共查询到19条相似文献,搜索用时 510 毫秒
1.
2.
3.
正【英国《国际核工程》网站2019年2月12日报道】欧洲铀浓缩美国公司(Urenco USA)近日宣布有能力提供高丰度低浓铀。世界上绝大多数在运核电机组通常使用铀-235丰度不到5%的低浓铀燃料。但是,目前正在开发的许多先进反应堆需要使用铀-235丰度为5%~20%的高丰度低浓铀燃料。这种低浓铀还可用于医用同位素生产以及科研活动。 相似文献
4.
5.
6.
溶液堆在医用同位素的生产方面具有一些优势,本文对溶液堆的发展过程进行了介绍,对用于医用同位素生产的水溶液均相反应堆的技术特点、核素生产以及相关的核燃料处理问题进行了综述.溶液堆可以提取的同位素主要有99Mo, 131I, 89Sr等.在核燃料处理方面,溶剂萃取法是切实可行的方法,针对硫酸和硝酸2种溶液体系,推荐了硝酸体系的φ=30% TBP流程.溶液堆运行1~2年左右,冷却3~5个月进行后处理,放射性浓度大于99%的裂变和腐蚀产物被去除,铀的回收率大于99.5%,回收的铀可以回堆继续应用,形成一个快速处理循环.在后处理设备方面,小型化的核用离心萃取器及过滤设备是最好的选择. 相似文献
7.
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。 相似文献
8.
9.
【国际原子能机构网站2006年4月20日报道】在2006年4月19日结束的一次秘密行动中,一批来自乌兹别克斯坦的高浓铀乏燃料被安全运回俄罗斯。这批乏燃料中含有的铀足以制造2.5枚核弹头。自前苏联解体以来,这是首次将研究堆的乏燃料运回俄罗斯。在严密的安全措施保护下,这批总计达63kg的高浓铀乏燃料被分4次运往俄罗斯的马雅克(Mayak)后处理厂。国际原子能机构(IAEA)视察员监督并核实了这次历时16天的运输过程。这批燃料是俄罗斯为乌兹别克斯坦核物理研究院的一座10MW研究堆提供的。这座研究堆目前被用于科学研究及生产医用同位素。这次运输… 相似文献
10.
11.
医用同位素生产反应堆(MIPR)以硝酸铀酰(或硫酸铀酰)水溶液为核燃料,主要生产医用同位素99Mo和131I。反应堆的安全性是需要关注的重要问题。当发生一次冷却水泵故障、误提棒、气回路氢氧复合能力丧失等事故而未能紧急停堆的情况下,由应急停堆系统实现反应堆停堆。本文介绍了应急停堆系统的设计原理及运行方式,并分析了“正压卸料”和“负压卸料”停堆方式应急停堆瞬态过程。结果表明,“正压卸料”应急停堆可在150 s内完成燃料的完全排出;“负压卸料”应急停堆可在700 s内完成燃料的完全排出。“正压卸料”的燃料排出速度比“负压卸料”快,该研究结果可对反应堆临界安全分析提供输入数据。 相似文献
12.
13.
《Annals of Nuclear Energy》2004,31(11):1265-1273
Pakistan Research Reactor (PARR-1) was converted from Highly Enriched Uranium (HEU) to Low Enriched Uranium (LEU) fuel, in 1992. The reactor is running successfully with an upgraded power level of 10 MW. In order to save money on the purchase of costly fresh LEU fuel elements, it is being thought to use some of the less burnt HEU spent fuel elements along with the present LEU fuel elements. In the present study steady-state thermal hydraulics of a proposed mixed fuel core (see Fig. 2) has been carried out. Results show that the proposed core, comprising of 24 LEU and 5 HEU standard fuel elements, with 4 LEU and one HEU control fuel elements, can be safely operated at a power level of 9.86 MW without compromising on safety. Standard computer codes and correlations were employed to compute various parameters, which include: coolant velocity distribution in the core; critical velocity; pressure drop; saturation temperature; temperature distribution in the core and margins to Onset of Nucleate Boiling (ONB), Onset of Flow Instability (OFI) and Departure from Nucleate Boiling (DNB). 相似文献
14.
15.
16.
M. Albarhoum 《Progress in Nuclear Energy》2011,53(1):73-75
The Low Enriched Uranium UO2 fuel performance in low-power research reactors is assessed in this paper. The usability of this fuel has been demonstrated in some research reactors in the world (SLOWPOKE-2). The fuel proved to be usable in the miniature neutron source low-power research reactors when about 50 fuel rods were substituted by as many dummy rods, while in SLOWPOKE reactors the number of fuel pins reduced by 98. About 3.8531 mk reactivity was rendered available at reactor start-up in MNSRs. The power of MNSRs needed to be increased by about 19%. Shut-down margin, effective shut-down margin, and control rod worth all decreased. 相似文献
17.
Christofer Willman Ane HåkanssonOtasowie Osifo Anders BäcklinStaffan Jacobsson Svärd 《Annals of Nuclear Energy》2006
Plutonium-rich mixed oxide fuel (MOX) is increasingly used in thermal reactors. However, spent MOX fuel could be a potential source of nuclear weapons material and a safeguards issue is therefore to determine whether a spent nuclear fuel assembly is of MOX type or of LEU (Low Enriched Uranium) type. 相似文献
18.
This work aims at simulation of reactivity induced transients in High Enriched Uranium (HEU) and Low Enriched Uranium (LEU) cores of a typical Material Test research Reactor (MTR) using PARET code. The transient problem was forced through specification of externally inserted reactivity as a function of time. Reactivity insertions are idealized by ramps and steps. Superdelayed-critical transients, superprompt-critical transients and quasistatic transients are selected for the analysis. Ramp and step reactivity functions were employed to simulate these perturbations. The effect of initial power on transient behavior has also been investigated. The low enriched uranium core is analyzed for transients without scram. The magnitudes of maximum reactivity insertions are chosen to be in the range of $0.05 to 2.0 for different reactivity insertion times. Transient simulation with scram reveals that response of both HEU and LEU-cores is similar for selected ‘ramps’ and ‘steps’. The difference is observed in the peak values of power and coolant, clad and fuel temperatures. Trip level is achieved earlier in case of LEU-core. The peak clad temperatures in both LEU and HEU-cores remain below the melting point of aluminum-clad for the selected reactivity insertions. Simulation show that the LEU-core is more sensitive to perturbations at low power as compared to the transients at full power. For reactivity transients at low power level, power rises sharply to a higher peak value. In transients at full power, the peak power barely exceeds the trip level. The power oscillations after the first peak are observed for transients without scram. 相似文献