Patent Number: 044473885
Section: claims

1. A bolt member for use in normally inaccessible parts of nuclear reactors which makes a normal inspection for cracks in the bolt member impractical, said bolt member having an enlarged head portion and a cylindrical body portion having a threaded lower end onto which a nut member is adapted to be screwed to retain nuclear reactor components in operative relationship, said bolt member having a bolt-crack indicator comprising: 2. A bolt member for use in normally inaccessible parts of nuclear reactors which makes a normal inspection for cracks in the bolt member impractical, said bolt member having an enlarged head portion and a cylindrical body portion having a threaded lower end onto which a nut member is adapted to be screwed to retain nuclear reactor components in operative relationship, said bolt member having a bolt-crack indicator comprising: 3. The bolt member as specified in claim 2, wherein an additional aperture is provided through the enlarged head portion of said bolt member, and said additional aperture connects a lower surface of the enlarged head portion proximate the cylindrical body portion of said bolt member to an upper surface of the enlarged head portion of said bolt member to permit passage of gas therethrough, whereby release of tag gas through the cylindrical body portion of said bolt member has ready access through said additional aperture to the environment outside said bolt member. 4. A bolt member for use in normally inaccessible parts of nuclear reactors which makes a normal inspection for cracks in the bolt member impractical, said bolt member having an enlarged head portion and a cylindrical body portion having a threaded lower end onto which a nut member is adapted to be screwed to retain nuclear reactor components in operative relationship, said bolt member having a bolt-crack indicator comprising: