This Radiant company profile covers the company's valuation, revenue, funding rounds, investors and history. Radiant works in energy, with a focus on nuclear microreactors. It was founded in 2019 and is headquartered in El Segundo, California, United States. Its latest valuation on record is More than US$1.8 billion (December 2025). Every figure links to a public source, and anything the company hasn't disclosed is marked as such.
Revenue
Funding history
| Date | Round | Amount | Valuation | Investors | Source |
|---|---|---|---|---|---|
| Dec 2025 | Series D | More than US$300M | More than US$1.8B | Draper Associates and Boost VC (leads); existing investors | DCVC |
Radiant timeline
Key dates from the sources on this page, oldest first. Metric snapshots are listed after the funding events.
- 2019 — Radiant is founded in El Segundo by Doug Bernauer (CEO) and Bob Urberger (CTO).
- Dec 2025 — Series D: More than US$300M, valuing the company at More than US$1.8B. Investors: Draper Associates and Boost VC (leads); existing investors.
Investors
Overview
Radiant is developing small, portable nuclear reactors, known as microreactors, that can be manufactured in a factory, shipped on a truck and deployed where power is needed. Its first product, the Kaleidos reactor, is designed to produce about one megawatt of electricity, enough to power a remote military base, a mine, a disaster zone or a small community, and to replace diesel generators that are expensive to fuel and polluting. The reactor uses high-temperature gas cooling and robust fuel designed to retain radioactive material even at very high temperatures.
Radiant was founded in 2019 by Doug Bernauer, a former SpaceX engineer, with Bob Urberger as co-founder and chief technology officer, and is based in El Segundo, California. In December 2025 it closed a Series D of more than US$300 million led by Draper Associates and Boost VC, which Axios reported valued the company at more than US$1.8 billion. The company said the money would fund its R-50 factory in Oak Ridge, Tennessee, and its first reactor test, planned at Idaho National Laboratory.
Products and plans
- Kaleidos: a roughly one-megawatt high-temperature gas-cooled microreactor that fits in a shipping container.
- TRISO fuel: particles of uranium fuel coated in layers of ceramic and carbon, designed to contain fission products at high temperatures.
- Factory production: the planned R-50 facility in Oak Ridge, Tennessee, intended to build reactors in series.
- Testing: a planned test at Idaho National Laboratory's DOME facility, a national test bed for microreactors.
Funding
Radiant raised early funding from investors including DCVC, Andreessen Horowitz, Founders Fund and Chevron Technology Ventures. It raised a US$165 million round led by DCVC in 2025, and in December 2025 it closed a Series D of more than US$300 million led by Draper Associates and Boost VC with participation from existing investors. Axios reported a valuation of more than US$1.8 billion.
Business model
Radiant plans to sell or lease reactors and power to customers that need reliable off-grid electricity and heat, such as the US military, remote industrial sites, data centres and island communities. A reactor could run for several years before refuelling, after which it would be returned to the factory. Early customers are likely to be government agencies, with commercial deployments planned to begin around 2028, according to the company.
Competition
Radiant competes with other microreactor developers, including Westinghouse's eVinci, BWXT, Oklo, Last Energy and Valar Atomics, as well as with diesel generators, batteries and other off-grid power solutions. In the longer term, fusion companies such as Helion Energy and Commonwealth Fusion Systems aim to supply clean power at larger scale.
Radiant at a glance
Radiant is an El Segundo, California nuclear company founded in 2019 by former SpaceX engineer Doug Bernauer. It is building Kaleidos, a portable one-megawatt microreactor, and a factory in Oak Ridge, Tennessee. It closed a Series D of more than US$300 million led by Draper Associates and Boost VC in December 2025 at a reported valuation of more than US$1.8 billion.
Timeline
- 2019: founded by Doug Bernauer and Bob Urberger.
- 2023: selected for testing at Idaho National Laboratory's DOME facility.
- 2025: raises a US$165 million round led by DCVC.
- December 2025: closes a Series D of more than US$300 million.
- 2026: plans to break ground on its R-50 factory and test its first reactor.
- 2028: targets initial customer deployments.
Why microreactors
Large nuclear power plants produce enormous amounts of electricity but take many years and billions of dollars to build, and several Western projects have suffered major cost overruns. Microreactors take the opposite approach: small units built in factories, like aircraft engines, rather than constructed on site. Factory production could lower costs through repetition and quality control, and portability allows reactors to serve places that are hard to reach. The trade-off is that each unit produces far less power, so economics depend on serving customers who currently pay high prices for power, such as remote sites relying on diesel.
Military and data centre demand
The US military uses large amounts of fuel at bases, and supply convoys are vulnerable in conflicts. Microreactors could provide resilient power for bases for years without refuelling. The Department of Defense and the Department of Energy have programmes to test and deploy microreactors. Separately, AI data centres need large amounts of reliable power, and some developers are exploring small reactors for on-site supply. While a single one-megawatt reactor is small relative to large data centres, clusters of microreactors could supply backup or baseload power.
Regulation
Nuclear reactors in the US require licences from the Nuclear Regulatory Commission or, for certain government applications, authorisation from the Department of Energy or Department of Defense. Licensing new reactor designs has historically taken many years. Recent US policy has aimed to speed up approvals for advanced reactors, and test programmes at national laboratories allow companies to demonstrate designs. Radiant's timeline depends on successful testing and regulatory progress.
Who funds Radiant
Radiant's investors include Draper Associates and Boost VC, which led its Series D, along with DCVC, Andreessen Horowitz, Founders Fund and Chevron Technology Ventures.
Valuation context
A valuation above US$1.8 billion before its first reactor test reflects renewed investor interest in nuclear energy, driven by electricity demand from AI and policy support. Our guides to nuclear energy startups and climate tech startups compare Radiant with peers.
Risks
- Technical risk: the reactor must perform safely and reliably in testing.
- Regulatory timelines: licensing could take longer than planned.
- Fuel supply: high-assay low-enriched uranium (HALEU) and TRISO fuel are in limited supply.
- Cost: factory production must reach volumes that deliver competitive prices.
- Public acceptance: communities may resist nuclear deployments.
Questions for prospective customers
- What will electricity cost per kilowatt-hour compared with diesel?
- How long can a reactor run before refuelling?
- What security and site requirements apply?
- Who is responsible for licensing, operation and spent fuel?
What to watch
Watch the Kaleidos test at Idaho National Laboratory, progress on the Oak Ridge factory, fuel supply agreements and first customer contracts.
Takeaways
Remote sites and the military could gain clean, reliable power without diesel convoys. Founders can see how aerospace-style engineering is entering nuclear. Investors should weigh long timelines and regulatory risk.
Sources
Every figure on this page comes from the public sources below. Where sources disagreed, we used the company's own announcement or a primary news report. Private-company data changes; check the date beside each figure.
Frequently asked questions
What does Radiant do?
Radiant is a energy / nuclear microreactors company headquartered in El Segundo, California, United States. It was founded in 2019.
What is Radiant's valuation?
Radiant was valued at More than US$1.8 billion as of December 2025, according to Axios Pro. Private company valuations are set at funding rounds or share sales and can change significantly between them.
How much revenue does Radiant make?
Radiant is a private company and has not publicly disclosed its revenue. Figures on third-party sites are usually modelled estimates rather than numbers reported by the company.
What was Radiant's latest funding round?
The most recent financing we have verified is a series d in Dec 2025: More than US$300M, at a valuation of More than US$1.8B. Source: DCVC.
Who are Radiant's investors?
Investors named in public announcements include Draper Associates, Boost VC, DCVC, Andreessen Horowitz, Founders Fund and Chevron Technology Ventures.
Who founded Radiant?
Radiant was founded in 2019 by Doug Bernauer (CEO) and Bob Urberger (CTO).
Is Radiant a public company?
No. Radiant is a private company (private, venture backed), so its shares are not traded on a stock exchange and it isn't required to publish its financial results.
Where is Radiant headquartered?
Radiant is headquartered in El Segundo, California, United States.