Partner und Internationale Organisationen
(Englisch)
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FZK (D), CEA Cadarache (F), VTT (FIN), KFKI (HU), Framatome ANP (D), EdF (F), PSI (CH), University of Tokyo (JP).
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Abstract
(Englisch)
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The HPLWR project objectives are: (a) to determine the state of the art of the technology with relevance to the HPLWR conditions, (b) to determine the technical merit and economic feasibility of an HPLWR, (c) to identify the main difficulties that may lie ahead, (d) to recommend future R&D program if the concept is found to be feasible.
At the conclusions of the HPLWR project, it is clear that all the major objectives set up at the beginning of the project were achieved. The effort invested by the partners in the HPLWR project far exceeded the effort originally foreseen. Substantial amount of technical information was generated and documented by the HPLWR project, as it can be demonstrated by the reference list of the project. The following accomplishments can be highlighted at the conclusion of the HPLWR project:
· A review and assessment of the state-of-the-art of supercritical-water cooled reactors, as well as relevant technological review of supercritical fossil power plants, has been performed and its results were considered during the execution of the HPLWR project. Consequently, a 'reference design' was selected in order to assess the technology and the available tools for the analyses of supercritical-water cooled reactors.
· General plant characteristics of a 1000 MWe once-through supercritical water reactor power plant, that has a potential to be economically competitive, were defined, in addition to the preliminary concepts for a fuel assembly, pressure vessel, containment and circuit diagram.
· Extensive neutronics and thermal-hydraulics core calculations were carried out in WP II on a benchmark problem generated from the 'reference design' and on potential fuel assemblies for the HPLWR. Independent calculations were carried out by several partners using different codes, in order to: verify the analyses, identify computer codes that could analyze the HPLWR core, identify any required code development effort and identify shortcomings in the design itself.
· The general safety features and safety philosophy of the HPLWR were defined and computer codes that could perform the safety analyses of the HPLWR were identified and tried under supercritical water conditions. At the conclusion of the HPLWR project, the design has not been completed in sufficient details to allow accurate safety analysis, the expected regulations have not been explored and the computer codes that could be used to perform safety analysis have not been validated and verified under supercritical water conditions. Nevertheless, very simple and preliminary results obtained by these safety analysis codes (e.g., RELAP5 and CATHARE), indicate that they could support the introduction and design of appropriate safety systems, and that they would be able to perform accurate safety analysis after additional code development. In support of the fuel assembly design, a thorough review of heat transfer at supercritical pressures was completed together with a thermal-hydraulics analysis of potential HPLWR sub-channels. These results will be used in the design of improved fuel assemblies.
· A state-of-the-art study was performed to investigate the operational conditions for in-vessel and ex-vessel materials in a HPLWR and to evaluate the potential of existing structural materials for application in fuel elements, core structures, reactor pressure vessel and out-of-core components. Based on extensive past experience of material behavior in LWRs, fast breeder reactors, supercritical fossil power plants, and supercritical waste oxidation, the partners were able to recommend promising HPLWR materials for in-vessel (up to 650 ºC) and ex-vessel applications that could be strong enough at the design temperature and also possess reasonable corrosion resistance characteristics. The in-vessel material selection was done in close cooperation with neutronic analysis in order to identify potential materials that are neutronically compatible. The preliminary identification of potential materials must be verified by additional analyses and extensive testing (in particular for corrosion) since the applicable data base is totally inadequate.
· The preliminary economic evaluation was performed. The HPLWR concept has a technical merit and a potential to be economically feasible in comparison with other nuclear or fossil power plants. An initial (believed to be achievable) economic target for the HPLWR is set at 1000 €/kWe and 3-4 cent/kWh levelized generation cost.
Despite the substantial technical progress made by the HPLWR project, a lot more remains to be done in the future before it can achieve a mature design concept. It is hoped that future support for the HPLWR will continue under the Commission's 6th FP, thus bringing the concept closer to the maturity. This is particularly important since the HPLWR concept is receiving recently significant attention and support in the USA and in Japan.
The following is a brief summary of recommended HPLWR future activities:
HPLWR concept refinement and assessment; HPLWR at higher neutron energies (fast); accurate and extensive core design effort; benchmark and validation of computer codes, including experiments in: neutron physics, sub-channel thermal-hydraulics, deteriorated heat transfer, transient, safety and corrosion; consideration of European requirements (EUR) and guidelines for future reactors (for example EUR, Technical Guidelines) for the HPLWR in particular with respect to safety criteria; iteration on the HPLWR design to reduce cost, including fuel cycle cost and multi-purpose concepts.
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