nuclear-news

Deal to build pint-size nuclear reactors canceled, ‘avoiding a giant financial debacle.’

NuScale Power’s small modular reactors promised cheaper nuclear power, but costs soared and utilities balked

Science, NOV 2023 BY ADRIAN CHO

A plan to build a novel nuclear power plant comprising six small modular reactors (SMRs) fell apart this week when prospective customers for its electricity backed out. Utah Associated Municipal Power Systems (UAMPS), a coalition of community-owned power systems in seven western states, withdrew from a deal to build the plant, designed by NuScale Power, because too few members agreed to buy into it. The project, subsidized by the U.S. Department of Energy (DOE), sought to revive the moribund U.S. nuclear industry, but its cost had more than doubled to $9.3 billion.

“We still see a future for new nuclear,” says Mason Baker, CEO and general manager of UAMPS, which planned to build the plant in Idaho. “But in the near term, we’re going to focus on … expanding our wind capacity, doing more utility-scale solar, [and] batteries.” NuScale, which was spun out of Oregon State University in 2007, declined to make anyone available for an interview. But David Schlissel of the Institute for Energy Economics and Financial Analysis says, “The communities and their ratepayers have avoided a giant financial debacle.”

To some observers, the plan’s collapse also raises questions about the feasibility of other planned advanced reactors, meant to provide clean energy with fewer drawbacks than existing reactors. NuScale’s was the most conventional of the designs, and the closest to construction. “There’s plenty of reasons to think [the other projects] are going to be even more difficult and expensive,” says Edwin Lyman, a physicist and director of nuclear power safety at the Union of Concerned Scientists.

The U.S. nuclear industry has brought just two new power reactors online in the past quarter-century. In a deregulated power market, developers have struggled with the enormous capital expense of building a power reactor. Two new reactors at Plant Vogtle in Georgia, one of which came online in May, cost more than $30 billion.

To whack down cost, engineers at NuScale decided to think small. Each NuScale SMR would produce just a fraction of the 1.1 gigawatts produced by one of the new Vogtle reactors. As originally conceived in 2014, the plant would contain 12 SMRs, each producing 60 megawatts of electricity, for $4.2 billion.

Small reactors are not an obvious winner. Basic physics dictates that a bigger nuclear reactor will be more fuel efficient than a smaller one. And a big nuclear plant can benefit from economies of scale. However, a small reactor can be simpler. For example, NuScale engineers rely on convection to drive cooling water through the core of each SMR, obviating the need for expensive pumps. SMRs also can be mass-produced in a factory and shipped whole to a site, reducing costs.

Size aside, NuScale’s SMR is relatively conventional. Whereas other advanced reactor designs rely on exotic coolants, NuScale’s sticks to water. It also uses the same low-enriched uranium fuel as existing power reactors. Those features helped the NuScale design win approval from the Nuclear Regulatory Commission (NRC) in September 2020—the only advanced reactor to have done so.

DOE agreed to host the plant at its Idaho National Laboratory, bypassing the long site permitting process commercial reactors ordinarily face. Still, by the time NRC approved the design, the cost for the project has risen to $6.1 billion. That led DOE to chip in $1.4 billion and developers to reduce the design to six modules, each pumping out 77 megawatts. In January, an analysis revealed that the cost had increased by an additional $3 billion. It suggested power from the plant would cost $89 per megawatt-hour, roughly three times as much as power from wind or utility-scale solar.

Why the costs sky-rocketed remains unclear. Lyman notes that NuScale’s first plant was always going to be expensive, as the company’s production lines still need to be developed. Even so, he says, NuScale designers overestimated how much they could save with a simpler design. “They never demonstrated that you could compensate for that penalty in economies of scale with these other factors.”

Jacopo Buongiorno, a nuclear engineer at the Massachusetts Institute of Technology, says the NuScale design has an Achilles’ heel. Each reactor’s core resides within a double-walled steel cylinder, with a vacuum between the walls to keep heat from leaking out. The reactor modules sit in a big pool of water, which in an emergency can flood into the vacuum space around a reactor to prevent it overheating. Compared with a conventional reactor’s building, the pool requires more reinforced concrete, the price of which has soared, Buongiorno says. “In terms of tons of reinforced concrete per megawatt of power, NuScale’s design is off the chart.”

UAMPS’s members balked at the cost of that power. UAMPS had to line up agreements to buy 80% of the plant’s 462 megawatt output before early next year, Baker says, but it had commitments for only 26%. On 7 November the 26 of the 50 UAMPS members that had signed up for the project voted to terminate it, Baker says.

Other, more ambitious nuclear projects are in the works. DOE has agreed to help a company called Terrapower develop a reactor that will use molten sodium as a coolant. It will also help another company, X-power, develop an SMR cooled by xenon gas. Both plants would use novel fuel enriched to 20% uranium-235. That fuel is not yet commercially available, and it could make those designs even more expensive, Lyman says………………………….. https://www.science.org/content/article/deal-build-pint-size-nuclear-reactors-canceled

November 13, 2023 - Posted by Christina Macpherson | business and costs, Small Modular Nuclear Reactors, USA