The pool-type research reactor operations sometimes require personnel to stand on top of the reactor tank. The radioactive N-16 isotopes with very high energy gamma rays that are produced through (n,p) reaction of O-16 in water are dragged with the coolant to the top of the tank, therefore, increase the radiation dose to workers. Since the half-life of N-16 is only 7.13 s, the solution for reducing the radiation risk is to increase the rise time of the N-16 radioisotopes in the tank and allow them to decay away naturally along the way. The diffuser in Istanbul Technical University TRIGA Mark II Research Reactor is designed for this purpose. In this article, the effect of diffuser on the pathways of N-16 radioisotopes were investigated with computational fluid dynamics simulations. The distribution of the N-16 radioisotopes in the tank and the rise time were obtained. The results showed that the diffuser approximately doubles the rise time and significantly reduces the exposure due to N-16 concentration on top of the reactor tank.

池式研究堆的运行有时需要人员站在反应堆的顶部。通过水中O-16的（n，p）反应产生的具有非常高能量的伽玛射线的放射性N-16同位素与冷却剂一起被拖到储罐的顶部，因此增加了对工人的辐射剂量。由于N-16的半衰期仅为7.13 s，因此降低辐射风险的解决方案是增加储罐中N-16放射性同位素的上升时间，并使其沿途自然衰减。伊斯坦布尔技术大学TRIGA Mark II研究堆的扩散器就是为此目的而设计的。在本文中，通过计算流体动力学模拟研究了扩散器对N-16放射性同位素途径的影响。获得了罐中N-16放射性同位素的分布和上升时间。结果表明，由于反应器罐顶部的N-16浓度，扩散器使上升时间大约加倍，并显着减少了暴露。