Summary: GAO discussed its views on the Department of Energy's (DOE) cleanup and modernization of its nuclear weapons complex. GAO noted that DOE needs to: (1) include in its current modernization efforts, adequate plans for environmental cleanup and decontamination of existing facilities; (2) determine the extent of environmental cleanups or which sites should receive priority; (3) include in its projected estimate, the true cost for new facility construction, potential cost overruns, and the cost of building new production reactors, including implementing new technologies; (4) hire technical experts, provide safety oversight, and apply its new policies and procedures to the design and construction of new facilities; (5) develop a spending plan, periodically update the plan to ensure effective use of funds, and keep Congress abreast of its overall direction, priorities, and progress; and (6) provide information on its future budget needs to allow Congress to make more informed decisions on how best to address cleanup and decontamination problems.