THTR-300
Reactor Data
Reactor Units
Every power reactor at this site as listed in the IAEA Power Reactor Information System (PRIS): reactor type and model, net electrical capacity, grid connection and commercial operation dates, and current status.
1 unit: 1 permanent shutdown.
| Unit | Type | Model | Net MWe | Construction | Grid | Commercial Op | Shutdown | Status |
|---|---|---|---|---|---|---|---|---|
| THTR-300 | HTGR | Pebble bed reactor | 296 | 1971-05-03 | 1985-11-16 | 1987-06-01 | 1988-09-29 | Permanent Shutdown |
Capacity, milestones and suppliers
| Unit | Design MWe | Gross MWe | Thermal MWt | First Criticality | Reactor Supplier | Turbine Supplier | Notes |
|---|---|---|---|---|---|---|---|
| THTR-300 | 296 | 308 | 760 | 1983-09-13 | HOCHTEMPERATUR-REAKTORBAU GMBH | BROWN BOVERI ET CIE | Decommissioning from 1993-10-22 |
Lifetime performance, through 2025
| Unit | Electricity Supplied | Load Factor | Energy Availability | Operating Factor |
|---|---|---|---|---|
| THTR-300 | 2.8 TWh | 49.4% | 49.4% | 63.8% |
Operator: HOCHTEMPERATUR-KERNKRAFTWERK GMBH
Owner: HOCHTEMPERATUR-KERNKRAFTWERK GMBH
Source: IAEA Power Reactor Information System (PRIS), as of 2026-10-19.
Working Here
Per Diem Rates FY 2026
Per diem covers lodging and meals & incidental expenses (M&IE) for government and contractor travel near this facility. Rates are from the U.S. State Department foreign per diem tables for FY 2026.
$237
Lodging/Night
$140
M&IE/Day
$377
Total/Day
Germany: rate for locations the State Department does not list separately
U.S. Department of State foreign per diem, for U.S. government and contractor travel.
Photos
Photos of this facility from the NukeWorker photo gallery. Click the header or any photo to browse the full album.
Facility Map
Interactive satellite map showing the facility's geographic location. Marker color indicates current status: green for online, red for offline, orange for reduced power. Click the header to open in Google Maps satellite view.
51.68, 7.9718
Location & Contact
Physical address, phone number, and website for this facility. Use the directions link to get driving directions via Google Maps.
Plant Facts
About This Site
Written by NukeWorker from public records: facts that do not change. Operator, status and capacity come from the live data elsewhere on this page. Sources: Wikipedia: THTR-300.
THTR-300 was a high-temperature nuclear power plant at Hamm-Uentrop in North Rhine-Westphalia, Germany. The Hochtemperatur-Kernkraftwerk GmbH built it.
Read more
It was a helium-cooled pebble-bed reactor with a rating of about 308 MWe from 750 MW thermal. Construction ran through the 1970s and early 1980s. The reactor first reached criticality on 13 September 1983 and was connected to the grid on 16 November 1985. On 4 May 1986 fuel pebbles jammed in the feed system after operator handling errors, and radioactive aerosols were released through an exhaust chimney. The IAEA lists its permanent shutdown as 29 September 1988. The plant was then placed in safe enclosure.