微型中子源堆低浓化堆芯的探讨

通过对２３５Ｕ富集度为１９．９％的ＵＯ２和Ｕ３Ｓｉ２－Ａｌ的弥散体２种燃料进行物理计算，从中筛选出了优化的堆芯方案，并对其静态物理参数，诸如有效倍增因子、绝对中子通量密度、上铍反射层反应性价值、反应性温度系数、控制棒价值等进行了计算。     

研究试验堆低浓化及在我国的实践

回顾了研究试验堆低浓化项目的缘起、发展历程、主要工作和进展,并简要介绍了我国在低浓化方面的一些实践。     

波兰研究堆完成燃料低浓化改造 并将高浓铀燃料返还俄罗斯

【本刊2012年11月综合报道】美国国家核军工管理局（NNSA）于2012年9月25日宣布,在美国、俄罗斯和波兰政府的帮助下,波兰国家核研究中心（NCBJ）已成功完成波兰唯一一座运行中研究堆即玛丽亚（Maria）研究堆的燃料低浓化改造工作,这座原本使用高浓铀燃料的研究堆目前已转为使用低浓铀燃料。此外,近期还将近90千克高浓铀燃料从玛丽亚研究堆返还其原产国俄罗斯。     

研究、试验堆低浓铀燃料的发展状况

本文介绍降低研究、试验堆燃料浓缩度工作,即发展高铀密度、低浓缩度燃料的进展状况。UAl_x-Al 和 U_3O_8-Al 弥散型板状燃料的铀密度已分别达到2.3—2.6克铀/厘米~3和3.1—3.6克铀/厘米~3;新发展的 U_3Si-Al 弥散型板状燃料的铀密度已经达到7.0克铀/厘米~3,它很可能是研究、试验堆燃料的后起之秀;UO_2陶瓷板型燃料的当量铀密度为9.1克铀/厘米~3,它既可以用来降低研究、试验堆燃料浓缩度,又适用于高功率密度的小型动力堆。预计到1986年,几乎所有的研究、试验堆将都可改用低浓铀燃料。     

研究试验堆用于同位素生产的物理分析

本文对研究试验堆开展同位素生产进行了物理分析。分析了控制棒提棒顺序对同位素产量的影响,提出了提棒因子的概念。依据点堆模型和反应性-燃耗线性公式,得到了同位素的转换比和产量公式。最后根据这些公式,分析了高通量工程试验堆(HFETR)在高浓铀和低浓铀堆芯装载下,堆芯炉的运行寿期、燃料元件装载数量、燃料元件初始平均燃耗和堆芯功率对同位素转换比和产量的影响。结果显示,从小到大提棒、增加堆芯燃料组件盒数和功率水平均会增加堆芯同位素产量,而全年运行段数（运行段间检修时间不变）和堆芯平均初始燃耗增加则起到相反的作用。这些结果已经用于指导反应堆的堆芯装载设计。     

一些国家和地区的研究堆将采用低浓铀

【英国《国际核工程》1989年6月第72页报道】目前在34个国家的118座研究堆中,正在使用美国和其它西方国家提供的高浓铀。其中36座在美国,82座在其它国家。这些高浓铀的浓缩度不低于20％,成了安全保障所关心的问题。在50年代,美国根据艾森豪威尔政府关于和平原子计划,开始出口研究堆燃料,但     

4座俄罗斯研究堆燃料低浓化改造具有技术可行性

【英国《国际核工程》网站2012年6月27日报道】美国和俄罗斯于2012年6月26日宣布,几座俄罗斯研究堆燃料低浓化改造的可行性研究工作已完成。这意味着俄罗斯国家原子能集团(Rosatom)和美国能源部(DOE)于2010年12月签署的实施协议已经     

美将帮助俄研制用于研究堆的低浓铀

[美国《核燃料》1993年12月6日刊第7页报道] 美国和俄罗斯官员上月说,美国降低研究和试验堆燃料浓度(RERTR)计划已经同莫斯科动力工程研究和发展研究所(RDIPE),以及其它一些组织达成一项合作协议,为多达50座前苏联设计的研究堆,设计和制造铀-235丰度为19.7％的燃料。     

高通量工程试验堆三维物理热工程序系统的验证

介绍了高通量工程试验堆 (HFETR)堆芯三维稳态物理热工计算程序系统的验证结果。该程序系统由 6个部分组成 :基于WIMS D4的栅元均匀化少群参数计算程序、基于SIXTUS 3的三维堆芯燃料管理程序S3BURN、节块精细注量率重组程序HFETRPPC、堆芯流量分配计算程序HFETRFD、燃料元件流场和温场三维数值计算程序CASH以及基于COBRA 1V的燃料考验组件热工水力分析程序。通过程序计算值与实测值广泛范围的比较 ,对程序系统进行了验证。从结果可以看出 ,该程序系统功能强、性能好、计算速度快 ,可以完成HFETR及配套设施的堆芯运行方案设计计算。     

高温气冷堆He载气中H2和CO转化实验研究

研究了Ｈ＿２和ＣＯ在ＣｕＯ－ＺｎＯ＿Ａｌ＿２Ｏ＿３催化床中转化成Ｈ＿２Ｏ和ＣＯ＿２的实验装置和实验结果，论证了不同床层工作温度、系统压力、杂质浓度、流量及露点温度等因素对氧化铜床工作性能的影响；测得了Ｈ＿２和ＣＯ在ＣｕＯ－ＺｎＯ－Ａｌ＿２Ｏ＿３床上的转化特性曲线等变化规律，获得了转化容量、工作周期和转化效率等实验数据，确定了最佳运行参数。结果表明，使用ＣｕＯ＿ＺｎＯ－Ａｌ＿２Ｏ＿３床可使净化后的Ｈ＿２和ＣＯ的体积分数都小于２×ｌ０￣（－６），满足高温气冷堆的净化要求。为高温气冷堆中氧化铜床装置提供了可靠的设计数据。     

重水型研究堆的堆功率和周期实时监测研究

指出了提高重水型研究堆运行的安全性，监测反应堆瞬时堆功率和周期的必要性，并介绍了一种简单易行的监测方法，提出了进一步改进的方向。     

高温气冷堆He载气中H2O和CO2吸附净化的实验研究

通过对高温气冷堆Ｈｅ载气中的Ｈ２Ｏ和ＣＯ２在５Ａ分子筛固定床上吸附净化的实验研究，得到了吸附穿透曲线，获得了５Ａ分子筛床对Ｈ２Ｏ和ＣＯ２的动态吸附规律。实验考察了吸附温度、工作压力、杂质浓度、流速及床层高度等因素对Ｈ２Ｏ和ＣＯ２单吸附及共吸附的吸附容量及转效时间的影响，获得了最佳运行参数。实验研究结果表明：净化后Ｈｅ气中Ｈ２Ｏ和ＣＯ２的质量分数低于１０－５，满足了净化系统的要求，为高温气冷堆中５Ａ分子筛固定床装置提供了可靠的设计数据。     

Experimental Study on Temperature Coefficient of Reactivity in Light-Water-Moderated and Heavy-Water-Reflected Cylindrical Core Loaded with Highly-Enriched-Uranium or Medium-Enriched-Uranium Fuel

By using the Kyoto University Critical Assembly (KUCA), a series of critical experiments was performed to measure the temperature coefficient of reactivity in a light-water-moderated and heavy-water-reflected cylindrical core loaded with highly-enriched-uranium (HEU) or medium- enriched-uranium (MEU) fuel. The measurement was performed for the approximately 20 to 70°C range to examine the effects of the size of light-water region in a heterogeneous multi- region type core, the reduced ²³⁵U enrichment, and the existence of boron burnable poison (BP) on this quantity by using six types of core configurations. In all the six types of cores, there were large light-water regions at the center of core and between the outer fuel region and the heavy-water reflector region, and it was found that these light-water regions caused a remarkably positive effect on the temperature coefficient of reactivity. In the present study, the temperature coefficients of the MEU core and the core without BP were more positive than those of the HEU core and the core with BP, respectively. The size of light-water region had a larger effect on the temperature coefficient rather than the reduced ²³⁵U enrichment and the existence of BP. The negative temperature coefficient would be realized by reducing the thickness of light-water layer existed in the core.     

Developing architecture for upgrading I&C systems of an operating nuclear power plant using a quality attribute-driven design method

This paper presents the architecture for upgrading the instrumentation and control (I&C) systems of a Korean standard nuclear power plant (KSNP) as an operating nuclear power plant. This paper uses the analysis results of KSNP's I&C systems performed in a previous study. This paper proposes a Preparation–Decision–Design–Assessment (PDDA) process that focuses on quality oriented development, as a cyclical process to develop the architecture. The PDDA was motivated from the practice of architecture-based development used in software engineering fields. In the preparation step of the PDDA, the architecture of digital-based I&C systems was setup for an architectural goal. Single failure criterion and determinism were setup for architectural drivers. In the decision step, defense-in-depth, diversity, redundancy, and independence were determined as architectural tactics to satisfy the single failure criterion, and sequential execution was determined as a tactic to satisfy the determinism. After determining the tactics, the primitive digital-based I&C architecture was determined. In the design step, 17 systems were selected from the KSNP's I&C systems for the upgrade and functionally grouped based on the primitive architecture. The overall architecture was developed to show the deployment of the systems. The detailed architecture of the safety systems was developed by applying a 2-out-of-3 voting logic, and the detailed architecture of the non-safety systems was developed by hot-standby redundancy. While developing the detailed architecture, three ways of signal transmission were determined with proper rationales: hardwire, datalink, and network. In the assessment step, the required network performance, considering the worst-case of data transmission was calculated: the datalink was required by 120 kbps, the safety network by 5 Mbps, and the non-safety network by 60 Mbps. The architecture covered 17 systems out of 22 KSNP's I&C systems. The architecture is implementable with the equipment developed in South Korea. The architecture can be used as a model to upgrade the existing I&C systems in a planned, large-scale, and one-shot manner. A more detailed architecture down to software level will be developed in the future.