Safe and economical solid and hazardous waste disposal is a serious global concern and challenge. Therefore, the production of new environmentally friendly products for safe waste disposal and its conversion into energy is a major need of governments and companies manufacturing waste management products. An R&D project mainly aims to present an innovation and solve a problem in the real world, and is thus very expensive and riddled with technical complexity and uncertainty. The accurate selection of the project and its risk assessment improve the project's success rate and limit the companies' costs. This article aims to review the important criteria for the accurate selection of new projects for safe municipal solid waste disposal and also to identify and evaluate the risk factors affecting these projects' performance. Herein, a new fuzzy risk-based decision model is presented to achieve the stated goals. This model utilizes MCDM methods and develops them based on R-numbers method which has recently been developed to model the risk of fuzzy numbers in dynamic environments. The proposed model is successfully applied in the Waste Management Organization of Tehran, Iran. The results reveal the superiority of the plasma pyrolysis system project over other projects, e.g., launching power plants based on landfill, plasma gasification, and waste pyrolysis system. The scores of the four technologies evaluated based on the R-TODIM method are1, 0.835, 0.789, and 0, respectively. The results of risk assessment of the plasma pyrolysis system also indicate the importance of risk factors, e.g., access to technology and laboratory equipment and new scientific resources, compared to other risk factors. The scores of the three mentioned risk factors are 4.864, 4.798, and 1.1, respectively.