Development of an Innovative Plate-Type SG for Sodium Cooled Fast Reactor: Concept and Test Fabrication

The concept of an innovative plate-type steam generator (SG) for a fast reactor, fabricated using hot isostatic pressing (HIP), was presented. The heat transfer plate, which is assembled with rectangular tubes and fabricated using HIP, is surrounded by a leak-detection layer. The optimum form for the detection layer was determined by crack extension analysis. The concept can be applied in both pool-type and loop-type liquid-metal cooled fast reactors (LMFR). In this report, the fabrication technique is described as applied to a loop-type LMFR. Optimum HIP conditions of [1423K (1150°C), 1200kgf/cm² (117MPa), 3hours] for modified 9Cr-1Mo steel were determined from HIP tests, tensile tests, and structural inspection. Nickel-type solder (BNi-5) and gold-type solder (BAu-4) were examined as potential joining materials to laminate the heat transfer plates. Tensile test comparisons showed that BAu-4 was superior, so it was used. No problems were observed in the fabrication of a partial model of an SG (HIP of the rectangular tubes, brazing the plates, welding the header, etc.).