The US Department of Energy’s (DOE’s) Idaho National Laboratory (INL) said on 24 May that its Advanced Test Reactor (ATR) would be shut down for a major overhaul. The ATR will shut it down for nine months, an outage that occurs about every 10 years on average, while experts replace the reactor’s core components. This refurbishment will make it possible to continue essential operations for another decade or more.
ATR supports a wide range of vital missions for the US Navy DOE’s Office of Nuclear Energy and also supports university research and nuclear industry research worldwide In addition it supplies isotopes for medical treatment and for NASA space exploration.
ATR is a one-of-a-kind pressurized water test reactor. Its cloverleaf design enables it to offer a range of unique capabilities. Its main function is to produce neutrons at very high levels, aided by reflectors made of beryllium metal surrounding the reactor core. By exposing fuel and material samples to this environment, researchers can test new materials and designs to assess their long-term operations in high-radiation environments.
INL said ATR’s designers realised its high level of neutrons would eventually take a toll on the reactor’s reflector blocks and other internal core components. Engineers therefore designed it to enable replacement of its key internal components through an overhaul process known as the Core Internals Changeout.
ATR has been through five core overhauls since it began operations in 1967, with the most recent starting in 2004. The sixth overhaul began in April 2021 and will take about nine months. “The highly complex core overhaul process requires careful planning and coordination, resulting in as-new performance to accommodate future experiments,” INL said. Before reactor operations can resume in early 2022, INL and DOE experts will assess all existing procedures and training to verify readiness.