Small modular nuclear reactors (SMR) have attracted a lot of attention over the last 10 years. A listing at Wikipedia gives an overview of over 20 designs. Some of these designs are quite small, down to 4MW where others, even in a relative small form factor, go up to 300MWe or more. Of most interest are the Molten Salt Reactors. As these designs do work with low pressure in the reactor vessel the construction can be smaller and with less heavy wall and piping construction. Most of these designs can be made in series in a factory. The reduced material cost and the series manufacturing lowers the cost per megawatt and thus increases the economic feasibility of nuclear electricity production. The below table gives an overview of what we see as the most promising designs for the coming years.

Note:  BWR – Boiling water reactor (Gen 3), MSR – Molten salt reactor – uranium and/or thorium.

The developments in Russia, China and India are not listed as it is difficult to get regular updates on the status of these initiatives. With all these developments it is likely that SMR will start to play a role in the world non CO2 emitting energy. Several studies indicate that the main sources of renewable being wind and solar will not grow fast enough to provide sufficient clean energy to satisfy the world demand in 2050. That is why we feel that nuclear power stations need to play a role for at least 20% of the total demand. Nuclear power plants can also replace gas and coal power plants as a back-up for both solar and wind based power systems. Both MOLTEX and Elysium Energy Inc. have indicated the costprice of the generated electricity to be in the range of $ 20 to $ 40 per MWh. This is competitive with coal and gas fired power plants. However it is also competitive with wind and solar in Europe and many other places in the world. Wind at Sea is advocated as being low cost, however if the additional network cost and the necessary back-up hydrogen power plants are taken into account, wind at sea is more expensive than coal or gas fired plants, so even more so when compared with a MSR.