D0 Silicon Upgrade: Cryogenic Lines at Refrigerator : Thermal Contraction Analysis of Four Cryogenic Utility Lines for the D0 Upgrade

The cryogenic lines GHE and LN2 contain two lines each, one for supply and the other for return. The tubing was stress analyzed per ASME code for pressure piping, standard ANSI/ASME B31.3. A commercial pipe stress analysis and design system by ALGOR{reg_sign} was used for the analysis along with the calculated maximum stress, 25,050 psi. They were all analyzed for combined pressure, thermal movement, and dead weight and all the stresses were below this allowable stress limit. There are sections of the transfer lines that will be increased from a 1-1/2-inch vacuum jacket to a 2-inch vacuum jacket. This increase accounts for the maximum displacement, 0.466-inch in troubled areas as seen in subsequent drawings. The greatest displacement allowed for a 1-1/2-inch vacuum jacket is 0.421-inch for a 1/2-inch pipe on the nominal centerline. The greatest displacement allowed for a 2-inch vacuum jacket is 0.658-inch. We will have a clearance of 0.192-inch when using the 2-inch vacuum jacket