The technology required to advance the state of the art of KrF amplifier construction to the 100-kJ output beam level is identified. The design of a non-lasing prototype machine that would test the soundness of the expanding flow diode concept and the viability of a modular and stackable approach to the electron guns and power supplies for very large amplifiers is presented and discussed in detail. The preliminary design of a 100-kJ power amplifier module is described, and key design problems and approaches are discussed. The realization of the technologies identified would lay the foundation for the construction of national facilities for the study of laser fusion at a near-optimum wavelength.