Design assurance programme for modifications at the Ringhals Nuclear Power Plant

The Engineering Department within the site organization is responsible for modifications and improvements of plant design. Internal and external specialists are also involved in the design activities. Modifications follow the procedures laid down in the Design Assurance Programme (DAP), according to the overall directions given in 10CFR50 APP B and the more detailed recommendations in American Nuclear Standard 3.2, and the United States Nuclear Regulatory Commission's Regulatory Guides 1.33 and 1.64. The site Quality Assurance Department has adapted these directions to Swedish conditions. All plant modifications are ordered from customers within the site organization. The design work is performed according to the following steps: priority of problems or requirements; overall analysis of problems or requirements; basic design (preliminary and final); detailed design (electrical, mechanical, civil); purchase of equipment; installation in plant; testing of installed equipment. The project engineer is responsible for modifications from the initiation of analysis until testing and documentation are finalized. For each step, procedures and checklists are available. Internal and external specialists as well as the Swedish Nuclear Inspectorate are involved when appropriate. Design engineers and QC/QE engineers are also involved. Special groups within the site organization handle purchase and installation. Testing the installed equipment is performed in co-operation with the operation staff. Deviations from DAP must be reported by all personnel, and corrective actions must be taken. Internal audits have to be done once a year for the entire DAP and the audit, with its findings and the corrective actions taken, must be reported to the QA group. (author)