An Exterior Communications Interface for the USNRC Consolidated Code

One of the requirements for the USNRC’s consolidated reactor safety analysis code is that it support parallel computations. One standard parallel calculation would speed calculations by distributing spatial regions (system components) to copies of the Consolidated Code running on separate processors. A more interesting form of parallel processing uses additional programs to provide special component or process models, to extend the code’s capabilities. We have developed a code structure and communications protocol that supports both these forms of parallelism. The Consolidated Code uses a flexible request driven exterior communication interface. A set of negotiations at the beginning of a calculation determines the data to be transferred. Both the requesting and responding tasks record source and destination pointers for transfers in special transfer tables. Actual transfer of data is a very simple process, using the transfer tables to fill or empty interprocess buffers.