SEFOR

SEFOR (Southwest Experimental Fast Oxide Reactor) is a deactivated experimental fast breeder reactor located in Cove Creek Township, Washington County, near West Fork, in northwest Arkansas (20 miles southwest of Fayetteville, Arkansas). The site consists of a deactivated 20-Megawatt (thermal), Sodium-Cooled Test Reactor, a Shop Building, an Operations Building, a Maintenance Shed, and an Electrical Transformer yard. It operated from 1969 to 1972 when the program ended. It was then acquired by the University of Arkansas, in hopes that it could be used as a research facility. However that never happened and the university has been paying $50,000 in maintenance fees yearly since. SEFOR is still considered contaminated and the University continues to seek federal funds to clean up the site.

It used MOX fuel and liquid sodium cooling, and generated 20MW of heat but no electricity. It was constructed particularly to test the suggested inherent safety features of the oxide fuel/sodium cooling configuration, and in particular the effect on the core of thermal expansion, including in an accident situation. The belief that this would stabilize the core was confirmed.

The design concept of using thermal expansion to stabilize a reactor core has since been featured in other reactor designs, notably in the pebble bed reactor which is however neither a fast neutron reactor nor a breeder reactor, and in subsequent Fast breeder reactors.

SEFOR operated from 1969 to 1972, when the original program was completed as planned. It was privately operated by General Electric and funded by the United States government through the Southwest Atomic Energy Associates, a nonprofit consortium formed by 17 power companies of the Southwest Power Pool and European nuclear agencies.

A proposal for funding to extend its operation to 1977 was rejected prior to the closure in 1972. The fuel and irradiated sodium coolant were removed and taken offsite later in 1972, and the facility was placed in safe storage. The reactor was acquired by the University of Arkansas in 1975 and is still owned by the university, and was used to calibrate equipment and as a research tool for graduate students. SEFOR was designated a Nuclear Historic Landmark site in October 1986, and that same year the university stopped using the facility but has continued to maintain surveillance through maintenance activities and periodic visits to the reactor. A caretaker also lives on site in the former Visitors’ Center.

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