Tehran Research Reactor

Tehran Research Reactor. It is a 5 MW light-water moderated pool-type reactor located at the Atomic Energy Organization headquarters in Tehran. Originally supplied by the United States under the Atoms for Peace program, the reactor has been a central facility for nuclear research, medical isotope production, and Neutron activation analysis in Iran for decades. Its operations and fuel supply have been a focal point in international diplomatic efforts concerning Iran's nuclear program.

History and construction

The reactor's origins trace to the 1960 bilateral agreement between the Imperial Government of Iran and the United States Atomic Energy Commission. The prime contractor was American Machine and Foundry, which constructed the facility based on a design similar to the University of Virginia's research reactor. It achieved criticality in 1967, initially fueled with highly enriched uranium (HEU) supplied by the U.S. Atomic Energy Commission. Following the Iranian Revolution in 1979, technical cooperation with the U.S. ceased, and the reactor was placed under the management of the newly established Atomic Energy Organization of Iran. In the 1980s, during the Iran–Iraq War, the reactor was reportedly targeted by Iraqi Air Force airstrikes but sustained only minor damage.

Technical specifications

The reactor is a pool-type design, moderated and cooled by light water. Its core uses MTR-type fuel assemblies, originally containing U-235 enriched to approximately 93%. The core is reflected by beryllium blocks and surrounded by a graphite thermal column for neutron spectrum experiments. It operates at a maximum thermal power of 5 MW, with a peak thermal neutron flux of approximately 2×10¹³ n/cm²·s. The facility includes several horizontal beam tubes, a Neutron radiography station, and a gamma irradiation cell, enabling a wide range of scientific applications.

Operations and utilization

Primary activities include the production of radioisotopes for medical diagnostics and treatment, such as Iodine-131 and Molybdenum-99. The reactor supports Neutron activation analysis for geological, environmental, and archaeological studies, and provides Neutron diffraction services for materials research. It also serves as a key training facility for nuclear engineers and scientists from the University of Tehran and other Iranian academic institutions. Operational schedules have occasionally been interrupted due to fuel supply challenges and international sanctions.

Fuel cycle and fuel supply

The reactor initially operated on a core of highly enriched uranium (HEU) fuel supplied by the United States. After the 1979 revolution, this supply was cut off. In the early 1990s, Argentina's state-owned company INVAP assisted in converting the reactor to use low-enriched uranium (LEU) fuel, fabricating new fuel elements using U₃O₈ enriched to 19.75% U-235. Subsequent fuel needs became a major issue in the 2000s, leading to the 2010 Tehran Declaration involving Brazil, Turkey, and the International Atomic Energy Agency (IAEA) for a fuel swap, which was not finalized. Later, fuel was supplied domestically from facilities like the Fuel Manufacturing Plant in Isfahan.

Safety and security features

The reactor incorporates multiple defense-in-depth safety systems, including negative temperature coefficients, redundant control rod drive mechanisms, and a confinement structure to contain radioactive releases. Its spent fuel is stored in an on-site storage pool under IAEA monitoring. Physical protection is managed by the Iranian Revolutionary Guard Corps, with surveillance systems and access controls consistent with IAEA guidelines on Nuclear security. The reactor's safety systems were reviewed during the Joint Comprehensive Plan of Action (JCPOA) implementation period.

Role in Iran's nuclear program

The reactor has been a cornerstone of Iran's nuclear program, providing essential experience in reactor operations, fuel management, and isotope production. Its fuel supply crises in the 2000s were central to diplomatic negotiations between Iran and the P5+1 nations, including the Joint Comprehensive Plan of Action. The reactor's operations are subject to regular IAEA inspections under NPT safeguards agreements. It represents a declared, peaceful facet of Iran's nuclear activities, though its historical use of HEU fuel has contributed to broader non-proliferation concerns within the international community. Category:Research reactors Category:Nuclear technology in Iran Category:Buildings and structures in Tehran