Pre and postprocessors have been written for an established hydraulic program (COMMIX-IHX) which enables prediction of the internal crossflow field for each tube of Argonne's Test Heat Exchanger and identification of those tubes most likely to experience fluid-elastic instability, together with the instability vibration mode. While the direct use of the HXVA method is limited to single pass, single-segmentally baffled tube bundle configurations, its algorithms and methods can be applied to any type of heat exchanger which can be analyzed by COMMIX-IHX. The processors are explained and an example problem is given along with comparisons of experimental results.

This report documents the operation of a 28 in. long sodium heat pipe in the Heat Pipe Test Facility (HPTF) installed at Argonne National Laboratory. Experimental data were collected to simulate conditions prototypic of both a fluidized bed coal combustor application and a space environment application. Both sets of experiment data show good agreement with the heat pipe analytical model. The heat transfer performance of the heat pipe proved reliable over a substantial period of operation and over much thermal cycling. Additional testing of longer heat pipes under controlled laboratory conditions will be necessary to determine performance limitations and to complete the design code validation.