高通量研究堆是开展反应堆燃料材料考验、工业及医用同位素生产、和基础探索研究的顶级设施，需求十分广泛，是解决我国核能发展卡脖子问题的关键途径，为实现我国核技术跨越式发展提供支撑。清华大学核能与新能源技术研究院初步设计了一座快、热中子通量均能达世界水平的宽能谱超高通量试验堆（以下简称“高通量堆”）。本报告根据初步设计的高通量堆物理方案进行了启停堆方案的设计和反应性引入事故的分析，验证了高通量堆的安全性。本文基于Relap5高通量堆模型，加入点堆动力学模型，使用系统分析程序Relap5进行了反应堆自稳定性验证，计算结果表明反应堆可以在负反馈效应的作用下快速达到稳定，具有良好的自稳定性。为保证反应堆正常启动、停堆过程的安全性，本文综合考虑反应性的引入量、中间稳定时间及引入速率大小等影响因素，设计出既安全又方便操作的启堆以及停堆方案。并针对启堆过程设置合理的安全限值，在事故工况下能够获得更多的安全裕度，保证反应堆的安全性。本文还针对控制鼓失控旋出引起的反应性引入事故进行分析和保护信号的设定，得到现阶段保守条件下适用于高通量堆的超温度保护和超功率保护信号，距离安全限值均有很大的裕量。并通过事故分析，初步验证了保护信号设计合理性以及堆芯的安全性。

High flux research reactors are important equipments in launching fundamental scientific research and producing various radioisotopes, which is widely used in nuclear engineering field. The accomplishment of the high flux research reactors’ design is the key to solve the bottleneck problems in the nuclear energy development. The Institute of Nuclear and New Energy Technology of Tsinghua University has initially designed a wide energy spectrum ultra-high flux test reactor whose fast and thermal neutron fluxes can reach the advanced level in the world. This report designed start-up and shutdown scheme based on the preliminary design of the high flux research reactor. The work evaluates the safety characteristic of this newly designed reactor.Based on the high flux research reactor model in Relap5, the work analyzes the self-stability with point reactor dynamic model. The numerical results show that the reactor can quickly achieve stability affected by Doppler effect of and negative temperature feedback coefficient in moderator, the reactor reveals self-stability and the key parameters gradually reduces to a stable value.To ensure the critical safety during the normal start-up and shutdown of the high flux research reactor, this work thoroughly analyze the influencing factors such as the addition amount of reactivity, the length of waiting time, the introduction rate, and then design a safe and convenient start-up and shutdown scheme. Reasonable safety limits are set for each stage of the reactor start-up process, so that the reactor can obtain more safety margins under accident conditions and ensure reactor safety.In this paper, the reactivity introduction accidents caused by uncontrolled spinning out of the control drum are analyzed, and conservative super-temperature/power protection signals are aquired. It is found that the current conservative conditions have a large margin from the safety limit. The safety of the protection signal design is preliminarily verified through accident simulation analysis.