Xe-100
Xe-100 is a helium-cooled reactor design from X-energy rated at 80 MWe. An application is docketed and under active regulatory review. It requires HALEU fuel.
Four units to supply process heat and power to a Dow chemical plant — the clearest industrial heat use case in the Western pipeline, since 750 °C helium can do things a PWR cannot. X-energy is building its own TRISO-X fuel plant at Oak Ridge because nobody else makes this fuel at scale.
| Tier | Under review |
|---|---|
| Regulator | US NRC |
| Application type | Construction permit |
| Docket / reference | NRC construction permit application, Long Mott Generating Station (Dow) |
| Application date | — |
| Review phase | Application docketed and under review |
| Decision expected | not stated |
| Coolant | Helium |
|---|---|
| Reactor family | High-temperature gas reactor (HTGR) |
| Electrical output | 80MWe |
| Thermal output | 200MWt |
| Fuel | TRISO pebbles |
| Enrichment | HALEUUp to 19.75% U-235 |
| First site | Seadrift, Texas |
| Offtakers | Dow Chemical |
This design needs HALEU — uranium enriched above 5% and below 20%. That is not the fuel any commercial Western power reactor uses today, and it is the single most common reason an advanced reactor timeline slips. Every Western facility that can make it or turn it into fuel:
| Facility | Capacity | Status |
|---|---|---|
| TRISO-X Fuel Facility (TX-1), Oak Ridge | not disclosed | construction |
| American Centrifuge Plant, Piketon | 900kg HALEU/yr | operating |
| Nuclear Fuel Services, Erwin | not disclosed | operating |
| Savannah River Site HEU downblending | 3,100kg HALEU total | operating |
| BWXT TRISO facility, Gillette | not disclosed | planned |
| Urenco Capenhurst HALEU line | not disclosed | planned |
Units announced with this design
16 units in the Global Nuclear Power Tracker carry the model name "Xe-100" — 8pre construction, 8announced. Announcement is not permission; compare this against the regulatory position above.
| Unit | Country | Status | Gross MW |
|---|---|---|---|
| Cascade SMR nuclear power plant 1 | United States | pre construction | 80 |
| Cascade SMR nuclear power plant 10 | United States | announced | 80 |
| Cascade SMR nuclear power plant 11 | United States | announced | 80 |
| Cascade SMR nuclear power plant 12 | United States | announced | 80 |
| Cascade SMR nuclear power plant 2 | United States | pre construction | 80 |
| Cascade SMR nuclear power plant 3 | United States | pre construction | 80 |
| Cascade SMR nuclear power plant 4 | United States | pre construction | 80 |
| Cascade SMR nuclear power plant 5 | United States | announced | 80 |
| Cascade SMR nuclear power plant 6 | United States | announced | 80 |
| Cascade SMR nuclear power plant 7 | United States | announced | 80 |
| Cascade SMR nuclear power plant 8 | United States | announced | 80 |
| Cascade SMR nuclear power plant 9 | United States | announced | 80 |
| Long Mott nuclear power plant 1 | United States | pre construction | 80 |
| Long Mott nuclear power plant 2 | United States | pre construction | 80 |
| Long Mott nuclear power plant 3 | United States | pre construction | 80 |
| Long Mott nuclear power plant 4 | United States | pre construction | 80 |
Sources
- US Department of Energy · retrieved 2026-09-06
- Announced units: Global Nuclear Power Tracker, Global Energy Monitor, August 2026 release — CC BY 4.0