Episode:
105
Tehran Research Reactor (TRR)
Country:
Iran
Years of Operation:
1967–present
Category:
Research & Experimental
Reactor Type:
PWR
Coolant:
Light Water
Fuel Type:
Highly Enriched Uranium (orig.) / LEU (current)
Moderator:
Light Water
Thermal Power (MWth):
5
Electrical Power (MWe):
5
Status:
Research & Experimental
timeline
First Criticality Year
1967
Commercial Op Year
Shutdown Year
Lessons Learned
Lessons Learned:
1. Standardization is a Shield: The TRR is a standard pool-type design. Its simplicity is its superpower. In a world of innovative HTGR or Sodium designs that struggle to survive a decade, the boring LWR has proven it can outlast empires.
2. The "Sticky" Nature of Tech: The TRR provided the tacit nuclear knowledge—the unwritten, hands-on expertise—that allowed a generation of Iranian engineers to learn the ropes of physics and fuel cycles.
3. Retrofitting is an Art Form: The Argentine conversion proved that obsolete HEU reactors don't need to be decommissioned. With the right fuel geometry and plate design, you can modernize a 60-year-old plant and keep it relevant for the next half-century.
Whether it’s a vintage 1967 reactor or a modern design, the physics doesn’t change: if you build it simple, build it solid, and keep the water clean, you’re not just building a power source—you’re building a permanent resident that refuses to move out.
sources
ARTICLE
In the world of nuclear engineering, we often talk about proven technology, but the TRR takes that concept to a level that would make a Maytag repairman weep.
Commissioned in 1967 as part of the U.S. Atoms for Peace program, this 5 MWth pool-type LWR is the ultimate geopolitical survivor. It’s a bit like finding a perfectly preserved 1967 Chevy Impala in a garage in downtown Tehran, except this Impala produces medical isotopes and neutrons instead of exhaust.
Construction started in the mid-60s when the U.S. and Iran were still on friendly terms. It went critical in 1967 and has been humming along ever since.
Since it’s a research and isotope production reactor, it doesn't push a single electron to the grid; it sits in a 50,000-gallon pool of pure water that acts as both coolant & shield.
A fascinating technical pivot happened in the late 80s. Originally, the TRR ran on 93% Highly Enriched Uranium provided by the US. After the 1979 Revolution, that supply chain evaporated faster than water on a hot fuel rod.
Enter Argentina. In 1987, Iran struck a deal with Argentina’s INVAP to convert the core to run on 19.75% HALEU. This wasn't just a fuel swap; it was a heart transplant. They had to redesign the fuel elements to a U3O8/Al matrix to maintain 5 MWth with "weaker" fuel. It’s like trying to win a drag race after swapping out nitro-methane for 87-octane unleaded; it takes some serious engineering wizardry to keep the performance up.
Despite the 1979 Revolution, the Iran-Iraq War, and even the ongoing conflict, the TRR remains untouched. While modern centrifuges are being turned into expensive scrap metal nearby, this 60-year-old American relic is still the backbone of Iran’s nuclear medicine.
SLIDE DECK
