γ辐照装置屏蔽方案评价

依据《γ辐照装置的辐射防护与安全规范》,针对典型γ辐照装置升源状态不同辐射照射途经进行计算分析，以验证屏蔽设计的可靠性；对不同照射途经的辐射剂量率进行比较，提出优化屏蔽计算及设计建议。结果表明：(1)该γ辐照装置屏蔽设计方案满足辐射屏蔽要求；(2)屏蔽计算过程中，屏蔽体外天空反散射剂量率贡献大于直射辐射剂量率，迷道入口散射辐射剂量率贡献大于直射辐射剂量率；(3)考虑γ辐照装置工作负荷较大，并遵循辐射防护最优化原则：在屏蔽设计过程中应考虑一次散射照射剂量率贡献，必要时进行局部加厚处理，对于迷道散射设计次数应在5次以上，楼顶区域不建议布置长期人员居留场所。     

γ辐照装置辐射安全监督管理的一些思考

结合γ辐照装置辐射安全例行监督检查活动中的一些新关注点,对γ辐照装置辐射安全监管中发现的一些问题进行探讨,提出γ辐照装置安全运行管理的建议,为加强装置安全运行管理提供相关参考。        

~(60)Co水下辐照试验装置

近年来辐射研究的领域不断扩大,要求设立更多的辐照装置。关于γ辐照装置,N.Tam-ura曾归纳了五种类型。其中第二类为辐照与贮藏采用同一口水井,故命为水下辐照装置。该类装置结构简单、造价低,曾被用于食品和高聚物研究,笔者以为此类装置至今对很多研究工作仍具采用价值。我国目前建造的γ辐照装置一律采用水泥防护室,但因耗资多而     

水池贮源型γ辐照装置辐射安全设施分析

本文叙述了水池贮源型γ辐照装置安全设施的概况。汇总了国内一些现有辐照装置的具体安全设施。对照国家相关标准,对辐照装置的安全设施按其功能分项进行了讨论,并分析了安全联锁中可能存在的逻辑错误。最后强调指出,辐照装置安全设施的设计、安装者,不能把辐射安全问题交给管理者;而辐射安全管理不能因为有了良好的安全设施而有丝毫的放松。     

辐射装置建设、运行管理学习班和交流会在山海关召开

中国核学会于1984年8月2日至14日在山海关召开了“辐照装置建设、运行管理学习班和交流会”。来自全国20个省、市的62名代表参加了会议,会议还特邀了12位同志做专题报告。会议分为三个阶段进行。首先就辐射技术应用的现状及发展,辐射的化学效应,辐射加工的剂量学等基础理论进行报告;然后介绍了国内外γ辐照装置,γ辐照装置的设计、建设概算和产品成本分析等有关辐照装置建设和管理的知识;最后是参加会     

固体球反应堆辐射回路——一种大型γ辐射源

固体球辐射回路装置是一种新的大型γ辐射源。辐射回路包括活化器、辐照器及其辅助系统。活化器和辐照器联结成一个回路,在回路内球形γ载体借助于气力传输而循环使用。装有气动单一器的活化器是放置在核反应堆堆芯附近(在其反射层中);而辐照器则可安     

上海辐射中心钴源装置剂量场计算

本文用γ辐照装置剂量场计算简化模型计算了上海辐射中心γ辐照装置剂量场分布,并与实测值进行了比较。计算和测量了辐照产品箱内累积最大和最小吸收剂量、均匀性等参数,介质为空气时符合较好,辐照产品为马铃薯时在10％以内符合。同时也给出了辐照产品为马铃薯时的产量和源利用率的计算值和实测值。     

二醋酸纤维素薄膜剂量计的制备和性能研究

为了改善醋酸纤维素薄膜剂量计在γ辐射剂量测定中稳定性欠佳的问题,拓展其辐射测量应用范围,采用离子液体均相乙酰化纤维素方法制得的二醋酸纤维素(CDA)粉末为原料,优化CDA薄膜制备工艺,研究其γ辐射变色性能及稳定性,制备适用于γ辐射剂量测量且性能优良的CDA薄膜剂量计。基于CDA的辐射变色机理,该薄膜剂量计在270 nm的单位厚度吸光度与吸收剂量存在良好的线性关系,剂量率、CDA的取代度和辐照气氛对薄膜的工作曲线影响较小。CDA薄膜剂量计的剂量检测量程为50～400 kGy,扩展不确定度为8.8%(K=2),辐照后24 h内吸光度测试稳定,具有良好的辐照稳定性,基本满足工业上对于辐射剂量计的使用要求,有望应用于γ辐射剂量的测量。     

湖南辐照中心60Co辐照装置辐射监测与预测分析

开展辐射监测是保障核技术利用装置安全稳定可靠运行的重要手段。本研究对湖南辐照中心⁶⁰Co辐照装置近5 a运行期间的工作场所、个人职业照射和贮源水井的辐射水平状况开展了监测与分析。结果表明：各场所及人员接受的辐射水平远低于国家的规定限值,贮源水井各项指标符合要求,未出现放射性活度超标的情况。引入用灰色GM(1,1)预测模型以5 a历史辐射监测数据为基础开展预测分析,结果显示,未来3 a的辐射水平变化较为稳定,且远低于规定限值,不会对周边环境与人员身体造成辐射危害。     

中国辐射加工新发展

中国同位素与辐射行业协会(CIRA)对中国辐射加工现状进行了调研。结果显示,中国现有束流功率在5kW以上工业用加速器45座,总功率为2005kW;有设计源强为1.11×10~4TBq以上γ射线辐照装置48座,另有源强低于1.11×10~4TBq的γ射线辐照装置75座,     

InGaAsP多量子阱激光二极管及其组件的γ辐射效应

本工作进行多量子阱激光二极管及其组件的γ辐照实验研究,总剂量（以Si计）达5.5×10⁴Gy。结果表明：多量子阱激光二极管抗γ射线辐照能力很强,在实验总剂量下,裸管形式的多量子阱激光二极管的P-I特性、I-V特性及中心波长基本未变化。而多量子阱激光二极管组件因包含光学窗口、耦合透镜及光纤等附属光学元件,这些附属元件受γ辐照后光学性能下降,最终导致激光二极管组件输出光功率随总剂量增大而下降,停止辐照后,不需加偏置,在室温下即能发生退火,使得斜率效率逐渐回升。     

伽马射线辐照技术制备石墨烯基功能材料的研究进展

综述了近年来利用伽马射线辐照技术在石墨烯及其衍生物的修饰改性、结构设计及功能应用等方面的研究进展,重点介绍了在液相体系和固相体系中,利用伽马射线辐照诱发的不同化学效应制备石墨烯及功能材料的研究工作,并展望了伽马射线辐照技术在石墨烯基材料研究与应用的发展前景。     

Effects of gamma-ray irradiation on electronic and non-electronic equipment of Large Helical Device

In a deuterium operation on the Large Helical Device,the measurement and control equipment placed in the torus hall must survive under an environment of radiation.To study the effects of gamma-ray irradiation on the equipment,an irradiation experiment is performed at the Cobalt-60 irradiation facility of Nagoya University.Transient and permanent effects on a personal computer,media converters,programmable logic controllers,isolation amplifiers,a web camera,optical flow meters,and water sealing gaskets are experimentally surveyed.Transient noise appears on the web camera.Offset of the signal increases with an increase of the integrated dose on the programmable logic controller.The DeviceNet module on the programmable logic controller is broken at the integrated dose of 72 Gy,which is the expected range of the integrated dose of the torus hall.The other equipment can survive under the gamma-ray field in the torus hall.     

Effects of gamma-ray irradiation on crevice corrosion repassivation potential of stainless steel in high temperature diluted simulated seawater

The crevice corrosion repassivation potentials (E_R,CREV) of type 304 stainless steel (304 SS) were measured in high temperature (373–553 K), diluted simulated seawater under gamma-ray irradiation, in order to confirm the effects of gamma-ray irradiation on the crevice corrosion behavior of a representative stainless steel in seawater. Overall, for high temperatures, the E_R,CREV values decreased with increasing chloride ion concentration, which was the same as the behavior observed under the non-irradiated condition. The E_R,CREV values measured under gamma-ray irradiation were the same or slightly higher than E_R,CREV values measured under the non-irradiated condition when the [Cl^?] was the same. Consequently, it was confirmed that the threshold potential of crevice corrosion of 304 SS for the gamma-ray irradiation of 1.8 kGy at least did not deteriorate compared with the non-irradiated condition. Under the conditions of this work (seawater composition, [Cl^?] range, dose rate, absorbed dose, flow rate, etc.), the crevice corrosion of 304 SS could be suppressed by maintaining the potential below the threshold potential which was determined approximately as ?0.3 V vs. SHE even for the irradiated condition at temperatures up to 553 K.     

Experimental simulations of planetary gamma-ray spectroscopy using thick targets irradiated by protons

To simulate planetary gamma-ray spectroscopy, gamma rays were measured during a series of five irradiations of up to 30-ton thick targets with protons beams of 1.5 and 2.5 GeV. The targets were steel (iron), basalt with structural steel, basalt with added S and Cl, and basalt with added H, S, and Cl. The pulsed proton beam was carefully monitored and counted. Spectra were collected with both proton beam on and beam off and with a lead shield both between the target and the germanium detector and with the lead shield removed. This set of four spectra was used to determine the fluxes of prompt gamma rays emitted from the target. Over 200 discrete gamma-ray lines per irradiation were observed and identified. Counting results for the more intense gamma rays were compiled, and gamma-ray fluxes determined for about 25 gamma rays of interest to planetary gamma-ray spectroscopy. The ratios of thermal and fast neutron induced gamma-ray fluxes between irradiations were similar. Thus the relative gamma-ray fluxes can be used in testing model calculations and interpreting planetary gamma-ray spectra.     

Effect of gamma-ray irradiation on the deoxygenation of salt-containing water using hydrazine

In spent fuel pools at the Fukushima Daiichi nuclear power plant, hydrazine was added to salt-containing water in order to reduce dissolved oxygen. Hydrazine is known to reduce dissolved oxygen in high-temperature pure water, but its deoxygenation behavior in salt-containing water at ambient temperature in the presence of radiation is unknown. Deoxygenation using hydrazine in salt-containing water was thus investigated using a ⁶⁰Co gamma-ray source and artificial seawater at room temperature. Water samples containing a small amount of hydrazine were irradiated at dose rates of 100–10,000 Gy/h. The concentration of dissolved oxygen in the water samples was measured before and after irradiation. Notably, a decrease in the dissolved oxygen was only observed after irradiation, and the dissolved oxygen concentration decreased with increasing dose rate and irradiation time. The rate of decrease in the amount of dissolved oxygen using hydrazine was slow in the presence of salts. Kinetic considerations suggested that the deoxygenation of the salt-containing water exposed to gamma-ray irradiation using hydrazine was suppressed by chloride ions.     

Effects of Heat-Treatment and Gamma-Ray Irradiation on the Etch-Pit Formation in Allyl Diglycol Carbonate Resin

Allyl diglycol carbonate resin plates possessing alpha tracks were etched after heat-treatment, or after gamma-ray irradiation. The strong heat-treatment and irradiation brought similar effects to two indicators: etch-pit diameter and bulk etching rate. The heat-treatment above 120°C lasting for 1h and irradiation above 4.0x10² Gy increased the indicators and caused the etch-pits to disappear faster. On the other hand, mild heat-treatment brought the opposite effects to under-cured resin. A reduction of the etch-pit diameter was observed in the resin exposed to heat-treatments between 80°C and 120°C lasting for 1h. These phenomena were observed in the study of plates in which alpha tracks were made after the above mentioned heat-treatment or irradiation. These results suggest not only the conditions under which the resin may be used, but also the possibility of enhancement or suppression of etching speed, and of estimation of thermal history or measurement of gamma-ray dosage.     

西安脉冲反应堆燃料元件燃耗的无损测定

介绍了利用1能谱法无损测定西安脉冲反应堆单棒燃料元件燃耗的方法。该法利用测定裂变产物^137Cs的活度．并进行相应的历史跟踪、校正计算、理论分析等得出燃耗值,同时也讨论了其它需要解决的关键技术。     

离子液体1-丁基-2,3-二甲基咪唑六氟磷酸盐对γ射线辐射稳定性研究

研究了憎水性离子液体1-丁基-2,3-二甲基咪唑六氟磷酸盐([BuMeMeIm]PF6),在氮气保护下,60Coγ射线照射,最大剂量为400 kGy的辐射稳定性。随着辐照剂量的增加,[BuMeMeIm]PF6的颜色逐渐加深,紫外-可见光谱(UV-Vis)中吸光度随辐照剂量的增加呈线性增长,但颜色及吸光度的变化均小于1-丁基-3-甲基咪唑六氟磷酸盐([BuMeIm]PF6)。辐照400 kGy后,[BuMeMeIm]PF6的傅利叶红外光谱(FTIR)和核磁共振氢谱(1H NMR)谱图均未出现变化。高效液相色谱法(HPLC)分析表明辐照400 kGy后,发生辐解的[BuMeMeIm]+的比例约为0.73%,小于同样条件下发生辐解的[BuMeIm]+。电喷雾质谱(ESIMS)结果显示[BuMeMeIm]+中N-butyl键的断裂可能是阳离子分解的重要原因之一。因此,咪唑环C(2)-H被甲基取代,将会增加咪唑阳离子的辐射稳定性,减小阳离子的辐射分解,使得[BuMeMeIm]PF6具有更高的辐射稳定性。     

Comparison of Methods for Irradiating Prone Patients

The results of irradiation with an 18 MeV rotating gamma-ray setup and three variants of equipment for proton beam transport – horizontal beam, rotating universal GANTRI, and a planar system with irradiation direction limited to ±45° to the horizontal – are compared. The average values of three parameters averaged over the target size and position are obtained for each type of equipment – the fraction of the total dose that strikes the target, the ratio of the average (specific) irradiation dose to healthy tissue to the dose in the target, and the ratio of these quantities. Comparing the results shows that it is desirable to adopt simple planar systems in proton and ion therapy.