CEFR堆芯围桶开孔处温度场及流场分析

应用CFX对堆芯围桶开孔处温度场及流场进行模拟计算并对结果进行分析。利用模型Ⅰ、Ⅱ分别计算得到堆芯围桶开孔处的温度场及流场,并得到在正常工况下堆芯围桶开孔处钠的流动方向。计算验证了事故余热排出系统（CAPX）水台架的试验结果,为CEFR堆芯围桶开孔的安全分析打下基础。     

核电厂放射性固体废物桶外γ测量重要影响因素的探讨

本文针对我国运行核电厂常用的两种桶外γ活度测量系统(整体γ射线测量系统(IGS)和分段γ射线测量系统(SGS)),阐述了桶装放射性固体废物的活度和密度分布不均匀条件下对测量系统探测效率和不确定度的影响。现场试验及蒙特卡罗模拟计算表明,桶外γ活度测量系统基本满足电厂桶装废物γ核素活度测量要求,活度分布和密度分布导致的测量结果不确定度分别在17%和20%之内;同时应正确认识桶外γ测量方法在桶装固体废物测量中的地位及作用,针对存在的问题,提出应制定废物桶活度桶外测量方法的技术规范、保证设备的工作环境和加强人员培训。     

硼饱和模拟废活性炭的桶外水泥固化

核电站在运行过程中会产生含硼废水浸泡且硼饱和的废活性炭,需要对其进行固化处理。采用2.5‰(质量分数)的硼酸溶液对活性炭进行浸泡直至含硼量达到稳定来模拟实际废物源项,然后脱去硼饱和后活性炭中的游离水,并采用桶外水泥固化工艺对其进行水泥固化。结果表明,试验过程稳定可靠。另外通过试验验证可知,华龙一号新增废物源项废活性炭能够利用现有桶外水泥固化技术进行废物的处理,对硼饱和模拟废活性炭采用桶外工艺固化后,养护形成的水泥固化体按照标准GB 14569.1-2011进行游离液体、机械性能、抗水性、抗冻融性以及耐γ辐照性试验测试,结果均满足要求,且活性炭颗粒在固化体中分布均匀,未出现上浮现象,其搅拌完成以及30min后自由流动度均大于200mm,完全满足桶外水泥固化工艺稳定可靠的运行要求。     

放射性废液综合处理车间正式启动运行

放射性废液综合处理车间建成于2003年，其主要功能是通过蒸发浓缩处理中放废液，并最终将废液转化为水泥固化体进行永久处置。该车间生产能力为每天蒸发处理废液12t，生产水泥固化体15桶。该车间建成后，先后进行了冷试验和整改，使该车间具备了设计的生产运行能力，在2004年底，顺利完成了车间的热试验，热试验完成处理废液约100m^3，产生水泥固化体约40桶。     

美国洛斯阿拉莫斯国家实验室的净化项目已经完成

【据因特网2001年12月20日报道】一个旨在挖出洛斯阿拉莫斯国家实验室(LANL)的放射性废物桶并对其进行检查的项目已经完成。 由于担心腐蚀作用和放射性物质可能发生泄漏,美国新墨西哥州环境部于1992年下令,将LANL的17000桶放射性废物从地下挖出,并将其贮存在地表以便检查,直到被送往它们永久的处所。 LANL官员表示,大约有30%的放射性废物桶已经发生腐蚀,有约200个桶的桶壁上出现小孔。 这些桶最终将与LANL的其他放射性材料一起被运往位于卡尔斯巴德附近的废物隔离试验工厂进行永久贮存。 美国洛斯阿拉莫斯国家实验室的净化项目已经完…     

200L低中放废物桶自由下落试验测试

介绍了对200L废物桶自由下落试验测试方法.试验通过加速度计、应变片测量了碰撞过程的加速度、应力应变,并使用DIC技术(高速摄像),分析了碰撞过程垂直于靶台的加速度,经对比,该技术带来的偏差约为20％.     

放射性有机废液贮存容器的研制

本文进行了聚乙烯、聚酯玻璃钢等材料耐甲苯、二氧六环等有机溶剂的试验。试验结果表明,用这些材料制成的容器存放放射性有机废液是不安全的。选用不锈钢研制了20L 有机废液贮存桶,经耐2kg 水压和1.2m 坠落试验,均无损漏;实际使用效果较为满意。     

水泥固化线运行参数优化改进研究

水泥固化法是目前较为成熟的放射性废物处理技术之一,其生产效率主要受制于固化体的养护时间。为确定最佳的运行参数,对水泥固化线进行参数优化改进及固化体综合性能验证试验,并通过试验确定最佳的运行参数。在固化体性能参数满足国标要求的基础上,生产能力由5桶/d提升至10桶/d。     

固化线桶外搅拌设备调试及改进建议

在方家山核电厂水泥固化线调试过程中，进行了浓缩液、废树脂固化和废过滤器芯固定试验。试验中发现了水泥固化配方、设备设计、设备可靠性等方面存在的问题，分析了问题的原因，提出应研制出兼顾泥浆流动性、固化体性能、废物最小化和适合桶外搅拌的配方；还应从设备设计、选型和加工制作多方面优化和提升设备的可靠性；在核电厂应用前应进行充分的工程验证，提高固化线桶外搅拌工艺的可靠性。      

核燃料盛装容器制造工艺故障树分析

核燃料包装桶由桶体、桶底、桶盖、锁紧环、密封胶圈等组成。它要求在运输、储存过程中保证其密闭性,以防止内容物外泄造成污染事故。包装桶的制造工艺包括下料、成形、缝焊、组装、除锈、涂漆。其中缝焊、桶体与桶底咬边是两个关键工序,磨坡口、桶口成形与桶底咬接缝预翻边是其重要工序。详细地研究了制造工艺故障,建立了工艺故障树。找出并剖析了原材料、工艺参数、设备、工艺方法及操作是产生工艺故障的五个方面     

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.     

Information for authors

<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-     

PLASMA SCIENCE AND TECHNOLOGY AUTHOR INDEX TO VOLUME 16(2014)

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