[en] The investigation was concerned with the influence of rotational shiftwork on operator performance, particularly in the nuclear power industry. In an analysis of the literature, the fundamental chronobiological knowledge was reviewed. Work physiological criteria for the design of shiftplans were assembled and their relevance to this industry was assessed. In addition, interviews were held with representatives from nuclear power utilities in the Federal Republic of Germany and also in Switzerland and the Netherlands. Characteristics of the shiftplans in current use were recorded and the basic operating principles of the shift systems were ascertained. The alternative designs were discussed and assessed from the point of view of operator performance and their significance to safety. The results of the analysis of the literature and of the interviews with the utilities are presented in two separate volumes of the report. (orig.)