Nuclear Fuel Cladding Extensometer

This device was designed and fabricated for the Westinghouse Handford, Co. It was used to help evaluate the impact of the intense neutron environment inside a reactor on the physical properties of the stainless steel fuel tubes. Since these tubes were highly radioactive when removed, a requirement of the design was that it be easy to handle inside a hot cell with remotely controlled manipulator arms. It achieved that goal.

As the tubes usually were not straight and tended to "wiggle" as they were pressurized to stress them, it was required that the calipers "float" with this motion. Constant contact pressure through out the measuring range was maintained by a lightly pressurized welded bellows.

The photo below shows the instrument without its outer housing (photo on home page shows the same instrument with outer housing in place). This housing was left in place on the vacuum system in the hot cell. The extensometer was inserted and rotated into measuring position in its outer housing each time the sample tube was changed. All insertion and bellows pressurization valve actuation was accomplished with the remote manipulator arm.