The newness of nuclear generation technology, the dominant place of the designer/builder in development of the system, and the extended process of plant design and construction before the first operating licence is issued tend to leave the impression that the central role is played by this group. However, it must be recognized that the designer/builder leaves the site shortly after first operation and has (at least in Canadian practice) no further responsibility for the plant, following handover from the vendor to an operating organization. Similar handover practices exist in most, if not all, countries. For example, in France where EDF is heavily involved in the building of nuclear plants as well as serving as the sole operating organiza­tion, handover of the plant must be formally executed from the building unit of the company to the operating unit of the same company. The prin­ciple remains the same. The primary role of the designer/builder is to deliver a plant to the operating organization that not only meets regulatory require­ments but also meets the staff and plant protection safety goals. During the operating phase, particularly in the early years, the designer/builder might perform support services to the operating organization. These services must eventually be taken over by either the operating company or a related organization whose only commitment is to support of operating stations. The operating company has a return responsibility to the designer/builder. It must inform designer/builder staff of the design features that are most useful during operation from the point of view of performance and safety, in addition to comprehensive operational feedback on any components or systems that require improvement. Practical considerations will vary in each individual case; in every case the essential linkages that must be sustained

over the whole operating life of the plant are illustrated in Fig 10.1. Fortunately, in recent years it has become ‘best practice’ for the designer/ builder to transfer to the operating organization the same comprehensive CADD (computer-aided drafting and design) model that was used to con­struct the plant. Associated materials lists and other supporting documenta­tion is also transferred to the operating organization, to serve as a complete record of the facility ‘as built’. This model then can be used by the operating organization to maintain a record of all in-service experience and mainte­nance operations. One alternative method for retention of these data is described in another INSAG report (INSAG, 2003).