The Engineering Test Reactor (ETR) was built to improve materials testing capabilities at INL, providing a higher "flux" of neutrons than the Materials Test Reactor.

The high-flux radiation fields available in this reactor made it possible to accelerate the screening of potential reactor materials. In its early years, the MTR contributed to the design of pressurized water, organic-moderated, liquid-metal-cooled, and other reactors. Successful operation of the MTR itself was a great experiment resulting in a family of plate-type reactors. The reactor operated at a power level of 30 megawatts until September 1955 when thermal output was increased to 40 megawatts.

Proving the Principle, Susan M. Stacy

Facts about ETR:

Startup:

9/19/57

Shut Down:

12/1981