Humboldt Bay Nuclear Power Plant
| Company type | Nuclear power plant |
|---|---|
| Industry | Energy |
| Founded | August 1963 |
| Defunct | July 2, 1976 |
| Fate | Permanently closed and decommissioned |
| Headquarters | Eureka, California , United States |
| Products | Electricity generation (nuclear) |
| Owner | Pacific Gas and Electric Company |
The Humboldt Bay Power Plant, Unit 3 was a 63 MWe nuclear boiling water reactor facility owned by Pacific Gas and Electric Company (PG&E). It operated from August 1963 until July 1976 and was situated near Eureka, California, specifically in the King Salmon and Fields Landing regions.
History
PG&E announced the commencement of significant construction for this nuclear unit on January 23, 1961. The construction expenses totaled $65 million, and the plant became operational in August 1963.
In July 1970, an operator mistake resulted in an abrupt loss of cooling water flow, causing the water level above the fuel rods to drop from the typical 9 feet to slightly more than 6 inches. Although radioactive steam was released inside the facility, it did not escape outside. According to Nuclear Regulatory Commission documentation, the fuel rods sustained damage but not to a severe extent.
The facility ceased operations in July 1976 to undergo refueling and seismic improvements. Nevertheless, subsequent discoveries of seismic faults and enhanced regulatory standards following the Three Mile Island incident rendered the economic viability of restarting this small plant impractical.
Missing fuel rods
In 2004, PG&E disclosed that three nuclear fuel rods were unaccounted for due to inconsistent location records. Despite never being retrieved, investigations by PG&E suggested that these rods remained within the spent fuel storage pool onsite. The inquiry reportedly incurred costs approaching one million dollars.
Shut down
The Humboldt Bay Nuclear Power Plant was permanently closed on July 2, 1976. This decision was influenced in part by seismological findings that revealed the plant’s location directly above the Little Salmon earthquake fault. The original design could not be sufficiently upgraded to endure potential seismic events, presenting serious safety hazards.
Decommissioning
PG&E declared its intention to decommission the plant in 1983 and transitioned it into SAFSTOR inactive status by 1988. In December 2003, PG&E submitted an application for a spent fuel storage license, which was approved in November 2005. By December 2008, all spent nuclear fuel had been moved into dry cask storage onsite.
Dismantling activities commenced in 2010 alongside the removal of two fossil-fuel steam generators. Later that year, power generation was replaced by advanced multi-fuel Wärtsilä reciprocating engine-generators. Full dismantlement was initially projected to be completed by 2018.
During the 2012 Nuclear Decommissioning Cost Triennial Proceeding (NDCTP), PG&E requested authorization for additional funding aimed at removing further underground structures. While initial plans called for leaving structures buried three feet or more below ground level (with the exception of the spent fuel pool), PG&E later concluded that complete extraction of the reactor caisson and installation of a cement slurry wall were essential to comply with NRC contamination requirements.
Decommissioning efforts were anticipated to finish by 2019 but were officially concluded on November 18, 2021, with total costs amounting to $1.1 billion. Between 2010 and 2018, after two decades in SAFSTOR status, the site underwent thorough decontamination and dismantlement. A license termination was granted in October 2021, allowing unrestricted future use of the property.
Onsite radioactive dry cask storage
Spent fuel rods are stored at an elevation of 44 feet above sea level within robust multilayered steel casks produced by Holtec International, a New Jersey-based company specializing in nuclear reactor components and decommissioning solutions. These casks serve as both radiation shields and protection against external impacts.
The design includes three concentric shells: an innermost containment shell, thick steel intermediate layers providing gamma radiation shielding, and an outer shell containing neutron-absorbing materials. These casks are housed inside an underground vault reinforced with concrete walls ranging from three to seven feet thick.
Filled with inert helium gas, these containers will remain onsite until obligations under the Nuclear Waste Policy Act of 1982 are fulfilled by the United States Congress and the Department of Energy. The Nuclear Regulatory Commission (NRC) has certified these five dry casks as safe for use for at least sixty years beyond their current licensing period. PG&E continues to hold responsibility for ensuring safe decommissioning of this storage area following final fuel disposition.