Patent Number: 
Section: claims

1. A sealing integrity testing apparatus for detecting a defective boiler tube plug comprising: a cylindrical plug sealably locatable within a boiler tube for sealing flow through the boiler tube;  a test monitor located around said cylindrical plug and said boiler tube to provide a sealed space for said plug and said tube;  means for pressurizing said sealed space to a known pressure; and  a pressure monitor connected to said space to measure the pressure therein to determine any pressure drop as an indication of a defective boiler tube plug. 2. An apparatus as set forth in  claim 1  wherein said test member comprises a cup shaped member having a O-ring seal along the open end thereof to seal said test member against a surface around said plug and said tube. claim 1 3. An apparatus as set forth in  claim 2  wherein said plug is a ribbed plug having an internally threaded extender member therein for pressing the ribs of said ribbed member against said tube to seal said tube thereby. claim 2 4. An apparatus as set forth in  claim 3  wherein said test member includes a hollow tubular member sealably extending through said cup shaped member and having a threaded mandrel at the end hereof for screwing into said extender member of said ribbed plug to seal said test member to said plug and said tube. claim 3 5. An apparatus as set forth in  claim 4  wherein said hollow tubular member has an aperture therein for communicating a fluid pressure in said test member to said ribbed plug area below said expanding member. claim 4 6. An apparatus as set forth in  claim 5  wherein said boiler tube is located inside a nuclear reactor. claim 5