Gas Cycle Testing Opportunity with ASTRID, the French SFR Prototype

by N. Alpy1, L. Cachon2, D. Haubensack1, J. Floyd1, N. Simon2, L. Gicquel2, G. Rodriguez2, M. Saez1, & G. Laffont1
French Commission for Atomic Energy and Alternative Energy
1CEA, DEN, DER, F-13108 Saint-Paul-lez-Durance, France
2CEA, DEN, DTN, F-13108 Saint-Paul-lez-Durance, France

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ASTRID (Advanced Sodium Technological Reactor for Industrial Demonstration) is the next French Sodium Fast Reactor prototype, to be put in operation by the 20’s. In addition to the important advances planned for example in the fuel and core vessel designs as well as inspection and repair techniques, the CEA is also currently assessing an alternative to the standard steam power conversion cycle to avoid issues related to the fast and energetic sodium/water reaction. Given the relatively short project timescales and the significant R&D work that remains to be carried out before the performance and safety of the innovative supercritical carbon dioxide (sCO2) Power Conversion System can be demonstrated at an industrial scale, the sCO2 cycle has not been selected as a potential candidate for ASTRID: a nitrogen cycle at 180bar is being currently investigated as the most likely alternative to a Rankine cycle. However, since 2007, dedicated research programs on the sCO2 cycle are underway at lead nuclear energy research organizations (including the CEA) as part of an international R&D collaboration for next generation nuclear reactors (GEN IV forum). Significant advances have been continuously made since the beginning of this collaboration, progressively increasing the support for the sCO2 option. In light of this positive trend, and since ASTRID is intended to have the ability to test new innovations, the sCO2 cycle may then form part of future tests of new technologies on this prototype reactor.

After a brief introduction of the ASTRID project’s main milestones, this paper presents a comparison of N2 and sCO2 power convertion system’s performance and preliminary component designs, which comply with the ASTRID specifications. In addition, CEA research relating to the sCO2 cycle is presented, which includes a comprehensive investigation of the cycle performance for various design points around the saturation dome, first use of the Plant Dynamic Code (provided by Argonne National Laboratory as part of the GENIV SFR Component Design & Balance Of Plant project) to design cycle components, and latest results from an ongoing experimental program on the Na/CO2 chemical reaction.