Holtec International has applied for a patent for multi-stage compressors that would enable any coal-fired plant to be repurposed by replacing its coal-fired boiler with clean steam from the SMR-160 small modular reactor.

A coal-fired power plant (Image: Tama66 / Pixabay)

The company said its "technical breakthrough" would enable most of the physical assets of the coal-fired plants to be preserved.

"The concept underpinning this approach is the use of multi-stage compressors which are capable of uprating the SMR-160's relatively low enthalpy steam (700 psi at 313°C) to the elevated pressure and superheat needed to run the turbogenerator of a fossil power plant," Holtec said. "The needed enthalpy boost can be modified to support continued operation of any plant's turbogenerator, and in most cases would not require any external energy input."

Holtec said a provisional patent application has been filed for this innovation "which opens the pathway to repurpose any coal-fired plant by replacing its coal-fired boiler with clean steam from the SMR-160 plant". It added: "Thousands of coal-burning plants around the world presently consigned to premature decommissioning can instead be repurposed as productive clean energy generating assets."

A study published in September by the US Department of Energy found that hundreds of coal power plant sites across the USA could be converted to nuclear plant sites, providing huge decarbonisation gains as well as bringing tangible economic, employment and environmental benefits to the communities where those plants are located. A coal-to-nuclear transition - siting a nuclear reactor at the site of a recently retired coal power plant - could help increase US nuclear capacity to more than 350 GWe, it said.

The SMR-160 is a pressurised light-water reactor, generating 160 MWe using low-enriched uranium fuel, with flexibility to produce process heat for industrial applications and hydrogen production. The design has completed the first phase of the Canadian Nuclear Safety Commission's three-phase pre-licensing vendor design review and is undergoing pre-licensing activities with the US Nuclear Regulatory Commission. Holtec has also applied for a Generic Design Assessment (GDA) of the SMR-160 in the UK.

"The ability for SMR-160 to deliver steam at any desired pressure also opens new vistas to use clean energy, such as for high-pressure steam as feed stock for industrial applications or providing low-pressure steam for district heating to cities and municipalities wishing to eliminate their current use of methane and CO2-producing fossil fuels, whether to meet clean energy goals or to protect against a forced scarcity of fossil fuels due to geo-political tensions," Holtec said.

Meanwhile, the company said it was also developing a highly efficient solar collector technology that can be co-located with SMR-160 reactors to coax additional power from the sun using the land no longer needed for coal and ash handling facilities at the coal-fired plants. Holtec expects the balance between the demand and supply of energy to be achieved 24/7 by deploying its high heat capacity Green Boiler, which it is developing to store surplus electricity generated by nuclear, solar or wind. This is a heavily insulated thermal energy storage device with integral steam generators capable of producing superheated high-pressure steam for a diverse range of applications including hydrogen production.