By John Kotek
Former Acting Assistant Secretary for the Office of Nuclear Energy

Thirty years ago this month, two events happened that had profound and lasting impacts on energy and environmental issues in the U.S. and around the world.  One overshadowed the other in public awareness, but both set the stage for a revolutionary approach to assuring nuclear safety.

As it happened, the April 26 event occurred in a poorly designed and mismanaged graphite reactor in Ukraine which resulted in the world’s worst nuclear accident.  The blast at Chernobyl caused dozens of deaths among plant staff and first-responders, and spread radioactive contamination over large swaths of Eastern Europe.

Lost in the global media flurry that followed Chernobyl was the importance of a series of inherent safety tests that preceded it, culminating on April 3 in a small sodium-cooled reactor in the high desert west of Idaho Falls, at what is now the Idaho National Laboratory site.

Throughout the historic Experimental Breeder Reactor‑II (EBR‑II) Shutdown Heat Removal Test series between 1984 and 1986, the precise, measured actions of nuclear scientists, engineers and operators deliberately induced the kind of accident conditions that would lead to catastrophe three weeks later, in a lesser reactor, on the opposite side of the world.  Thanks to its unique properties, EBR‑II responded to the series of coolant flow and other heat removal accident scenarios with barely a hiccup and a stubborn insistence on shutting itself down without operator action.

EBR‑II’s designers referred to these unique properties as “inherent safety,” or passive safety, and many of the aspects are now regarded as requirements for any advanced nuclear power plant design.  Data gathered from these tests is being used by researchers working on some of the innovative, advanced reactor concepts being developed today.

To mark the 30th anniversary of these historic tests, young researchers from Idaho, Argonne, and Oak Ridge national labs are gathering today in the EBR-II control room for a technical symposium with the pioneers of inherent safety, to learn about the test series and its application to today’s advanced reactor research.  The innovators of EBR‑II will share details about the design features built into the reactor, minor changes needed to subject the core to loss of coolant and loss of heat sink scenarios, how well the results compared with their predictions, and the assessment of the fuel core used during the tests.

The EBR‑II pioneers proved that reactors can be made inherently safe and virtually immune to the type of accident that overshadowed their work for so many years.  Combined with growing public and Congressional support, the foundation is now in place for young researchers to create the advanced reactor designs of the future – and ensure the lasting legacy of the researchers, engineers and operators of EBR‑II.