In recent years, one of the methods that is considered in designing and optimization of the engines and turbines with high efficiency is maximum temperature crystal sensors (MTCS). These sensors are usually very small in size and made of materials such as 3C-SiC, Diamond, Graphite, etc. They can be placed in the desired location inside the turbine or engine and measure the maximum temperature created. These sensors could be obtained a very accurate spatial distribution of the created temperature due to the small dimensions and the very high accuracy of the measurement. For producing these sensors, a very high fluence of fast neutrons is required. Therefore, the number of the core 18 of the Tehran research reactor (TRR) is simulated and the calculations of the maximum flux of fast neutrons were carried for the 3C-SiC sample. The simulation results show that the channel F4 will provide the highest flux of fast neutrons for this purpose. Also, activity calculations were done using ORIGEN code and dose rate through MCNP6 code. The results show that the amount of activity of the sample has decreased by 65% after 4 months. Therefore, the total dose rate has also reached a value lower than the criteria of 10 µSv/h. Next, the 3C-SiC sample was irradiated at 5 MW power in the TRR, then the crystal size and the amount of strain before and after irradiation were calculated. Finally, according to the results of this article, it can be said that the 3C-SiC sample will be suitable as a MTCS.