Corrosion and solubility in a TSP-buffered chemical environment following a loss of coolant accident: Part 4 – Integrated chemical effects testing

Abstract

This paper presents the results of an integrated chemical effects experiment executed under conditions representative of the containment pool following a postulated loss of coolant accident (LOCA) at the Vogtle nuclear power plant, operated by the Southern Nuclear Operating Company (SNOC). This test was conducted for closure of a series of bench scale experiments conducted to investigate the effect of the presence of trisodium phosphate (TSP) on the corrosion and release of aluminum (Howe et al., 2015) and zinc (Pease et al., 2015) from metallic surfaces, and calcium from NUKON fiberglass insulation (Olson et al., 2015) . The integrated test was performed in the Corrosion/Chemical Head Loss Experimental (CHLE) facility with representative amounts of zinc, aluminum, carbon steel, copper, NUKON fiberglass, and latent debris. The test was conducted using borated TSP-buffered solution under a post-LOCA prototypical temperature profile lasting for 30 days.The results presented in this article demonstrate trends for zinc, aluminum, and calcium release that are consistent with separate bench scale testing and previous integrated tests under TSP conditions. The release rate and maximum concentrations of the released materials were slightly different than the separate effect testing as a result of different experimental conditions (temperature, surface area-to-water volume ratio) and/or the presence of other metals and chemicals in the integrated test. Samples of metal coupons and fiberglass were selected for analysis using Scanning Electron Microscopy (SEM) and Energy Dispersive X-ray Spectroscopy (EDS).