Chicago Pile-1 was soon moved by the lab to a more remote site in the Argonne Forest, where its original materials were used to build an improved Chicago Pile-2 to be employed in new research into the products of nuclear fission. Another reactor, Chicago Pile-3, was built at the Argonne site in early 1944. This was the world's first reactor to use heavy water as a neutron moderator. It went critical in May 1944, and was first operated at full power in July 1944. The Metallurgical Laboratory also designed the X-10 Graphite Reactor at the Clinton Engineer Works in Oak Ridge, Tennessee, and the B Reactor at the Hanford Engineer Works in the state of Washington.