U.S. Idaho National Laboratory (INL) recently completed the sixth major core overhaul of the Advanced Test Reactor (ATR), the world’s most powerful materials test reactor.

Completion of the 11-month project will be followed by a testing and measurement phase to calibrate new instruments and sensors for the reactor’s control systems and experiment loops. Normal operations of the ATR are expected to begin by late spring to test nuclear fuels and materials for the U.S. Department of Energy, the U.S. Navy’s nuclear propulsion program, industry and university researchers.

The overhaul process occurs approximately every 10 years and entails accessing the reactor core by removing the reactor vessel head, removing the main core components and installing new components. The replacement reactor components must be precisely aligned during installation to ensure proper operation of fuel and reactor safety systems.

Source: U.S. Idaho National LaboratorySource: U.S. Idaho National Laboratory

The pressurized water test reactor generates very high levels of neutron irradiation that cause strain or microscopic damage to internal components, particularly its beryllium reflectors used to help concentrate neutrons on the fuels and materials being tested. The overhaul project allows for the replacement of components that endure the most wear and tear during routine operation and the restoration of the main ATR core components to a like-new condition.

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