SRS Partnership Leads to Milestone in Mission to Dissolve Spent Nuclear Fuel

Therrell noted that almost 400 NASNF bundles safely stored in L Basin need to be processed for permanent disposal in the coming years.

"With SRNL's help, SRNS was able to select the first group of NASNF that can be safely processed in the H Canyon chemical separations facility at SRS," he said. "This material will eventually be stabilized in a glass form by the site's liquid waste contractor. We also have set up the rest of the program for success by establishing plans for ongoing technology development to deal with the remaining NASNF."

The makeup of the roughly 400 NASNF bundles varies in content, size and composition, making some of the fuel more challenging to dissolve. Each different type of fuel requires specific flowsheets due to safety requirements.

The site will use an electrolytic dissolver to process the first set of NASNF. While the aluminum-clad spent nuclear fuel can be chemically dissolved, a relatively easy process involving heating nitric acid to dissolve the aluminum, the zirconium- and stainless-steel-clad fuel is more challenging and must be electrolytically dissolved, adding electricity to the nitric acid dissolution process.

SRNL performed experiments to overcome challenges for that work, and SRNS developed strategies to prepare the fuel for use in the dissolver.

"SRNL has spent years evaluating and tackling the challenges of processing NASNF," said Tam Truong, SRNL researcher. "We have conducted electrolytic dissolution experiments and leveraged processing knowledge and experience to develop the dissolution parameters for the first group of NASNF."