锆-氘反应热力学特性研究

The p-c-T curves and the relation between equilibrium pressure and temperature of deuterium absorption and desorption from zirconium were measured in the temperature range of 400～675 ℃. Equilibrium pressure of the absorption and desorption at different temperatures were given and then the thermodynamic parameters and the deuterium absorption capacity were determined according to Vant Hoff equation. There are different changes of enthalpy and entropy when zirconium changes to different phases. The change of enthalpy in the phase of α plus δ is -98.9 kJ·mol^-1 in the temperature range of 400～475 ℃. The changes of enthalpy in the first and second plateau are -75.1 kJ·mol^-1 and -161.7 kJ·mol^-1, respectively in the temperature range of 525～675 ℃. The corresponding changes of entropy are -66.5 J·K^-1·mol^-1, -32.4 J·K^-1·mol^-1 and -146.5 J·K^-1·mol^-1, respectively. There are obvious lagging effects when zirconium desorbs deuterium.     

外电场对ZrH2(ZrD2,ZrT2)固溶体热力学函数的影响

采用Gaussian03程序及密度泛函(B3P86)方法,对Zr原子利用外部基函数8s7p3d,对H2(D2,T2)利用6-311g**全电子基函数,优化了在外电场作用下ZrH2分子微观结构,研究了锆与氢同位素气体反应的热力学函数及氢同位素平衡压力随温度和外电场的变化关系.研究表明:随着正向电场的增加,分子微观结构及其气体平衡压力发生明显变化.在293.16K,外电场从-0.004 a.u.到0.004 a.u.变化时,氢平衡压力相差六个数量级.说明外电场对金属氢化物的热力学函数具有一定的影响.     

Effect of microstructure on ~3He migration in TiT_(1.9) films

Two kinds of films were prepared to study the effect of microstructure on helium migration in Ti tritides. Both films showed different release behaviors and helium bubble distributions. In the film consisting of columnar grains, a twolayered structure was observed. Inclusions with a strip feature were found at the grain boundary, and no helium bubbles were distributed in these inclusions. However, helium preferred to migrate to the boundaries of these inclusions. Bubble linkage as a ribbon-like feature developed parallel to the film surface in the film consisting of columnar grains. More cracks were developed at the grain boundaries of the film consisting of columnar grains, although the helium content in the film consisting of columnar grains was less than that in the film consisting of equiaxed grains. A surface region with a small number of bubbles, or "depleted zone", was observed near the surface. The cracks extending to the film surface were the pathways of the critical helium released from the film. The helium migration was strongly influenced by the grain microstructure.     

Ab initio study of H and He migrations in β-phase Sc, Y, and Er hydrides

Ab initio calculations based on the density functional theory have been performed to investigate the migrations of hydrogen(H) and helium(He) atoms in β-phase scandium(Sc),yttrium(Y),and erbium(Er) hydrides with three different ratios of H to metal.The results show that the migration mechanisms of H and He atoms mainly depend on the crystal structures of hydrides,but their energy barriers are affected by the host-lattice in metal hydrides.The formation energies of octahedral-occupancy H(H oct) and tetrahedral vacancy(V tet) pairs are almost the same(about 1.2 eV).It is of interest to note that the migration barriers of H increase with increasing host-lattice atomic number.In addition,the results show that the favorable migration mechanism of He depends slightly on the V tet in the Sc hydride,but strongly on that in the Y and Er hydrides,which may account for different behaviours of initial He release from ScT2 and ErT2.     

激光拉曼定量分析氘气方法研究

应用拉曼光谱法对氘气在不同条件下的谱峰信噪比进行了实验研究。采用32 mW功率的Ar+激光器(514 nm),通过石英玻璃管,研究了光栅、激光功率、曝光时间和气体压强对氘气拉曼谱图信噪比的影响,得出了氘气拉曼光谱信噪比与激光功率、曝光时间和气体压强呈正比关系。绘制出适用于本套实验仪器的不同压力与信噪比的标准曲线,并用三组随机样品对关系式SNR(J 2→2)=10.6×10-4p+1.271 34进行验证。当氘气压强为21 280 Pa时,相对误差是4.8%,并且当压强增大到67 235 Pa时,相对误差下降到1.46%。     

反应堆一回路不锈钢管道沉积物制备及去污的模拟研究

反应堆一回路管道通常以不锈钢为基材,长期运行中面临沉积物的产生及大量积累的问题。本文通过溶液反应模拟沉积物的产生,采用的水溶液中含有Ca²⁺、Mg²⁺,以及裂片核素¹³⁷Cs和活化核素⁶⁰Co的稳定同位素阳离子¹³³Cs+和⁵⁹Co²⁺,CO₃^2-、SO₄^2-等阴离子,以及基材氧化物Fe₂O₃等;开展了沉积物化学溶解去污处理技术研究。实验结果表明,沉积物中含钙、镁、钴、铯及铁等元素;采用苹果酸+柠檬酸双组份的去污体系,沉积物的溶解率可达98.44%,且该弱酸复配体系去污液对不锈钢基体的腐蚀作用较小。