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SPENT FUEL STORAGE CORROSION MANAGEMENT

The Corrosion Surveillance program was applied for 30 MW GA Siwabessy Multi Purpose Research Reactor on 2006. The objective of this experiment is to understand the Pitting, Crevice, Galvanic and General corrosion of the research reactor material structure, especially for primary water cooling structure materials. The experiment has been started at 2006. The first inspection was done after a year immersion on 2007. The second inspection was done after three (3) years immersion and will be reported in this paper. The coupons were analyzed by visual as well as photographic evaluation of coupon surfaces. Metallographic examination under reflected optical microscope equipment with camera was applied for investigating of pits and surface changing. The water quality is analyzed by measuring conductivity (on-line conductivitimeter), pH (on-line pH meter), Chlor (UV-Viss spectroscopy) and Total Dissolved Solids (TDS, on-line TDS meter). The pH of trapped water between two coupons was measured soon after withdrawing by inserting pH paper. From the results, it is known that the trapped water pH between the coupons is 4, one digit lower than the pool water (pH 5.4–5.5 that was measured digitally with accuracy of 0.1). No significant differences were found for trapped water pH observed between horizontally and vertically racks, and also for the sample of a year immersion. The conductivity, pH, Chlor and TDS were analyzed as 1.3–1.7 μS/cm, 5.2–5.5, none and 0.7–0.9 μS/cm, respectively. The range permitted and measured inlet temperature for water purification is 23–34 o C. From the visual observation, it is known that (a) water quality of primary water is required the SAR, (b) crevice and galvanic effect are the main corrosion; (c) no pitting; (d) no biofilm observed. The experience and scientific results gained is very useful to be implemented for Indonesia Research Reactor Ageing Program and future NPP.