ASME-Landmark:Vallecitos Boiling Water Reactor


The Vallecitos Boiling Water Reactor was the first privately owned and operated nuclear power plant to deliver significant quantities of electricity to a public utility grid. It was a pilot plant, a collaborative effort of the General Electric Company and Pacific Gas and Electric Company, with Bechtel serving as engineering contractor. Its construction was approved by General Electric Company's management in 1955, begun in 1956, and completed in 1957; it went critical on August 3 of that year and was connected with the utility grid on October 19.

The plant featured a light-water moderated and cooled, enriched uranium reactor using stainless steel-clad, plate-type fuel. From the time of its first operation until it was shut down on December 9, 1963, it delivered approximately 40,000 megawatt-hours of electricity. It was designed with a high degree of operating flexibility for testing various aspects of its operation, and during its lifetime, it helped to develop and test boiling water reactor fuel, core components, controls, and systems for the Dresden project, a Commonwealth Edison plant built in Illinois five years later. It was also a valuable training facility for engineers, physicists, supervisors, and operators.

Samuel Untermyer, the GE engineer responsible for the initial design of the reactor, had performed much of the conceptual research at Argonne National Laboratory while conducting heat transfer and nuclear physics experiments, including the BORAX (boiling reactor experiment) tests. See ASME website for more information