【作者】 马爱锋；

【导师】 张少泓； 蒋校丰；

【作者基本信息】 上海交通大学 ， 核能科学与工程， 2007， 硕士

【摘要】 如何对次临界反应堆的次临界度进行监测是ADS研究中的一项重要内容。由于外源驱动次临界堆独特的物理特性,使得目前在临界反应堆中广泛应用的基于点堆模型发展起来的传统反应性测量方法很难应用于该系统的次临界度监测。本文从基础的堆物理理论出发,基于有外源条件下次临界堆内的稳态中子通量密度分布既跟系统的本征函数有关也跟系统的本征值有关的特性,提出了通过少量的测量获取次临界堆内通量密度空间分布形状的信息,进而由这些信息来监测反应堆次临界度的新方法,并以IAEA ADS基准题和我国启明星1#实验装置为例,用数值模拟的方法说明了该方法的可行性。相比于传统反应性测量方法,该方法具有应用简便、不受外源强度影响等优点,也避免了传统方法其测量易受空间效应干扰的困难。为从理论上配合原子能科学研究院针对启明星1#实验装置所开展的实验研究工作,论文还开展了该装置的数值模拟工作,采用蒙卡方法,计算了该装置的有效缓发中子份额,并对原子能院在该装置上已开展的外推临界实验以及瞬发中子衰减特性实验进行了数值模拟。论文结合数值模拟的结果,对原子能院有关的实验数据进行了独立的分析,就该装置的次临界度,得出了与原子能院不同但我们认为更合理且自洽的结果。论文研究成果对ADS次临界度的监测以及以启明星1#实验装置为对象,通过理论与实验相结合的方式更好地开展次临界堆物理特性的研究具有重要意义。更多还原

【Abstract】 How to measure or monitor the sub-criticality of a subcritical reactor of ADS is a key issue of ADS research. Due to the unique reactor physics characteristics of a subcritical reactor driven by an external neutron source, conventional reactivity measurement methods developed on the base of point reactor model and extensively applied in current critical reactors will be difficult to be directly applied to ADS. In this thesis, starting from the fundamental reactor physics theory, we have illustrated that differing from that of a critical reactor the static neutron flux spatial distribution of a subcritical reactor is determined not only by the eigen-functions of the system but also the eigen-values. Based on this feature, we have proposed a new methodology for subcriticality monitoring via the measuring of in-core neutron flux spatial distribution. The feasibility of the new methodology has been preliminarily demonstrated by numerical tests on IAEA ADS benchmark problem and Chinese Venus 1# experimental device. Comparing against the conventional reactivity measurement methods, the new method has the merits of simplicity, freedom from the impacts of external source fluctuation and high-order harmonics spatial effect as well.In order to cooperate with CIAE to undertake both theoretical and experimental studies of subcritical experimental device Venus 1#, we have numerically analyzed the device by use of MC method. Effective delayed neutron fraction, both experiments on extrapolation criticality assessment and measurement of decay constant of prompt neutron have been analyzed. Based on the numerical results, we have independently studied the experimental data and derived our own result on the subcriticality of the device. The result is much different from the one CIAE obtained, but we consider that our result is more reasonable and consistent.In conclusion, the new subcriticality monitoring methodology we have proposed更多还原