National Nuclear Security Administration NNSA Nationales Amt für nukleare Sicherheit National Nuclear Security Administration Administración Nacional de Seguridad Nuclear Administración Nacional de Seguridad Nuclear Administration nationale de la sécurité nucléaire המנהלה הלאומית לביטחון גרעיני राष्ट्रीय न्यूक्लियर सुरक्षा प्रशासन 国立核安全保障局 Administração Nacional de Segurança Nuclear 国家核安全局 NNSA National Nuclear Security Administration The National Nuclear Security Administration (NNSA) is a United States federal government agency responsible for enhancing national security through the military application of nuclear science.