New Projects, Nuclear, Reactors

Can SMR Technology Revitalize the Business of Nuclear Power?

Issue 7 and Volume 122.

Industry observers have created a lot of hype surrounding the development and promise of small modular reactors. However, not a single company has built a commercial SMR unit in the U.S. and it may be several years before they even break ground.

The company making the most headway in the design and development of SMR technology is NuScale Power. The company’s SMR design, the first to be reviewed by the Nuclear Regulatory Commission (NRC), recently completed the first and most intensive phase of the NRC’s application review.

The NRC is expected to certify NuScale’s design, and the company’s first customer, Utah Associated Municipal Power Systems (UAMPS), is planning a 12-module SMR plant in Idaho slated for operation by the mid-2020s based on the certified design.

NuScale Chairman and CEO John Hopkins said the design is “positioned to revitalize the domestic nuclear industry.”

In May, Bloomberg New Energy Finance issued a report concluding more than a quarter of U.S. nuclear plants don’t make enough money to cover their operating costs. Nicholas Steckler, an analyst with Bloomberg, said 24 of the nation’s 66 nuclear plants won’t be profitable through 2021 or are already scheduled to be shut down. The decline stems from a glut of cheap gas-fired generation, flat demand for power, and power prices too low to cover basic operating costs. In short, the business of nuclear power is collapsing because the market cannot support the nation’s available capacity.

The optimism over SMRs is borne from the fact that the technology responds to some of the most prevalent causes for hesitation over nuclear power. Because the reactor is modular and designed for replication, inherent safety features are built into the plant. SMRs are designed with passive safety equipment so that, in the case of an emergency or if no power is available, the reactors can operate safely for several days before manual intervention is needed.

A cutout of the NuScale small modular reactor. Photo Courtesy: NuScale

The chances of a meltdown are next to nil because the SMR design siphons the heat away.

SMR plants offer several hundred MW of generating capacity. They are designed for modular construction, meaning the parts can be put together offsite, then moved into place in the power plant. Conversely, large-scale reactors are built on site from the ground up, which usually calls for a large amount of land, materials, workers and equipment.

Meanwhile, NuScale said in June it has found a way to generate 20 percent more power from its SMR design. The revelation stems from advanced testing and modeling tools designed to optimize performance for UAMPS’ 12-unit SMR plant in Idaho. What’s more, the uprate would lower the cost of generation from $5,000/kWh to $4,200/kWh, and the levelized cost of electricity would also fall by as much as 18 percent. The results demonstrate why NuScale “is one of the most influential and innovative energy disruptors the world has ever seen,” Hopkins said.

UAMPS said it plans to begin preparing an Idaho National Laboratory site for the 12-unit project in 2021. “This new development is yet another way NuScale is changing the SMR game and pioneering this technology in the U.S.,” UAMPS CEO Doug Hunter said in a statement. “This substantial reduction in cost per kilowatt is not only incredibly good news for the country’s first SMR plant, which we are thrilled to be deploying, but also because it will increase the value of our plant over time.”

NuScale said UAMPS will “reap the benefits” of this optimization without licensing or construction delays. NuScale said the company’s achievements puts the U.S. on a path to beat foreign competitors like Russia, China, South Korea and Argentina in a race to be the first to market. Some estimates place global SMR capacity somewhere between 55 GW and 75 GW by 2035. If those numbers are realized, the global SMR market would be valued at around $1 trillion. In April, the U.S. Department of Energy awarded NuScale $40 million to assist the company in bringing its design to market.

“Twelve modules stacked side by side would give power producers and grid managers up to 600 MW of carbon-free capacity.”

Factory built and shipped by truck, each NuScale module provides about 50 MW of capacity. Twelve modules stacked side by side would give power producers and grid managers up to 600 MW of carbon-free capacity to help maintain perfect balance between supply and demand. What’s more, the cost of producing power with NuScale’s SMR technology is now below or competitive with all other sources of power generation.

The NuScale SMR is an advanced light-water reactor. Each module. is a self-contained unit that operates independently within a multi-module configuration. Up to 12 modules are monitored and operated from a single control room.

The reactor measures 65 feet tall and 9 feet in diameter. It sits within a containment vessel.

The reactor and containment vessel operate inside a water-filled pool that is built below grade. The reactor operates using the principles of natural circulation; hence, no pumps are needed to circulate water through the reactor. Instead, the system uses a convection process. Water is heated as it passes over the core.

As it heats up, the water rises within the interior of the vessel. Once the heated water reaches the top of the riser, it is drawn downward by water that is cooled passing through the steam generators.

The cooler water has a higher density. It is pulled by gravity back down to the bottom of the reactor where it is again drawn over the core. Water in the reactor system is kept separate from the water in the steam generator system to prevent contamination. As the hot water in the reactor system passes over the hundreds of tubes in the steam generator, heat is transferred through the tube walls and the water in the tubes turns to steam. The steam turns turbines which are attached by a single shaft to the electrical generator. After passing through the turbines, the steam loses its energy. It is cooled back into liquid form in the condenser then pumped back to the steam generator.

Factory built and shipped by truck, each NuScale module provides about 50 MW of capacity. Photo Courtesy: NuScale

Factory built and shipped by truck, each NuScale module provides about 50 MW of capacity. Photo Courtesy: NuScale

Features of NuScale’s SMR design include

Thermal capacity – 160 MWt

Electrical capacity – 50 MWe (gross)

Capacity factor – >95 percent

Dimensions – 76› x 15› cylindrical containment vessel module containing reactor and steam generator

Weight – ~ 700 tons as shipped from fabrication shop

Transportation – Barge, truck or train

Cost – Numerous advantages due to simplicity, off-the-shelf standard items, modular design, shorter construction times, <$5,100/KW

Fuel – Standard LWR fuel in 17 x 17 configuration, each assembly 2 meters (~ 6 ft.) in length; 24-month refueling cycle with fuel enriched less than 4.95 percent

In designing the NuScale Power Module and power plant, NuScale has achieved a paradigm shift in the level of safety of a nuclear power plant facility. It is a solution to one of the biggest technical challenges for the current fleet of nuclear plants.

NuScale’s comprehensive safety features are incorporated to provide stable long-term nuclear core cooling under all conditions, including severe accidents. These safety features include:

• The Triple Crown for Nuclear Plant Safey design safely shuts down and self-cools, indefinitely with no operator action, no AC or DC power, and no additional water.

• High-pressure containment vessel, redundant passive decay heat removal, and containment heat removal systems.

• The integrated design of the NuScale Power Module, encompassing the reactor, steam generators, and pressurizer, and its use of natural circulation eliminates the need for large primary piping and reactor coolant pumps.

• A small nuclear fuel inventory, since each 50 MWe (gross) NuScale Power Module houses approximately 5 percent of the nuclear fuel of a conventional 1,000 MWe nuclear reactor.

• Containment vessel submerged in an ultimate heat sink for core cooling in a below grade reactor pool structure.

In January, NuScale said the NRC agreed NuScale’s SMR design approach requires no safety-related power to safely shut down. “No operating nuclear plant in the USA can make that claim,” the company said in a June 6 press release.

POWER-GEN International 2018

Several advancements in Next-Gen Nuclear technology, including SMR designs, will be discussed during several conference sessions at POWER-GEN International 2018 Dec. 4-6 in Orlando, Florida.