Consortium to develop floating nuclear power plants

SAMSUNG Heavy Industries (SHI), Korea Hydro & Nuclear Power (KHNP), and Seaborg Technologies have announced a consortium to develop floating nuclear power plants.  

The group plan on using Seaborg Technologies' innovative compact molten salt reactor (MSR) technology, which is still in the concept verification phase. A prototype is scheduled for around 2025, and the firm expects to be ready for at scale deployment by 2028. 

There are many different types of MSRs, but at a basic level, MSRs use nuclear fuel that's mixed with hot fluoride or chloride salts to produce heat. The core allows the salt solution to flow at high temperatures - around 500°C or higher - while remaining at fairly low pressures. Due to its thermal stability, the liquid salt also functions as a coolant for the nuclear fuel, replacing the high-pressure water cooling in conventional reactor designs. 

Since the fuel and coolant are at atmospheric pressure, and there is no chemical reactivity with air or water, the fuel salt is not reactive with the environment, nor is there a violent expulsion of coolant if a leak occurs – instead it cools down and solidifies into rock. As a solid it is easier to clean up if an incident does occur, however it does still contain nuclear fuel, so precautions are needed. 

Seaborg says its compact MSR has a 12-year fuel cycle, after which the spent fuel is returned to the supplier where the short-lived fission products are separated and sent to storage. 

Since the fuel is chemically stable and the fission products are short-lived, the waste is radiologically similar to radioactive hospital waste and can be handled using conventional methods, which for low-level radioactive waste (LLW) means it is typically sent to land-based disposal immediately following its packaging for long-term management. Seaborg said it's goal is to reuse its own waste with the ambition to close its fuel cycle.

Each reactor can generate 200 MW of electricity, and is expected to save over 26m t of CO2 emissions over its 24-year lifetime compared with a coal-fired power plant. Its modular design means that the power barge will be able to deliver up to 800 MW of electricity, as well as clean water from desalination, and district heating/cooling. 

Additionally, the outlet temperature of the reactor is high enough to efficiently produce carbon-neutral hydrogen, synthetic fuels and fertilisers, Seaborg said.  

Seaborg points out that its technology has the added advantage of being portable. The shipping-container sized reactors will be built in Denmark, then sent to shipyards in South Korea to be installed on floating barges and moved to their final locations.  

Navid Samandari, CEO of Seaborg Technologies said: "This consortium is unique for deploying nuclear power at scale. We are proud to say we have partnered with the best for construction and operations as part of our shared mission to develop and deploy the power barges." 

Pros and cons

Despite the positives there are drawbacks to the technology to consider. Salt is very corrosive, so metal degradation can be a problem and, if lithium is used in the salt, tritium will be produced, which is radioactive and extremely mobile. 

Still, with a growing demand for clean and reliable energy, nuclear experts see MSR as a complementary means to support electricity grid balancing, along with the rising share of renewable energies.