铍光中子对研究堆瞬态特性影响研究

摘要

在采用铍材作为慢化剂或反射层的热中子反应堆中，由于235 U裂变产物放出的高能γ光子会与9 Be发生（γ， n）反应，产生光激发缓发中子，即铍光中子，会对反应堆的动态特性产生影响。本文选取经典的铍光中子分组参数，采用系统程序relap5，研究了铍光中子对研究堆瞬态特性的影响。研究表明，铍光中子的存在导致反应堆剩余裂变功率增多和持续时间增加，从而提高了余热水平；铍光中子的存在使得瞬态中核功率变化滞后，对反应堆安全有一定的影响。%In the thermal neutron reactors adopted beryllium material as moderator or reflector, the photo neutron would be emitted as (γ, n) reaction caused by the high energyγemitted by fission products , the reactor kinetics performance will be influenced as the existence of photo neutron� The typical group con⁃stants for Be-photo neutrons were selected, and the influence of Be-photo neutrons on the transient per⁃formance of reasearch reactor was studied by relap5� The results shows that the amount of residual fission power will increase and the sustained time will aslo be extend;the change of nuclear power of reactor will be delayed in the transient as the existence of photo neutron, therefore the safety of reactor will be affected.