摘要
为了顺利开展低浓铀转化,使用MCNP、WIMSD和CITATION程序建立了尼日利亚微堆(低浓铀)模型,计算了尼日利亚微堆(低浓铀)的几个主要参数,并在微堆零功率装置上完成了零功率实验,测量获得中心控制棒、上铍、最外围元件、内辐照管和外辐照管等实验部件的反应性效率,实验数据和计算结果符合较好。完成了尼日利亚微堆(低浓铀)现场安全功能实验,实验结果证实尼日利亚微堆(低浓铀)具有良好的安全性能,标志着中国原子能科学研究院完成了尼日利亚微堆(低浓铀)低浓铀转化。
The Nigerian miniature neutron source reactor(MNSR)is a research reactor developed and constructed by China Institute of Atomic Energy.The high enriched uranium(HEU)fuel is used in the reactor core fuel.In order to prevent nuclear proliferation,the Chinese government is committed to actively assisting other countries completing the conversion of low enriched uranium(LEU)of the research reactor,then the work of Nigerian MNSR with LEU core is started.In order to carry out the conversion of LEU smoothly,Nigerian MNSR with LEU core model was constructed using MCNP,WIMSD and CITATION codes,and main parameters of the Nigerian MNSR with LEU core were calculated,such as critical mass,central control rod reactivity efficiency,upper beryllium reactivity efficiency in outer ring,thermal neutron fluence rate in inner and outer irradiation tubes,core reactivity efficiency,irradiation tubes reactivity efficiency of core radial and axial in-homogeneity coefficients,fuel temperature coefficient,moderator temperature coefficient,effective delayed neutron fraction and prompt neutron lifetime,etc.Then,the zero-power experiment was completed on MNSR zero-power experiment device,the reactivity efficiencies of experimental components such as the central control rod,upper beryllium,fuel elements in outer ring,inner irradiation tube and outer irradiation tube were measured using the classical periodic method in reactor physics experiments.The experimentally measured value of the reactivity efficiency of the central control rod is measured as 742 pcm,the maximum backup reactivity of the Nigerian MNSR with LEU core is 400 pcm,and the minimum shutdown depth is 342 pcm,which meets the safety requirements for MNSR shutdown.The value of the reactivity efficiency of the upper beryllium reflector layer is 1750 pcm.According to the operating experience,if the reactivity is consumed at 50 pcm per year,the Nigerian MNSR with LEU core can continue to operate for about 35 years without replacing the core.The zero-power experimental measurement data are in accordance with the design calculation data whose relative deviation between them is basically whin 5%.On the basis of these experimental and calculation data,the Nigerian MNSR with LEU core safety function experiment was successfully completed.The neutron fluence rate increases to a peak of about 2.2×1012cm-2·s-1,and then gradually decreases.Due to the temperature negative feedback and characteristics of the Nigerian MNSR with LEU core,when the control rod is stuck in the reactor and a large reactivity is accidentally introduced,the reactor can be automatically adjusted and in a controllable safety level.The results of the experiment confirm the good safety performance of the Nigerian MNSR with LEU core,marking the completion of the Nigerian MNSR from HEU to LEU,which has contributed to the prevention of nuclear proliferation in the international community.
作者
吴小波
李义国
彭旦
洪景彦
王梦娇
WU Xiaobo;LI Yiguo;PENG Dan;HONG Jingyan;WANG Mengjiao(Reactor Engineering Technology Research Institute,China Institute of Atomic Energy,Beijing 102413,China)
出处
《原子能科学技术》
EI
CAS
CSCD
北大核心
2023年第3期576-582,共7页
Atomic Energy Science and Technology
关键词
尼日利亚微堆
低浓铀
零功率实验
Nigerian miniature neutron source reactor
low enriched uranium
zero-power experiment
