Regarding the sum of the operation and maintenance (O&M) and fuel cycle components of the LUEC for advanced SMRs, it is likely to be close to the corresponding sum for a large reactor (of similar technology). This observation results from the combined action of the following two factors:

• The SMR vendors often indicate the O&M contribution to the LUEC could be lower than in present day large reactors due to a stronger reliance of SMRs on the inherent and passive safety features, resulting in simpler design and operation.

• Regarding the fuel costs, SMRs generally offer lower level of fuel utilisation compared to state-of-the-art large reactors, mainly because of the poorer neutron economy of a smaller reactor core. Lower levels of fuel utilisation results in a higher fuel cost (per MWh), which is most sharply manifested for SMRs with long refuelling intervals.

Thus, in this study, the sums of the O&M and fuel costs for land-based SMRs were taken to be equal to the corresponding sums for reference large reactors. For barge-mounted plants, the corresponding sums were multiplied by a factor of 1.5 reflecting the assumption of a higher O&M costs from the need for periodical factory repairs of a barge.

Because of the discounting in the LUEC calculation, the impact of the decommissioning costs (which are the expenditures to be made in 40-60 years after the start-up of commercial operation of a plant) on LUEC is very small for both SMRs and large reactors.

Co-generation of energy products

NPP operation in a co-generation mode with co-production of heat or desalinated water can potentially lead to significant additional revenue or credit[3] expressed in a currency unit per MWh. For

some SMR designs operating in a co-generation mode, the values of LUEC could be in this way improved by about 20-30%.

However, co-generation is not an attribute of SMRs only. From a technical point of view it could be realised with NPPs with reactors of any capacity. However, the SMR power range seems to better fit the requirements of the currently existing heat distribution infrastructure. Also, in isolated and remote areas the co-generation of heat or desalinated water is a high priority and must be implemented in the power plant (nuclear or not).