Japan’s nuclear power plants have over 57,000 tons of large equipment that have, or will in time, become radioactive industrial waste and may be destined to be disposed of overseas, a tally of electric power company data showed Saturday. The scale of the would-be hazardous waste underscores the ongoing move within the government to reexamine a rule banning the exports of radioactive waste at a time when few municipalities are willing to accept such waste. Creating an exception to the rule under the foreign exchange law would allow power companies to commission contractors overseas to dispose o…