We are saddened to report the passing of our dear friend, mentor, and colleague, Kenneth L. “Ken” Nash, radiochemist and former Chair of the NUCL Division (2012). Ken passed away peacefully on November 13, 2025, at Haven Hospice Care Center, with his loving family at his side.

Ken was a devoted husband, father, and grandfather whose generosity of spirit inspired both his family and his colleagues. He will be remembered for his kindness, his unique perspectives, and, above all, his deep love of learning and his joy in sharing that knowledge with others.

Ken began his academic journey at Lewis College (IL), where he met his future wife, Robin. He went on to earn his master’s degree in Inorganic Chemistry at Florida State University under the supervision of Greg Choppin. After a brief period working in industry, he returned to complete his Ph.D. in Inorganic Chemistry, conducting some of the earliest studies on actinide interactions with naturally occurring humic and fulvic acids.

Following graduation, Ken launched his professional career in nuclear and radiochemistry, specializing in actinide–lanthanide solution chemistry. His first appointment was at the U.S. Geological Survey in Denver, where he worked with Jesse M. Cleveland. Soon afterward, he was recruited to Argonne National Laboratory, where his expertise was applied to nuclear waste management and the chemistry of the f-elements in the nuclear fuel cycle. After seventeen years at Argonne, Ken and his family moved to Pullman, Washington, where he found his true calling as a professor of chemistry at Washington State University.

At WSU, Ken established the distinguished Nash Group focused on solvent extraction, separations chemistry, and the solution chemistry of rare earth elements and heaviest radioactive elements. Throughout his career, the professor with the trademark mustache co-authored hundreds of publications, co-edited numerous books, and reviewed countless manuscripts, leaving an indelible impact on chemistry. His transition to academia was also of timely national significance: at a moment when educational opportunities in actinide fuel-cycle chemistry were scarce, his research and teaching filled a critical gap that might otherwise have allowed national understanding in this field to disappear entirely.

Over the years, Ken mentored undergraduate, master’s, and Ph.D. students, as well as postdoctoral associates. As a teacher, scientist, and colleague, Ken nurtured the careers of innumerable people, forming close and enduring relationships that spanned decades. He welcomed individuals from all over the world, giving each the opportunity to learn from his expertise and encouragement.

Outside the lab, Ken enjoyed a rich and vibrant life; his love of chemistry was matched only by his passion for his thousands of DVDs and his cherished 1996 Mustang Cobra SVT. One of the most important lessons he instilled in his mentees was that while science matters deeply, nurturing a full life beyond the lab is essential to a life well lived.

Ken’s many honors culminated in the awarding of the prestigious ACS Glenn T. Seaborg Award for Nuclear Chemistry in August 2024.

As permanent members of the Nash Group, we feel we can paraphrase and adapt the In Memoriam that Ken once wrote for his mentor, Greg Choppin, words that now capture how many of us feel today:

“Professor Nash was an exceptional mentor to many young scientists, a guardian of scientific integrity, a sharp and productive research scientist, and a valued colleague; his influence will continue to radiate through the values he instilled in those of us who crossed his path. Though we will miss his ever-present smile under the mustache, we will never forget his life lessons. Thanks, Ken.” (adapted from Nash, In Memoriam: Gregory R. Choppin, SXIX)

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