**In brief:** A Finnish startup is developing what they say could be the world's simplest commercial nuclear reactor. As if that does not sound strange enough, the reactor will solely produce heat – no electricity – in a "cost-competitive" manner.
The reactor dubbed LDR-50 offers a thermal output of 50 MW, running at a cozy 150°C, which is far below the scorching temps of conventional nuclear plants. That low operating temperature also allows the reactor to use natural circulation for cooling instead of energy-hungry pumps.
Steady Energy, the company building the reactor, said [heating](https://www.globenewswire.com/news-release/2024/12/05/2992087/0/en/Tractebel-supports-Steady-Energy-in-developing-the-world-s-simplest-nuclear-reactor-for-clean-heating.html) water to 150°C for various purposes single-handedly accounts for 10 percent of global emissions. The LDR-50 aims to solve this problem by providing a more eco-friendly way to heat the water.
The facility will supply the generated heat to district heating networks, industrial processes, desalination plants, and more. Steady Energy aims to drastically reduce construction costs and timelines compared to alternatives by sidestepping the complex steam turbines and generators needed for electricity production.
The simple design also allows the LDR-50 to come in a cargo container-sized package. The company can easily install the reactor underground to boost safety while saving coveted urban space.
The company has not explicitly mentioned the nuclear fuel the LDR-50 uses. However, such small modular reactors (SMRs) typically use low-enriched uranium, a white-grey, waxy solid used to make nuclear fuel.
Steady Energy spun out of Finland's VTT research center just last year, but it's already signed deals for 15 LDR-50 reactors across its homeland. The company is backed by Belgian engineering firm Tractebel's nuclear expertise. Tractebel is a well-established name in the global energy and infrastructure sectors, and it's signed on to provide third-party support for the reactor's design and safety cases. The two companies say they're working to establish a "severe accident management program," which is required by national and international legislation despite the technology being inherently simple and safe.
Finland's nuclear watchdog is assessing the LDR-50, and Steady Energy hopes to start constructing its first reactor heating plant by 2029. If all goes to plan, the world's simplest new nuclear option could warm neighborhoods across the country in just a few years.