Yes, fellow sport fans - This is NOT a drill: The United States Nuclear Regulatory Commission said Wednesday that "some" of the core of a "stricken" Japanese reactor had "probably" leaked from its steel pressure vessel into the bottom of the containment structure, implying that the damage was even worse than previously thought. The statement came as the Tokyo Electric Power Company, the operator of the Fukushima Daiichi plant, started to inject nitrogen into the reactor containment vessel of unit No. 1, to prevent a possible explosion. The Nuclear Regulatory Commission's statement regarded unit #2, and the agency underscored that its interpretation was speculative and based on high radiation readings that Tokyo Electric had found in the lower part of unit No.2's primary containment structure, called the drywell. The statement said that the commission "does not believe that the reactor vessel has given way, and we do believe practically all of the core remains in the vessel." The agency's statement was issued after Representative Edward J. Markey, Democrat of Massachusetts, told a House hearing on Wednesday morning that the commission had told him that the core had melted through the vessel.