Future of ORNL’s reactor is complicated

hfirornlThe High Flux Isotope Reactor has operated since the 1960s at Oak Ridge National Laboratory, and it’s considered one of ORNL’s most valuable assets, with plans to keep it running for decades to come.

There are discussions, however, about a billion-dollar replacement reactor to prepare for future needs. A steady stream of neutrons for production of radioisotopes and experiments with materials is considered an essential part of the lab’s missions.

ORNL hosted a workshop last spring to gather input on the needs and requirements for future research reactors at Oak Ridge and elsewhere around the globe. The lab recently released a report that included feedback from the workshop and recommendations.

The topic is not just about research needs at ORNL.

It also relates to nuclear non-proliferation and efforts to keep weapons-making materials out of the hands of terrorists and rogue states. HFIR, as well as several other high-performance research reactors, uses highly enriched uranium as fuel.

A U.S.-led program has made progress in converting reactors to low-enriched uranium fuel (under 20 percent U-235), but others — including the ORNL reactor, with fuel enriched to 93.8 percent — continue to use bomb-grade uranium.

“You start with the easy ones,” ORNL Director Thom Mason said of the conversion program, noting that the High Flux Isotope Reactor is one of the most challenging because of the very high power density that makes it special.

While there has been progress in developing low-enriched fuels with enhanced capabilities, there is not yet one that’s a proven replacement for HFIR, Mason said.

“Even if you had a fuel you knew would work you’d still probably be a decade out,” the lab director said.

“To qualify a new fuel for a reactor takes a long time.”

Therefore, the decision on whether to convert the fuel at the 50-year-old Oak Ridge reactor mixes and mingles with talk about constructing a new reactor — presumably using a fuel without proliferation concerns.

The official view is that if a suitable fuel becomes available, ORNL convert the High Flux Isotope Reactor, Mason said.

However, if it takes so long that the reactor is nearing the end of its useful life, you’d have to question the value of converting, he said.

“To be honest, we’re going to have to watch and monitor that to make the decision,” Mason said.

In the meantime, most of HFIR’s critical components that are subject to aging effects can be replaced or even upgraded with proper attention and funding. So, it could still be around for another 40 or 50 years.

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About Frank Munger

Senior Writer Frank Munger covers the Dept. of Energy's Oak Ridge facilities and many related topics — nuclear weapons, nuclear waste and other things nuclear, environmental cleanup and science of all sorts. Atomic City Underground is, first and foremost, a news blog, but there's room for analysis, opinion and random thoughts that have no place else to go.