高温堆燃料元件研制(英文)

我国10MW高温试验模块堆采用球形燃料元件,这种燃料元件由包覆燃料颗粒弥散在石墨基体里的燃料区和由不含燃料的同样基体材料外壳组成,燃料区和无燃料区之间没有物理上的分界面。用修改了的溶胶凝胶工艺制备燃料核芯,该工艺兼有内、外凝胶工艺的优点,包覆燃料颗粒采用TRISO结构。实验室产品的冷态性能和文献资料上发表的国际同类产品的相当,初步辐射结果良好;用化学提纯工艺制出了核纯天然石墨粉;用准等静压的方法制造球形燃料元件,性能指标达到了设计要求;建立并发展出高温堆燃料研究和发展所需的常规的及非常规的性能测试方法,满足了实验研究的需要。     

高温堆燃料元件研制

我国10MW高温试验模块堆采用球形燃料元件,这种燃料元件由包覆燃料颗粒弥散在石墨基体里的燃料区和由不含燃料的同样基体材料外壳组成,燃料区和无燃料区之间没有物理上的分界面。用修改了的溶胶凝胶工艺制备燃料核芯,该工艺兼有内、外凝胶工艺的优点,包覆燃料颗粒采用TRISO结构。实验室产品的冷态性能和文献资料上发表的国际同类产品的相当,初步辐射结果良好;用化学提纯工艺制出了核纯天然石墨粉;用准等静压的方法制造球形燃料元件,性能指标达到了设计要求;建立并发展出高温堆燃料研究和发展所需的常规的及非常规的性能测试方法,满足了实验研究的需要。     

10 MW高温气冷堆球形燃料元件制造

10 MW高温气冷实验堆球形燃料元件的制造使用橡胶模具冷准等静压工艺.制造了44批,约20 540个燃料元件.燃料元件的冷态性能符合设计指标,44批燃料元件的平均自由铀含量为4.57×10-5,正品率为99%.     

辐照后HTR-10球形燃料元件电化学解体及裂变产物分布研究

辐照后检验是开展燃料性能评价的重要手段。在10 MW高温气冷堆(HTR-10)球形燃料元件的辐照后检验中,为研究元件中TRISO包覆燃料颗粒的破损机制,本文利用基于电化学氧化原理的两步解体法,对所选元件(燃耗约35 GW·d/tU)进行了包覆燃料颗粒与基体石墨的分离,获得了元件中不同位置区域的包覆燃料颗粒、解体石墨粉和电解液,通过γ能谱定量分析了解体石墨粉和电解液中的放射性核素成分及含量,并基于此明确了放射性核素在辐照后球形燃料元件基体石墨中的分布。结果表明：部分电解液中裂变产物¹³⁷Cs与¹⁴⁴Ce活度显著高于其他电解液样品,表明其对应区域中可能存在破损包覆燃料颗粒;元件表层位置对应的电解液中活化产物⁶⁰Co高于内部区域,主要来源于HTR-10一回路的放射性粉尘沾污。本工作初步建立了高温气冷堆辐照后球形燃料元件电化学解体和解体样品分析测试的平台及方法,为TRISO型包覆燃料颗粒破损机制分析及其堆内行为研究提供了重要基础。     

球床式高温气冷堆示范工程球形燃料元件的研制

为满足球床式高温气冷堆（HTR-PM）示范工程对球形燃料元件大批量生产、单球高铀含量和低破损率的要求,必须对10 MW高温气冷堆时期的球形燃料元件生产工艺进行改进和优化。通过对基体石墨粉、穿衣、压制、车削和热处理等关键设备及相关工艺进行重新设计和优化,建立了规模化的球形燃料元件生产工艺。采用该工艺生产的球形燃料元件,冷态性能如压碎强度、热导、磨损和腐蚀等均满足HTR-PM的技术指标,特别是球形燃料元件的平均自由铀含量与HTR-PM球形燃料元件的自由铀含量指标（6.0×10^-5）相差近1个数量级。采用优化后的规模化生产工艺,成功地研制出符合HTR-PM技术要求的球形燃料元件。     

HTR-10辐照后石墨球~(14)C含量研究

高温气冷堆中球形燃料元件与不含燃料的石墨球在14 C产生机制上基本相同,为获得10MW高温气冷堆(HTR-10)中燃料元件及石墨球中14 C的含量,研究了14 C在石墨球中的产生机理。总结了石墨球及燃料元件中14 C的产生途径,计算经过堆芯辐照后的石墨球中14 C总量,比较现有石墨球的解体技术,提出了分解石墨球制取14 C样品的实验测量方法。本文工作为进一步的实验研究工作奠定基础并提供理论计算结果比对。     

包覆燃料颗粒应力的有限元分析

高温气冷堆的燃料元件由包覆燃料颗粒弥散在石墨基体中组成。在反应堆运行过程中,辐照及各复杂的物理化学反应产生的应力会使包覆燃料颗粒发生破损,对包覆燃料颗粒进行应力分析是评价燃料元件和反应堆运行安全性能的主要内容之一。本文基于压力壳模式,主要考虑内压作用下的球形壳层应力及包覆燃料颗粒的非球形因素,用有限元法对应力进行了分析。     

HTGR燃料元件制造工艺及性能研究

本文介绍了高温气冷堆(HTGR)球形燃料元件的半/全冷等静压制造工艺。该工艺主要包括:石墨压型粉制备,颗粒“穿衣”,半/全冷等静压成型,碳化和高温真空热处理,外形机加工。用半/全冷等静压工艺制备的球形燃料元件样品的冷态性能测试表明:元件的冷态性能满足10MW HTGR 设计要求,并达到国际设计标准。     

10 MW高温气冷堆燃料元件辐照后检验

为了评价10 MW高温气冷堆(HTR-10)用燃料元件的性能,从第1和第2生产批次中分别随机抽取两个球形燃料元件进行辐照考验.辐照考验在俄罗斯的IVV-2M堆内进行,采用动态辐照试验的方法,可分别控制每个辐照盒中燃料元件的温度和测量气态裂变产物的释放.辐照后检验包括外观检查、尺寸测量、固体裂变产物在基体石墨内的分布测量、包覆燃料颗粒破损率测量和金相观察.辐照后检验结果表明辐照没有引起燃料元件中包覆燃料颗粒的破损, 生产的燃料元件满足10 MW高温气冷堆的设计要求.     

HTR-10堆芯氧化模拟

对10 MW高温气冷堆(HTR-10)的堆芯模型进行简化,研究燃料元件在正常运行工况下的氧化情况,包括水蒸汽氧化及水蒸汽和氧气的共同氧化情况。结果表明,在燃料元件平均驻留期内石墨材料的水蒸汽腐蚀比较均匀,且主要发生在温度较高的底部;而氧气和水蒸汽对石墨材料的氧化则比较剧烈,底层燃料元件的石墨材料表面被腐蚀掉。     

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。     

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.     

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.     

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<正>1.NUCLEAR SCIENCE AND TECHNIQUES(NST),a bimonthly journal,is devoted to all aspects of nuclear science and technology,theoretical or experimental.Its special interest lies in the subjects of synchrotron radiation science and technology;low energy accelerators,radiation technology and applications;radiochemistry,radiopharmaceuticals and nuclear medicine;nuclear electronics and instrumen-