The purpose of this thesis is to develop a Fortran [sic] Computer Program to model the radiation section of a pyrolysis tube reactor designed for cracking 100 percent ethane feed. The model calculates the length of the tubular reactor required to obtain a specified ethane conversion or the ethane conversion for a specified reactor length. The resulting solution yields a conversion profile, a temperature profile, and the reactor residence time as a function of tube length. From this data it can be determined if the design is adequate and lies within the reactor model's constraints.