The international literature presents several studies about the economics of Power Plants, however these analyses usually consider only the classical accounts related to Construction, Operation & Maintenance, Fuel and Decommissioning cost. Beside these accounts there are many factors, from now on named External Factors (e.g. social acceptability, Security of Fuel supply, etc.) able to heavily determine the profitability and the feasibility of a certain investment. This paper lists the External Factors and, under this prospective, ranks under different scenarios the following technologies suitable for the base-load: hydro, coal, oil, gas and nuclear. First the paper provides a list of these factors considering the international literature. As second step each factor is analyzed and quantified. Then an overall multi-attribute model, based on the Quality Function Deployment approach, is introduced to obtain a weight for each factor, dividing its impact into three different sustainability dimensions (economic, environmental, social), each weighted according to the investor sensitiveness. Finally the factor weights and their performances are coupled to obtain an overall ranking specific describing the specific environmental coming out by the combination of conditions and investors’ strategies. The results show that hydroelectric plants are usually the best solution, however there is a shortage of new sites for the further deployment of these plants, therefore other plants have to be considered to fulfill the energy growth. Coal and Nuclear could be a good choice even if each type of plant has its strengths and weaknesses. Nuclear technology has good performances on “fuel supply and environmental impact factors”, but his main weak is on the social acceptability. On the opposite the oil and gas -fired plants are always the worst choice. It is important to highlight that some factors are quantified using historical data (for the nuclear sector related to GEN II reactors). This assumption does not bias the analysis since the progress in nuclear energy is present as well as in other technologies. However is clear from the analysis that the innovative passive reactors could overcome other technologies and become the most suitable choice for the base load generation.

Several improvements have been made in the nuclear energy sector during the last decade leading to new design for advanced nuclear power plants. Literature presents several studies about the economics of these new Power Plants, however the economic analysis of these plants usually considers only the classical accounts related to Construction, Operation & Maintenance, Fuel and Decommissioning. Beside these accounts there are many factors, from now on named External Factors (e.g. social acceptability, enhanced safety, emergency planning zone reduction, etc.) able to heavily determine the profitability of the investment. This paper presents the differential impact of these External Factors on nuclear technology with different sizes. According to the classification currently in use in the IAEA, small reactors are those with electric generation power lower than 300 MW, while medium sized reactors are those with electric power between 300 and 700 MW [1]. We define “Small Medium Reactors” (SMR) reactors with an electrical output smaller than 700 MW (usually 335 MWe) and as “Large reactors”, (LR) reactors with an equivalent electric power greater than 700 MW. (usually 1340 MWe) Starting from the international literature point of view, the paper provides a list of external factors distinguished in economically quantifiable or not. Two different approaches have been used for their assessment: a monetary ranking and a strategic one. Then, using a Quality Function Deployment approach, a multi-attribute model is introduced to obtain a weight for every external factor, dividing their impacts into three sustainability dimensions (economic, environmental and social). The results show that the new SMR perform better than LR thanks to the smaller size which allows an enhancement of the safety level (which affects the public opinion) and a greater flexibility in the market.