核电厂运行安全指标

本文着重介绍了 IAEA 所制定的核电厂运行安全指标,同时也介绍了美国所制定的类似指标。这些指标为定量地评估和比较各国核电厂运行安全提供了可靠的依据。     

多重散射X_α方法计算Na_3原子簇的探讨

从已有的多重散射统计总能量公式出发,我们计算了Na_3原子簇。该原子已用CI-SCF和LSD膺势方法计算过。为了进一步讨论这种方法的应用,我们计算了Na_3原子簇的统计总能量、轨道能量、电离能。借助于这些结果,讨论了这种方法的优缺点。     

石家庄市室内氡及其子体浓度

本文报道了用双滤膜法对石家庄市室内空气中氡及其子体浓度的调查结果。47个房间室内氡年平均浓度为17.0Bq·m~(-3),氡子体平均浓度是7.14Bq·m~(-3)。氡及其子体浓度的日变化是清晨4—8时出现峰值。季节变化是夏秋季低,冬季高,全年的最低值出现在8月,最高值出现在11月。     

TEM study of PLZT ceramics

The microscopic structures of PLZT(7.9/70/30 and x/65/35, x = 7 or 8) ceramics were studied by means of transmission electron microscopy. The presence of micro-regions in PLZTs was first verfied.     

Combined shape and sizing optimization of truss structures

 In this paper, an evolutionary optimization method is presented for weight minimum problem of a 3-dimensional truss structure in terms of nodal coordinates and element cross-sectional areas. The structure is subject to stress, local buckling and displacement constraints. Two types of design variables with different natures are optimized separately: (1) a fully stressed design (FSD) and scaling techniques are applied to sizing variables and (2) the evolutionary node shift method is applied to shape variables. Alternating procedure is utilized to couple the two types of variables and to combine the results. The optimum solution is achieved gradually from the initial configuration design. Two typical truss structures are examined to illustrate the validity of the method. Received: 22 October 2001 / Accepted: 04 June 2002 This research work is supported by the National Natural Science Foundation of China under the guarantees no. 10072050 and 10172072, respectively.     

Fuel management of the HTR-10 including the equilibrium state and the running-in phase

The mode of fuel management of the HTR-10 was studied, including the simulation of the fuel shuffling process and the measurement of the burnup of a fuel element. The prior consideration was the design of the equilibrium state. Based on this the fuel loading of the initial core and the fuel shuffling mode from the initial core through the running-in phase into the equilibrium state were studied. The code system VSOP was used for the physical layout of the HTR-10 at the equilibrium state and in the running-in phase. For the equilibrium state, in order to lessen the difference between the peak and the average burnup, 5-fuel-passage-through-the-core was chosen for the fuel management. The average burnup of the spent fuel for the equilibrium core is 80 000 MWd t⁻¹, and the peak value of it is less than 100 000 MWd t⁻¹ when the burnup of the recycled fuel element is under 72 000 MWd t⁻¹. The mixture of fuel element and graphite element was used for the initial core loading, the volume fractions of the fuel and the graphite elements were 0.57 and 0.43, respectively. During the running-in phase, the volume fraction of graphite will decrease with the fresh fuel elements being loaded from the top of the core and the graphite elements discharged from the bottom of the core. The fuel shuffling mode is similar to that of the equilibrium state. The burnup limit of recycled fuel element is also 72 000 MWd t⁻¹ and the peak burnup is less than 100 000 MWd t⁻¹. Finally the core will be full of fuel elements with a certain profile of burnup and reaches the equilibrium state. According to the characteristics of the pebble-bed high temperature gas-cooled reactor, a calibrating method of concentration of ¹³⁷Cs was proposed for the measurement of fuel burnup.