ADS启明星Ⅱ号临界外推实验

正启明星Ⅱ号ADS零功率实验装置,是以原重水零功率堆为基础建造的具备水堆和铅堆双堆芯的临界实验装置,于2016年12月底完成调试。随后在启明星Ⅱ号水堆和铅堆上分别实现了首次临界,并开展了一系列反应堆中子物理学参数测量实验,如控制棒价值、燃料元件价值、散裂靶价值、中子通量密度分布等,以及一系列次临界反应性监督实验。首先根据二分之一装料原则向堆芯装料,通过布置在石墨反射层内的启动监测装置记录每次     

启明星Ⅱ号中子吸收体反应性价值测量

为验证加速器驱动的次临界系统（ADS）次临界反应堆设计时理论计算所使用的计算程序和核数据,在ADS启明星Ⅱ号零功率装置的铅冷堆芯中采用不锈钢元件作为中子吸收体,利用周期法对不锈钢中子吸收体的反应性价值进行实验研究。实验结果表明：吸收体的反应性价值随元件与中心径间距离的增加而降低,实验测量与理论计算的反应性价值接近,变化趋势相互吻合。经实验验证的理论计算程序和核数据可用于ADS次临界反应堆的设计。     

启明星Ⅱ号中子吸收体反应性价值测量

为验证加速器驱动的次临界系统(ADS)次临界反应堆设计时理论计算所使用的计算程序和核数据,在ADS启明星Ⅱ号零功率装置的铅冷堆芯中采用不锈钢元件作为中子吸收体,利用周期法对不锈钢中子吸收体的反应性价值进行实验研究。实验结果表明:吸收体的反应性价值随元件与中心径间距离的增加而降低,实验测量与理论计算的反应性价值接近,变化趋势相互吻合。经实验验证的理论计算程序和核数据可用于ADS次临界反应堆的设计。     

中国加速器驱动嬗变研究装置次临界反应堆概念设计

根据中国加速器驱动嬗变研究装置(CiADS)的建设要求,完成了CiADS中次临界反应堆的概念设计。次临界反应堆为液态铅铋冷却快中子反应堆,采用半池式-半回路式的布置方式,通过主容器的中心管实现了与散裂靶在结构上的耦合。燃料组件及换料方式采用相对成熟的技术方案,设置了铅铋主冷却剂辅助系统,通过多种专设安全设施来保证反应堆的安全。CiADS次临界反应堆充分考虑了堆靶耦合界面的可实现性,利用了液态铅铋冷却剂良好的传热性,结合了池式堆冷却剂自然循环的特性及回路式堆冷却剂装量少的特性,具有良好的可行性、安全性、布置灵活性和技术扩展性。     

液态铅铋合金流动速度场测量技术研究

液态铅铋合金是先进反应堆-加速器驱动的次临界系统(ADS)优选的靶材和冷却剂材料,液态铅铋流动速度场的测量是优化堆芯组件分布以及靶窗结构的一种重要手段。同时,冷却剂流动速度也是反映反应堆热工水力特征的重要参数之一。本文采用实验研究的方法,设计旋转搅动装置,通过对常温水与液态铅铋的流动速度场测量,验证了超声多普勒测速技术用于液态铅铋合金速度场测量的可行性。     

ADS启明星Ⅱ号散裂靶样品反应性价值测量实验

正工程化ADS反应堆堆芯由散裂靶和金属冷却反应堆堆芯耦合构成,在强外源作用下,存在着强烈的散裂靶与反应堆的耦合效应。根据ADS堆靶耦合的发展需求,在启明星Ⅱ号上设计了不同材料的圆柱型靶材,并开展了散裂靶反应性影响验证实验。靶样品的外包壳为不锈钢,内部可以装入不同的靶材料制成散裂靶,如钨铁镍合金颗粒靶、纯钨靶、纯铅靶等。通过周期法分别给出了不同靶样品的反应性实验测量结果,利用蒙特卡罗程序MONK配合点截面数据库CENDL-3.1给出了不     

小型轻量化铅铋反应堆燃料组件几何结构研究

燃料组件的几何结构和栅格参数显著影响铅铋反应堆的物理/热工特性,采用不同几何结构燃料组件的堆芯在相同换料周期、热工限值约束下的临界尺寸、燃料装载量存在差异。本文开展小型轻量化铅铋反应堆的燃料组件几何结构研究,通过建立铅铋反应堆堆芯模型,选取棒束型、环形、蜂窝煤型燃料组件方案,比较分析了3种方案在堆芯尺寸、燃料装载量、冷却剂流通面积、包壳和气隙体积相同和在换料周期为10 a、稳态热工安全裕量基本一致条件下堆芯的燃耗特性、反应性系数、稳态热工特性参数。结果表明：相比于棒束型与环形燃料组件,蜂窝煤型燃料组件良好的稳态热工特性与较硬的中子能谱,采用蜂窝煤型燃料组件的堆芯可以实现更小的堆芯尺寸及燃料装载量,具备显著的膨胀负反馈,同时能够有效展平功率分布和降低堆芯压降,是有利于铅铋反应堆小型化及轻量化的燃料组件方案。     

跳源法测量ADS启明星Ⅱ号的次临界度及动态特性

本文主要利用²⁵²Cf外中子源驱动的ADS启明星Ⅱ号次临界装置来验证理论计算的次临界度及不同次临界度下的断束动态特性。简要介绍了利用跳源法在ADS启明星Ⅱ号上测量次临界度的原理、实验装置、测量系统、堆芯布置及实验结果等。实验通过变化堆芯燃料棒的装载来模拟3个次临界状态,即k_eff分别为0.99、0.98和0.97。实验结果与理论计算结果符合较好,验证了理论计算的正确性。经过实验验证的理论计算程序和核数据,为将来的中国科学院战略性先导科技专项--未来先进核裂变能ADS嬗变系统的次临界反应堆设计提供参考价值。     

使用MCNP程序验证ADS的设计

利用MCNP程序对加速器驱动次临界系统(ADS)堆芯设计进行验证。在确定堆芯尺寸的情况下,当ADS的靶源和冷却剂是铅、铅-铋合金、铋和汞时,通过MCNP程序进行模拟计算得到相应的keff值、中子能谱和中子通量密度;并对铅、铅-铋合金、铋和汞的数据进行对比分析。结果表明,铅-铋合金是ADS系统的最佳材料,根据相应数据,提出堆芯设计的优化方案。     

加速器驱动次临界嬗变堆的参数敏感性分析

采用自主开发的加速器驱动次临界堆芯稳态分析程序LAVENDER,对加速器驱动次临界系统(ADS)的冷却剂种类、堆芯次临界度、燃料组件几何尺寸以及堆芯热功率进行敏感性分析。计算结果表明,针对加速器质子束流、次锕系核素(MA)嬗变率或热工安全裕量等单一堆芯性能参数进行优化时,往往导致其他堆芯性能参数的恶化。因此在ADS堆芯设计时,应做出折中选择以平衡不同设计目标参数。     

Preparation of Zn/TiO2 powder and its photocatalytic performance for oxidation of P-nitrophenol

Zn-doped TiO2 catalysts were prepared using a sol-gel method and characterized by XPS,UV-Vis, BET, XRD in this study. Under the irradiation of simulant sunlight, the photocatalytic activity for the degradation of p-nitrophenol was studied too. After irradiation for 2.5 h, the degradation percentage of p-nitrophenol could rise to more than 80 %. The results showed that the spectrum absorption band edge of Zn/TiO2 powder does not broaden obviously comparing with pure TiO2 powder. Zinc exists as Zn （11）. When calcined at 973 K, there is a new phase as ZnTiO3 in Zn/TiO2 catalyst. The order of photocatalytic activity of Zn/TiO2 catalysts calcined at different temperatures for p-nitrophenol is 773 K 〉 673 K 〉 873 K 〉 573 K 〉 973 K and the photocatalytic activity of Zn/TiO2 catalyst calcined at 773 K is better than TiO2 catalysts heated at the same temperature, and outclasses that of commercial TiO2 catalyst. It also showed that the photocatalytic degradation of p-nitrophenol follows first-order kinetics under the irradiation of simulant sunlight.     

Current status of radiation therapy for prostate cancer

Radiotherapy for the treatment of prostate cancer has been extensively explored in the past. Along with the comprehensive understanding of the biology of prostate cancer and rapid advances in terms of technology, the out- come of treatment for the patients with prostate cancer has improved. The authors review radiotherapy as the primary treatment for the disease, with particular emphasis on the technological advances from both the radiobiological and radiophysics aspects. Nonconventional fractionated irradiation like hyper- or hypo-fractionation has been imple- mented in the clinic, the final results still need to be confirmed in the future. Technological advances like IMRT, IGRT, in the last two decades have significantly improved the delivery of external radiotherapy to the prostate. This has re- sulted in an overall increase in the total dose that can be safely delivered to the prostate, which has led to modest im- provements in the biochemical outcome. However, establishing the standard therapy for prostate cancer remains con- troversial. It is hoped that the next decades will bring continued advances in the development of biologicals that will further improve current clinical outcomes.     

The control system for SSRF injection and extraction

This paper introduces the injection and extraction control system design for SSRF,which is a distributed control system aimed at stability and reliability of the pulse power supplies,PPS(Personnel Protection System)and MPS(Machine Protection System).The hardware environment is mainly based on PLC(Programmable Logic Con- troller),and ARM(Advanced RISC Machine)is also applied for studying stability of the power supplies.WinCC and EPICS(Experimental Physics and Industrial Control System)have been selected as the platforms of SCADA(Super- visory Control and Data Acquisition).For unifying the interfacing to the control computer,all front-end equipments are connected via Industrial Ethemet.     

水平管内含空气蒸汽强制对流冷凝换热模型研究

为研究含空气蒸汽在水平管内强制对流冷凝换热特性,基于对传热传质过程的分析,建立了管内为环状流与波状流条件下的流动冷凝换热模型。从潜热、显热和液膜3个环节对整个换热过程进行建模,最终得到计算局部冷凝换热系数的理论关系式。模型预测结果与实验数据的对比表明,二者相对偏差在±20%以内,验证了该换热模型的准确性与适用性。通过进一步的研究发现：从换热管入口至出口,随着冷凝的进行,管内换热主要热阻由液膜热阻向气液界面的凝结热阻转变;主流气体对流换热过程基本可忽略。     

Investigations on landmine detection by BF3 detector

Experiments were carried out to investigate the possible use of neutron backscattering for the detection of polyethylene (PE) sample buried in the soil. In detection of landmine by neutrons, the neutron detector and its shield play an important role. In this paper, the effects of graphite, heavy water, polyethylene and boric acid moderators on the flux of back scattered neutrons were investigated. We have also experimentally verified the effect of BF3 detector shield and obtained good agreement with theory.     

Web Services interface of SSRF archive data analysis system

Accelerator database stores various static parameters and real-time data of accelerator. SSRF (Shanghai Synchrotron Radiation Facility) adopts relational database to save the data. We developed a data retrieval system based on XML Web Services for accessing the archive data. It includes a bottom layer interface and an interface applicable for accelerator physics. Client samples exemplifying how to consume the interface are given. The users can browse, retrieve and plot data by the client samples. Also, we give a method to test its stability. The test result and performance are described.     

Assessment of radioactivity levels in some oil samples from the western desert, Egypt

Distributions of natural gamma-emitting radionuclides were determined in 93 oil samples collected from some petroleum fields in the western desert of Egypt. The radioisotope activities in the area under investigation lay in the range of (21 ± 4) to (38 ± 13) Bq?L-1 for 226Ra, (9 ± 2) to (15 ± 5) Bq?L-1 for 232Th, and (154 ± 28) to (303 ± 54) Bq?L-1 for 40K. The mean values were 27, 12, and 201 Bq?L-1, respectively. Among oils, variations in radionuclide ac- tivities could be on account of differences in TDS, HCO3, and Ba, with high or low pH. In this environment, oil prop- erties differently affected the mobilization of natural radionuclides. The range of 226Ra variation had been compared with available data from other countries. The calculated absorbed dose rate ranged from 22.33 to 32.66 nGy?h-1 in lo- cation (B) and (E) respectively, which was less than the accepted value.     

Preparation and properties of 117m Sn(IV)-TTHMP in in-vitro and in small animals

In this work,TTHMP was synthesized and labelled with 117m Sn.The preparation conditions,stability and lipophilicity of 117m Sn(IV)-TTHMP were investigated.Biodistribution of the complex in rabbits and mice was studied.It was found that the quantity of TTHMP and pH value of the prepararion solution had vital effects on the labeling yield of 117m Sn(IV)-TTHMP.It was also found that 117m Sn(IV)-TTHMP was hydrophilic and stable at room temperature and 37℃ in open air 117m Sn(IV)-TTHMP showed unexpectedly high bone uptake and bone-to-blood ratio in the animals.This made it potentially useful as an reagent for skeletal scintigraphy and radiotherapy of bone tumors.     

The role of AGFA high-energy CR in the calibration and quality control of multileaf collimators （MLC）

Linear accelerators equipped with multileaf collimators （MLC） are becoming more common and are widely used in the intensity-modulated radiotherapy （IMRT）. There is an imperative need to ensure the commissioning specification of the linear accelerators for the sake of quality assurance （QA） and quality control （QC）. This paper is aimed to investigate the role of AGFA high-energy CR （Computed Radiography） in calibrating dynamic multileaf collimators and evaluating the accuracy of the leaf position. The result shows that AGFA high-energy CR can easily and conveniently be used to calibrate MLC and verify its position. Hence, the application of AGFA high-energy CR is proved to be an accurate and time-saving method for routine MLC QC, especially when MLC calibration adjustments are required.     

Gamma radiation levels in the ambient environment of the QNPP Base

Monitoring results of gamma dose rate level in 1992～2004 in the ambient environment of the Qinshan Nuclear Power Plants(QNPP)Base,the northeast of Zhejiang Province,are reported in this paper.It is shown that the gamma dose rate of five monitoring sites of 2.5 km to QNPP Base is 84～113 nGy/h,with an average of 96 nGy/h in the 13 years.The average value is close to the background level of 93 nGy/h prior to operation of the QNPP Base,and is lower than the monitoring result of 101 nGy/h at the reference site in Hangzhou City.Within 50 km from the QNPP Base,the cumulative dose rate of the thermoluminescent dosimeter(TLD)is 90 nGy/h,which is lower than the back- ground level of 111 nGy/h.