Method of failed fuel detection

A method for accurately detecting flaws in a fuel element which need not be removed from its surrounding radioactive environment comprises forming a replica of the element which is then visually inspected for damage. A material hardenable at normal temperatures such as silicon rubber is coated on the inner side of an arcuate supporter which is inserted within the radioactive environment by means of a manipulator and tightly applied to the surface of the failed element in the vicinity of the flaw. Upon hardening of the coating material the supporter is removed and the coating is peeled off, extracted from the radioactive environment and cleaned for removal of radioactivity, thus enabling it to be directly handled. The hardened coating bearing a reverse impression of the flawed fuel element surface is then employed as a mold to produce an exact flaw replica which may be safely handled and inspected. It is therefore possible to directly and safely inspect the flaws in damaged fuel elements while they are still confined within a reactor or hot cell without relying upon periscopes, boroscopes or stereoscopes. (Owens, K. J.)