[2] WNP-1 and -4 are located on 972 acres (393 ha), within the boundaries of the Hanford Reservation in the U.S. state of Washington, approximately 1.5 miles (2.4 km) east of the Columbia Generating Station.

[5] Labor disputes at Hanford halted construction on WNP-1, -2 and -4 in 1980 and the forecast electric demand had failed to materialize, prompting WPPSS to install new management and re-evaluate the cost and schedule for all five nuclear projects.

[6] With the shutdown of the nearby N-Reactor in 1987, a Department of Energy proposal to complete and convert WNP-1 to a tritium-producing reactor for the production of nuclear weapons materials was advanced.

[22] In late 2020 the federal government awarded two $80 million initial fundings to build the TerraPower and X-energy reactors at sites 4 and 1 respectively within the next 5 to 7 years.

[25] In October 2024 Amazon has signed an agreement to pay for the initial feasibility phase to further develop the X-energy modular reactors near this site.

Under current plans, the first modules in Washington could be generating power by 2031 or 2032, said Bob Schuetz, Energy Northwest chief executive officer.

Elements of the design are similar to earlier B&W NSSSes installed at Davis Besse, ANO-1, Crystal River 3, Three Mile Island, Oconee and Rancho Seco.

WNP-1/4 would have received make-up water from the adjacent Columbia River and was equipped with forced-draft low-profile cooling towers and a spray pond.