[en] This report searches for and analyzes events and precursors to events of pressure vessel thermal shock (PVTS) at US pressurized-water reactors (PWRs). The data base includes close to 16,000 licensee event reports of 47 PWRs, covering 329 reactor years (RYs) from 1963 through 1981. Ninety-nine events were found in half as many computer searches. Original reports and other published data on these finds were located and subsequently analyzed to extract information on severity, initiation sequences, causes, and frequencies. Five categories of severity were defined, with categories 0, 1, and 2 being considered insignificant and categories 3 and 4 being considered significant. In addition, an event of lower severity is considered a precursor to a higher severity event of the same cause and initiation sequence. An exhaustiveness analysis indicated that the 34 significant events may have covered two-thirds of all such events, while the 65 insignificant events may represent only 25% of all such events that took place in operating plants