医院中子照射器物理启动

医院中子照射器是专门用于硼中子俘获治疗的核装置。在堆芯相对两侧，设有热中子束流和超热中子束流用于治疗，另外，在热中子束流内引出1条热中子束流用于病人血硼浓度测量。本文介绍其物理启动的6个实验，实验结果表明：满功率最大运行时间为12 h，最终后备反应性为4.2 mk，满功率运行时各工艺房间辐射水平满足设计辐射分区要求，4.2 mk反应性释放实验证明医院中子照射器具有固有安全特性。

Physics Startup of In-hospital Neutron Irradiator

In-hospital neutron irradiator (IHNI) was specially designed for boron neutron capture therapy (BNCT).On the both sides of the reactor core, there are two neutron beams. One is thermal neutron beam, and the other opposite to the thermal beam, is epithermal neutron beam. A small thermal neutron beam is specially designed for the measurement of blood boron concentration by the prompt gamma neutron activation analysis (PGNAA). The six experiments were completed during startup. The results show that the maximum continuous operation time at full power is 12 h, and the final excess reactivity is 4.2 mk. The radiation dose rates at different rooms meet the designed requirement. When the positive reactivity with 4.2 mk is inserted into the reactor suddenly, the power will increase to peak power, and then, it will turn to the normal value due to the negative temperature effect, and the release result of reactivity shows the inherent safety of IHNI.