Nuclear reactors in the US rely on analog controls to operate. That's a problem, since replacement parts are becoming more scarce and expensive.

However, Purdue University says it now has the first American reactor with entirely digital instruments and controls.

The reactor's new license to operate digitally may be a sign that the larger and declining US nuclear power industry could more easily follow suit.

A Purdue engineer said "there are no scenarios which would put the Purdue facility in an unsafe state," even through hacking or equipment failure.

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An all-digital upgrade to Indiana's aging nuclear reactor may signal coming changes for the American energy industry — and possibly a shift in the fight to curb climate disruption.

Nearly 100 nuclear reactors in the US provide about 20% of the country's electricity. While these reactors generate practically no greenhouse gases, companies are planning to shut down more and more of them. At the current clip, none may be operational by 2050, according to a 2017 government study.

The reasons for these reactor shutdowns are numerous and complicated; politics is playing a role, as is the rise of wind and solar energy. But current US regulations are to blame, too, since they make implementing upgrades to aging reactors — in particular new electronics that would improve safety, reliability, and longevity — hard and expensive to do. Meanwhile, supplies of approved analog parts are waning and their costs increasing.

That's why the announcement that Indiana's Purdue University Reactor Number One (PUR-1) has swapped out all of its dated analog controls for modern digital ones may represent an important turning point.

The Purdue University Reactor Number One (PUR-1) is the first nuclear reactor in the US with all-digital controls. Here its core glows blue from Cherenkov radiation. Purdue University PUR-1 is a roughly house-size nuclear facility in the basement of Purdue's electrical engineering department (though it's run by the university's nuclear engineering school). Contractors built the small reactor in 1962 for research purposes, so it's not very powerful. In fact, PUR-1 is permitted to put out no more than 12 kilowatts of thermal energy, or roughly the warmth given off by a dozen hair dryers.

The facility used to be controlled by slow, bulky, and aging analog parts. But a modernization project that began in 2012 has switched out that old equipment for modern, computer-powered hardware.

"We're going from the vacuum tubes and hand-soldered wires of the '60s to LEDs, ethernet cables, and advanced electronics," Clive Townsend, an engineer and supervisor of Purdue's reactor, said in a press release.

Below is an animation provided by Purdue that compares a historic console photo with one of the recent upgrade:

Paper tags on hooks used to help operators like Townsend keep track of the core's configuration of fuel rods and other elements. New digital displays now reduce the chance for errors, as the following animation shows.

'Suppliers no longer manufacture the requisite parts'

The Nuclear Regulatory Commission (NRC), which oversees all nuclear reactors in the US (and any changes to them), approved PUR-1's license for all-digital operations on April 1. Purdue announced the completion of its project on Monday.

The university believes its upgrade will usher in a new era of reactor technology development in part because PUR-1 can now easily, electronically, and instantly share experiment and reactor status data with researchers.

"Going digital means that much more data can be processed and analyzed, opening the door to capabilities that haven't been as possible yet in the nuclear sector, such as predictive analytics, machine learning and artificial intelligence," the university said in its release.

Digital systems can alert reactor operators about failing components, step in automatically to fix a problem, and allow many issues to be fixed with software updates instead of by tracking down old, hard-to-find, and expensive components.

"[A]s the number of nuclear constructions dwindled in the '90s and '00s, many of these suppliers pursued other business opportunities and no longer manufacture the requisite parts," Townsend told Business Insider in an email.

Why the US is taking so long to go digital with nuclear

A view of the Purdue University Reactor Number One (PUR-1) with its all-digital controls installed. Vincent Walter/Purdue University

Digital components aren't new to US reactors. Oconee Nuclear Station in South Carolina, for example, has upgraded many of its analog systems to digital ones. Meanwhile, the few new facilities under construction in the US all plan to start with entirely digital controls.

However, fully modernizing analog systems in 97 existing reactors at 60 US nuclear power stations has proven costly and time-consuming. This has contributed to a spate of planned closures in the coming decades.

Reactors cost billions of dollars to build, run, secure, and maintain. Meanwhile, a growing number and decreasing cost of alternative power sources — wind, solar, and natural gas among them — have made nuclear profit margins thinner than ever.

NRC regulations also pose a necessary hurdle, since giving nuclear companies total freedom to make changes might lead to unsafe conditions. But in recent decades, critics have said the commission's process for approving upgrades that could make reactors safer and last longer has been "opaque, cripplingly expensive, and far too time-consuming."

"It is urgent that we get on with this," Doug True, a representative of the Nuclear Energy Institute (which represents the US nuclear industry), told NRC commissioners in May. "We have plants that are aging, we have plants that are making decisions about moving into subsequent license renewal where digital controls are important."

PUR-1 is about 0.001% as powerful as the average commercial nuclear power station in the US, which made its upgrade a "much simpler safety case to demonstrate," Scott Burnell, an NRC spokesperson, told Business Insider in an email.

A view of PUR-1 engineers at the nuclear reactor's digital workstations. Vincent Walter/Purdue University

Still, Burnell said PUR-1's new license is "certainly significant" and called the process used to gain NRC approval "innovative." This is in part because the commission borrowed some standards from the German nuclear safety commission (or KTA) instead of limiting itself to all-American ones.

"The fact that the NRC is accepting a digital console for a small research reactor, with parts certified under the KTA standards, signals the regulatory body moving toward approval in a large industry reactor," Townsend said in the release.

Burnell added that the NRC is actively working with the nuclear power industry to resolve issues that are keeping bigger, more powerful reactors from going digital. Outsiders have been positive about the commission's change of direction in recent years, too.

"Through its transformative and collaborative efforts, the NRC is becoming more transparent, communicative, and flexible in its approach to the regulatory process and interactions with advanced reactor developers," Third Way, a think tank, wrote in November 2018.

Townsend acknowledged that hacking, equipment failures, software problems, and other faults are a concern with electronic systems, but he said "there are no scenarios which would put the Purdue facility in an unsafe state" due to its fail-safe design. (The reactor is constructed to automatically shut down if everything goes offline.)

Purdue plans to perform a ribbon-cutting ceremony on its refurbished reactor in September. Meanwhile, a number of companies — including startups like Flibe Energy and Bill Gates' TerraPower — are working toward a new generation of advanced nuclear reactors that are theoretically safer as well as more efficient, versatile, and useful.

And after years of setbacks, those designs are finally beginning to cut through some American regulatory red tape.