The objective of the USDOE EEDB Program is to provide periodic updates of technical and cost (capital, fuel and operating and maintenance) information of significance to the US Department of Energy. This information is intended to be used by USDOE in evauating and monitoring US civilian nuclear power programs, and to provide them with a consistent means of evaluating the nuclear option and proposed alternatives. The data tables, which make up the bulk of the report, are updated to January 1, 1980. The data in these tables and in the backup data file supercede the information presented in the Second Update (1979). Where required, new descriptive information is added in the text to supplement the data tables.