共查询到17条相似文献,搜索用时 62 毫秒
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本文系统介绍了“大型先进压水堆及高温气冷堆核电站”国家科技重大专项课题“CAP1400数值反应堆关键技术研究”的主要研究成果。课题首先分别开发了基于确定论方法和蒙特卡罗方法的高保真堆芯物理计算程序,然后开发了pin by pin先进子通道分析程序和基于精细网格的燃料棒性能分析程序,以此为基础建立了物理 热工 燃料性能多物理耦合的CAP1400数值反应堆系统。利用国际基准题VERA、AP1000启动物理实验参数对数值反应堆系统进行了验证和确认,并进一步实现了CAP1400大型先进压水堆的启动物理参数、循环模拟分析和部分功率能力分析的示范应用。数值结果表明,所开发的数值反应堆关键分析软件具有很高的计算精度,可直接服务于CAP1400的设计验证、物理启动和运行支持。 相似文献
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本文研究了核安全规划中关于"实际消除大量放射性物质释放的可能性"这一安全目标要求的技术内涵,从确定论和概率论两方面提出了对"设计上实际消除大量放射性物质释放的可能性"的解读,给出了确定论设计和分析要求,同时,建议概率安全目标中的大量放射性物质释放频率不超过1×10^(-7)/堆年,并建议将放射性释放量超过500TBq剂量等效^(131)I的放射性释放定为"大量放射性释放"。在对比分析了CAP1400安全设计与上述要求的符合性后,认为CAP1400设计可满足"实际消除"安全目标。 相似文献
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气载放射性流出物在近场范围内的扩散是核设施环境影响评价研究的重要内容之一,传统的高斯模型由于受到复杂建筑物的影响导致计算结果偏差比较大,不宜用于近场扩散的数值模拟。本文采用计算流体动力学(Computational Fluid Dynamics,CFD)方法以2 MW液态钍基熔盐实验堆的拟定场址为研究对象,开展放射性气态流出物在近场范围内分布规律的研究,分析风速、烟囱高度、风向等参数对气态流出物大气弥散因子分布的影响。结果表明,对于高架排放,由烟羽抬升的影响使得风速越大近场范围的放射性核素大气弥散因子越高;在下风向建筑群迎风侧均易出现放射性核素集聚区,烟囱高度越低集聚现象越明显。本研究的结果可为熔盐堆场区辐射环境影响评价及建筑物的布局、核应急提供参考依据。 相似文献
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为研究真实工况下CAP1400反应堆压力容器下降段气-液逆向流现象,以CAP1400为原型,搭建压力容器下降段高度和直径比为1:1、60°切片的试验台架。试验工质为空气和水,试验研究了不同安注(DVI)供水量、不同气量的气-液两相流动和应急堆芯冷却剂(ECC)旁通现象。试验结果表明,DVI供水量相同时,随着供气量的增加,气-液逆向流现象明显,当质量流速达到4kg/s及以上时,安注水不能全部进入堆芯;Kutateladze经验关系式和UPTF经验关系式都与试验结果存在较大偏差,不适用于CAP1400压力容器下降段试验;基于试验数据,拟合了新的经验关系式,且通过比较有无DVI挡块的试验数据,验证了DVI挡块可以降低ECC旁通水量,增强安注能力。 相似文献
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核电站事故情况下气载放射性致厂址周围公众集体剂量当量的估算方法 总被引:1,自引:0,他引:1
对核电站潜在的放射性物质外泄事故可能导致后果的严重程度给出一个合理保守的评价方法是十分必要的。本文给出一个厂址周围80km范围内集体剂量当量的估算方法,该方法借鉴U.S.NRC.1.145事故后果的概率处理方法,将大气弥散情况下人口分布相结合,计算给出的集体剂量当量的超越概率不大于5%。 相似文献
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作者对本地区某大型电厂燃煤及烟道灰中天然铀、钍含量进行了测定,对1980年全年的逐时气象资料进行了分析,采用P-T法进行天气稳定度分类,计算了风向、稳定度、风速联合频率f_(ijk)及降雨的风向频率f_(rljk),估算了该厂气载排出物(烟尘)造成厂区外周围半径60km范围内近地面空气中天然铀、钍的污染浓度,地面沉积量及其分布。计算中对高空风速、烟云抬升、静风及沉积(特别是降雨引起的湿沉积)引起的空气污染浓度降低进行了必要的修正。 计算结果表明,空气最大年平均污染浓度出现在SE方位1km处,该处U_(max)=1.95×10~(-7)mg·m~(-3),X_(Thmax)=3.45×10~(-7)mg·m~(-3)。在距烟囱10km以内的范围内,地面沉积量主要来自降雨冲洗造成的湿沉积,10km以外则应同时考虑于沉积的贡献。 相似文献
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作者对本地区某大型电厂燃煤及烟道灰中天然铀、钍含量进行了测定,对1980年全年的逐时气象资料进行了分析,采用P-T法进行天气稳定度分类,计算了风向、稳定度、风速联合频率f_(ijk)及降雨的风向频率f_(Rjk),估算了该厂气载排出物(烟尘)造成厂区外周围半径60km范围内近地面空气中天然铀、钍的污染浓度,地面沉积量及其分布。计算中对高空风速、烟云抬升、静风及沉积(特别是降雨引起的湿沉积)引起的空气污染浓度降低进行了必要的修正。计算结果表明,空气最大年平均污染浓度出现在SE方位地1km处,该处x_(U_(max))=1.95×10~(-7)mg·m~(-3),x_(T_(max))=3.45×10~(-7)mg·m~(-3)。在距烟囱10km以内的范围内,地面沉积量主要来自降雨冲洗造成的湿沉积,10km以外则应同时考虑干沉积的贡献。 相似文献
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Masanori Takeyasu Masanao Nakano Hiroki Fujita Akira Nakada Hitoshi Watanabe Shuichi Sumiya 《Journal of Nuclear Science and Technology》2013,50(3):281-286
In response to the accident at the Fukushima Daiichi Nuclear Power Plant, emergency monitoring of the environmental radiation was performed at the Nuclear Fuel Cycle Engineering Laboratories (NCL), Japan Atomic Energy Agency (JAEA). This article describes the results of the monitoring, including air absorbed dose rate and radionuclide concentration in air and fallout. The air absorbed dose rate began to increase from about 1 am on 15 March 2011 and varied over time, with three peaks: 4.8 μGy/h, 2.1 μGy/h and 3.1 μGy/h at 8 am on 15 March, 5 am on 16 March and 4 am on 21 March, respectively. The increase in the radionuclide concentrations in air and fallout showed a tendency similar to that in the case of the dose rate. The 131I/137Cs concentration ratio in air varied considerably every day, and the maximum was about 100. The 137Cs amount in the fallout for a month from 15 March to April 15 was about 120 times higher than that after the Chernobyl accident in May 1986 and about 30 times higher than that in Tokyo in June 1963 during the atmospheric nuclear weapon tests. The committed effective dose due to inhalation was estimated from the observed radionuclide concentration in air. 相似文献
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Shigekazu Hirao Hiromi Yamazawa Takuya Nagae 《Journal of Nuclear Science and Technology》2013,50(2):139-147
The atmospheric release rates of I-131 and Cs-137 from the Fukushima Daiichi nuclear power plant in March 2011 were estimated by comparing environmental monitoring data of air concentration and deposition rate on a regional scale with calculated values from an atmospheric dispersion model. Although the release rates were not estimated for all days after 11 March, because of lack of monitoring data, temporal changes in the release rates were reasonably estimated with estimated uncertainties in a factor of 3.3 and 2.9 for I-131 and Cs-137, respectively. A large release was estimated from the night of 14 March to at least the afternoon of 15 March, with maximum values of 7.2 × 1015 Bq h?1 for I-131 and 1.5 × 1014 Bq h?1 for Cs-137. The release rates during other periods were estimated at one- to two-orders of magnitude smaller than the largest release rate on 15 March. Uncertainty in the estimated release rate for 15 and 20 March was larger than for other periods. The significant release during 14 and 15 March and the trend of the release rate by the end of March were consistent with previous reports. This agreement, despite using different datasets, shows robustness of the temporal changes estimated in the studies. 相似文献
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Jun Moriizumi Atomu Oku Naoki Yaguchi Yu Kuwahara Hiromi Yamazawa 《Journal of Nuclear Science and Technology》2020,57(5):495-513
ABSTRACTA hybrid method for estimation of atmospheric concentrations of multiple radionuclides was developed and applied to NaI(Tl) pulse height records measured in Ibaraki Prefecture in the morning of 15 March 2011 when three radioactive plumes from the Fukushima Dai-Ichi Nuclear Power Plant Accident passed. The method is based on the simple principle for separation from deposited radionuclides’ contribution and the concentration estimation for multiple radionuclides. Difficulty in the concentration estimation due to complexity of surrounding terrains and geometry was overcome to obtain spatiotemporal variations in atmospheric concentrations of Xe-133, Te-132, I-131, I-132 and I-133 in the three plumes at 21 monitoring stations. The plume axis with higher I-131 concentration of 5.40 kBq m-3 than the previous estimations during the second plume was found in the northwestern inland area. A substantially lower Xe-133/I-131 concentration ratio of the first plume than those of the others was again recognized. The details of non-uniform spatial distribution of the radionuclide composition were found for each of the three plumes. 相似文献
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鉴于国家标准《核动力厂环境辐射防护规定(GB 6249—2011)》表1中仅给出不区分核素的、以年排放活度(Bq/a)表示的“碘”和“粒子”排放控制值,造成核动力厂气载放射性排放限值与公众个人年剂量不匹配,难于执行或执行混乱。为解决此问题,提出采用区分核素的方法,并监测对剂量贡献较大的重要核素的建议。根据IAEA第19号安全报告,探讨了核动力厂气载放射性流出物中碘类和粒子类的重要核素,为标准补充或修订提供建议。 相似文献