Fouling on the secondary side of nuclear steam generator tube: Experimental and simulated study

Abstract

The fouling in the steam generator (SG), seriously affecting the internal integrity of SG tube, heat transfer efficiency and control of water chemistry, is commonly caused by the growth of thick oxides and deposition of soluble particles in the secondary circuit of pressure water reactor (PWR) nuclear power plant (NPP). Herein we describe the nucleation, aggregation and growth mechanism of fouling containing different metallic cations. Three fouling layers were observed at the crevice position of SG tube and the large Fe3O4 fouling particles exhibited a double layer structure. The growth process and direction of fouling particles were found to be related with the oxide layer. Meanwhile, the deposition process of fouling is affected by the matrix shape and distribution of the massive fouling particles, and large fouling particle grows preferentially in the direction of primary crystal plane on the surface of the oxide layer. The nucleation, agglomeration, adsorption, growth of the oxide was identified to be affected significantly by fouling deposition, however, it exhibited possibly opposing impacts on the reliability of SG tubes.