   

9.
SCWR堆芯三维瞬态物理-热工水力耦合程序开发   总被引:2,自引:1,他引:1  
耦合三维中子时空动力学程序和超临界水堆(SCWR)热工水力计算程序,开发了适用于SCWR堆芯瞬态和事故分析的三维瞬态分析程序STTA。采用第二类边界条件节块格林函数方法 NGFMN_K求解瞬态中子扩散方程,采用串行耦合方法将SCWR子通道程序ATHAS嵌入NGFMN_K程序。通过压水堆基准题NEACRP-L-335和SCWR弹棒问题检验STTA程序,结果表明:STTA针对压水堆问题的计算结果与参考解符合良好,针对SCWR问题的计算结果合理可信,可用于SCWR堆芯的三维瞬态性能分析。  相似文献   

10.
针对超临界水冷反应堆(SCWR)堆芯冷却剂密度沿轴向变化剧烈的特点,开发用于SCWR堆芯稳态物理-热工水力耦合计算的程序系统CASIR。CASIR由改进的压水堆堆芯中子学计算程序和适用于SCWR燃料组件计算的子通道热工-水力程序组成,具备调整堆芯下腔室入口流量分配的功能。针对CSR1000双流程的SCWR首循环堆芯,通过与蒙特卡罗程序对比寿期初时刻计算结果的方式,初步验证CASIR计算SCWR堆芯中子学问题的准确性;通过SCWR堆芯燃耗模拟,以及调整堆芯流量分布使得最大包壳表面温度(MCST)满足设计限值的测试,表明CASIR满足SCWR堆芯设计的要求,可应用于方形燃料组件的SCWR堆芯概念设计。  相似文献   

11.
We have determined a number of transport properties of U0.7Ce0.3O2-x at 1273 K for various deviations from stoichiometry and compared them with available results on (UPu)O2 ? x. They are: the electrical conductivity, Seebeck coefficient, effective charge number and chemical diffusion coefficient.A very characteristic behaviour is observed for the electronic properties of (UCe)O2 ? x. A p-type conduction for all the studied deviations from stoichiometry (up to x = 3 × 10?2) is interpreted in terms of a high electronic disorder in the stoichiometric compound. Electronic disorder at stoichiometry is probably less important in (UPu)O2 ? x, which presents a sharp p-n transition at x = 5 × 10?3.Ionic transport properties obtained on (UCe)O2 ? x indicate an approximate proportionality between the ionic conductivity resulting from oxygen ions transport and the deviation from stoichiometry. Results available on (UPu)O2 ? x do not appear to be compatible with ours and some arguments are presented which cast doubt on their validity.  相似文献   

12.
Using Schuhmann's method the chemical potentials of three components in nonstoichiometric ternary uranium oxides MyU1?yO2+x(M = Mg and Pu) have been calculated. The obtained results are shown in the form of equi-chemical-potential curves (surface of partial molar free energy) in the composition triangle. In the hypostoichiometric region the contour lines of the surface are dense and run parallel with each other. Taking account of this fact the difficulty in attainment of homogeneity in the fabrication of mixed oxide fuel is discussed.  相似文献   

13.
Because of its high incorporation capacity and of the high thermal neutron capture cross-section of hafnium, Hf-zirconolite (CaHfTi2O7) ceramic can be envisaged as a potential waste form for minor actinides (Np, Am, Cm) and plutonium immobilization. In this work, Nd-doped Hf-zirconolite Ca1−xNdxHfTi2−xAlxO7 (x = 0; 0.01 and 0.2) ceramics have been prepared by solid state reaction. Neodymium has been used as trivalent actinide surrogate. The ceramic samples structure has been studied by X-ray diffraction and refined by the Rietveld method. This revealed that Nd3+ ions only enter the Ca site, whereas part of Hf4+ ions substitute titanium into Ti(1) sites and Al3+ ions mainly occupy the Ti(2) split sites and Ti(3) sites of the zirconolite structure. Using various spectroscopic techniques (electron spin resonance, optical absorption and fluorescence), the environment of Nd3+ cations in Hf-zirconolite has been studied and compared with that of Nd3+ cations in Zr-zirconolite (CaZrTi2O7). Different local environments of Nd3+ cations have been detected in Hf-zirconolite that can be attributed to the existence of an important disorder around Nd in the Ca site probably due to the statistical occupancy of the next nearest cationic site of neodymium (a split Ti site) by Ti4+, Al3+ cations and vacancies. No significant differences were observed concerning Nd3+ cations environment and distribution in Hf- and Zr-zirconolite ceramics.  相似文献   

14.
Phase relations in the composition range from UO2+x to U3O8?z were studied by electrical-conductivity measurements and X-ray diffraction in the ranges 1025°C ? T ? 1140°C and 10?7atm ? PO2 ? 10?3atm. The plot of log σ versus log PO2 showed straight lines with distinct slopes, which corresponded to four regions (UO2+x, U4O9?y, U4O9+y and U3O8?z). The existence of the hyperstoichiometric U4O9+y phase was suggested in the temperature range from 1025 to 1126°C. The peritectoid temperature (U4O9±y = UO2+x + U3O8?z) was estimated to be present between 1126 and 1131°C. The partial free enthalpies and entropies for the two-phase equilibrium (U4O9+y + U3O8?z, and U4O9?y + UO2+x) were calculated and compared with previous results. From the dependence of the electrical conductivity on the oxygen partial pressure the nonstoichiometric defect structures of UO2+x and U4O9±y were interpreted as consisting of doubly charged oxygen interstitials (Oi'') and doubly charged oxygen vacancies (VO''). At room temperature, the homogeneity range of the U4O9 phase was investigated with a Debye-Scherrer camera.  相似文献   

15.
A study of the effects of ion irradiation of hybrid organic/inorganic modified silicate thin films on their mechanical properties is presented. NaOH catalyzed SiNawOxCyHz thin films were synthesized by sol-gel processing from tetraethylorthosilicate (TEOS) and methyltriethoxysilane (MTES) precursors and spin-coated onto Si substrates. After drying at 300 °C, the films were irradiated with 125 keV H+ or 250 keV N2+ at fluences ranging from 1 × 1014 to 2.5 × 1016 ions/cm2. Nanoindentation was used to characterize the films. Changes in hardness and reduced elastic modulus were examined as a function of ion fluence and irradiating species. The resulting increases in hardness and reduced elastic modulus are compared to similarly processed acid catalyzed silicate thin films.  相似文献   

16.
Strained SiGe/Si structures have been proposed as substrates for fabrication of high speed metal oxide semiconductor transistors. However, influence of strain and/or presence of Ge atoms on damage creation during ion irradiation have not been explored to a significant extent. In this study, Rutherford backscattering spectrometry (RBS) was used to characterize Si1−xGex/Si structures irradiated by 140 keV He+ ions at room temperature. When compared with pure Si, strained samples show enhanced damage accumulation as a function of He fluence. Channeling angular scans did not reveal any specific configuration of displacements. Possible mechanisms for enhanced damage in strained Si are discussed.  相似文献   

17.
Center-of-mass best values for the normalized Legendre coefficients and the 0° differential cross sections as functions of input energy have been derived from various experimental results for the reactions 7Li(p,n)7Be and 7Li(p,n)7Be1 (431 keV). This information has been used to calculate laboratory differential cross sections as functions of the laboratory proton energy and neutron emission angle which are given in tabular form together with the corresponding neutron energies.  相似文献   

18.
The paper outlines the preparation of UAlx-Al dispersion fuel plates for thermal high-flux reactors. The work described includes the preparation of UAl2, UAl3 and UAl4 compounds by induction melting and their processing to Al-clad fuel plates using the picture-frame technique. Induction melting in alumina crucibles and subsequent homogenisation can be used to produce relatively homogeneous UAlx compounds. After comminution to a predetermined size range and blending with Al, the pressed compacts can be rolled into Al-clad fuel plates. UAl3 and UAl2 compounds react with Al forming UAl4. The reactions begin at about 673 K, and have an activation energy of 52.6 and 42.6 kcal/mol, respectively. The measured properties of the dispersions and UAl-phases such as thermal expansion, thermal and electrical conductivity, tensile strength, microhardness and hot hardness are affected by the concentration of the dispersed phase and can be explained in the light of existing theoretical models. Due to its potential as a high-flux reactor fuel with higher uranium content the preparation and properties of UAl2-Al dispersions as well as the preliminary data about their stability under irradiation may be of particular interest.  相似文献   

19.
Tables of wavelengths and classifications of observed emission lines due to 2s22pn?2s2pn + 1 and 2s2pn?2pn + 1 transitions are presented. The accuracy of data derived from different experimental methods is discussed. Revised and predicted wavelengths are added. Energy levels are derived from the wavelength data.  相似文献   

20.
The stability and the nature of bonding in hypostoichiometric ThH2, hcp ThC0.46Hx and fcc ThNyHx (y = 0.486 and 0.692) are studied on the basis of statistical thermodynamics. The discussions are made in terms of the atomic partition function of H in these condensed phases and of the interaction energy terms. It is concluded that the nature of bonding in ThNyHx is approximately the same as that in ThH2. On the other hand, the nature of bonding in ThCyHx is found to be significantly different from that in ThH2.  相似文献   

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