奥氏体不锈钢在400～720℃下的电子辐照成核和肿胀

用高压电子显微镜(HVEM)研究了被电子辐照的奥氏体不锈钢在400～720℃范围内,温度对其肿胀行为的影响。样品材料包括:固溶退火的316不锈钢(316SA)、冷轧316不锈钢(316CW)和加钛的奥氏体不锈钢(Ti-mod.SS),HVEM的电子能量为1MeV。研究了平均孔洞密度、平均孔洞直径、肿胀、肿胀率同孕育剂量与温度的关系。认为辐照温度影响样品的微结构、总尾闾强度和中性尾闾与偏向性尾闾强度之比,从而使316SA、316CW和Ti-mod.SS的孔洞成核、孔洞长大及肿胀行为有所不同。还研究了氦预植入对孔洞成核的影响,实验结果表明:氦虽成为活跃的孔洞核心,但对孔洞长大并无直接影响。     

奥氏体不锈钢在400～720℃下的电子辐照成核和肿胀(英文)

用高压电子显微镜(HVEM)研究了被电子辐照的奥氏体不锈钢在400～720℃范围内,温度对其肿胀行为的影响。样品材料包括:固溶退火的316不锈钢(316SA)、冷轧316不锈钢(316CW)和加钛的奥氏体不锈钢(Ti-mod.SS),HVEM的电子能量为1MeV。研究了平均孔洞密度、平均孔洞直径、肿胀、肿胀率同孕育剂量与温度的关系。认为辐照温度影响样品的微结构、总尾闾强度和中性尾闾与偏向性尾闾强度之比,从而使316SA、316CW和Ti-mod.SS的孔洞成核、孔洞长大及肿胀行为有所不同。还研究了氦预植入对孔洞成核的影响,实验结果表明:氦虽成为活跃的孔洞核心,但对孔洞长大并无直接影响。     

Xe~+离子辐照诱导国产T91及316Ti钢微结构变化研究

对国产T91及316Ti钢进行室温下200keV的Xe~+离子辐照,使用X射线衍射(XRD)、透射电镜(TEM)等检测方法研究不同损伤剂量下辐照对材料相的稳定性和微观结构变化的影响。研究结果表明:T91钢辐照后未发生明显相变,而316Ti发生了γ(FCC)→α(BCC)的马氏体相变,且随辐照损伤剂量的增加,α相含量增加,相变的主要驱动力为辐照离子在辐照层的聚集从而产生的剪切应力;T91钢中的M_(23)C_6颗粒随辐照损伤剂量的增加,非晶化越来越明显,主要是由于辐照粒子的轰击削弱了M_(23)C_6颗粒晶格的稳定性,晶格塌陷成为非晶状态;316Ti钢在较低辐照损伤剂量(4.6dpa)下出现黑斑结构,而在高辐照损伤剂量(37.1dpa)下黑斑结构进一步聚集形成位错环。     

SCWR候选不锈钢的低周疲劳性能研究

采用MTS材料试验机研究316Ti、347和HR3C奥氏体不锈钢在650℃和室温下±0.5%应变幅的低周疲劳性能,并采用扫描电镜对试验后样品进行断口分析。结果表明,347和HR3C不锈钢在室温下疲劳寿命较高,347不锈钢在650℃疲劳寿命也较高。3种材料在两种温度下的弹性变形量均在0.1%～0.15%之间,且滞后回线面积变化不大,这表明弹性变形量与疲劳寿命高低无直接联系。3种材料在两种温度下呈现出不同的循环硬化/饱和行为,316Ti不锈钢的650℃峰值应力与室温峰值应力无明显变化,而HR3C和347不锈钢的差别较大,但316Ti不锈钢的650℃循环硬化效应显著,347不锈钢的硬化效应较低。在650℃低周疲劳试验后,347不锈钢样品断口表面的疲劳条带间距仅为1.87μm,而对于316Ti和HR3C不锈钢则分别达到4.67μm和3.0μm,进一步表明347不锈钢在650℃的疲劳寿命最高。     

实验快堆发展计划中包壳材料轻离子辐照损伤探讨

一、开展快堆包壳材料轻离子辐照工作的意义快堆堆芯材料(包括包壳材料和组件材料广泛采用316不锈钢)处在高的工作温度(>500℃)及高注量快中子(E>0.1 MeV)的辐照场下工作。在整个寿期内,要经受注量达3×10~(23)n/cm~2的快中子辐照,相当于100～120 dpa。在超过空洞孕育期(～10~(22)n/cm~2)后,包壳材料出现严重的辐照肿胀(对316不锈钢,在快堆寿期末,肿胀量可达到10%),其肿胀按(φt)~n方式增加,其中φ为快中子注量,t为时间,n为大于1的指数。对快堆     

聚变驱动次临界堆第一壁材料辐照损伤的初步研究

介绍了中子对材料的辐照损伤原理及化合物原子平均离位(DPA)截面计算方法;使用辐照损伤计算程序SPECTER计算了聚变驱动次临界堆(FDS-I)第一壁材料CLAM钢的辐照损伤参数,并将CLAM钢的辐照损伤计算结果与相同条件下316SS、SiC等聚变堆结构材料的计算结果进行了比较.     

HFETR辐照石墨材料中子注量验证试验

钍基熔盐堆石墨材料辐照考验目标为:中子注量为5×10~(20)cm~(-2)(±15%)(E>0.1 Me V),堆内辐照试验温度650℃(允许偏差±50℃)。为了满足辐照考验要求,在高通量工程试验反应堆(HFETR)第92-I炉的K07孔道进行辐照验证试验。该验证试验辐照装置采用分段构成的型式,主要由辅助密封段、辐照试验段、气管组件3部分构成,辐照罐外围为去离子水,辐照罐内为惰性气体用于控制辐照试验温度。使用MCNP程序对各样品中子注量进行预示计算,同时在辐照装置阳面和阴面都布置了探测器进行中子注量测量。试验表明:在辐照试验过程中,在辐照装置调气系统最佳导热模式下辐照温度略高于上限700℃;利用MCNP程序预示计算中子注量结果为5.7×10~(20)cm~(-2)(E>0.1 Me V),而中子注量测量结果为4.83×10~(20)cm~(-2)(E>0.1 Me V),基本满足石墨材料辐照考验中子注量要求。     

独立温度补偿型高温材料辐照考验装置设计研究

为实现材料堆内650±50℃的高温辐照考验,提高辐照温度的均匀性,进行了高温材料辐照考验装置的设计研究。通过筛选合适的材料进行辐照考验装置的加工制造,提高了辐照考验装置的耐高温性能。以条件辐照试验结果为基础,对辐照考验装置进行了热工分析,提出了阴阳面温度独立控制技术和阶梯间隙温度补偿技术,确定了辐照考验装置的关键尺寸,实现了650±50℃的辐照温度,减小了辐照温度的差异。     

SCWR候选不锈钢的蠕变性能研究

采用RDL50型蠕变持久试验机研究奥氏体不锈钢316Ti、347、HR3C和6XN在550℃/90 MPa、600℃/85 MPa、650℃/70 MPa和700℃/65 MPa条件下的蠕变性能。结果表明,在550℃/90 MPa条件下,347的蠕变性能最佳,但随着温度的提高,600℃以上HR3C的蠕变性能优势逐渐体现;316Ti在4种条件下的蠕变性能均最差。结合实验数据分析,应力指数n排序为316Ti>347>HR3C,激活能Q排序为HR3C>347>316Ti,进一步表明了上述3种材料蠕变性能的优劣为HR3C>347>316Ti。     

ADS散裂中子源材料不锈钢和钨的辐照效应(英文)

研究了80 MeV碳或85 MeV氟离子辐照在国产改进型316L不锈钢、普通不锈钢和钨中产生的辐照效应。实验结果表明,不锈钢的抗辐照性能比钨的好;它们中,国产改进型316L不锈钢具有最好的抗辐照性能。选用不锈钢做ADS散裂中子源的束窗等材料是较好的选择,采用国产改进型316L不锈钢是最佳的选择。     

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.