Here’s what that Richland truck convoy was carrying. Each load weighed 24 tons

Morning commuters on the Richland bypass highway may have seen a convoy of trucks headed toward Pacific Northwest National Laboratory on Wednesday.

They were loaded with three brand-new nuclear fuel containers weighing more than 24 tons each.

Now unloaded just north of PNNL’s Richland campus, they’ll be the centerpiece of research into how safe stainless steel containers are for long-term storage of used nuclear fuel.

With no national repository for used nuclear fuel, as was planned at Yucca Mountain, Nev., nuclear fuel may remain stored in canisters for many decades.

Currently, 88,000 tons of used fuel is in storage across the nation, including some stored on an outdoor pad near Richland at Columbia Generating Station, the Northwest’s only commercial nuclear reactor.

“No one intended to store the fuel for this long,” said PNNL nuclear engineer Steven Ross.

Research planned at PNNL will help determine how best to store used nuclear fuel long term and also if and when it should be repackaged.

Researchers want to determine whether what’s going on inside the canisters can be monitored without opening them and learn more about very small cracks that may form in their walls.

“Before degradation happens how do we detect it?” said PNNL nuclear engineer Brady Hanson. “How do we mitigate it? And if it does happen, how do we repair it so it doesn’t affect the health or safety of the environment, our staff, or the public?”

Some research has been done using pieces of canisters, mockups or models, but the new canisters provided by the Department of Energy will allow more complete investigations.

“When you work on pieces or mockups or models you’re always at some level of disadvantage in that you haven’t been able to demonstrate your concept on an actual system,” said PNNL nuclear engineer Ryan Meyer.

Researchers plan to place heaters inside the containers to mimic the heat generated by waste and observe what brines form from salts and the air on their exteriors. The brines can cause cracks too small to be seen with the naked eye.

Researchers also plan to put sensors that emit acoustic pulses in the canisters to see if they can provide information from within the containers on flaws or small amounts of water.

This story was originally published April 15, 2021 at 9:59 AM.