VC dollars into fission
Every disclosed venture round into fission startups — the advanced-reactor developers racing to criticality and the fuel-cycle newcomers behind them — source-linked and summed. The capital side of the story told by the reactor race → and the AI datacenter deal book →
Disclosed since 2024
$5.23B
20 rounds, source-linked
2026 so far
$2.14B
disclosed this calendar year
Largest round
$1.0B
Valar Atomics · Aug 3, 2026
Companies
11
reactor developers + fuel cycle
Cumulative disclosed private capital into fission startups since 2024. Each dot is one round, sized by amount — click through to the announcement.
| Date | Company | Round | Amount | Valuation | Led by | Source |
|---|---|---|---|---|---|---|
| Aug 3, 2026 | Valar Atomicsreactor | Series B | $1.0B | $6.0B | Sequoia Capital | TechCrunch |
| Jul 27, 2026 | Antares Industriesreactor | Growth | $470M | — | Not disclosed | TechCrunch |
| Apr 2026 | Deep Fissionreactor | Private placement | $80M | — | Not disclosed | Deep Fission |
| Mar 31, 2026 | Valar Atomicsreactor | Growth | $450M | $2.0B | Not disclosed | Tech Funding News |
| Jan 26, 2026 | Standard Nuclearfuel cycle | Series A | $140M | — | Decisive Point | Business Wire |
| Dec 2, 2025 | Antares Industriesreactor | Series B | $96M | — | Shine Capital | Business Wire |
| Dec 2025 | Radiant Industriesreactor | Series D | $300M | — | Draper Associates / Boost VC | Radiant Nuclear |
| Nov 24, 2025 | X-energyreactor | Series D | $700M | — | Jane Street | X-energy |
| Nov 10, 2025 | Valar Atomicsreactor | Series A | $130M | — | Snowpoint Ventures / Day One / Dream Ventures | CNBC |
| Sep 8, 2025 | Deep Fissionreactor | Private placement | $30M | — | Not disclosed | Business Wire |
| Aug 19, 2025 | Aalo Atomicsreactor | Series B | $100M | — | Valor Equity Partners | TechCrunch |
| Jun 18, 2025 | TerraPowerreactor | Growth | $650M | — | Not disclosed | TerraPower |
| May 28, 2025 | Radiant Industriesreactor | Series C | $165M | — | DCVC | Radiant Nuclear |
| May 16, 2025 | The Nuclear Companyreactor | Series A | $51M | — | Eclipse | TechCrunch |
| Apr 14, 2025 | General Matterfuel cycle | Series A | $50M | — | Founders Fund | source |
| Feb 20, 2025 | Valar Atomicsreactor | Seed | $19M | — | Riot Ventures | TechCrunch |
| Feb 6, 2025 | X-energyreactor | Series C-1 | $700M | — | Amazon (Climate Pledge Fund) | X-energy |
| Oct 2024 | Antares Industriesreactor | Series A | $30M | — | Alt Cap / Caffeinated Capital (co-led) | Maginative |
| Aug 2024 | Last Energyreactor | Series B | $40M | — | Gigafund | Canary Media |
| Aug 2024 | Aalo Atomicsreactor | Series A | $27M | — | Fifty Years / Valor Equity Partners (co-led) | Aalo Atomics |
Methodology
RealCounts disclosed private-market raises (equity, and structured debt only when disclosed as part of the round — noted per row). Excludes public-market offerings (IPOs, ATMs, bought deals), government awards/grants and cost-share, undisclosed rounds, fusion companies (this is a fission tracker), and radioisotope power systems (decay heat, not fission reactors). Scope is currently US-headquartered startups; international fission startups (newcleo, Copenhagen Atomics and peers) are a planned expansion. Valuations recorded only when disclosed or credibly reported (noted). Coverage begins 2024; earlier rounds are backfilled as they are verified. Amounts are the companies' or reporters' own disclosed figures.
New rounds are detected automatically: a daily cron scans the news feed for fission funding announcements and flags candidates for review; each is verified against its primary source before it ships (hover a row for its note). Not exhaustive — undisclosed rounds exist by definition. See full methodology.
Cite this page
Using our data in an article or report? Please credit Yellowcake Analytics with a link.
Yellowcake Analytics. "Fission Startup Funding Tracker." Yellowcake Analytics, 2026, https://www.yellowcakeanalytics.com/fission-funding.
<a href="https://www.yellowcakeanalytics.com/fission-funding">Fission Startup Funding Tracker</a> — Yellowcake Analytics (www.yellowcakeanalytics.com)
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