Abstract: Heat pipe cooled nuclear reactor has unique advantages, such as passive heat transfer technology, modular design and inherent safety. It has been extensively used in deep space, deep sea and decentralized electricity markets. Recently, Los Alamos National Laboratory designed a 5 MW_th heat pipe cooled nuclear reactor for decentralized electricity markets. This paper aimed to provide an appropriate reference for the choice of types of monolithic core in the engineering design of heat pipe cooled nuclear reactor. With the help of a Monte Carlo simulation program RMC, reactivity, neutron spectrum, breeding performance and burnup evolution were explored on the heat pipe cooled nuclear reactor with monolith materials SS-316, SiC and Mo-14Re, respectively. The results show the reactor with monolith materials SS-316, Mo-14Re and SiC can achieve a 10-year operation when the enrichment of the initially loaded ²³⁵U is about 19.35%, 28.80% and 17.10%, respectively. The SiC monolith core requires the least initial ²³⁵U enrichment. Besides, the core with SiC monolith can produce the highest mass of fissile ²³⁹Pu and ²⁴¹Pu (about 11.91 kg) and minor actinides (about 92.08 g) for a 10-year operation. Thus, SiC monolith is recommended for the pipe cooled nuclear reactor.