PROBABILITY BASED CORROSION CONTROL FOR HIGH LEVEL WASTE TANKS: INTERIM REPORT

摘要: Controls on the solution chemistry (minimum nitrite and hydroxide concentrations) are in place to prevent initiation propagation of pitting stress corrosion cracking high level waste (HLW) tanks. These controls based upon a series experiments performed carbon steel coupons simulated solutions. An experimental program was undertaken investigate reducing minimum molar concentration required confidently inhibit pitting. A statistical basis quantify probability for tank wall, when exposed various dilute solutions, is being developed. Electrochemical coupon testing within framework test matrix determine necessary inhibitor concentrations develop quantitative model predict propensity. subset original used an applied understanding response environments. The interim results suggest that there exists some critical sufficiently inhibits against localized mechanisms due nitrates/chlorides/sulfates, beyond which further additions unnecessary. combination visual observation cyclic potentiodynamic polarization scans indicate potential significant reductions without consequence specifically at nitrate near more » 1 M. complete data sets will be using inhibition with current pH controls. Once complete, revised control devised solutions allow specific implementation. « less