Riley Rexford Chase IV

Riley Rexford Chase IV, 74, of Idaho Falls, Idaho, passed away surrounded by loved ones on August 7, 2025, at the Idaho Falls Community Hospital. He was born into a military family, to Margaret Emily Peasley Chase and Riley Rexford Chase III, on September 25, 1950, in Holyoke, Massachusetts. Being in a military family, he and his big sister Corliss moved frequently. They were stationed at many Air Force bases, which included England, Northern Maine, and Puerto Rico, eventually settling in Moses Lake, Washington. Riley graduated from Moses Lake High School in 1968.

In 1969, Riley enlisted in the US Naval Nuclear Program and served on the Fast Attack Nuclear Submarine USS Guitarro, SSN 665. He also qualified as a Navy Diver. In 1973, Riley married Nancy Lynn Oswood, and they eventually moved to Idaho Falls, where he began his career at the Advanced Test Reactor (ATR) in 1980, on the Idaho National Engineering Laboratory. In 1995, Riley was moved to the Idaho Nuclear Technology & Engineering Center (INTEC), serving as the Site Area Director. When the Idaho National Laboratory (INL) was formed in 2005, Riley came over to the Material & Fuels Complex (MFC), as the Director of Nuclear Operations until moving on to serve as the the INL Deputy Laboratory Director, Nuclear & Laboratory Operations, retiring in 2014.

As a life-long sportsman and fly-fisherman, in retirement, Riley and Nancy made frequent trips to their favorite fishing spot of Key West, Florida.

Riley is survived by his wife of 52 years, Nancy, his sister Corliss Chase (California) and her children, Steffani and Joshua, who reside in California. A memorial service will be scheduled at a later date.