Will Denver International Airport be the site of Colorado’s first nuclear power station in the 36 years since the shutdown of the Ft. Saint Vrain reactor in 1989?

That’s what airport officials want to find out, and here’s information on the questions about the proposal.

DIA announced Thursday the start of a $1.25 million investigation into the possibility of building a small modular nuclear reactor power station on its 34,000-acre campus to meet its expected power needs independently into the indefinite future, serving its anticipated 120 million passengers by 2045.

The airport currently uses about 45 megawatts of energy and has “nearly 50 megawatts” of solar energy available from its more than 200 acres of solar panels. The airport thinks it might need up to 400 megawatts in the future.

“Studying the potential of small modular nuclear reactors is a responsible step in understanding how we can deliver reliable, clean energy at scale. This is about thoughtful planning, long-term sustainability, and our commitment to a healthier planet for generations to come,” said Denver Mayor Mike Johnston in a news release.

The nuclear power industry is experiencing a renaissance as a zero-carbon solution to meet the need for steady, reliable power to fill the gaps left by intermittent renewable energy sources, such as wind and solar power.

The technology for nuclear power that doesn’t require supplying a thousand or more megawatts of energy has advanced significantly in the last decade. Several different reactor technologies are being developed or are under review by federal nuclear agencies.

Here’s what you need to know:

Are Small Modular Reactors a viable solution for the airport’s long-term energy needs?

One advantage is that nuclear reactors typically have a lifespan three-to-four times that of wind turbines or solar panels. According to the U.S. Department of Energy, modern wind turbines are designed to last 20 to 25 years, and solar PV modules are designed to last about 30 to 35 years.

Typically, nuclear reactors are approved for a 40-year lifespan. However, some of the existing 94 large reactors in the U.S. are seeking operating extensions. Eighty-seven reactors have already received extensions from 40 to 60 years.

Two plants, comprising four reactors, have been approved for 80 years of operation, and another 25 are either seeking extensions or have expressed an intention to do so.

Small modular reactors, despite being new to the power market, are expected to be licensed for a default period of 40 years.

The U.S. has been operating small reactors safely in its naval vessels since 1955.

What SMR technologies are currently available?

There are 22 different SMR designs currently under development in the U.S., and more than 90 worldwide.

Only one reactor design has received design approval so far: The NuScale Power Module is approved in both a 50-MW and a 77-MW version. A module is intended to be installed in a NuScale VOYGR power plant configuration, which can include four, six, or 12 individual modules in a single installation.

The NuScale module is a pressurized water system that uniquely circulates both hot and cool water passively through convection, without the need for electrical pumps. It is a closed-loop system where steam is recondensed, passively cooled, and reused.

One feature of the NuScale design is that in a 6-reactor module plant, the modules are submerged in a 2.5 million-gallon pool of water that can absorb heat when reactors are shut down.

Another feature is that the entire reactor containment is built below ground.

The TerraPower Natrium reactor is another contender. It employs an entirely different system, utilizing molten salt as both a coolant and a heat source for generating electricity.

Salt heated by the core is stored in a separate tank, where heat exchangers create high-pressure steam to turn the generator in a closed-loop system. It is an atmospheric pressure reactor that uses pumps to circulate the salt coolant, while also featuring passive cooling systems that operate independently of electrical power.

A feature of the Natrium plant is that the boiling point of the sodium coolant is above that temperature that the radioactive core can generate. This means that even in the case of a core runaway, the sodium coolant can continue to be circulated to remove the heat.

What about water use?

Both reactor designs can eliminate the need for vast amounts of water typically required by conventional large nuclear reactors for cooling. Both can use closed-cycle dry or hybrid cooling to reduce water consumption by 80 to 95%.

According to calculations made by the ChatGPT 5 AI, water consumption for either type of reactor using dry cooling could vary from 0.07% to 0.14% of the City of Denver’s average daily water consumption of 179 million gallons, as reported by Fitch Ratings in its 2023 Denver Water report.

The NuScale plant requires some 2.5 million gallons to fill the cooling pool initially.

What about nuclear waste?

Spent nuclear fuel assemblies are encased in stainless steel casks after several years of passive cooling in water after removal from the reactor. The casks are then encased in approved concrete overpacks and stored on site — as is the case at all nuclear power plants, pending the development of a permanent disposal facility.

There are several types of casks and overpacks, but the most frequently seen overpacks are about 11 feet in diameter and 18 feet tall with a wall thickness of about 30 inches. Both the casks and overpacks must be certified for use, which includes testing of the durability of both components, including drop tests, fires and severe impacts.

Some of the transportation-related testing takes place at the MvX Rail research facility, located outside Pueblo.

Regulations call for a replacement fuel cycle of 18-24 months for the Natrium reactor and 24 months for the NuScale reactor.

What is a potential cost estimate, and what are potential funding options for an SMR facility?

Being a new technology, SMRs are subject to wide variability in costs and numerous unknowns. Rough estimates for a 462 MW NuScale 6-module plant were provided by the Institute for Energy Economics and Financial Analysis in January 2023, at $9.3 billion, or approximately $1.5 billion per individual reactor module.

TerraPower estimates the cost of the first-of-its-kind 345 MW Natrium reactor at approximately $4 billion, which includes a 50/50 cost share between the DOE and private investors.

TerraPower says it aims to reduce future Natrium fuel plant costs to about $1 billion per plant.

By comparison, the most recent large nuclear power plants to become operational — the Vogtle Units 3 and 4, each designed to provide 1,114 MW of electricity — were estimated at $14 billion for both reactors in 2009. Significant delays caused by supply chain issues and cost overruns increased the price to $34-$36.8 billion by the time both units came online.

Are federal grants and subsidies available for small modular reactor technology?

The Department of Energy’s Advanced Reactor Demonstration Program, initiated in 2020, provided NuScale Power and the Utah Carbon Free Power Project with $1.4 billion in DOE cost-sharing funds. However, the project was cancelled in November 2023 due to cost increases, which led Utah utilities that had signed on to the project to withdraw.

The TerraPower 345 MW Natrium molten salt reactor, which received $2 billion in 50/50 cost-sharing with private partners, who included Microsoft’s Bill Gates, is currently under construction in Kemmerer, Wyoming.

The Department of Energy has invested more than $1 billion in SMR development since 2012.

Critics, including Taxpayers for Common Sense, argue that SMR subsidies pose a substantial risk to taxpayers due to high costs and questionable commercial viability.

The DOE argues that the development of SMRs plays a crucial role in enhancing energy security and providing carbon-free power.