模块式套管型随堆辐照考验装置的研制

为进行材料在高γ释热区的辐照考验,研制了模块式套管型随堆辐照考验装置(MTIR)。该随堆辐照考验装置具有辐照温度测量和调节功能,在高γ释热率条件下能够对试验段进行强化冷却。堆内验证试验表明,该装置能够实现材料样品的辐照考验指标,可使高通量工程试验堆(HFETR)内层辐照孔道得到有效利用,缩短材料堆内辐照试验周期,提高HFETR辐照能力。     

新型镍基合金热电偶在 HFETR 中的辐照标定

本文叙述了在高通量工程试验反应堆(HFETR)堆内辐照对热电偶标定的影响,铅的熔点(327.5℃)作为标定热电偶的标准参考温度。材料的γ加热和调节辐照试验装置内气体成分的比例保证了热电偶的辐照温度在350±20℃,并实现了在铅熔点对热电偶的标定。本实验研究了热电偶的辐照刻度偏差 △t 与积分中子通量以及辐照瞬时效应 △t_1与γ照射量率的关系。     

10 MW高温气冷堆包覆燃料颗粒辐照考验

TRISO型包覆燃料颗粒由燃料核芯、疏松热解炭层、内致密热解炭层、碳化硅层和外致密热解炭层组成.在冷态性能检验合格的基础上,进行了10 MW高温气冷堆包覆燃料颗粒的静态辐照试验和动态回路辐照试验.在辐照温度1 000 ℃、累积快中子注量1.28×1025 m-2和燃耗(以金属铀计)达到95 GW·d·t-1时,包覆燃料颗粒的放射性裂变产物85Krm的释放率为1.02×10-6,辐照后检验未发现包覆燃料颗粒破损.辐照考验结果表明,包覆燃料颗粒的性能可以满足我国10 MW高温气冷堆安全运行的要求.     

双面冷却辐照装置的试验研究

本文介绍了双面冷却新型辐照装置的研究试验。该装置是为克服高通量工程试验堆(HFETR)γ发热量大给材料辐照带来的困难而进行的探索。通过堆内和堆外试验,结果证明性能良好,并已成功地应用在核电站压力壳钢的辐照试验中。     

10 MW高温气冷堆燃料元件的辐照考验

10 MW高温气冷堆燃料元件的辐照考验在俄罗斯IVV-2M堆内进行,辐照考验于2000年7月13日开始,现仍在进行中.至2002年6月14日,燃料元件最高燃耗(以金属铀计,全文同)已达77 000 MW*d/t,累积快中子注量达8.59×1020 cm-2.本文描述辐照样品的冷态性能、辐照装置、辐照条件和已获得的辐照考验结果.     

美日合作研制快堆燃料元件

【英国《国际核工程》1981年8月号报道】根据美国与日本签订的新协定,美国能源部和日本“动·燃”事业团将联合在快中子高通量试验装置(FFTF)上进行快堆燃料组件和包壳的辐照试验,在EBR一H堆上进行快堆的性能试验。日本"动·燃"事业团承担     

模块式套管型随堆辐照考验装置Ansys CFX热工分析

模块式套管型随堆辐照考验装置应用于高通量工程试验堆高通量区材料辐照试验。本文利用计算流体动力学(CFD)软件Ansys CFX对该装置试验段进行热工分析。分析表明,材料样品堆内辐照试验结果与热工分析结果基本一致,Ansys CFX的热工分析结果准确,可以应用于辐照考验装置设计。     

国产快堆燃料元件包壳材料316不锈钢的中子辐照效应

介绍国产六种不同成分与工艺的快堆燃料元件包壳材料316不锈钢(316SS)经650℃高温、积分中子注量3.1×1021n/cm2(En>0.1MeV)的辐照概况,以及辐照后在650℃与室温下的拉伸力学性能试验和金相检查的结果及评述。     

用于HFETR的材料辐照试验的新型装置

针对各种反应堆结构材料辐照样品的温度与中子注量要求，设计了一种适用于在高通量工程试验堆(HFETR)堆内进行材料辐照试验的新型辐照装置。本文简要介绍了该装置的结构特点、技术特点、辐照罐的设计以及测试系统与试验情况。目前，该装置已完成了多种材料的辐照试验，结果表明：装置具有温度调节范围宽(0-120℃)、系统调节能力强、安全可靠和出入反应堆方便等优点．完全能满足各种反应堆结构材料的高低温辐照试验要求。     

高温与反应堆辐照对玻璃纤维绝缘电缆的影响

试验在反应堆孔道内进行。所达到的最高累积辐照水平为热中子1.6×10~(20)n/cm~2,快中子(能量≥1 MeV)3.8×10~(19)n/cm~2,γ剂量1.1×10~(11)R。电缆在堆内辐照时的温度一般在550℃以上。试验结果表明电缆性能良好。得到的主要结论有:(1)电缆绝缘电阻受温度影响,与堆功率有关,在一定范围内与辐照积分通量关系不大;(2) 中子与γ射线在电缆上引起感应电流,其大小与堆功率成正比,在一定范围内与辐照积分通量无关,γ射线对感应电流有较大影响;(3)电缆辐照后的机械性能良好。     

高温熔盐试验回路系统设计及验证研究

The Thorium Molten Salt Reactor (TMSR) project plans to construct a 2 MWt liquid fuel molten salt reactor. After successful R&D of the proto-type equipment like pump, heat exchanger and freeze valve, construction of a high temperature fluoride loop is designed and constructed to test them. The rated power of heat exchange is designed to be 200 kW, and the flow rate is set as 15 m3/h by the caloric equation. Hence the pipe caliber chose to be DN50. The numerical computation by Fluent revealed that the pressure drop of the loop system is about 155 kPa, and the overdesign of the pump head is set as 20 m accordingly. To avoid thermal stress concentration of the pipeline, both the electric heater and radiator are designed to be fixed on a flexible universal sphere support, except the pump which is anchored on steel support directly. The structural design of the equipment and the loop hase been verified by several tests with an accumulated operating time near 4000 hours. The actual pressure drop of the loop is about 110~120 kPa, which still needs to be accurately measured by differential manometer in future. The analysis of the impurity of the molten salt shows that the contents of Cr and Mo increased by two orders of magnitude after loop operation, which means that an obvious material corrosion occurs. The level of moisture and oxygen, which is the main reason that cause fluoride corrosion, should be controlled considerably lower than the original design level of 100 μL/L.     

Experimental and numerical evaluation of IR thermography method for Final Acceptance Tests of the ITER divertor dome

The divertor dome (DO), being part of the ITER divertor, is designed to extract the major part of the plasma thermal energy. As a plasma-facing component (PFC), the DO experiences high heat fluxes (up to 5.0 MW/m²). Such severe operation conditions of the DO imply stringent requirements for the DO design and its cooling system to ensure the required temperature operation regime of the dome. Hence, Final Acceptance Tests (FAT) shall be performed on each DO final assembled component with the aim to demonstrate that none of parallel coolant channels are completely or partially blocked. The paper presents the results of the analytical and experimental testing of the thermography method capability to perform the FAT. The aim is to determine defective hypervapotrons of the divertor dome. The method consists in contactless measurement of the dynamic temperature field of the PFC surface at a step-like increase (from zero to constant value) in the coolant flow rate with a temperature higher than that of the hypervapotron.     

Identification of radiation treatment of wheat （Triticum aestivum. L）and rice （Oryza sativa. L） samples using thermoluminescence of contaminating minerals

Food irradiation is gaining popularity worldwide and this technology is important to improve quality and reduce the post harvest losses of food. Because of the rapid commercialization of irradiated foods throughout the world, compliance of different regulations relating to use of technology in different countries and demand of consumers for clear labelling of irradiated foods, there is need for the development of analytical methods to detect radiation treatment of food. Among several methods studied so far, thermoluminescence （TL） is an important method that can be used to find out the irradiation history of food that contain even a very minute amount of dust particles. In this study, the irradiated and unirradiated wheat and rice samples were analyzed using the TL method. The samples were purchased from the local market of Peshawar and irradiated to radiation doses of 0.5 and 1.0 kGy using Co-60 gamma irradiator at the Nuclear Institute for Food and Agriculture （NIFA）, Peshawar. The mineral contaminants were isolated by jet water, ultrasonic treatment, and density gradient. TL glow curves of the isolated minerals from irradiated and unirradiated samples were recorded between the temperature ranges of 50-500℃ using a TL reader. Generally, the glow curves for irradiated samples showed much higher TL intensities （TL1） than the unirradiated samples. The results were normalized by rerradiation of mineral samples to gamma-ray dose of 1.0 kGy followed by determination of the second glow curves （TL2）. The ratio of the area of first glow curve to that of second glow curve （TL1/TL2） was calculated for selected temperature intervals and compared with the recommended values for unirradiated and irradiated samples. Finally, the shapes of the glow curves for irradiated and unirradiated samples were also analyzed. On the basis of these results （comparison of TL-intensities, TL1/TL2 ratios and shapes of the glow curves）, all the irradiated and unirradiated samples of wheat and rice were unequivocally identified.     

有效探测面积大于1000 cm2的正比计数器测量系统性能测试

为对自制的活性面积高达1 000 cm²的大面积源进行表面发射率定值,同时作为现有2πα、2πβ表面发射率标准装置能力的扩充,研制了一套内置式大面积2π多丝正比计数器测量系统,并利用活性区直径为8 mm的²⁴¹Am点源及活性区面积为10 cm×15 cm的大面积²⁴¹Am和⁹⁰Sr-⁹⁰Y源对其进行计量学性能测试。结果表明：计数器内计数响应均匀性优于±0.4%,有效探测面积达1 400 cm²;所得²⁴¹Am源高压坪曲线的坪长为1 400 V,坪斜为0.27%/100 V,坪区内计数变化为0.87%;⁹⁰Sr-⁹⁰Y源高压坪曲线的坪长为300 V,坪斜为0.75%/100 V,坪区内计数变化为0.80%;10次测量重复性好于0.4%,8 h内短期稳定性好于0.3%,1 a内长期稳定性好于0.8%。     

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.     

Interaction between uranium and humic acid (Ⅰ): Adsorption behaviors of U(Ⅵ) in soil humic acids

The adsorption behaviors of uranium on three soil humic acids (HAs), which were extracted from soils of different depths at the same site, were investigated under various experimental conditions. The adsorption results showed that U(Ⅵ) in solutions can be adsorbed by the three soil HAs, with the order of FHA (HA from 5 m depth of soil) ＞SHA (HA from the surface) ＞THA (HA from 10 m depth of soil) for adsorption efficiency in each desirable condition, and the adsorption reached equilibrium in about 240 min. Although the maximum adsorption efficiency was adsorption could be described with Langmiur isotherm or Freundlich isotherm equation. The L/S (liquid/solid, mL/g)ratio and pH were important factors influencing the adsorption in our adsorption system besides uranium concentration. The adsorption efficiency decreased with the increase of the L/S ratio and pH at the pH range of 2.0-3.0 for SHA and THA or 2.5 - 6.0 for FHA. However, no significant difference in adsorption of U(Ⅵ) was observed at the experimental temperature. All the results implied that humic substances have different characteristics in samples even collected at the same site.     

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。     

The preclinical pharmacological study of dopamine transporter imaging agent 18F-FP-β-CIT

The paper is to study pharmacologic characteristics of 18F-FP-β-CIT (18F-N-(3-fluoropropyl)-2β- carbomethoxy-3β- (4-iodophenyl)nortropane) as an imaging agent for dopamine transporter. The radiochemical purity of 18F-FP-β-CIT in aqueous solution was over 95% after standing at room temperature for 4h. Biodistribution displayed rapid uptake in rat brain (1.375 %ID/organ at 5min and 0.100 %ID/organ at 180 min) and the striatal uptake was 1.444,0.731, 0.397, 0.230 and 0.146 %ID/g at 5, 30, 60, 120 and 180 min, respectively. The values of striatum/cerebellum,striatum/frontal cortex and striatum / hippocampus in rat's brain at 30 min were 3.38, 2.17 and 2.40 respectively. The uptake in striatum can be blocked by β-CFT, suggesting that 18F-FP-β-CIT binds to DAT peculiarly. The compound was rapidly cleared from monkey's blood. The striatal uptake was bilaterally decreased in the left-sided lesioned PD rats, compared with normal control. Brain PET imaging studies in normal monkey showed that 18F-FP-β-CIT was concentrated in striatum. The test of undue toxicity showed that the dose received by mice was 1250 times as by human, which indicates that 18F-FP-β-CIT is very safe. So 18F-FP-β-CIT is a promising PET imaging agent for DAT with safety and validity.