脉冲中子源法测量铅基零功率反应堆Venus-Ⅱ次临界度

本文利用脉冲中子源法测量了铅基零功率反应堆Venus-Ⅱ在4种燃料棒装载情况下的次临界度,简要介绍了脉冲中子源法测量次临界度的原理、测量系统及实验结果等,通过面积比法分析了各探测器的计数率时间谱，确定了系统次临界度。测量结果表明，当系统有效增殖因数在0.94附近时，不同位置处的探测器测量结果之间呈明显差异。基于MCNP理论模拟计算，分别用空间修正因子和普适的微扰法对面积比测量结果进行必要修正，消除了空间效应对实验结果的影响。在系统有效增殖因数约0.94时，经修正的面积比法能精确给出系统的次临界度。本实验研究为ADS嬗变系统的次临界度精确测量提供了一种有效方法。

Subcriticality Monitoring for Lead-based Zero Power Reactor Venus-Ⅱ Using Pulsed Neutron Source Method

In this paper, the pulsed neutron source method was used to determine the subcriticality of four different configurations of lead-based zero power reactor Venus-Ⅱ. Basic theory, measurement system and experimental results of pulsed neutron source method were briefly introduced. The subcriticality for the studied reactor configurations was extracted through the evolution of the counting rate of detectors using the area-ratio method. The measured results of different positions exhibit obvious discrepancies, especially for the effective neutron multiplication factor k_eff≈0.94. Two kinds of correction methods, including the correction factor and the generalized perturbation method, were used to correct the measured results by MCNP simulation, and the corrected measurement results for different positions were found to be consistent. The corrected area-ratio method can be used to determine the subcriticality with satisfied accuracy while the k_eff of the system is around 0.94. This study can provide an useful technique to determine the subcriticality of ADS transmutation system.