Washington Nuclear Power (WNP) projects 1 and 4 are partially completed nuclear projects located on the Hanford Site. The Washington Public Power Supply System (WPPSS) filed an application in May 1974 for the WNP-1/4 projects. After holding hearings in 1974, Governor Daniel J. Evans signed a Site Certification Agreement (SCA) for the combined projects on August 8, 1975. Construction of WNP-1 was halted in 1982. In May 1994, the WPPSS board of directors adopted a resolution terminating WNP-1. In June 1995, EFSEC approved a Site Restoration Plan for WNP-1 that deferred demolition. In the interim, Energy Northwest carried out a minimal level of maintenance and security control at the WNP-1 project site.
In 2003, Energy Northwest, the U.S. Department of Energy (DOE) - Richland Office, the Bonneville Power Administration (BPA), and the State of Washington agreed on a WNP-1/4 Site Restoration and Funding Plan (also known as the "Four-Party Agreement"). The plan called for: (1) certain health, safety, and environmental protection activities; (2) commencement of final site restoration by 2026; (3) BPA funding of the site restoration; and (4) $3.5 million from BPA for offsite environmental mitigation. In April 2010, EFSEC approved an amendment to the SCA to address completion of the near-term health, safety, and environmental protection activities set out in the Four-Party Agreement. The amended SCA included only those requirements deemed necessary to complete restoration activities. Some areas within the original site boundaries of WNP-1/4 were designated for reuse and referred to as the Industrial Development Center (IDC). Various buildings and facilities within the IDC were leased for a time, but all leases have since ended. In 2013, DOE and Energy Northwest determined that the existing water supply infrastructure at the IDC based on withdrawals from two groundwater wells was inadequate. To support reuse of the site, DOE, in its role as landowner, submitted an application to the Washington Department of Ecology for a surface water right from the Columbia River on October 31, 2013. Ecology signed the water right on January 8, 2015.
Currently, Energy Northwest is in the final phase of restoration per the terms of the Four-Party Agreement. Energy Northwest extended its lease with DOE for the WNP-1/4 site on July 1, 2017. The new agreement contains options for additional 10-year lease extensions, but the lease will expire no later than January 2052.