1945 - Patent for Pressurized Water Reactor

Filed Aug. 29, 1945 (and later issued as U.S. Patent 2,736,696-A), the Weinberg/Wigner et al. patent describes a "water-based power-reactor system" built around (i) a moderated uranium lattice, (ii) "circulating coolant channels", and (iii) a "primary heat-removal loop feeding a heat exchanger/steam system", with substantial attention to **geometry, shielding, and operability constraints** that govern whether the concept can be engineered at useful power levels. Technically, the text spends meaningful effort on the "neutron-economy trade between heavy water (deuterium oxide) and ordinary water", emphasizing deuterium’s much lower capture cross-section and the implications for critical size, while also discussing practical system arrangements that include "light water as a coolant" in certain configurations. Although the patent does not frame itself as a naval design, its core architectural ideas—**a closed water-cooled primary system, heat exchange to a secondary power cycle, and packaging/shielding logic aimed at a compact, controllable plant**—map directly onto the engineering “shape” of what became the early Navy pressurized-water approach; in that sense, it is best treated as an **intellectual and technical precursor** that helped establish water-cooled reactor configurations as buildable power plants, later enabling Rickover’s program to standardize and execute the PWR path that culminated in Nautilus**.