[en] This report is Part 1 of a two part evaluation of the ability of the RELAP5 computer code to calculate N Reactor transients. The RELAP5/MOD2 computer code, in modified form, has been used by EG and G Idaho and Westinghouse Hanford to model hypothetical N Reactor transients. Because RELAP5/MOD2 was developed primarily to model commercial pressurized water reactors (PWR), which have vertical fuel channels, its ability to accurately calculate the thermal-hydraulic phenomena in N Reactor type horizontal fuel channels has never been assessed. Part 1 of this study relies on readily available modeling information and Part 2 involves obtaining horizontal channel data and making new calculations and data comparisons