医源性电离辐射损伤及其生物医学防护

随着核与辐射技术在医学检查、诊断和治疗领域运用的增加,世界范围受照人群不断增多,医源性辐射已成为人类最主要的人工辐射来源之一。医疗机构和个人在选择利用放射手段获取诊断和治疗利益的同时,需要注意和防护伴随的辐射损伤效应。本文介绍了医源性辐射及其危害、机体组织的辐射损伤特性和类型、辐射生物效应分子及效应调节研究的进展,简要概述目前临床已经使用或最具应用潜力的辐射防护策略。     

Distribution and Fixation of Cesium and Strontium in Zeolite A and Chabazite

The selective removal and fixation of Cs and Sr have been studied in zeolite A and chabazite. Cesium ion was preferentially distributed into chabazite with a high distribution coefficient (K _Cs>10³ cm³·g^?1) in the presence of NaCl (10^?1 mol·dm^?3). The K _Sr values for zeolite A attained about 10³ cm³·g^?1 in the pH range of 8～10, and they gradually decreased with an decrease in pH.

The initial rate of Cs adsorption was fairly fast in chabazite, and the adsorption ratio reached almost 100% within a few hours. The adsorption ratio of Sr in binderless A zeolite reached almost 100% after 15 h. The adsorption of Cs and Sr on these zeolites was followed by Langmuir-type isotherm. Cesium forms of these zeolites recrystallized to pollucite (CsAlSi₂O₆) above 900°C for zeolite A and above 1,200°C for chabazite. As for Sr forms, these zeolites changed to SrAl₂Si₂O₆ above 900°C.

These recrystallized phases were suitable hosts for the immobilization of Cs and Sr in the nuclear waste solutions.     

全国核与辐射安全监管信息系统的研究和建议

文章简要介绍了全国核与辐射安全监管信息系统的前期规划建设情况,包括基本建设内容、系统总体架构、以及工作中发现的影响和制约工作开展的主要问题,并提出了建议。     

Development and diversity and defense-in-depth application of ABWR feedwater pump and controller model

This work developed an advanced boiling water reactor (ABWR) feedwater pump and controller model, which was incorporated into Personal Computer Transient Analyzer (PCTran)-ABWR, a nuclear power plant simulation code. The feedwater pump model includes three turbine-driven feedwater pumps and one motor-driven feedwater pump. The feedwater controller includes a one-element/three-element water level controller and a specific feedwater speed controller for each feedwater pump. The performance tests, including step change of dome pressure, feedwater pumps transfer, inadvertent closure of all turbine control valves, and one feedwater pump trip at 100% power, demonstrate the feasibility of dynamic response of stand-alone model and incorporated model. Furthermore, a diversity and defense-in-depth analysis is performed to demonstrate the feasibility for motor-driven feedwater pump as an emergency core cooling system (ECCS) automatic diverse back-up. In Lungmen nuclear power plant (NPP), a diverse manual initiation means for the high pressure core flooder (HPCF) loop C is designed as the back-up of digitalized engineered safety features actuation system (ESFAS). If the motor-driven feedwater pump (MDFWP) can be an automatic digital diverse back-up for ESFAS, Lungmen NPP would be more robust to defend against software common-cause failure (CCF).     

清洁解控和退役若干动向与新发展

对国际辐射防护协会第 1 0届大会 ( IRPA-1 0 )涉及的清洁解控和退役问题作了论述 ,包括排除、豁免、清洁解控和废物最少化 ;退役工程技术的发展 ,包括去污技术、切割解体技术、探测技术 ;介绍了一个研究堆退役例子和加速器退役 ;最后 ,还论及了退役中受关注的一些问题 ,如 :石墨废物、混凝土废物、重水堆退役的氚防护、退役时间和退役废物量等。     

核与辐射风险的认知与沟通

面对公众对核与辐射风险极度敏感的现象,本文阐述了对风险的认知及影响认知程度的因素,介绍了风险沟通的发展阶段和四种类型,并给出了若干有效的风险沟通策略建议。     

Thermophysical and mechanical properties of CrB and FeB

ABSTRACT

Fuel debris in the Fukushima Daiichi nuclear power plant is thought to contain borides that are generated from B₄C control material. In order to successfully devise methods to effectively remove the debris material, characterization of the properties of the fuel debris is essential. This paper presents some of the thermophysical and mechanical properties of two types of borides, FeB and CrB, and compares them with those of Fe₂B and ZrB₂. These are the representative borides that might have been generated in the Fukushima Daiichi (1F) nuclear power plant accident. We observed that the thermal conductivity values of both CrB and FeB are much lower than that of ZrB₂, and are similar to that of Fe₂B. Moreover, the Vickers hardness and fracture toughness of FeB and CrB are almost identical to each other, and similar to those of ZrB₂ and Fe₂B.     

Sorption methods of separating barium and radium,aluminum and gallum,and zirconium and hafnium

Chromatographic methods of separating elements with very similar properties have now been developed. However, a number of these methods are difficult to use industrially as their throughput is low. The efficiency of chromatographic separation methods could be increased considerably by using appropriate complex formers, which decrease the effective concentration of the ions being separated, and,in the first approximation, this is equivalent to a decrease in the amount of elements being separated. The difference in the formation constants of the complex compounds increases the separation coefficient. By investigating chromatographic separation with the use of various complex formers, we found the optimal conditions for separating barium and radium, zirconium and hafnium, and aluminum and gallium. The throughput of these methods, with respect to the macroelement was 15–60 kg/hr per m² of column cross section.     

测温热电偶拔出回收技术及回收处理装置

核电站反应堆测温热电偶回收装置是堆芯热电偶检修、更换、回收的专用设备。本文结合３００ＭＷ反应堆型，介绍了一种结构简单、操作方便、使用安全可靠的热电偶拔出回收技术及回收处理装置。     

PTFE的辐射裂解、交联及其应用

聚四氟乙烯（PTFE）是一种性能优异的工程塑料,通常被认为是典型的辐射裂解材料。PTFE可以在不同条件下实现裂解并生成PTFE微粉。在高于PTFE的熔点即温度为330～340℃,真空或惰性气氛下进行辐照,可实现PTFE的交联。本工作综述了PTFE辐射裂解和交联研究的历史和最新进展,并对交联PTFE在润滑材料、燃料电池、光刻等领域的应用进行了介绍。     

^177Lu-EDTMP和^177Lu-DOTMP的制备及其生物分布

研究了乙二胺四甲撑膦酸（EDTMP）和四膦酸亚甲基-四氮杂环十二烷（DOTMP）的^177Lu标记,优化了标记条件,并对标记物在正常小鼠体内的生物分布进行了研究。^177Lu-EDTMP的最佳标记条件为：EDT—MP25mg、^177LuCl3溶液100μL（12．8MBq）、pH8,100℃下反应30min;^177Lu—DOTMP的最佳标记条件为：DOTMP6．3mg、^177LuCl3溶液100μL（5MBq）,pH9,100℃下反应15min。^177Lu-EDTMP和^177Lu-DOTMP均具有较好的体外稳定性,室温下存放7d,放化纯度仍〉98％。生物分布结果显示,^177Lu-EDTMP和^177Lu-DOTMP主要浓聚于骨组织,经肾脏排泄,^177Lu-DOTMP较^177Lu-EDTMP的血液清除快。该结果表明两者都具有良好的骨靶向性。     

Mechanical and thermal properties of Zr-B and Fe-B alloys

ABSTRACT

After the core meltdown in the Fukushima Daiichi (1F) nuclear power plant, various compounds in metal boride systems could potentially form as a result of the reactions between B₄C (control material) and Fe, Zr alloys (control-blade sheaths, zircaloy claddings, channel box, etc.). Some previous studies have focused on the properties of intermetallic compounds of the Zr-B and Fe-B systems, such as ZrB₂, FeB, and Fe₂B. However, during the solidification of fuel debris, composites of these intermetallics rather than large chunks of single-phase intermetallics will form. This situation makes the understanding of the composition dependence of the mechanical and thermal properties of these metal borides a major task before debris retrieval takes place. In this study, we first investigated the temperature-dependent thermal conductivity of Fe-B and Zr-B eutectics from room temperature up to 900^°C. We were then able to evaluate the composition-dependent indentation hardness of these metal borides at room temperature. Based on our experimental data, we concluded that the hardness and thermal conductivity of the Fe-B, Zr-B composites can be well estimated using the properties of the composites’ corresponding components, with Rule of Mixtures and Effective Medium Theory (EMT) calculations, respectively.     

核电与常规电的异同——浅议从常规电向核电工作转变的体会和认识

随着国家"积极推动核电发展"指导思想的贯彻落实,尤其是2006年国家确定引入美国西屋AP1000核电技术路线之后,以常规电为背景的一些电力集团均不同程度地参与了核电前期开发、工程建设等方面的工作,传统的核电企业如中核集团、中广核集团也大量地招聘、招收了一定比例的常规电从业人员。这些长期从事常规电工作的人员从事核电工作以后,如何能够尽快实现工作转变,早日适应核电的工作要求,做到从工作的转变到观念的转变,知识的转变,思维方式的转变,熟练驾驭的转变,从而成为一名合格的核电工作者。本文从核电的技术特点、管理特点、文化特点和从事核电工作应关注的几个方面问题进行阐述,以期为这一特定时期的核电发展贡献一份力量。     

A New Static and Dynamic One-Point Equation and Analytic and Numerical Calculations for a Subcritical System

In this study we derived a new one-point equation based on the balance of fission neutrons. The equation has the same form as the conventional equation using k _eff which represents the neutron balance in the whole core. The variables of the new equation are the number of fission neutrons and delayed neutron precursors, and the coefficients are the multiplication rates of prompt fission neutrons, delayed neutrons and source neutrons. In the conventional equation, the variables are weighted by the adjoint flux; in other words, they are adjusted to the critical state. The variables in the new equation correspond to actual values even in a deep subcritical state; hence, the physical meaning of each term is clear.

The dynamic behavior of a slab core with an external source was analyzed through calculations based on the new equation. Deterministic and probabilistic calculations of the equation were performed for a typical accelerator-driven system in the static state.     

Plastic and dissipated work and stored energy

This paper depicts one theoretical and experimental method to take into account the energy phenomena, associated with the elasto—plastic deformation process, during the elaboration of behaviour laws. The energy balance definition is examined in order to relate the stored energy of cold work to the hardening state variables. Two experimental approaches are used to study the evolution of the energy balance. The first one uses microcalorimetric technique and the second infrared technique. Several industrial metallic materials are studied by both approaches. Energy data are used to control the validity domain of the classical behaviour laws and to elaborate new more appropriate ones. Therefore, the hardening parameters cannot be identified with the thermodynamical forces. The use of energy considerations allows the definition of new thermodynamical forces and state variables, in the case of isotropic or kinematical hardening.     

99TcmN-DMCHI和99Tcm-DMCHI的制备及其生物分布

合成并表征了新的异腈配体2,3-二甲基环己基异腈(DMCHI)及其铜络盐。分别通过配体交换法和直接标记法制备得到放化纯大于95％的脂溶性配合物^99Tc^mN-DMCHI和^99Tc^m-DMCHI,二者在室温下均可稳定6h以上。在正常小鼠体内的生物分布实验结果表明,^99Tc^mN-DMCHI和^99Tc^m-DMCHI在血液中均有较高的摄取和很好的滞留,而且血／心、血／肝和血／肺比值均大于1,有望用于心血池显像。     

Construction and operational experience with small and medium power reactors and expected improvements

Past experience with small and medium power reactors (SMPRs) in the areas of construction and operation is examined in this paper. Current development of SMPRs focuses on passive safety features; larger design and safety margins; reduction of construction periods through simplification, modularization and increased shop fabrication.     

丝状真菌F54的分离鉴定及其对铯的吸附特性

从新疆放射性污染土壤样本中,采用微生物分离方法,结合压力试验及吸附实验,获得一株对放射性核素污染具有修复能力的土著丝状真菌F54。通过形态学、分子生物学鉴定及Biolog碳源利用实验,F54为镰刀霉菌属真菌,与Fusarium oxysporum strain ATCC MYA-3931同源性最高。最适宜生长条件是:马铃薯葡萄糖培养基,30℃,pH=7.0。菌株F54吸附Cs+的最佳条件是:pH=7.0,30℃,伴随生长进行吸附约3~4d,吸附率最高能达到约84%,常见金属阳离子K~+、Na~+、Ca~(2+)、Mg~(2+)、Al~(3+)、Fe~(3+)对其吸附均有一定的抑制作用。菌株F54能够耐受10kGy的钴源照射,对重金属离子Ni~(2+)、Cr~(3+)、Zn~(2+)、Co~(2+)、Pb~(2+)、Hg~(2+)均有较高耐受性,对放射性137 Cs的吸附率为62%。菌株F54在有较高的重金属离子混合污染的放射性环境中具有一定的修复应用潜能。