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介绍了秦山核电二期工程反应堆及反应堆冷却剂系统源项计算方法、程序和计算结果.该辐射源项用于确定核电站厂房、换料设备和设施屏蔽厚度及其辐射剂量场. 相似文献
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~(16)N是压水堆一回路冷却剂中的主要活化产物,也是一回路中的主要辐射源。本文在传统~(16)N源项计算模型的基础上,根据堆芯内冷却剂的流向,考虑堆芯区域以及下降段区域的中子通量差异,将堆芯划分为活化区域以及反射区域,并建立了相应的计算模型,以典型三代压水堆核电站为例进行了计算与验证,计算结果与技术文件吻合良好,偏差在10%以内,验证了模型的正确性。最后分析了一回路典型部位的~(16)N平衡放射性活度浓度,发现在反应堆堆芯出口处最高,随着冷却剂流向逐步减少。研究结果表明,优化的计算模型可更准确计算压水堆核电站冷却剂的~(16)N源项,为分析反应堆一回路的辐射源项提供参考依据。 相似文献
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秦山核电厂大修期间辐射源项分析 总被引:1,自引:0,他引:1
本文介绍了秦山核电厂大修期间主要系统设备辐射源项的特点,分析了辐射源项的主要核素及影响因素,提出了降低大修作业现场辐射源项的措施。 相似文献
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集体剂量是核电运行业绩重要指标之一,需要通过管理措施和技术手段促使其呈良好的下降趋势。降低集体剂量是遵循辐射防护最优化原则的重要体现。影响集体剂量的因素是全流程的,包括核电站的设计、设备制造和安装、机组调试和运行阶段的控制等;影响集体剂量的因素也是全方位的,包括辐射源项的控制情况、年度检修工作量的多少、检修工作效率的高低等。本文通过对集体剂量影响因素的梳理分析,总结出降低核电站集体剂量主要从辐射源项控制(例如通过实施一回路设备易活化材料的替代换型、水化学控制减少一回路设备腐蚀、一回路水过滤器滤芯升级提高净化效率等措施,控制辐射源项)与放射性作业人工时控制(例如通过维修大纲的优化调整,优化延长设备的检修周期;提高设备可靠性,降低故障率,以减少检修工作量;通过提升工作人员技能、通过机械化和智能化技术的应用,提高工作效率等)两个方面开展工作。同时,不论是控制辐射源项,还是控制放射性作业人工时,均需要从组织管理上足够重视和给予管理政策的支持。 相似文献
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活化产物为压水堆核电站中主要辐射源,有必要对其建立分析手段。分析了压水堆核电站堆芯外材料中活化产物源项的产生途径,建立了压水堆核电站堆芯外材料中活化产物源项的计算模型,并分别基于矩阵指数法和切比雪夫有理近似法求解所建立的计算模型。开发了具有良好人机界面的计算程序CPAP,并采用典型材料活化例题与国外同类软件进行了对比测试。测试结果表明:CPAP程序对于测试算例的计算结果与国外同类软件的计算结果之间的偏差在工程可接受的范围内。CPAP程序具有人机界面友好以及求解器可选的优点,可广泛应用于压水堆核电站的设计、运行和退役阶段。 相似文献
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基于VVER机组停机过程中辐射源项的释放和迁移原理,本文结合系统的设计功能建立了一套覆盖机组状态的大修全过程辐射源项控制方法,提出了一套覆盖机组状态的大修全过程辐射源项控制体系。该体系经某VVER核电机组验证,通过一回路pH和溶氢等水化学控制措施,可以降低设备的腐蚀速率和腐蚀产物被活化的几率。使用一回路冷却剂净化系统(KBE)、冷却剂贮存系统(KBB)树脂床对一回路介质可以实现对放射性核素的有效净化,其中一回路贮存水箱的净化效率可以达到90%以上;系统介质或者外接冲洗设备对高剂量率系统设备进行冲洗、净化,净化效率可以达到50%以上。结合VVER机组辐射源项控制经验和最新的源项控制技术,提出了后续VVER机组辐射源项控制的优化和研究方向。 相似文献
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Seismic protection systems (SPS) have been developed and used successfully in conventional structures, but their applications in nuclear power plants (NPPs) are scarce. However, valuable research has been conducted worldwide to include SPS in nuclear engineering design. This study aims to provide a state-of-the-art review of SPS in nuclear engineering and to answer four significant research questions: (1) why are SPS not adopted in the nuclear industry and what issues have prevented their deployment? (2) what types of SPS are being considered in nuclear engineering research? (3) what are the strategies for location of SPS within NPPs? and (4) how may SPS provide improved structural performance and safety of NPPs under seismic actions? This review is conducted following the procedures of systematic reviews, where possible.The issues concerning the use of SPS in NPPs are identified: cost, safety, licensing and scarcity of applications. NPPs demand full structural integrity and reactor's safe shutdown during earthquake actions. Therefore, horizontal isolation may be insufficient in active seismic zones and isolation in the vertical direction may be required. Based on the results in this review, it is likely that next generation reactors in seismic zones will include state-of-the-art SPS to achieve full standardised design. 相似文献
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核事故应急撤离是核应急响应的重要组成部分, 目的在于快速有效地将可能受到事故影响的人员转移至安全地区。本文根据海上浮动核电站的运行场址与运行特点, 对海上浮动核电站应急响应特征进行分析, 给出了浮动核电站应急等级划分和应急计划区范围。结合陆地核电站场区撤离与海洋平台撤离疏散方法, 制定了海上浮动核电站应急撤离情景与撤离分析假设。对浮动核电站人员撤离的分析结果表明, 浮动核电站人员撤离满足客船撤离要求, 及海上浮动核电站应急撤离的时间要求。关键词: 海上浮动核电站; 核应急; 应急计划区;应急响应; 应急撤离 相似文献
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压水堆核电厂功率运行期间,反应堆压力容器外的环形空腔空气中所含的40Ar被中子活化,形成具有放射性的41Ar。文章采用二维离散纵标输运计算程序DORT分析了反应堆堆腔区域的中子注量率分布情况,采用NJOY评价核数据处理程序,根据DORT分析得到的通量作为权重通量,利用基础评价核数据库ENDF/B-Ⅶ.0制作40Ar中子俘获反应的微观截面,在此基础上,分析了百万千瓦级压水堆核电厂每台机组反应堆堆腔空气中40Ar中子活化生成41Ar的生成率以及电厂41Ar的环境排放源项。文章给出的41Ar源项分析方法可作为压水堆核电厂设计中确定41Ar源项的最佳估算值的参考。 相似文献
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氚是核电站运行过程中向环境中排放较大的放射性核素之一,控制核设施中氚的产生和排放量越来越引起人们的重视。本文通过分析核电站产生氚的主要途径,结合国际上的运行经验参数,对比分析了不同国家、不同堆型核电站氚的排放量和浓度限值。分析结果表明:三十年间,全球核电站流出物中气态氚的排放量显著高于液态氚,重水堆是各堆型核电站中氚排放的主要贡献者,也是氚排放所致公众剂量的主要来源。为了更加有效的控制氚的排放,法国等国家核安全监管机构根据电站的装机容量、排放工艺、堆型等制定了各自国家核电站氚的年排放总量限值;加拿大等国的监管机构根据剂量限值制定了导出排放限值,该值的优点是便于审查核电站正常运行时氚的排放量;其它核电国家则是以剂量限值的形式提出了氚的排放限值。 相似文献
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Life extension is investigated as a safeguard assessment for the stability on the operation of the nuclear power plants (NPPs). The Cobb-Douglas function, one of the production functions, is modified for the nuclear safeguard in NPPs, which was developed for the life quality of the social and natural objects. Nuclear Safeguard Estimator Function (NSEF) is developed for the application in NPPs. The cases of NPPs are compared with each other in the aspect of the secure performance. The results are obtained by the standard productivity comparisons with the designed power operations. The range of secure life extension is between 1.008 and 5.353 in 2000 MWe and the range is between 0.302 and 0.994 in 600 MWe. So, the successfulness of the power operation increases about 5 times higher than that of the interested power in this study, which means that the safeguard assessment has been performed in the life extension of the NPPs. The technology assessment (TA) is suggested for the safe operation which is an advanced method comparing conventional probabilistic safety assessment (PSA). 相似文献
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Takao Nakamura Setsuya Nakada Kichisa Iwata Tsutomu Ono Fumio Hamasaki 《Journal of Nuclear Science and Technology》2016,53(7):929-943
Japan is one of the countries with abundant active volcanoes and has a long history of developing countermeasures to mitigate volcanic disasters. In the field of nuclear energy, it is also necessary to assess safety against volcanic hazards, and in 2009, a voluntary guideline was published as JEAG4625 in order to set up requirements of site assessments and basic designs of nuclear power plants (NPPs). This guideline has been revised to satisfy the requirements for examining the necessity of considering volcanic phenomena and concrete countermeasures in detailed designs of NPPs. This paper focuses on the background and technical basis of this voluntary guideline and shows the basic policy to ensure safety of NPPs and the requirements to prevent nuclear hazards due to volcanic phenomena based on the defense in depth concept. 相似文献