中子活化分析法测定热中子诱发^235U裂变中^135Cs的产额

应用裂变反冲法和中子活化分析法测定了热中子诱发＾２３５Ｕ裂变中＾１３５Ｃｓ的裂变产额，主要研究内容包括：＾２３５Ｕ靶的制备，反冲捕集装置的设计加工；用Ａｕ作为中子监测器监测＾１３５Ｃｓ活化时的中子注量率，＾１３７Ｃｓ和＾１３６Ｃｓ的放化分离和测量，以＾１３７Ｃｓ的裂变产额主标准得到＾１３５Ｃｓ的裂变产额值为（６．３４±０．４６）％。     

^235U,^147Pm,^153Sm单独及混合照射时对骨肉瘤细胞的增殖抑制作用

本研究运用四氮唑（ＭＴＴ）显色反应,观察了＾２３５Ｕ,＾１４７Ｐｍ,＾１５３Ｓｍ单独及混合照射骨肉瘤细胞时,对瘤细胞增殖抑制作用的程度比较,结果表明,各核素单独照射（照射用放射性活度为：＾２３５Ｕ,１２８．４Ｂｑ;＾１４７Ｐｍ,７．４×１０＾５Ｂｑ;＾１５３Ｓｍ,７．４×１０＾５Ｂｑ）及混合照射（＾２３５Ｕ＋＾１４７Ｐｍ,＾２３５Ｕ＋＾１５３Ｓｍ,＾１４７Ｐｍ＋＾１５３Ｓｍ,其放射性活度均为各自单     

^235U诱发细胞凋亡及IL—2和IL—6的防护作用

本文采用ＤＮＡ琼脂糖凝胶电泳研究了＾２３５Ｕ诱发的免疫细胞（人淋巴细胞白血病细胞株Ｍｏｌｔ－４细胞和巨噬细胞株Ａｎａ－１细胞）凋亡,探讨了细胞因子ＩＬ－２和ＩＬ－６的防护作用。结果表明,经＾２３５Ｕ照射达６ｈ以上的各组Ｍｏｌｔ－４和Ａｎａ－１细胞,均可观察到呈现凋亡细胞特征的阶梯状条带形成;而预先使用细胞因子ＩＬ－２和ＩＬ－６,对＾２３５Ｕ诱发的免疫细胞ＤＮＡ链断裂有显著的防护作用。     

浓缩铀诱发免疫细胞凋亡的形态观察及IL—2和IL—6的 …

对浓缩铀＾２３５Ｕ内照射人淋巴细胞白血病细胞株Ｍｏｌｔ－４细胞和巨噬细胞株Ａｎａ－１细胞诱发的细胞凋亡及细胞因子的防护作用进行了研究。实验中估算了＾２３５Ｕ在不同阶段培养细胞中的辐射累积吸收剂量。通过荧光显微镜形态观察，发现免疫细胞在受＾２３５Ｕ辐照后，可诱发明显的以核断裂和核固缩为特征的细胞凋亡。     

铀氢锆燃料成分对堆芯物理性能影响的分析

主要分析Ｈ／＾２３５Ｕ原子比对临界质量的影响，铀在铀氢锆中所占重量百分比对瞬发负温度系数的影响、＾２３５Ｕ富集度对负温度系数的影响以及铀氢锆燃料中杂质含量对有效增殖因子的影响，并地结果进行了讨论。     

天然海水中^238U,^234Th的富集,纯化与测定

以＾２３２Ｕ－２３４Ｔｈ平衡溶液为产额示踪剂，利用Ｆｅ（ＯＨ）３共沉淀法富集大体积海水中的Ｕ、Ｔｈ的放射活度分别用α能谱仪和β计数仪测定，两台仪器间的相对探测效率用位素标准源校正。由地获得南沙海域、南海东北部海域、厦门湾塔角附近海域以及九龙江口表层水溶解态、颗粒态＾２３８Ｕ、＾２３４Ｔｈ的放射性浓度、讨论了各箱＾２３８Ｕ、＾２３４Ｔｈ的空间分布变化。该研究为海洋真光层颗和学和海洋新生产力的同位素示     

燃料元件厂可燃含铀废物γ扫描装置

文章描述了燃料元件制造厂可燃含铀废物的γ扫描装置和无损分析刻度方法，采用４个高效率ＮａＩ（Ｔｌ）探头系统对已包的废物进行旋转γ扫描。系统包括多路讯号线性混合、多道缓冲存贮存和计算机获取和能谱处理硬件和软件。当废物包中＾２３５Ｕ的含量为０．０１５ｇ时，１８５ｋｅＶ峰面积与本底面积之比为０．４１。１０ｍｉｎ测量灵敏度计算值为１０ｍｇ＾２３５Ｕ。在１－２６．４ｇ＾２３５Ｕ动态范围内，１０ｍｉｎ测量峰面积     

浓缩^235U诱导免疫细胞凋亡的电镜和琼脂糖凝胶电泳研究

研究了浓缩＾２３５Ｕ内照射诱发人淋巴细胞白血病细胞株Ｍｏｌｔ－４细胞和巨噬细胞株Ａｎａ－１细胞白细胞凋亡，估算了浓缩＾２３５Ｕ在不同阶段培养细胞中的辐射累积吸收剂量，通过电镜对免疫细胞的形态观察，发现Ｍｏｌｔ－４和Ａｎａ－１细胞在受＾２３５Ｕ内照射作用下的呈现核染质边聚，ＤＮＡ链断裂和膜包裹的凋亡小体形成，对Ｍｏｌｔ－４和Ａｎａ－１细胞的ＤＮＡ抽提，进行ＤＮＡ琼脂糖凝胶电泳也显示是梯状条带形成的细     

铀材料的识别

对铀材料的探测和识别进行了研究，给出了不同浓缩度铀的γ特征谱，并对其中＾２３５Ｕ与＾２３８Ｕ的丰度比和其γ射线强度比进行了分析。根据实验结果，可以直接由铀材料的γ特征谱得到其浓缩度，并计算出该铀材料的质量。     

乏燃料后处理溶液中U,Pu的^57Co原激发K—XRF分析

自制一套＾３７Ｃｏ源激发与Ｋ系Ｘ射线荧光（Ｋ－ＸＲＦ）分析系统，用＾３７Ｃｏ的ｋｅＶγ射线激发工艺溶液中Ｕ，Ｐｕ的Ｋ系Ｘ射线荧光，用ＨＰＧｅ探测器－多道微机分析系统进行测量，并以１２２ｋｅＶγ射线康昔顿散射线为内标，建立强度比－浓度校正曲线，快速同地测定了ＰＷＲ乏燃料后处理工艺溶液中Ｕ，Ｐｕ浓度，测定范围为０．５－２００ｇ／Ｌ，精密度为５．０％－１．５％。方法适于ＰＷＲ乏燃料后处理工艺中，Ｕ，Ｐｕ     

基于核数据调整基准例题的235U协方差数据测试

核数据协方差是评估核装置设计不确定度和核数据调整的重要输入，直接影响设计不确定度量化评估和核数据调整的结果。为测试基于不确定度源项分析和线性最小二乘法评价的²³⁵U平滑区协方差数据的合理性，采用OECD/NEA WPEC/SG33提出的核数据调整基准例题和自主研发的核数据调整程序NDAC，开展了以JENDL-4.0库为基础的核数据调整测试，得到了应用了²³⁵U cov版²³⁵U数据的调整结果。测试结果显示，²³⁵U cov版²³⁵U数据的非弹性散射截面协方差不合理，阈能附近的不确定度过大；裂变和俘获截面的不确定度偏小。     

铀冶金炉渣的破坏性分析及对NDA分析仪器SGS和AWCC的校验

为了校验非破坏性分析（ＮＤＡ）仪器——分段γ扫描吸收装置（ＳＧＳ）和有源中子井型符合计数装置（ＡＷＣＣ）的准确性，采用流动注射（ＦＩＡ）、高效液相色谱（ＨＰＬＣ）和Ｘ光荧光（ＸＲＦ）３种破坏性分析方法（ＤＡ）分析了铀冶金炉渣中铀的含量。结果表明：３种方法的分析数据符合良好，得到了铀冶金炉渣中铀含量的准确量值。核对了非破坏性分析仪器ＳＧＳ和ＡＷＣＣ分析铀冶金炉渣的结果。     

Test of235U Covariance Data with Nuclear Data Adjustment BenchmarkWU Haicheng

Nuclear data covariances are important input data for quantificational assessment of nuclear facility design uncertainty and nuclear data adjustment (NDA), which give direct impact on estimated uncertainties and results of NDA. To test the rationality of the newly evaluated nuclear reaction cross sections covariance in smooth region for²³⁵U which is generated based on the analysis of source of experiments uncertainties and linear least-square method, the data were tested with the NDA benchmark exercises recommended by the OECD/NEA WPEC/SG33. The input data of the NDA generated from JENDL-4.0 library were updated with the cross sections and covariances of ²³⁵U fission, capture and inelastic scattering reactions from²³⁵U cov, and used in NDA calculation. The new results were compared with the original JENDL-4.0 ones. The test results show that the covariance data from²³⁵U cov are unreasonable. Too large uncertainties around threshold energy of inelastic scattering reaction were found. The uncertainties of fission and capture cross sections in smooth region are too small to be supported by NDA results.     

上海光源BL15U1束线的SRXRF定量分析

本文介绍了用于同步辐射X射线荧光(XRF)定量分析的基本参数法(FP)和MC模拟法。上海光源(SSRF)硬X射线微聚焦光束线(BL15U1)应用上述两种方法对样品进行定量分析,验证了方法的有效性并用定量分析结果计算了BL15U1光束线部分元素的荧光探测限。实验结果表明,对样品中μg/g量级元素含量的定量分析结果相对误差都在10%以内,而使用MC模拟法可以直观地比较不同参数下的模拟谱与实验谱,辅助实验参数的确定,从而减小参数引起的误差,得到更为准确的结果。此外,对BL15U1探测限的计算表明该光束线具备开展高性能荧光实验的能力。     

~(235)U/~(231)Pa质谱法测铀年龄

建立了同位素稀释-多接收电感耦合等离子体质谱法测~(235)U/~(231)Pa原子比得到高浓铀年龄的方法。经过两次TTA萃取-反萃后从母体237 Np中分离得到233Pa稀释剂,Pa中去Np的去污因子均在200以上。在用标准物质CRM U900对233Pa稀释剂的浓度进行标定后,分别以233 U、233 Pa作为~(235)U、231 Pa的稀释剂,质谱测得~(235)U/~(231)Pa原子比计算高浓铀年龄,采用该法对标准物质CRM U850进行年龄测量,其结果与参考值的相对偏差为1.97%。该法可用于核法证与核保障监督中的高浓铀年龄测定。     

分光光度法测定飞来峡水库水中的铀、钍

用Fe(OH)2共沉淀淡水样中的铀和钍,经硝酸溶解后,用^235N－环己烷萃取铀钍,在盐酸介质中分光光度法分别测定飞来峡水库水样铀、钍的含量。结果表明,铀、钍的回收率稳定在80％以上,方法稳定可靠;飞来峡水利枢纽建成后库区水体中铀、钍的含量维持在以前的水平。     

Primary study on holdup measurement of 235U in pipe using γ-ray spectrometry and Monte Carlo simulation

The pipe holdup measurement is very important for decommissioning nuclear facilities and nuclear-material control and accounting. The absolute detection efficiencies (εsp) of full-energy γ rays peak under different source density distribution function have been simulated using the Monte Carlo (MC) software, and the counting rates (n0) of the characteristic γ rays have been measured using the γ spectrometer followed by the calculation of the holdup. The holdup is affected by the energy of γ rays, distance at which they are detected, pipe material, thickness,and source distribution of pipe, especially source distribution at a short distance. The comparative test of 235U reference materials on the inner wall of Fe and A1 pipes (the total mass of 235U is 44.6 mg and 222.8 mg, respectively) have been accomplished using this method. The determined result of 235U is 43.2mg (U0.95rel=5.4%) and 216.2mg (U0.95rel= 3.2%), respectively, which are in accordance with the reference values.     

Fission Product Yields for 14 MeV Neutrons on U, U and Pu

We report cumulative fission product yields (FPY) measured at Los Alamos for 14 MeV neutrons on ²³⁵U, ²³⁸U and ²³⁹Pu. The results are from historical measurements made in the 1950s–1970s, not previously available in the peer reviewed literature, although an early version of the data was reported in the Ford and Norris review. The results are compared with other measurements and with the ENDF/B-VI England and Rider evaluation. Compared to the Laurec (CEA) data and to ENDF/B-VI evaluation, good agreement is seen for ²³⁵U and ²³⁸U, but our FPYs are generally higher for ²³⁹Pu. The reason for the higher plutonium FPYs compared to earlier Los Alamos assessments reported by Ford and Norris is that we update the measured values to use modern nuclear data, and in particular the 14 MeV ²³⁹Pu fission cross section is now known to be 15–20% lower than the value assumed in the 1950s, and therefore our assessed number of fissions in the plutonium sample is correspondingly lower. Our results are in excellent agreement with absolute FPY measurements by Nethaway (1971), although Nethaway later renormalized his data down by 9% having hypothesized that he had a normalization error. The new ENDF/B-VII.1 14 MeV FPY evaluation is in good agreement with our data.     

Isotope c(U)/c(U) relation in PIK reactor fuel elements

Isotope c(²³⁴U)/c(²³⁵U) relation in PIK reactor fresh fuel elements is investigated by non-destructible γ-spectroscopic method. The 60 PIK fuel elements were measured. Isotope c(²³⁴U)/c(²³⁵U) relation in PIK fuel elements equals (0.82±0.07)%.     

浓缩~(235)U诱发免疫细胞凋亡的电镜和琼脂糖凝胶电泳研究

研究了浓缩235U内照射诱发人淋巴细胞白血病细胞株Molt－4细胞和巨噬细胞株Ana－1细胞的细胞调亡。估算了浓缩235U在不同阶段培养细胞中的辐射累积吸收剂量。通过电镜对免疫细胞的形态观察，发现Molt－4和Ana－1细胞在受235U内照射作用下可呈现核染质边聚，DNA链断裂和膜包裹的凋亡小体形成。对Molt－4和Ana－1细胞的DNA抽提，进行DNA琼脂糖凝胶电泳也显示出阶梯状条带形成的细胞调亡特征。从而证实了浓缩235U内照射可导致免疫细胞Molt－4和Ana－1细胞的凋亡发生。