Twelve advanced reactor designs from U.S. nuclear startups racing toward zero-power criticality and continuous operation under the federal reactor pilot program.
✓ Target Met4 reactors critical — EO 14301's three-reactor goal reached ahead of the July 4 deadline, America's 250th birthday.
T+129DAYS
№
Company · Reactor
Pilot Site
NSDA
PDSA
FDSA
ZPC
Beyond ZPC
01
Valar AtomicsWard-250
San Rafael Energy LabUtah
✓
✓
✓
4/23/26
✓
6/18/26
Coolant flowing~100 kWt
02
Antares NuclearMark-0
Idaho National LabIdaho
✓
✓
1/26/26
✓
4/6/26
✓
6/4/26
Zero power only
03
Deployable EnergyUnity
Idaho National LabIdaho
✓
✓
5/22/26
✓
6/11/26
✓
6/30/26
Zero power only
04
Aalo AtomicsAalo-X CTR
Idaho National LabIdaho
✓
✓
3/3/26
✓
4/30/26
✓
7/4/26
Zero power only
05
Oklo Inc.Groves
Lockhart, TexasTexas
✓
3/17/26
✓
6/18/26
✓
7/1/26
✓
8/5/26
Zero power only
06
Last EnergyPWR-5
Texas A&M RELLISTexas
✓
✓
5/28/26
✓
10/7/26
?
—
07
Radiant IndustriesKaleidos
INL - DOME FacilityIdaho
✓
✓
2/9/26
✓
10/29/26
?
—
08
Oklo Inc.Aurora
Idaho National LabIdaho
✓
3/17/26
✓
6/11/26
◐
?
—
09
Natura ResourcesMSR-1
Abilene Christian Univ.Texas
✓
7/21/26
◐
—
?
—
10
Deep FissionGravity
Parsons, KansasKansas
✓
8/6/26
◐
—
?
—
11
Oklo Inc.Pluto
Site TBD
✓
○
—
?
—
12
Terrestrial EnergyIMSR
Site TBD
?
○
—
?
—
Milestone Sequence
NSDASafety Agreement
Nuclear Safety Design Agreement — consensus on fundamental safety.
PDSAPreliminary DSA
Preliminary Documented Safety Analysis — equivalent to a Construction Permit.
FDSAFinal DSA
Final Documented Safety Analysis — equivalent to an Operating Permit.
ZPCZero-Power Crit.
First sustained chain reaction at zero power — neutronics validated.
BEYONDPast ZPC
Whether coolant carried nuclear heat out of the core, and the highest power the developer has documented. Power conversion and sustained runs are tracked on the Commercial Scale Demo board.
Status Key
✓
Approved — milestone cleared.
◐
In Review — under active regulator evaluation.
○
Pre-App — early engagement; no formal submission filed.