Status of the Sodium Gas Heat Exchanger (SGHE) development for the Nitrogen Power Conversion System planned for the ASTRID SFR prototype

Abstract : In the framework of the CEA RandD program developing the Advanced Sodium Technological Reactor for Industrial Demonstration (ASTRID), the present work describes the current status of an innovative compact heat exchanger and highlights the industrial challenges this technology raises. One of the main innovative options under investigation for ASTRID is the use of a Brayton cycle gas-power conversion system. This system permits to avoid the energetic sodium-water interaction, which can occur in steam generators in case of tube failure if a traditional Rankine cycle is used. In this novel concept, steam generators would be replaced by the Sodium Gas Heat Exchanger (SGHE). The first part of this paper presents the details of the original design of this heat exchanger which allows a high thermal compactness. The main studies supporting this development are described in the second part of the paper. The thermal hydraulic program demonstrates the potential of the technology used. An innovative geometry is also studied on the gas side improving the thermal compactness. Thermomechanical analyses show the good behavior of this exchanger under the ASTRID operating conditions. The manufacturing / welding process optimization is ongoing in order to produce a component with nuclear specifications. Specific sensors and control techniques are also being developed in order to assess the manufacturing process quality and to allow future in-service inspections. At last, the qualification program is presented and the first results obtained on an operating small scale SGHE mock up working under ASTRID conditions are described.