Deep Fission | Corium

← DOE PILOT

DEEP FISSION

FOUNDED

2021

San Francisco, CA

TYPE

Private

Also tracked in: DOE PILOT

Signal Indicators

FUNDING STRENGTHMEDIUM

DOE Reactor Pilot cost-share · seed stage

COMMERCIAL TRACTIONLOW

Pre-commercial · differentiated underground concept

REGULATORY MOMENTUMMEDIUM

OTA signed · early milestone stage

SUPPLY CHAIN READINESSHIGH

Standard LEU — no HALEU dependency

Signal indicators reflect Corium editorial assessment based on public data. Not investment advice.

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DOE REACTOR PILOT CIRCUIT

OTA SIGNED — DOE PILOT

▶ HOLDING POSITIONLast activity: date unknown

Last verified: April 2026 · Source: NRC ADAMS / Press Release · Scoring methodology ℹ

Recent Activity

No recent activity on record

Company Profile

Deep Fission, headquartered in San Francisco, California, is developing the Gravity — an underground pressurized water reactor designed to be deployed in deep boreholes. The concept places the reactor hundreds of meters below the surface, using geological shielding in place of conventional containment structures. Deep Fission is competing in the DOE Reactor Pilot Program after signing an OTA agreement with the Department of Energy. The design uses standard low-enriched uranium fuel with no HALEU dependency. Deep Fission targets deployment in locations where above-ground construction is prohibitively expensive or politically constrained.

Reactor Specs

REACTOR DESIGN

Gravity · Underground PWR

Uses pressurized light water as coolant instead of water. Operates at higher temperature for greater thermal efficiency.

POWER OUTPUT

10 MWe

Powers ~8,130 average US homes. A standard large nuclear plant produces ~1,000 MWe.

COOLANT

Light Water

Standard water under high pressure. Proven technology used in 90% of operating commercial reactors worldwide.

FUEL TYPE

Low-enriched UO₂

Standard uranium dioxide ceramic pellets. Used in virtually every operating commercial reactor. Well-understood supply chain.

TARGET OPERATION

2026

US nuclear projects historically require 7–10 years from construction permit to first power. The 2026 target assumes factory-built modular components and no major regulatory delays.

SITE LOCATION

TBD

Site not yet selected. Selection typically occurs 2–3 years before license application, driven by grid capacity, water access, and state regulatory climate.

Licensing Milestone Tracker

PRE-APPLICATION

APPLICATION

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UNDER REVIEW

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RAI RESOLVED

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DESIGN CERTIFIED

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CONSTRUCTION PERMIT

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