Pursuant to a legislative requirement, GAO: (1) compared the relative effectiveness of conventionally powered and nuclear-powered aircraft carriers in meeting national security requirements; (2) estimated the total life-cycle costs of conventionally powered and nuclear-powered carriers; and (3) identified implications of an all-nuclear carrier force on overseas homeporting in Japan and overseas presence in the Pacific region.

GAO noted that: (1) its analysis shows that conventional and nuclear carriers both have been effective in fulfilling U.S. forward presence, crisis response, and war-fighting requirements and share many characteristics and capabilities; (2) conventionally and nuclear-powered carriers both have the same standard air wing and train to the same mission requirements; (3) each type of carrier offers certain advantages; (4) for example, conventionally powered carriers spend less time in extended maintenance, and as a result, they can provide more forward presence coverage; (5) by the same token, nuclear carriers can store larger quantities of aviation fuel and munitions and, as a result, are less dependent upon at-sea replenishment; (6) there was little difference in the operational effectiveness of nuclear and conventional carriers in the Persian Gulf War; (7) investment, operating and support, and inactivation and disposal costs are greater for nuclear-powered carriers than conventionally powered carriers; (8) GAO's analysis, based on an analysis of historical and projected costs, shows that life-cycle costs for conventionally powered and nuclear-powered carriers (for a notional 50-year service life) are estimated at $14.1 billion and $22.2 billion (in fiscal year 1997 dollars), respectively; (9) the United States maintains a continuous presence in the Pacific region by homeporting a conventionally powered carrier in Japan; (10) if the U.S. Navy transitions to an all-nuclear carrier force, it would need to homeport a nuclear-powered carrier there to maintain the current level of worldwide overseas presence with a 12-carrier force; (11) the homeporting of a nuclear-powered carrier in Japan could face several difficult challenges, and be a costly undertaking, because of the need for nuclear-capable maintenance and other support facilities, infrastructure improvements, and additional personnel; and (12) the United States would need a larger carrier force if it wanted to maintain a similar level of presence in the Pacific region with nuclear carriers homeported in the United States.