Nuclear radiation emitted by fusion reactors, nuclear power plants, and medical establishments presents potential risks to living organisms personnel, necessitating the implementation of protective measures. To enhance radiation protection for patients workers, various materials can be utilized. Concrete, augmented with various additives, has historically acted as a shielding material. Hence, recent research has predominantly focused on enhancing concrete's ability to attenuate the harmful energy emitted by nuclear sources through modifications to its composition. Accordingly, in the present work, the dose evaluation and radiation shielding characteristics of a range of concrete magnetite (CM) formulations designated as CM-0 (control sample), CM-25, CM-50, CM-75, and CM-100 have been analyzed using MCNPX Monte Carlo (MC) approach and theoretical computations concerning 252Cf mixed radiation radionuclide. In this work, the Watt Fission distribution was employed to derive the neutron spectrum of CM samples, and findings have been thoroughly elucidated in the presence and absence of the specified samples. Then, utilizing the Doppler Effect, the gamma photon spectrum within shielding materials exposed to a spontaneous fission 252Cf source is extracted and characterized. Estimation of Half Value Thickness (HVT) and Mean Free Path (MFP) are provided across a broad spectrum of energy levels. The analysis confirms the successful development of a new type of concrete magnetite (CM) sample that exhibits lower radiation exposure compared to the control sample. This study offers valuable insights into the use of concrete in shielding against mixed radiation radionuclides and opens the door for future research involving similar materials. Specifically, the CM-100 sample demonstrated the lowest half-value thickness (HVT) and provided the most effective reduction of both neutron and gamma radiation. The findings suggest that increasing the concentration of magnetite in concrete greatly enhances its ability to shield against mixed neutron-gamma radiation. This innovation has promising potential for applications in radiation protection, particularly within nuclear reactors and medical facilities. The CM-100 sample showed a notable improvement, achieving an HVT of 0.012 cm and a dose rate reduction of 2.95 × 10−9 Sv.h−1, in contrast to the control sample (CM-0), which had an HVT of 10.358 cm and an equivalent dose rate of 2.84 × 10−9 Sv.h−1. These results underscore the superior shielding properties of the magnetite-doped concrete formulations.