颗粒床反应堆燃料组件瞬态特性研究  

Investigation on transient characteristics of fuel assembly in particle bed reactor core

作　　者：毛晨瑞 吉宇 孙俊[1] 郎明刚 石磊[1] MAO Chenrui;JI Yu;SUN Jun;LANG Minggang;SHI Lei(Key Laboratory of Advanced Reactor Engineering and Safety of Ministry of Education,Institute of Nuclear and New Energy Technology,Tsinghua University,Beijing 100084,China)

机构地区：[1]清华大学核能与新能源技术研究院先进反应堆工程与安全教育部重点实验室,北京100084

出　　处：《火箭推进》2024年第4期76-82,共7页Journal of Rocket Propulsion

基　　金：国家自然科学基金项目(52106256)。

摘　　要：核热推进系统不仅要像传统动力堆产生预期功率,还需具备快速启动与推力调节的能力,以满足其变轨与机动的需求。因此,瞬态分析对于核热推进系统的方案设计、运行策略和集成试验等有重要作用。以颗粒床反应堆燃料组件为研究对象,建立了一维瞬态热工水力模型,并分析了功率提升过程以及反应性引入后的响应特性。研究发现由于颗粒床反应堆热量载出能力强,且燃料颗粒自身热容小,因此在启动等瞬态过程中换热滞后现象较弱,从而避免了堆芯内由于蓄热效应显著可能造成的超温或热应力过大等现象,有利于实现快速启动。额定工况下引入阶跃反应性,冷却剂载热滞后于堆芯释热约0.1 s,同样有利于系统功率和推力的快速调节。此外,颗粒床反应堆堆芯阻力会随着功率升高而增大,因此在启动和推力调节等过程中需要进一步研究反应性引入与推进剂供应量的匹配技术,以实现核热推进系统的运行与控制。To achieve orbit transfer and maneuver,the nuclear thermal propulsion(NTP)system should not only release the expected heat like the traditional power reactor but also have the capability of rapid start and thrust regulation.Therefore,transient analysis is important for system design,operation strategy,and integrated test of NTP.In this paper,a one-dimensional transient thermal hydraulics model of the Particle Bed Reactor(PBR)fuel assembly was established and the response performance was analyzed under a condition of power raising.It was observed that during the start-up procedure,the delay between heat transfer on the particle surface and heat release in the fuel kernel was minimal due to the strong heat removal by the coolant and the low heat capacity of the fuel particle.The effect prevented the over temperature and high thermal stress resulted from thermal storage,which benefits the rapid start.Under rated operating conditions,introducing a reactivity step change results in a thermal response that delays behind the variation in neutron density by about 0.1 s,which also benefits the system power and thrust rapid adjustment.Furthermore,the PBR core resistance rapidly increases with the elevation of core power.Therefore,further research is needed to optimize the matching of reactivity insertion and propellant supply during startup and thrust regulation processes.This study can inform the operation and control strategies of nuclear thermal propulsion systems.

关 键 词：颗粒床反应堆 核热推进系统 燃料组件 瞬态模型 快速启动 

分 类 号：V439.5[航空宇航科学与技术—航空宇航推进理论与工程]