Task: Question Answering
Input (English): In March 1943, DuPont began construction of a plutonium plant on a 112-acre (0.5 km2) site at Oak Ridge. Intended as a pilot plant for the larger production facilities at Hanford, it included the air-cooled X-10 Graphite Reactor, a chemical separation plant, and support facilities. Because of the subsequent decision to construct water-cooled reactors at Hanford, only the chemical separation plant operated as a true pilot. The X-10 Graphite Reactor consisted of a huge block of graphite, 24 feet (7.3 m) long on each side, weighing around 1,500 short tons (1,400 t), surrounded by 7 feet (2.1 m) of high-density concrete as a radiation shield.The greatest difficulty was encountered with the uranium slugs produced by Mallinckrodt and Metal Hydrides. These somehow had to be coated in aluminum to avoid corrosion and the escape of fission products into the cooling system. The Grasselli Chemical Company attempted to develop a hot dipping process without success. Meanwhile, Alcoa tried canning. A new process for flux-less welding was developed, and 97% of the cans passed a standard vacuum test, but high temperature tests indicated a failure rate of more than 50%. Nonetheless, production began in June 1943. The Metallurgical Laboratory eventually developed an improved welding technique with the help of General Electric, which was incorporated into the production process in October 1943.Watched by Fermi and Compton, the X-10 Graphite Reactor went critical on 4 November 1943 with about 30 short tons (27 t) of uranium. A week later the load was increased to 36 short tons (33 t), raising its power generation to 500 kW, and by the end of the month the first 500 mg of plutonium was created. Modifications over time raised the power to 4,000 kW in July 1944. X-10 operated as a production plant until January 1945, when it was turned over to research activities.
Output (English): In what month was the first plutonium created?