摘要
作为原子核裂变后的重要特征之一,裂变碎片发射的缓发中子在核技术及工程领域应用广泛。重大核反应堆事故(切尔诺贝利,福岛)通常伴随爆炸发生,为合理评估裂变产物形成的缓发中子剂量场,需考虑冲击波对裂变缓发中子输运的影响。采用蒙特卡罗方法模拟缓发中子输运,建立质量厚度与缓发中子剂量的对应关系。使用基于镜像方法的LAMBR模型计算冲击波扰动下缓发中子源附近空气密度复杂分布。基于质量厚度等效衰减规律,结合LAMBR模型,计算给出地面测点处典型裂变核素缓发中子剂量场,分析冲击波对缓发中子输运的影响。研究表明,若冲击波源强确定,随着源高增加冲击波对缓发中子输运的增强效应也随之显著。此外,当源高接近地面且冲击波源强较大时,地面反射波可能会削弱缓发中子输运。
[Background]Delayed neutron,as a key signature of nuclear fission,plays a significant role innuclear technology and engineering.Major nuclear reactor accidents(e.g.,Chernobyl,Fukushima)are oftenaccompanied by explosions,which generated shockwaves that may affece the transport of delayed neutrons andconsequently influence the delayed neutron dose assessment.Understanding the influence of the shockwaves on thetransport of delayed neutrons is critical for accurate radiological evaluation in such scenarios.[Purpose]This studyaims to investigate the influence of a shockwave on the transport of delayed neutron released from fission products andto calculate the resulting dose field at ground-level monitoring points.[Methods]A correspondence between massthicknesses and delayed neutron doses was established by using the Monte Carlo method.The LAMBR model,basedon a mirroring technique,was used to calculate the complex air density distribution arising by the shockwave at aroundthe delayed neutron source.By combining the mass-thickness equivalent attenuation law with the LAMBR model,thedelayed neutron dose fields of typical fission nuclides were calculated.[Results]The results indicated that when thestrength of the shockwave source is fixed,the enhancing effect of the shockwave on the transport of delayed neutronsbecomes more pronounced as the source height increased.Conversely,when the source is close to the ground and thestrength of the shockwave source is sufficiently strong,the ground-reflected shockwave may attenuate the transport ofdelayed neutrons.[Conclusions]The transport of delayed neutrons is significantly influenced by the shockwave,andfurthermore the influence is closely related to the height and strength of the shockwave source.These findings providevaluable insights for improving dose assessment in accident conditions involving explosions.
作者
胡佳琦
商鹏
朱金辉
左应红
刘利
牛胜利
Hu Jiaqi;Shang Peng;Zhu Jinhui;Zuo Yinghong;Liu Li;Niu Shengli(State Key Laboratory of Intense Pulsed Radiation Simulation and Effect,Northwest Institute of Nuclear Technology,Xi’an 710024,China)
出处
《强激光与粒子束》
北大核心
2025年第10期121-128,共8页
High Power Laser and Particle Beams
