D0 Silicon Upgrade: Thermal Contraction Analysis of the Solenoid and VLPC Cryogenic Transfer Lines for the D0 Upgrade

Abstract

The stresses developed in the solenoid and VLPC transfer lines have been investigated with the PipePlus v4.5 software package from Algor. 4 cases were considered for each transfer line and the following results were obtained. Pipe deflections have also been kept to a minimum by carefully considering the location of spider guides. Their placement should be as close as possible to the locations shown in Figures 4-7. With regard to chosen pipe sizes, the 2.5-inch OD Cu radiation shield in the solenoid transfer line should be replaced with a 3.5-inch OD tube. The vacuum jackets should also be replaced with 5-inch or larger pipe. These changes should safely accommodate the maximum displacements caused by thermal loading. This engineering note investigates the ability of the solenoid and VLPC cryogenic transfer lines to accommodate thermal stresses. The solenoid and VLPC transfer lines are similar in their construction in that they consist of an outer vacuum jacket, liquid nitrogen supply and return lines, a copper thermal radiation shield, and liquid helium supply and return lines. See Figure 1 for details on their specific construction. Line drawings for the solenoid and VLPC transfer lines are shown in Figures 2 and 3, respectively. The transfermore » line system, as a whole, does not lend itself to simple analysis such as the 'Simplified Method for Flexibility Analysis' or the chart method. These methods demand that the piping system be rigidly anchored at two ends with no intermediate branches. Therefore, a major part of the analysis was performed on the PipePlus v4.5 software package by Algor. Considerations have been given to dead weight, pressure, and thermal loads, boundary conditions such as end displacements, and restraints caused by intermediate supports. The Appendices contain selected information from the PipePlus analysis. Only the pipe geometry, boundary conditions, loading, node displacements and stresses have been reported. The electronic version of the PipePlus databases are stored on the DMACS NT Fileserver under the 'Pipe' directory. These databases can be used to generate the complete reports.« less