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| Fig. 1: The Akademik Lomonosov floating nuclear power plant. (Source: Wikimedia Commons) |
The Akademik Lomonosov (Fig. 1) is the first commercially operating floating nuclear power plant and is powered by two KLT-40S reactors. Floating nuclear plants are often discussed as potential cogeneration systems. In addition to electricity, they may deliver useful thermal energy for applications such as district heating or desalination, especially in remote coastal regions where heat, freshwater, and stable power can all be valuable co-products. The plant is rated at 70 MWe and 300 MWt. [1] However, not all the heat that the plant generates can be used for desalination or district heating. In particular, only "high-grade" heat can be harvested, meaning that the heat produced at steam exhaust close to ambient temperature can only go to waste. Thus, only a fraction of the 300 MWt heat generation capacity can be useful for other applications.
According to literature, the Akademik Lomonosov is already providing district heating to the town of Pevek at 50 Gcal/h (58 MWt). [2] This heat supply assumes that the electric generation plant is running in full capacity at 70 MWe. Additionally, the Akademik Lomonosov can prioritize heat generation over electricity. When the electricity generation plant runs at 38.8 MWe, it achieves maximum thermal power generation capacity at 146 Gcal/h (170 MWt). [3] Note that the numbers reported here are both in usable high-grade heat, thus much less than the nominal 300 MWt, which involves low-grade heat. Since it is difficult to estimate the amount of usable high-grade heat using other methods, we will use the district-heating statistics as a proxy and assume that the usable heat for desalination also ranges from 58 MWt to 170 MWt.
Literature reports that the plant could be converted into a desalination plant capable of producing 20,000 - 100,000 m3/day of freshwater. [3] To test the reported estimation, energy-based estimates are used. While one report claims that Multi-Effect Distillation (MED) was determined to be the most probable method of desalination onboard Akademik Lomonosov, the exact type of method is not published (or if at least some part of the desalination plant is not already installed for future conversion, then the actual type of method is not determined yet). [4] Therefore, calculations for two types of heat-based conversion methods are presented: Multi-Stage Flash (MSF) and MED.
Literature reports that MSF uses approximately 21 kWht/m3 of heat-equivalent energy plus 4 kWh/m3 of mechanical-equivalent energy. [5] Using only the high-grade heat supply estimate of 58 MWt, the available daily thermal energy is
If all the high-grade heat is used and loss is ignored, the daily fresh water production is
This is within the range of the published figure. Therefore, the published estimate is quite plausible for an MSF type desalination.
It is also reported that a standard MED system has an overall specific energy consumption between 14.2 and 21.6 kWht/m3, and that MED consumes less thermal energy than MSF and is thermodynamically the more effective process. [5] If the same residual heat budget is applied as an equivalent energy estimate, the freshwater production range becomes 64,400 - 98,000 m3/day, using the same calculation method as above. Notably, the higher bound of this range is very close to the estimated maximum desalination capacity published by literature.
This analysis shows that the cogeneration potential of the Akademik Lomonosov is governed less by its nominal thermal rating and more by how much high-grade heat can be extracted without undermining the steam cycle that produces electricity. Using the plant's demonstrated district heating capacity as a practical proxy for usable heat avoids treating condenser reject heat as available for desalination. Under that physically realistic assumption, the order-of-magnitude desalination capacities reported in the literature are consistent with the energy-balance estimates presented in this report for both MSF and MED. Overall, the Akademik Lomonosov is best understood as a compact floating cogeneration system that conveniently supports activity in remote Arctic or coastal environments, where both freshwater and useful heat can be highly valuable. Considering that Akademik Lomonosov and all future floating nuclear power plants most likely will have immediate access to saltwater, they are especially well suited for cogeneration and water production instead of just stand-alone electricity generation units.
© Jason Ye. The author warrants that the work is the author's own and that Stanford University provided no input other than typesetting and referencing guidelines. The author grants permission to copy, distribute and display this work in unaltered form, with attribution to the author, for noncommercial purposes only. All other rights, including commercial rights, are reserved to the author.
[1] K.-H. Lee et al., "Recent Advances in Ocean Nuclear Power Plants," Energies 8, 11470 (2015).
[2] K. E. Holbert, "A Review of Maritime Nuclear Reactor Systems," J. Nucl. Eng. 6, 5 (2025).
[3] V. I. Kostin et al., "Floating Power-Generating Unit With a KLT-40S Reactor System For Desalinating Sea Water," At. Energy 102, 31 (2007).
[4] W. Dowdall and W. J. F. Standring, "Floating Nuclear Power Plants and Associated Technologies in the Northern Areas," Østeråas: Norwegian Radiation Protection Authority, StrålevernRapport 2008:15, 2008.
[5] P. P. Gohil et al., "Current Status and Advancement in Thermal and Membrane-Based Hybrid Seawater Desalination Technologies," Water 15, 2274 (2023).
