The utility that operates a shuttered California nuclear power plant where a radiation leak occurred last year knew about design problems with generators before they were installed, Sen. Barbara Boxer and Rep. Ed Markey said yesterday. Boxer (D-Calif.), the Senate Environment and Public Works Committee's chairwoman, and Markey (D-Mass.), ranking member of the House Natural Resources Committee, sent a letter to Nuclear Regulatory Commission Chairwoman Allison Macfarlane, urging NRC to launch an investigation.