Specialty Formulated Polyurethane Applied to Increase Containment Leak Tightness

Abstract

When the results of periodic containment leak tests performed from 1981 to 1987 at two CANDU power plants in Canada have shown a striking increase, the need was felt to improve the situation. The paper describes the investigation performed to find the causes and the tests performed to select and qualify to the Canadian Nuclear Code requirements a suitable material which could be applied on top of the existing liner, at the inside face of the containment, to increase its leak tightness. Also described are the tests performed to qualify an "in service" application procedure without any detrimental effect upon the equipment and piping systems.