[en] The Heavy-Section Steel Technology (HSST) Program is conducted for the Nuclear Regulatory Commission (NRC) by Oak Ridge National Laboratory (ORNL). The program focus is on the development and validation of technology for the assessment of fracture-prevention margins in commercial nuclear reactor pressure vessels. The HSST Program is organized in 11 tasks: program management, fracture methodology and analysis, material characterization and properties, special technical assistance, fracture analysis computer programs, cleavage-crack initiation, cladding evaluations, pressurized-thermal-shock technology, analysis methods validation, fracture evaluation tests, and warm prestressing. The program tasks have been structured to place emphasis on the resolution fracture issues with near-term licensing significance. Resources to execute the research tasks are drawn from ORNL with subcontract support from universities and other research laboratories. Close contact is maintained with the sister Heavy-Section Steel Irradiation (HSSI) Program at ORNL and with related research programs both in the United States and abroad. This report provides an overview of principal developments in each of the II program tasks from October 1, 1991 to March 31, 1992