Kaleidos — Earth's first mass-produced portable nuclear microreactor
Radiant, founded in 2019 by former SpaceX engineer Doug Bernauer and based in El Segundo, California, is building the Kaleidos — a 1MWe portable nuclear microreactor designed to be mass-produced and transported by truck or cargo aircraft, aimed at replacing diesel generators for remote sites, disaster zones and defense applications. After a $165M Series C in mid-2025, the company raised over $300M in a December 2025 Series D at a roughly $1.8B valuation, with backing from Founders Fund, a16z's American Dynamism team, Decisive Point and Draper Associates, as it advances its Kaleidos Demonstration Unit toward a planned 2026 startup at Idaho National Laboratory.
Energy / Climate📍 El Segundo, CAFounded 2019
Current Valuation
$1.8B
as of 2025-Q4
UNICORN
QL Price
$1.9B
+6% vs last round
QuantLogix's current estimate for Radiant, published 2026-09-05 — above the last disclosed round of $1.8B (2025-Q4).
Confidence
medium
Basis
secondary led
What backs this price
Last disclosed round
$1.8B
2025-Q4
weight 0.62
Secondary market print
$2.0B
2026-06-27
weight 0.65
How this price has held up
No round has priced for Radiant since QuantLogix began publishing a price for it, so there is nothing to grade yet. The claim above is on the record from 2026-09-05 and will be graded against the next priced round. See the full accuracy record →
Which publicly-traded funds already hold it, what $10,000 buys, and whether any route is open to you.
Cite this price as QuantLogix QL Price, Radiant, 2026-09-05 (5c550186d2efec2f).
The id pins this exact claim, so a citation stays checkable after the price moves.
Model estimate for research — not a quote, target price, or investment advice.
IPO Outlookprivate
Is Radiant going public?
No. Radiant is private and has not filed to go public. There is no S-1 on file.
What is Radiant's valuation in 2026?
Radiant is valued at $1.8B as of 2025-Q4, set by its Series D ($300M, Dec 2025). That is the last confirmed mark, not a live price — private shares do not trade continuously.
Has Radiant filed an S-1?
No public S-1 is on file for Radiant.
Who are Radiant's investors?
Radiant's investors include Founders Fund, Andreessen Horowitz, Decisive Point, Draper Associates, Union Square Ventures, McKinley Alaska Private Investment and 2 more.
Answers are derived from the roster record shown on this page — filing status, last round and confirmed marks. Where the record is silent, the answer says so rather than guessing.
Company Profile
CEO
Doug Bernauer
Founded
2019
HQ
El Segundo, CA
Employees
~200+
Total Raised
$600M
Growth
First reactor (Kaleidos Demonstration Unit) targeting startup in 2026
Last Round
Series D — $300M (Dec 2025) · Lead: Founders Fund
IPO Status
private
Fundraising Status
Series D · $300M · 9 mo ago
privateTotal raised $600M
Secondary Market
Implied price / share
$47.28
Last round price / share
$42.32
vs last round
+11.7%
Open interest
3
Last round price vs secondary price
Secondary price return by period
Implied per-share price from private secondary transactions, as of Jun 2026. This is a point estimate, not a quote — the feed carries no bid, ask or spread, and a secondary print is evidence of what someone paid on that date rather than a live market. Compare across every tracked name →
Latest Funding Round
Round
Amount
Date
Lead Investor
Post-Money
Series D
$300M
Dec 2025
Founders Fund
—
Talent Signal
Hiring trend
● First snapshot
trend accrues with monthly sweeps
Open roles
29
via ashby
Product-build share
59%
engineering, research, product, design
Trajectory
steady
product-led hiring — 59% of open roles build product; the rest are go-to-market and G&A.
Counted from Radiant's live job board as of 2026-08-17; role functions classified from posting titles. Open-role counts are an activity signal, not headcount. Refreshed monthly.
Founders & Key People
Doug BernauerBob Urberger
Investors
Founders Fund · Andreessen Horowitz · Decisive Point · Draper Associates · Union Square Ventures · McKinley Alaska Private Investment · ARK Invest · Nucleation Capital
Products
Kaleidos 1MWe portable microreactor
Kaleidos Demonstration Unit (KDU) at Idaho National Laboratory
Competitors
Oklo · X-energy · NuScale Power · Last Energy
EnergyClimate TechNuclearUnicornDeep Tech
Private-company numbers are not real-time. Reflects publicly disclosed valuations from press releases, news reports, and tender offers as of 2025-Q4. Refreshed quarterly.