The prototype reactor became critical on 11 November 2003 and was declared operational on 22 September 2006.

Also on display at the site are two prototype reactors from the Aircraft Nuclear Propulsion Project of the 1950s.

Molten lead cooling has been used in naval propulsion units as well as some other prototype reactors.

The Indian prototype reactor has been using uranium-carbide fuel.

British Nuclear Fuels at this present time require plutonium for the prototype reactor at Dounreay.

We, here, are hi the final stages of constructing our own prototype reactor.

The MSRE was a core region only prototype reactor.

The SL-1 was a prototype reactor intended for use by the US Army in remote polar locations.

In a written response to questions submitted in writing, officials said, "All naval prototype reactors have engineered safeguards to help insure safe operation."

A $350 million prototype reactor, known as the SP-100, is currently under development.