The use of volume sources, such as nuclear pumping, presents some unique features in the design of photolytically driven systems (e.g., lasers). In systems such as these, for example, a large power deposition is not necessary. However, certain restrictions, such as self‐absorption, limit the ability of photolytically driven systems to scale by volume. A photon transport computer program was developed at the University of Missouri‐Columbia to study these limitations. The development of this code is important, perhaps necessary, for the design of photolytically driven systems. With the aid of this code, a photolytically driven iodine laser was designed for utilization with a3He nuclear‐pumped system with a TRIGA reactor as the neutron source. Calculations predict a peak power output of 0.37 kW. Using the same design, it is also anticipated that the system can achieve a 14‐kW output using a fast burst‐type reactor neutron source, and a 0.65‐kW peak output using 0.1 Torr of the alpha emitter radon‐220 as part of the fill. The latter would represent a truly portable laser system.