Our modern energy picture shows a strong tilt to a dominant reactor design, the light water reactor. Its history tends to be portrayed as a logical progression centered around Admiral Hyman Rickover, who, so goes the narrative, so resoundingly demonstrated the design’s efficacy with nuclear submarines, that when he built the world’s first fully commercial power reactor at Shippingport, it was destined to cement the LWR design as the best.
Yet the Shippingport reactor almost faltered before construction began. The May issue of trade journal Nucleonics (quite a perky publication) shared some gossip revealing not only that Rickover’s design was “controversial” but that it required political horse-trading to ensure funding:

Controversial PWR project – only utility-scale U.S. nuclear power plant now in the advanced design stage – came near being torpedoed by the Joint Congressional Committee. Strong assurances from AEC saved it. The crucial action came just two days before AEC accepted the Duquesne Light Co. partnership offer on the project. Here is the sequence of events … At a closed-door meeting March 12th three Commissioners and AEC reactor chief Lawrence R. Hafstad promised to make every reasonable effort to incorporate new ideas into PWR to make it more economic. They also made other still-undisclosed commitments regarding the PWR project. This was what the subcommittee wanted. It cleared the project…
Nucleonics. 1954. “Controversial PWR project.” Nucleonics 12 (May), p. 75.