Abstract: A method and system for rapidly connecting and rapidly disconnecting a large number of point contacts onto a pipe surface for detecting defects in pipe and other structures is taught. The method and system involve independently pressing a plurality of sharply pointed pin contacts onto the pipe surface by a means, such as a spring. The system comprises a plurality of electrodes each having a plurality of pins, as illustrated seventeen (17) pins, arranged in a pattern. Each of the plurality of pins is held in a conforming opening in the electrode and is urged by springs means, such as a coil spring, against the surface of the structures. Each of the plurality of pins (sixteen (16) current pins and one voltage pin) are individually connected to a power supply and sensing apparatus. This system and method has proved operable for detecting defects in structures, such as pipe.

Abstract: A method is provided for measuring crack growth within a material utilizing reversing d.c. potential measurements across a preformed crack. Preferably, the material is representative of structural components of interest and the material is located within the aggressive environment of such components. The measured values are plotted versus distance to obtain intercept values. These intercept values correspond to the depth of the crack at the time the measured values were obtained.

Abstract: A nuclear fuel element for use in the core of a nuclear reactor is disclosed and has a composite cladding having a substrate and a metal barrier metallurgically bonded on the inside surface of the substrate so that the metal barrier forms a shield between the substrate and the nuclear fuel material held within the cladding. The metal barrier forms about 1 to about 30 percent of the thickness of the cladding and is comprised of a low neutron absorption metal of substantially pure zirconium. The metal barrier serves as a preferential reaction site for gaseous impurities and fission products and protects the substrate from contact and reaction with such impurities and fission products. The substrate of the composite cladding is selected from conventional cladding materials and preferably is a zirconium alloy. Methods of manufacturing the composite cladding are also disclosed.

Abstract: A nuclear fuel element for use in the core of a nuclear reactor is disclosed and has an improved composite cladding comprised of a moderate purity metal barrier of zirconium metallurgically bonded on the inside surface of a zirconium alloy tube. The metal barrier forms a shield between the alloy tube and a core of nuclear fuel material enclosed in the composite cladding. There is a gap between the cladding and the core. The metal barrier forms about 1 to about 30 percent of the thickness of the composite cladding and has low neutron absorption characteristics. The metal barrier serves as a preferential reaction site for gaseous impurities and fission products and protects the alloy tube from contact and reaction with such impurities and fission products. Methods of manufacturing the composite cladding are also disclosed.