一种新型无机复合交换剂回收~(137)Cs的研究

本文叙述了磷酸锡-AMP(磷钼酸铵)的制备及其对~(137)Cs的交换性能,测定了不同制备条件所得产物对交换容量的影响,做了吸附-淋洗实验和~(60)Co γ辐照实验,求出了C/Co=0.01时的击穿容量和~(137)Cs的回收百分数。用相应的放射性料液配制模拟液进行了~(137)Cs的回收实验,对回收的~(137)Cs产品用γ能谱法测定了γ杂质含量;用~(85-89)Sr作指示剂,通过实验和计算求出了在~(137)Cs产品中Sr的百分含量。     

利用无机离子交换剂—多聚锑酸从1AW中提取裂变核素~(90)Sr的研究

本文叙述了改进多聚銻酸的制备方法,得到含5个結晶水的PAA晶体,从模拟的1AW废液中直接回收~(90)Sr。对溫度、流速、酸度在回收~(90)Sr的的影响,以及淋洗条件等进行了一系列的实驗,并用裂变产物进行了模拟回收~(90)Sr的实驗。說明这种改进的PAA无机离子交換剂,对锶具有較大的选择交换容量,对杂質离子具有較好的去污效果和較快的交換速度。能够从1AW模拟液中直按回收~(90)Sr,并初步确定了回收~(90)Sr的流程方案。     

核反应堆辐照元件的轴向和径向γ射线扫描

本文描述了用于辐照核燃料元件轴向和径向γ扫描的系统,包括扫描台架、准直装置、探测器及其电子学设备。给出了对金属铀辐照元件轴向和径向扫描的实验结果,包括:1.~(137)Cs,~(95)Zr-~(85)Nb沿元件轴向的分布;2.~(137)Cs沿元件径向的分布和热中子自屏蔽系数的测定值。     

三聚氰胺磷钼钒酸盐的制备和离子交换性能的研究

一、前言 杂多酸盐是一种无机离子交换剂。文献[1—2]报道了三聚氰胺磷钼酸盐的制备和离子性能的研究。它对~(137)Cs有很高的离子交换容量,是颗粒状的结晶,适合柱分离操作,但淋洗效果和耐辐照性能较差。本文研究了三聚氰胺磷钼钒酸盐(MPMV)的制备方法与对~(137)Cs的离子交换性能,并和三聚氰胺磷钼酸(MMP)的离子交换性能作了对比,得到相应的实验结果。     

γ辐照和热作用下改性钠基膨润土对~(137)Cs吸附性能的研究

为研究γ辐照和热作用对缓冲材料吸附性能的影响,以高庙子改性钠基膨润土为研究对象,采用批式法对改性钠基膨润土原土、γ辐照的改性钠基膨润土和γ辐照-热顺序作用的改性钠基膨润土对137Cs的分配系数进行了测定。结果显示,在本研究的实验条件下,相较改性钠基膨润土原土,经γ辐照后对137Cs的吸附能力增加了30.1%~39.4%;相较γ辐照后改性纳基膨润土,γ辐照-热顺序作用可使得该膨润土对137Cs的吸附能力进一步增加,平均增量为16%。     

NaI(T1)航测谱仪对~(137)Cs模拟面源的刻度

根据数值积分原理,用有限个~(137)Cs点源模拟了两个有限大(半径为15 m)和一个无限大~(137)Cs均匀面源,对一台安装在运五飞机内的NaⅠ(T1)航测谱仪进行了地面刻度。对两个有限大~(137)Cs模拟均匀面源,NaⅠ(T1)航测谱仪的刻度因子平均值为2.98×10~(-2) m~2;对无限大~(137)Cs均匀面源,其值为3.77×10~(-2) m~2,估计其不确定度小于20％。用角响应函数方法,计算了实验条件下的刻度因子,结果与实验值在10％范围内符合。     

~(137)Cs稳谱源的研制

通过对~(137)Csγ射线穿过陶瓷体源芯、不锈钢源壳和钨钢壳后衰减规律的研究,参考用户提供的~(137)Cs稳谱源的表面γ剂量率,确定~(137)Cs稳谱源的活度。对陶瓷体源芯吸附性能进行研究,以提高~(137)Cs稳谱源γ射线输出率的一致性,最终确定~(137)Cs稳谱源的制备工艺。经使用证明,该源的γ射线输出率准确、产品一致性好,已应用于岩性密度测井仪测井,可实现~(137)Cs稳谱源的国产化。     

用无机离子交换法从酸性高放废液中去除铯研究进展

60年代以来人们十分关注用离子交换法从配性高放废液中去除和回收∧137Cs。本文对比和评价了沸石、多价金属磷酸盐、磷钼酸铵及其复合离子交换材料、不溶性亚铁氰化物、钛硅化合物等无机离子交换剂。结合笔者的最新研究成果,并考虑了含铯废液交换剂的进一步处置问题,提出了为我国生产堆高放废液中去除∧137Cs的无机离子交换材料,对我国的后处理中去除铯的研究提供参考。     

由~(137)Cs,~(144)Ce和~(148)Nd为监测体测定燃耗中的辐照史校正方法

在通过测定~(137)Cs,~(144)Ce,~(148)Nd等裂变产物监测体浓度推算辐照燃料燃耗的方法中,需要裂变产物的平均裂变产额、(n,γ)俘获反应的修正量、放射性裂变产物的堆内衰变修正量,可裂变核素的平均裂变能量等参数。这些参数是同燃料的辐照历史密切相关的。本文介绍一种计算这些参数的方法、计算机程序概况和计算结果。本方法有下述特点:1.采用燃耗物理计算获得的可裂变核素核密度及裂变截面作为本程序的输入数据。2.采用燃耗值的初始实验结果反推燃料辐照期间的中子通量。3.精确计算了~(137)Cs和~(148)Nd两种监测体(n—1)衰变链和n衰变链中子俘获反应的修正量。从而提高了各种参数的精确度。对于浅燃耗天然铀辐照燃料的应用例,计算结果表明,~(137)Cs,~(144)Ce,~(148)Wd获得燃耗结果的修正量分别为 0.29%, 16.40%,-2.75%。本方法对燃耗结果可能引入的误差分别为±0.1%,±0.3%,±0.6%。     

γ辐照器的设计、评价和操作

【民主德国《同位素实践》1987年12月号第442页报道】民主德国莱比锡同位素和辐射研究中心研究所(ZF1)的全景型~(60)Co辐照装置已运行10年多了,下面是其经验介绍摘要。 ~(60)Co或~(137)Cs的γ射线辐照已广泛用于     

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.