瞬发超临界系统内持续裂变链的发展过程

Establishment of persistent fission chains in a super prompt critical system

根据基本的概率理论和瞬发临界附近有限裂变链的发展规律,推导了单脉冲源条件下脉冲堆引发持续裂变链过程中的中子数与时间关系式,并得到CFBR-II堆上实验的验证.该关系式进一步发展了Hansen理论模型,除了可以描述裂变链后期的发展趋势,还可以描述持续裂变链产生初期中子数的快速增长行为.讨论了引发时间与源强的关系,指出在弱源条件下,引发时间几乎不依赖于源强.

Through using the basic probability theory and establishing the law of finite chains near the prompt criticality, we deduce the formula of relation between the neutrons number and time in the process of persistent chains initiated by a single-pulse neutron source in burst reaction. The formula is validated by the experiments of CFBR-II. The formula is the development of Hansen theory model because it can describe not only the developing tendency in the later stages but also the rapid increasing of neutron number in the early stage. Furthermore, according to the relation between the initial time of burst reaction and the intensity of neutron source, we illustrate that the initial time is hardly dependent on the intensity of weak neutron source.