The paper presents the design objectives and structure of China's accelerator-driven subcritical system subcritical assembly Venus-1. The core of Venus-1 is a coupled core with afast neutron zone and a thermal neutron zone. The fast neutron zone is at the center of the core and is formed by natural uranium fuel. A fast neutron spectrum field can be produced in the fast neutron zone and used for transmutation. The thermal neutron zone surrounds the fast neutron zone and is formed by low-enriched uranium fuel; it is a fission zone. Venus-1 is driven by an Am-Be or other steady neutron source (252 Cf, D-D reaction or D-T reaction) to research the effect of an external neutron source with different energies on it or is driven by a D-T pulsed neutron source through the China Institute of Atomic Energy pulsed neutron generator to research the dynamic characteristic. On July 18, 2005, the first fuel element was loaded into the Venus-1 subcritical assembly, and some preliminary experiments on subcritical and neutron distribution have been performed. The final load has been determined by preliminary experiments on Venus-1. The relative neutron importance of the external source, the relative distribution of the thermal neutron flux in the fast neutron zone, and the variation of the neutron count with the addition of natural uranium fuel also have been determined by preliminary experiments on Venus-1.

China’s accelerator-driven sub-critical system (ADS) sub-critical experimental assembly—Venus-1 and the preliminary experiment is presented. The core of Venus-1 is a coupled one of a fast neutron zone and a thermal neutron zone. The fast neutron zone is at the centre of the core and formed by natural uranium fuel. A fast neutron spectrum field can be produced in the fast neutron zone and used for the transmutation of minor actinides (MAs). The thermal neutron zone surrounds the fast neutron zone and is formed by low-enriched uranium fuel. It is a fission zone. An epithermal neutron zone between the fast neutron zone and the thermal neutron zone can be established for the transmutation of longlived fission products (LLFP). On July 18, 2005, the first fuel element was loaded into the Venus-1 sub-critical assembly and some preliminary experiments about the sub-critical neutronics were performed. The Venus-1 can be driven by an Am-Be source or other steady neutron source (Cf-252, D-D reaction and D-T reaction) to study the effect of the external neutron source with different energies or a D-T pulsed neutron source on the dynamic characteristics.

Tthe design purpose,requirement and construction of the sub-critical assembly-Venus 1# for accelerator driven sub-critical system(ADS) are described.It is a coupling core of the fast neutron spectrum zone and thermal neutron spectrum zone(driven) by D-T reaction neutron source generated by pulsed neutron generator.The fast neutron spectrum zone is in the inner layer of core and the thermal neutron spectrum zone is in the outer layer of core.The fast neutron zone can give fast neutron spectrum and also is an amplifier for an external neutron source,and the thermal neutron zone is a fission zone and gives energy amplification.

Study on the optimization of solid spallation target in accelerator-driven reactor system are carried out. The geometry of the solid target is optimized. The leaked neutron yield of this optimized target, the leaked neutron spectrum and energy deposition in target are studied. A target assembly consisting of tungsten diskes and water layers is proposed in the present work. The problem of large energy deposition in soild target is solved without decreasing the leakage neutron production.

The standard spallation target of ADS (Accelerator-Driven System) was theoretically calculated with Monte Carlo codes of DCM/CEM and LAHET in the present work. The spallation target (0.6 m long and 0.2 m in diameter) bombarded with 0.15—1.6 GeV energetic proton beam was simulated. The proton energy deposition in tar- get, neutron yield, neutron fluence distribution on the outer surface of target and the neutron spectrum distribution were simulated with the two codes. It is shown that, in the proton energy range of 0.8—1.0 GeV, both calculated re- sults agree to each other; but when the proton energy falls outside this energy range, there are some differences be- tween the results with both codes.

运用蒙卡程序DCM/CEM对ADS标准散裂中子靶进行了计算研究.计算了在0.1～1.6 GeV的质子轰击下,标准Pb靶发生散裂反应产生的泄漏中子产额及分布、中子能谱以及靶内能量沉积分布.计算结果与文献理论数据、实验数据进行了比较.

The geometry of the solid target for the accelerator-driven system was optimized. The yield and spectrum of leaked neutrons, and the energy deposition in the target were studied. A target assembly consisting of tungsten diskes and water layers was proposed in the present work. The problem of large energy deposition in solid target was solved without decreasing the leakage neutron production.

The neutron distribution for a spallation neutron source of (  8cm×20cm)lead target bombarded by 7.4GeV proton beam was studied using LR 115 2B detector. The theoretical code of CEM was used to interpret the experimental results, meanwhile, the activation method was exploited to check the experimental results of LR 115 2B and the theoretical simulation.

The experimental and theoretical methods were used to study the application of Lavsan detectors in the studies of spallation neutron source in the present work. The Lavsan detectors were utilized to measure the spallation distribution in the laed target (  8cm×20cm) bambarded by 3.7GeV proton beam. And the experimental results were compared with the theoretical simulation, meanwhile, the Lavsan results were also checked with the measurements of spallation product in the lead target.

一、核能--人类能源的最终解决之道 经历数百万年而形成的煤、石油和天然气等化石能源,为人类的过去和现在提供了生存和发展的基础.20世纪以来,人们将它们的化学能转化为更为方便的电能.经济的迅猛发展和人口的急速增长,人类正在加快耗尽这种不可再生能源.据估计,人类可以继续依赖化石能源的时间不过百来年.除了资源问题,化石能源开采和利用所带来的生态与环境问题,已经向我们这代人提出了严峻的挑战.

本文从基础科学、核能及核工程、核医学等几个方面回顾了20世纪中子科学的成就,概述了中子科学研究平台的发展趋势.作者认为:(1)中子科学在20世纪对科学技术的发展和人类社会经济发展作出了举世公认的贡献;(2)中子科学研究平台--中子源的强度和品质决定了中子科学研究的广度、深度和水平,21世纪中子科学研究平台的发展趋势是强流加速器驱动的散裂中子源;(3)这样一个先进的中子科学装置将覆盖21世纪大量的科学前沿问题和国家迫切需要解决的重大工程技术问题;(4)根据国家的诸多需要,建设一台先进的多用途的加速器驱动的散裂中子源非常必要.

The mass and charge distribution of residual products produced in the spallation reaction needs to be studied because it can provide useful information for the disposal of nuclear and the radiation damage in the spallation target. The mass and charge distribution of the spallation products is studied by using quantum molecular dynamic (QMD) models. The simulation results are well agreed with the experimental data of the spallation fragment and empirical formula. However, QMD model does not include the fission process; the calculations can not reproduce the fission fragment. The fission model is introduced into QMD model to investigate the fragment products from proton-induced reactions on Pb. The results are in good agreement with the experimental data.

作为核裂变能可持续发展的一种创新技术,加速器驱动次临界系统(ADS)是近十余年来国际核能科技界研究的热点.本文分析了在我国开展此项研究计划的合理性,评述了ADS研究、开发中主要的科学与技术课题,并简单介绍了本项目5年中的"工作包"及正在进行的研究活动.

This work concerns in the evolution of the nuclides in the sub critical reactor of ADS. The analysis results indicate that the long life nuclear waster can be transmutated in the ADS. The comparison between thermal and fast ADS demonstrate that the fast ADS has large power output, less minor actinide production and small fission products poisoning effect compared with thermal system.

High Power Proton Accelerator (HPPA) is being studied all over world for numerous applications, which includes the waste transmutation, spallation neutron source and material irradiation facilities. In China, a multi-purpose verification system as a first phase of our ADS program consists of a low energy accelerator (150MeV/3mA proton linac) and a swimming pool light water sub-critical reactor. In this paper the activities of HPPA technology related to ADS in China, which includes the intense proton ECR source, the RFQ accelerator and some other technology of HPPA, are described.

对加速器驱动洁净核能系统(ADS)次临界堆内核素的转换进行了研究.研究结果表明:ADS具有充分利用核资源的可能性.次临界热堆只能工作在φ＜1×1014 cm-2·s-1的中子注量率下,快堆则在φ＝1015～1016 cm-2·s-1下仍可稳定工作,且平衡时的易裂变核素(233U和239Pu)数目与初始装料核素的比值远高于热堆的.ADS中,外源中子可有效地将可裂变核素转换成易裂变核素.为加速达到平衡,初始装料中加入少量233U及239Pu是一种可行的选择.

. The double differential cross section of emitting particles, the mass and charge distribution of the residual nuclei from proton-induced reaction on 208 Pb with incident energy 590 MeV and 322 MeV have been analyzed by the quantum molecular dynamics (QMD). The time scale of the change of reaction mechanism in the process of reaction is investigated. The reaction process can be divided into three stages i.e., the direct, the cascade and the evaporation stage with the corresponding time scale of about <30 fm/c, 30–100 fm/c and >100 fm/c, respectively.