LONG-TERM AGING OF LIGHT-WATER REACTOR CONCRETE CONTAINMENTS

This paper evaluates the aging of light water reactor concrete contain ments and identifies three degradation mechanisms that have the potent ial to cause widespread aging damage after years of satisfactory exper ience: alkali-silica reactions; corrosion of reinforcing steel, steel liner, and prestressing steel; and sulfate attack. The aging evaluatio n is based on a comprehensive review of the relevant technical literat ure. Low-alkali cement and slow-reacting aggregates selected according to ASTM requirements cause deleterious alkali-silica reactions. Low c oncentrations of chloride ions can initiate corrosion of the reinforci ng steel if the hydroxyl ions are sufficiently reduced by carbonation, leaching or magnesium sulfate attack. Magnesium sulfate attack on con crete can also cause loss of strength and degradation of cementitious properties of the containment concrete after long-term exposure. The t echniques for inspecting, mitigating and repairing these long-term agi ng effects are discussed. (C) 1998 Elsevier Science S.A. All rights re served.