Caramel UO2 fuel is a new type of fuel that is suitable for use in high power density research reactors with reduced fuel enrichment. Reducing the thickness and flatness of caramel fuels increases heat transfer and reduces the fuel temperature. The purpose of this study is to investigate the neutronic and thermal-hydraulics properties of caramel fuel. The MCNP nuclear code have been used to analysis the neutronic parameters of caramel fuel and compare it with the neutron parameters of Tehran research reactor. Also, ANSYS engineering software using finite element method (FEM), thermal-hydraulics and mechanical efficiency of caramel fuel has been evaluated. In this research, the important and measurable quantity of neutrons is the study of reactivity and effective multiplication factor of the core of the redesigned open reactor, and in the mechanical analysis of fuel, stress and strain phenomena are obtained. The results obtained from the open reactor designed with caramel fuel have been investigated with the results of Tehran reactor with U3O8-Al fuel. According to the results, it can be said that caramel fuels in terms of heat increase heat transfer and lower fuel temperature, and also in terms of neutrons with a lower percentage of enrichment than the fuel loaded in the core of the Tehran reactor to the desired and to arrives at the beginning of the cycle.