One of 13 positions offered by the University of Granada aimed at university graduates and doctoral degree holders to carry out a research, training and mobility programme at international research centres and laboratories related to the IFMIF-DONES project
The post-doc will work with RAMI and nuclear safety specialists in the Research Unit (RU) working in the Eurofusion ENS work programme. Periods working in European RUs are foreseen. In the course of the study, the successful applicant will gain a good understanding of fusion systems and aspects of the DONES design, will further deepen his/her knowledge of RAMI and nuclear safety principles and their application to fusion, and gain good experience of setting up and using complex engineering computer models for RAMI analyses.
DONES (DEMO Oriented Neutron Source) will be a neutron source able to irradiate, up to 30, 40 and 50 dpa with a neutron spectra similar to the one in the fusion reactors, sets of specimens of materials relevant for the construction of the future DEMO reactor.
Key elements of its engineering development are identification of reliability and availability requirements (or targets), reliability and availability analysis, reliability testing, and “reliability growth”, the structured process of finding root causes for reliability problems and predicting and monitoring the increase of system’s reliability through successive phases. Since reliability and availability are strictly related to maintenance and inspection activities performed on the plant during the operating phases, the integrated approach in reliability and availability optimization is based on the four issues: Reliability, Availability, Maintainability and Inspectability (RAMI).
Many factors are important to achieve a satisfying RAMI level: design of systems; manufacturing quality; the operational environment; the design and development of the support systems; the level of training and skills of the people operating and maintaining the system; the availability of spare parts to repair the system; and the diagnostic aids and tools (instrumentation) available to check system processes and capability to detect normal and abnormal operating parameters. All these factors must be understood to achieve a plant with a desired level of RAMI. During pre-conceptual design phases, the most important activity is to understand the rationale of the plant, the related functions, requirements and constraints for the different systems. During plant development, the most important RAMI activity is to identify potential failure mechanisms and to make design changes to remove them or to mitigate consequences of the failures. During realization and installation, the most important RAMI activity is to ensure quality in manufacturing so that the inherent RAMI qualities of the design are not degraded. Finally, in operations and support, the most important RAMI activity is to monitor performance in order to facilitate retention of RAMI capability, to enable improvements in design (if new plant upgrading will be foreseen), or of the support system (including the support concept, spare parts storage, etc.). Inadequate reliability or failed failure indications of components deemed safety critical items may directly jeopardize the public and worker safety. For that reason, deterministic and probabilistic safety assessments (PSA) have to be strongly integrated with the RAMI assessments.
Once reliability and safety of plant operation is assured, further objective is to obtain plant’s mission at minimum cost. Then, cost/benefit analysis to justify and prioritize plant changes, modifications and enhancements during design and operation have to be undertaken and have to be matched with RAMI and PSA during the overall phases of plant life. The above relationship between the facility design process and the parallel development of the facility safety analysis lets us to set the RAMI programme in a widest context called more generically the reliability assurance programme.