EBR-II

EBR-II
Name	Experimental Breeder Reactor II
Country	United States
Location	Idaho National Laboratory, Idaho
Status	Decommissioned
Construction began	1957
Commissioned	1964
Decommissioned	1994
Reactor type	Fast breeder reactor
Cooling	Liquid sodium
Fuel	Uranium-Plutonium alloy
Electrical capacity	20 MWe (experimental)

EBR-II

The Experimental Breeder Reactor II operated as an integrated research facility testing fast reactor concepts, fuel cycle technologies, and passive safety principles at the Idaho National Laboratory site near Arco, Idaho. It served as a focal point for collaboration among the Argonne National Laboratory, the United States Atomic Energy Commission, the Department of Energy (United States), and contractors such as General Electric, influencing programs including the Integral Fast Reactor development, the Fast Flux Test Facility, and international projects like those at the Cadarache research center and Monju Nuclear Power Plant. The reactor’s work connected to institutions including the Oak Ridge National Laboratory, Los Alamos National Laboratory, and regulatory frameworks like the Nuclear Regulatory Commission.

Introduction

EBR-II was built at the National Reactor Testing Station (later Idaho National Laboratory) to demonstrate breeder and fast reactor operations, sodium coolant engineering, and fuel reprocessing concepts. Its mission aligned with mid-20th century initiatives promoted by the United States Atomic Energy Commission and engineers trained at facilities such as Argonne National Laboratory-West and research programs tied to the Manhattan Project legacy. The project engaged specialists from universities including Massachusetts Institute of Technology, University of California, Berkeley, and University of Michigan and industries like Westinghouse Electric Company.

Design and Technical Specifications

EBR-II was a pool-type fast breeder reactor using liquid sodium coolant and a metallic uranium-plutonium alloy fuel, reflecting designs explored in breeder programs at Britain Atomic Energy Authority sites and the CEA programs in France. The primary system included a reactor core, intermediate sodium loop, and sodium-to-water heat exchangers similar in concept to systems studied for the Superphénix and BN-600 reactors. Key components and materials were developed with input from metallurgists linked to Los Alamos National Laboratory and engineers from General Electric. Instrumentation and control systems paralleled research at Sandia National Laboratories and conformed to standards later adopted by the International Atomic Energy Agency for fast reactors. Reactor physics modeling drew on computational tools originating at Argonne National Laboratory and mathematical methods promoted by scientists at Princeton University and Harvard University.

Operational History

Commissioned in 1964, the reactor supported irradiation testing for fuel assemblies, materials experiments, and demonstration of breeder performance, engaging international partners from Japan and France. EBR-II’s operations informed programs at the Fast Flux Test Facility and the Integral Fast Reactor initiative, and its data were cited in studies by agencies such as the Nuclear Energy Agency and research at Cadarache. Staff and visiting researchers included personnel with affiliations to Brookhaven National Laboratory, Argonne National Laboratory-East, and academic collaborators from University of Illinois Urbana-Champaign and Pennsylvania State University. The facility conducted test campaigns that influenced designs for commercial and prototype fast reactors like Monju, BN-800, and concepts studied at Électricité de France.

Safety and Incidents

EBR-II contributed to safety research by demonstrating passive safety phenomena that later featured in analyses for designs associated with the Integral Fast Reactor concept and in international safety reviews by the International Atomic Energy Agency. Sodium handling and leak mitigation policies echoed experiences from incidents at reactors such as Monju Nuclear Power Plant and lessons cataloged by World Nuclear Association summaries. While operational anomalies occurred during test programs, investigations collaborated with experts from Sandia National Laboratories and the Nuclear Regulatory Commission to refine accident analysis, emergency preparedness, and human factors guidance used by national laboratories and reactor designers.

Decommissioning and Decontamination

Shutdown and defueling followed national policy shifts in the 1990s; decommissioning activities involved specialists from Idaho National Laboratory, contractor organizations including Bechtel, and oversight by the Department of Energy (United States). Radiological characterization, sodium removal, and waste packaging were performed consistent with protocols influenced by decommissioning at sites like Shippingport Atomic Power Station and guidance from the Environmental Protection Agency (EPA). Lessons from dismantlement informed waste disposition strategies coordinated with the Office of Environmental Management (United States) and storage practices employed at Hanford Site and Savannah River Site facilities.

Legacy and Influence on Reactor Technology

The reactor’s demonstration of metallic fuel performance, on-site pyroprocessing concepts, and passive safety margins shaped subsequent fast reactor research and policy discussions at bodies such as the Generation IV International Forum, the Nuclear Energy Agency, and advisory panels to the Department of Energy (United States). Technical heritage from the facility contributed to projects at Argonne National Laboratory, influenced designs like the Versatile Test Reactor proposals, and informed international experimental programs at JAEA facilities in Japan and research centers in Russia associated with the BN series. Academic curricula and textbooks at institutions including Massachusetts Institute of Technology and University of California, Berkeley incorporate case studies derived from its operations, and its archives remain a resource for historians and engineers affiliated with American Nuclear Society and archival projects at the National Archives and Records Administration.

Category:Nuclear reactors in the United States Category:Idaho National Laboratory