核电厂非放射性污水排放执行标准的探讨

根据核电厂非放射性污水的特点,探讨了现有污水排放标准对核电厂非放射性污水排放的适用性问题,建议在目前阶段应主要依据《城镇污水处理厂污染物排放标准》(GB18918—2002)执行排放,并提出有必要开展核电厂非放射性污水排放标准的研究和编制。     

美国内陆核电厂液态放射性流出物排放环境辐射监测与评估

系统分析了2005—2012年美国38个内陆核电厂液态放射性流出物在受纳水体介质中的活度浓度水平,包括沉积物、地表水、饮用水和水生生物。结果表明,除个别核电厂受纳水体(地表水)中的氚活度浓度较高外,其它受纳水体介质(包括沉积物和鱼类)中来自核电厂排放的放射性物质的活度浓度一般处于正常水平。个别内陆核电厂由于受纳水体环境条件的限制,氚的活度浓度水平偏高,但均低于美国环保署(EPA)规定的饮用水中氚的指导水平。核电厂受纳水体排放放射性核素对公众造成的辐射剂量评估表明,美国内陆核电厂运行因液态放射性流出物排放对公众造成的辐射剂量很小。通过分析美国核管会(NRC)规定的监测探测下限和报告水平的要求和内陆核电厂2005—2012年间监测结果,反映了NRC认可的美国内陆核电厂受纳水体受到核电厂液态放射性流出物排放的影响很小。     

确定核电厂气载放射性流出物排放限值的设计方法研究

为了使核电厂的气载放射性流出物排放所致环境公众辐射剂量满足法规标准要求,本文从辐射防护剂量限值、大气污染物扩散规律及核电厂源项特点等方面考虑,通过实例分析,探讨了确定核电厂气载放射性流出物排放限值(排放率、排放浓度、地面浓度限值)的设计方法,提出了限值的建议值,并与已有核电厂的气载流出物排放报警阈值进行了验证,确认了方法的合理性。     

燃煤电厂对环境的放射性污染

本文介绍了南昌发电厂燃煤,炉碴,飞灰及烟尘中~(210)Pb 的比放射性,估算了向大气排放的~(210)Po 水平及对居民肺组织所造成的剂量当量。     

后处理设施放射性液体贮罐泄漏事故环境释放源项估算

放射性液体泄漏事故是后处理设施典型的事故,泄漏事故通常发生在设备室。高放废液贮槽泄漏后气载放射性核素生成包括两个过程:一是在泄漏放射性液体的过程中惰性气体从溶液中释放,以及与空气、地板相互作用产生的气溶胶;二是泄漏后的蒸发过程(包括冲洗前稀释前和稀释后)。气溶胶在设备室内生成后会发生沉积,同时随着设备室排风系统,经过滤后向环境排放。本文给出了一种放射性溶液贮槽泄漏事故源项估算方法,实现了事故泄漏质量、泄漏活度、设备室气载放射性活度浓度及积分浓度、环境释放源项估算,为事故应急决策和响应行动提供数据支持。     

美国内陆核电厂放射性液态流出物累积影响的评估

调研美国38个典型内陆核厂2005—2011年的环境监测资料,分析其液态放射性流出物受纳水体沉积物中放射性核素浓度水平。研究表明,近年来美国内陆核电厂运行排放的液态放射性流出物未对受纳水体沉积物造成明显的累积影响,少数核电厂在局限于厂址排放口附近或局域范围内检测到来自核电厂排放的放射性物质,而这些放射性物质与沉积物中的天然放射性核素浓度相比,是非常微量的,个别核电厂监测到来自核电厂排放的放射性核素浓度略高,与核电厂受纳水体水文条件较差有关。岸边沉积物外照射剂量估算结果表明,公众受核电厂排放液态放射性物质造成的剂量水平与美国公众受到的天然本底辐射剂量水平以及NRC对核电厂流出物规定的剂量约束值相比是可以忽略的。相应结论可为我国内陆核电厂的选址、建设和运行提供参考借鉴。     

北京正负电子对撞机对环境辐射影响的分析

北京正负电子对撞机(Beijing Electron Positron Collider,简称 BEPC)建于西郊玉泉路高能物理所西侧,主体工程全部位于地下。BEPC 的直线加速器隧道顶部复盖3.5m 的土,贮存环隧道顶部复盖0.5m 的混凝土。对位于 BEPC 邻近的居民,加速器顶部屏蔽体泄漏的杂散辐射所产生的剂量水平不大于30μSv/a;在隧道中气体作连续排放这一最不利情况下,由短寿命放射性气体云所造成的浸没照射剂量小于40μSv/a,总剂量水平不超过0.1mSv/a。BEPC 在紧靠隧道的2—3m 的土层中所产生的放射性核素数量很少,增加的比活度在土壤中天然放射性核素本底的涨落范围内。在采取适当的防护措施以后,BEPC 不会对环境产生放射性污染。     

法国核场区发生少量放射性泄漏

【美联社巴黎2002年12月10日电】 2002年12月9日,有关官员发现位于法国南部马尔库尔的核场区向罗纳河排放了少量放射性液体。该场区由法国高杰马公司(Cogema)负责运营,曾用于后处理核废物,现在用于为法国的国防计划生产氚。在发现处理放射性排放的系统出现故障后,有关人员立刻停止了排放,并开始修理。 有关官员于12月10日表示,此次事件不会对环境造成任何危害。 在国际核事件分级表中,这次泄漏被定为1级事件。 法国核场区发生少量放射性泄漏     

2001年绵阳科学城地区辐射环境监测与质量评价

2001年绵阳科学城地区主要环境介质(大气、河水、土壤和沉降等)中放射性水平与科学城开工前天然本底辐射没有显著性差别。通过对每个核设施烟囱流出物的测量与估算,获得了烟囱排放源项数据。利用该地区的大气扩散模式和多烟囱排放的剂量叠加原理,在评价坐标系中计算了叠加剂量分布。辐射环境质量评价表明80km范围内最大个人有效剂量是公众剂量限值的十万分之四,健康危害是危害约束值的千万分之二。表明环境影响是微弱的,是人们可以接受的。     

福岛第一核电站地下贮水槽泄漏及其处理

2013年4月3日，福岛第一核电站2号地下贮水槽东北侧的排水孔内所采水样中分析出了10 Bq/cm3（全β）的放射性含量；4月5日，于其相邻泄漏监测孔内水样中也测得了103 Bq/cm3（全β）的放射性水平，以及高浓度的Cl-。因此，东京电力株式会社（以下简称“东京电力”）判断存在有放射性污水向外泄漏的可能。     

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.     

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.     

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。     

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.     

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).     

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.