Speaking of the NNSA- it is not an old agency but a fairly new one :
Established by Congress in 2000, NNSA is a semi-autonomous agency within the U.S. Department of Energy responsible for enhancing national security through the military application of nuclear science in the nation’s national security enterprise. NNSA maintains and enhances the safety, security, reliability, and performance of the U.S. nuclear weapons stockpile without nuclear testing; reduces the global danger from weapons of mass destruction; provides the U.S. Navy with safe and effective nuclear propulsion; and responds to nuclear and radiological emergencies in the U.S. and abroad.
Wesley Clark and Andrew Cuomo are also board members at NNSA:
https://nanonuclearenergy.com/board-of-executive-advisors/?v=7516fd43adaa