共查询到20条相似文献,搜索用时 15 毫秒
1.
The construction of the China Spallation Neutron Source (CSNS) has been initiated at Dongguan,Guangdong,China.In spallation neutron sources the target station monolith is contaminated by a large number of fast neutrons whose energies can be as large as those of the protons of the proton beam directed towards the tungsten target.A detailed radiation transport analysis of the target station monolith is important for the construction of the CSNS.The analysis is performed using the coupled Monte Carlo and multi-dimensional discrete ordinates method.Successful elimination of the primary ray effects via the two-dimensional uncollided flux and first collision source methodology is also illustrated.The dose at the edge of the monolith is calculated.The results demonstrate that the doses received by the hall staff members are below the required standard limit. 相似文献
2.
ZHANG Bin CHEN Yi-Xue YANG Shou-Hai WU Jun YIN Wen LIANG Tian-Jiao JIA Xue-Jun 《中国物理C(英文版)》2010,34(11):1775-1778
The construction of the China Spallation Neutron Source (CSNS) has been initiated at Dongguan,Guangdong,China.In spallation neutron sources the target station monolith is contaminated by a large number of fast neutrons whose energies can be as large as those of the protons of the proton beam directed towards the tungsten target.A detailed radiation transport analysis of the target station monolith is important for the construction of the CSNS.The analysis is performed using the coupled Monte Carlo and multi-dimensional discrete ordinates method.Successful elimination of the primary ray effects via the two-dimensional uncollided flux and first collision source methodology is also illustrated.The dose at the edge of the monolith is calculated.The results demonstrate that the doses received by the hall staff members are below the required standard limit. 相似文献
3.
The construction of China Spallation Neutron Source (CSNS) has been initiated in Dongguan, Guangdong, China. Thus a detailed radiation transport analysis of the shutter neutron beam stop is of vital importance. The analyses are performed using the coupled Monte Carlo and multi-dimensional discrete ordinates method. The target of calculations is to optimize the neutron beamline shielding design to guarantee personal safety and minimize cost. Successful elimination of the primary ray effects via the two-dimensional uncollided flux and the first collision source methodology is also illustrated. Two-dimensional dose distribution is calculated. The dose at the end of the neutron beam line is less than 2.5 μSv/h. The models have ensured that the doses received by the hall staff members are below the standard limit required. 相似文献
4.
T. Yu. Karpushkin 《Physics of Atomic Nuclei》2012,75(13):1564-1569
A technique to calculate the burnup of materials of cells and fuel assemblies using the matrices of first-flight neutron collision probabilities rebuilt at a given burnup step is presented. A method to rebuild and correct first collision probability matrices using average chords prior to the first neutron collision, which are calculated with the help of geometric modules of constructed stochastic neutron trajectories, is described. Results of calculation of the infinite multiplication factor for elementary cells with a modified material composition compared to the reference one as well as calculation of material burnup in the cells and fuel assemblies of a VVER-1000 are presented. 相似文献
5.
The back-streaming neutrons from the spallation target at CSNS are very intense,and can pose serious damage problems for the devices in the accelerator-target interface region. To tackle the problems,a possible scheme for this region was studied,namely a specially designed optics for the proton beam line produces two beam waists,and two collimators are placed at the two waist positions to maximize the collimation effect of the back-streaming neutrons. Detailed Monte Carlo simulations with the beams in the two different CSNS phases show the effectiveness of the collimation system,and the radiation dose rate decreases largely in the interface section. This can ensure the use of epoxy coils for the last magnets and other devices in the beam transport line with reasonable lifetimes,e.g.,thirty years. The design philosophy for such an accelerator-target interface region can also be applicable to other high-power proton beam applications. 相似文献
6.
The back-streaming neutrons from the spallation target at CSNS are very intense, and can pose serious damage problems for the devices in the accelerator-target interface region. To tackle the problems, a possible scheme for this region was studied, namely a specially designed optics for the proton beam line produces two beam waists, and two collimators are placed at the two waist positions to maximize the collimation effect of the back-streaming neutrons. Detailed Monte Carlo simulations with the beams in the two different CSNS phases show the effectiveness of the collimation system, and the radiation dose rate decreases largely in the interface section. This can ensure the use of epoxy coils for the last magnets and other devices in the beam transport line with reasonable lifetimes, e.g., thirty years. The design philosophy for such an accelerator-target interface region can also be applicable to other high-power proton beam applications. 相似文献
7.
This paper shows the calculations of radioactivity and afterheat
in the components of the China Spallation Neutron Source (CSNS) target
station, with the Monte Carlo codes LAHET, MCNP4C and the multigroup
code CINDER'90. These calculations provide essential data for the
detailed design and maintenance of the CSNS target station. 相似文献
8.
本文采用高能粒子输运程序MCNPX 2.5.0,对中国散裂中子源(CSNS)靶站重要部件所使用的钨、SS316不锈钢与Al-6061等材料,由于中子与质子辐照所引起的损伤能量截面与原子离位截面进行了计算,对钨靶体、靶的不锈钢容器、慢化器与反射体的铝容器等部件的辐照损伤量——原子离位次数(displacement per atom,DPA)进行了计算与分析,并给出了质子束斑形状对靶体及靶容器DPA峰值的影响. 这些计算与分析对正在建设的中国散裂中子源靶站的设计及参数选择具有重要的实际意义.
关键词:
中国散裂中子源
损伤能量截面
原子离位截面
DPA 相似文献
9.
M. I. Gurevich M. A. Kalugin A. V. Pryanichinikov O. V. Tel’kovskaya D. A. Shkarovskii 《Physics of Atomic Nuclei》2010,73(13):2180-2187
The first collision probability (FCP) method allows generalization by introducing several angular modes in each zone. Algorithms
are proposed for calculating the components of the corresponding first collision tensor. These algorithms do not increase
the computational complexity beyond that of the matrix calculation algorithm in the traditional FCP method and allow calculating
a system described in terms of combinatorial geometry. Fourfold integrals are numerically taken in calculation of a three-dimensional
system and twofold integrals are taken for two-dimensional geometry. The geometrical capabilities are ensured by using the
standard geometrical module of the Monte Carlo method. 相似文献
10.
The small angle neutron scattering (SANS) instrument is presently being constructed at Chinese Spallation Neutron Source (CSNS) in China, and the biological shielding design is needed to prevent the instrument from causing excessive dose rates in accessible locations. In this paper, the study of shielding design for SANS that relies on Monte Carlo simulation is introduced. Beam line shielding calculations are performed considering both scenarios of closed versus open T0 chopper. The basic design scheme of the beam stop is discussed. The size of the T0 chopper rotor is also estimated. 相似文献
11.
《中国物理C(英文版)》2015,(5)
A new H-ion source has been installed successfully and will be used to serve the China Spallation Neutron Source(CSNS). In this paper, we report various components of the ion source, including the discharge chamber, temperature, cooling system, extraction electrodes, analyzing magnet, remote control system and so on.Compared to the previous experimental ion source, some improvements have been made to make the ion source more compact and convenient. In the present arrangement, the Penning field is generated by a pair of pole tip extensions on the 90°analyzing magnet instead of by a separate circuit. For the remote control system, F3RP61-2L is applied to the accelerator online control system for the first time. In the running of the ion source, a stable pulse H-beam with a current of 50 m A at an energy of 50 ke V is produced. The extraction frequency and pulse width is 25 Hz and500 μs, respectively. Furthermore, an emittance scanner has been installed and measurements are in progress. 相似文献
12.
�� �������������� ��������ѧ 《核聚变与等离子体物理》2017,37(4):392-398
In order to improve the computational accuracy of fusion reactor deep penetration shielding problems with complex streaming gaps, MC-SN coupling method is developed. Based on the Theta Weighted differencing scheme, the Directional Theta Weighted and Exponential Directional Weighted differencing schemes, which have adaptive features, are introduced. Biased quadrature sets are also constructed on base of Legendre-Chebyshev sets and angular refinement technique to deal with shielding calculation problems of strong fusion neutron penetration and anisotropic scattering. Through the comparative analysis with MCNP simulation results, it can be found that these methods can effectively improve the accuracy for some deep penetration shielding calculation in fusion reactors. 相似文献
13.
为了提高具有复杂孔道的聚变堆深穿透屏蔽问题的计算精度,研究了蒙特卡罗法和离散纵标法(MC-SN)的耦合方法。同时,在权重差分方法的基础上引入具有自适应特性的定向权重和指数定向权重方法,并基于勒让德-切比雪夫求积组和极角细化技术研究了偏倚求积组,有效解决聚变中子穿透能力强、强各向异性散射等屏蔽计算难点。通过与MCNP程序模拟结果的比较分析发现,这些研究方法能有效提高聚变堆深穿透屏蔽计算的精度。 相似文献
14.
There are two cooling systems to maintain the thermal stability of the CSNS H ion source during its operation: Air-cooling in the source body of the discharging chamber and water-cooling in the flange on which the discharging chamber is installed.The optimal cooling parameters to ensure the operation of the H-ion source are determined through a thermal analysis. In addition, a transient analysis is also performed to know exactly the transient temperature variation during the whole 40 ms period of the pulsed mode operation of the ion source. 相似文献
15.
There are two cooling systems to maintain the thermal stability of the CSNS H- ion source during its operation:Air-cooling in the source body of the discharging chamber and water-cooling in the flange on which the discharging chamber is installed.The optimal cooling parameters to ensure the operation of the H- ion source are determined through a thermal analysis.In addition,a transient analysis is also performed to know exactly the transient temperature variation during the whole 40 ms period of the pulsed ... 相似文献
16.
There are two cooling systems to maintain the thermal stability of the CSNS H^- ion source during its operation: Air-cooling in the source body of the discharging chamber and water-cooling in the flange on which the discharging chamber is installed. The optimal cooling parameters to ensure the operation of the H^- ion source are determined through a thermal analysis. In addition, a transient analysis is also performed to know exactly the transient temperature variation during the whole 40 ms period of the pulsed mode operation of the ion source. 相似文献
17.
为了解决三维目标电磁散射计算中准确性与有效性的矛盾,建立了有限元-边界法的计算模型,对三维腔体目标的电磁散射计算方法进行了研究。首先,分析了针对三维电磁腔体目标的电磁散射计算边界积分方法,引入了矢量格林函数,利用麦克斯韦方程得到电磁场形式与三维腔体形式的关系,建立了三维开口腔体边界模型;然后,结合光电目标曲面建模方法及高阶基函数的方法,建立了三维光电目标的有限元泛函,完成了有限元-边界法在三维腔体目标电磁散射计算中的应用;最后,进行了实例验证。分析显示,当三维腔体内部为空或为各向异性物质时,角度吻合非常理想,与传统模式匹配法所得结果的吻合度达90%以上。结果表明,采用本方法对三维腔体目标进行电磁散射计算,准确度、效率均有所提高。 相似文献
18.
A Penning surface H- ion source test stand has been developed for the China Spallation Neutron Source (CSNS) at the Institute of High Energy Physics (IHEP). H- beams with a current up to 50 mA and a pulse length up to 520μs at a repetition rate of 25 Hz are obtained at present. In order to improve the extraction system based on both the results of the emittance measurements in experiment and the simulation results of the effect of the extraction system on the beam emittance, three dimensional electromagnetic finite element analysis and particle tracking are undertaken. First, the magnetic field of the deflecting magnet is studied in detail, and then the effect of the extraction geometry on the beam transport is also investigated. 相似文献
19.
A new H- ion source has been installed successfully and will be used to serve the China Spallation Neutron Source (CSNS). In this paper, we report various components of the ion source, including the discharge chamber, temperature, cooling system, extraction electrodes, analyzing magnet, remote control system and so on. Compared to the previous experimental ion source, some improvements have been made to make the ion source more compact and convenient. In the present arrangement, the Penning field is generated by a pair of pole tip extensions on the 90° analyzing magnet instead of by a separate circuit. For the remote control system, F3RP61-2L is applied to the accelerator online control system for the first time. In the running of the ion source, a stable pulse H- beam with a current of 50 mA at an energy of 50 keV is produced. The extraction frequency and pulse width is 25 Hz and 500 μs, respectively. Furthermore, an emittance scanner has been installed and measurements are in progress. 相似文献