Abstract: controls, turbines, condensers, and secondary feedwater conditioning systems. RELAP5/MOD3 code documentation is divided into five volumes: Volume 1 describes modeling theory and associated numerical schemes, Volume 2 contains detailed instructions for code application and input data preparation, Volume 3 provides the results of developmental assessment cases that demonstrate and verify the models used in the code, and Volume 4 presents a detailed discussion of RELAP5 models and correlations. Volumes 1--4 are in varying stages of development. This document, Volume 5, contains guidelines that have evolved over the past several years through use of the RELAP5 code.