[en] The DEMO heat transfer and the power conversion systems (PCS) are both part of DEMO Balance of Plant (BOP). Since a tokamak operates in pulsed mode, a concept using an internal thermal energy storage system was elaborated to allow for flexible operation of the power plant also under dwell time conditions. As part of the Power Plant Physics and Technology (PPPT) conducted by the EUROfusion Consortium for the development of fusion energy, the balance of plant develops the necessary systems and interfaces to relevant DEMO systems to allow efficient energy production. This includes design adaptation and safety analyses in order to identify safety provisions to address issues not acceptable to licensing authorities. As an example, the proposed safety provisions for the integrity of the vacuum vessel (VV) are given. An outlook summarizes design development and safety investigations. (author)

[en] Full text: Following the European roadmap to the realization of fusion energy, a demonstration fusion power plant (DEMO) is currently in preconceptual design phase until 2020. In this context an external stakeholder group formulated a nuclear licensed manufacturing and construction (M/C) as the top level requirement for a DEMO, translating essentially to the confinement of radioactive and hazardous materials as the most fundamental safety function in normal, abnormal and accidental situations. In a first step energy sources and radioactive source have been assessed for a conceptual DEMO configuration. Based on the European Plant Description Document (PDD) the main systems have been classified as active or passive systems with respect to their confinement functionality. By means of a bottom-up approach at system level, the major DEMO systems are analyzed regarding a potential confinement function. On the basis of those DEMO systems identified as having a confinement function a confinement strategy for EU DEMO has been proposed with respect to confinement barriers and confinement systems. In addition, confinement for the maintenance has been issued as well. The assignment of confinement barriers to the identified sources under abnormal and accidental conditions has been performed, and the DEMO main safety systems have been proposed as well. Confinement related open issues such as discharge of the huge magnet energy in an accidental case, confinement concerning plant states, investigation on further passive and active methods for the confinement, confinement during the procedure of removing and replacing in-vessel components, etc., need to be resolved in parallel with DEMO development. (author)

[en] Confinement of radioactive and hazardous materials is one of the fundamental safety functions in a nuclear fusion facility, which has to limit the mobilisation and dispersion of sources and hazards during normal, abnormal and accidental situations. In a first step energy sources and radioactive source have been assessed for a conceptual DEMO configuration. The confinement study for the European DEMO has been investigated for the main systems at the plant breakdown structure (PBS) level 1 taking a bottom-up approach. Based on the identification of the systems possessing a confinement function, a confinement strategy has been proposed, in which DEMO confinement systems and barriers have been defined. In addition, confinement for the maintenance has been issued as well. The assignment of confinement barriers to the identified sources under abnormal and accidental conditions has been performed, and the DEMO main safety systems have been proposed as well. Finally, confinement related open issues have been pointed out, which need to be resolved in parallel with DEMO development. (paper)