A substantial research and development program on spent-fuel direct disposal was carried out in the Federal Republic of Germany to develop this option to technical maturity as an alternative to the fuel cycle back end with reprocessing. All issues important to safety to be considered in a license application were appropriately addressed and resolved. After the work was concluded, it was regarded as advisable to devote additional time and effort to optimize systems, improve engineered barriers, and obtain additional information about issues not finally resolved. To cover these needs, a dedicated development program, consisting mainly of in situ tests to be carried out in the Gorleben exploratory mine, is proposed.