The National Nuclear Security Administration’s (NNSA) longest-serving associate administrator Jeffrey Johnson, the chief of nuclear security, announced his retirement on Monday. Johnson served eight years at NNSA following a 20-year career in uniform and seven years as a civilian employee with the U.S. Marine Corps, according to a statement from the NNSA. The NNSA did not specify a retirement date for Johnson or say who might replace him as head of security. Whoever steps into the role will be responsible…
