Michael Dunning retired as the acting head of the Lawrence Livermore National Laboratory’s Weapons and Complex Integration Directorate on Wednesday, capping a 30 year career at the nation’s second-oldest weapons laboratory.

“Michael Dunning has retired after a long and impactful career at LLNL,” a spokesperson for the California facility said by email Thursday. “It was a retirement he had planned for some time.”

Dunning joined Livermore in 1989 and spent substantially his entire career at there. He became principal deputy principal associate director for weapons complex and integration in January 2015, making him the No. 2 manager in the Livermore directorate responsible for maintaining and refurbishing U.S. nuclear weapons without relying on nuclear-explosive tests.

Dunning served less than a year as the acting principal associate director for weapons complex and integration after full-time head Charles Verdon left the lab in 2018 to become deputy administrator for defense programs at National Nuclear Security Administration headquarters in Washington. 

With Verdon and Dunning both gone from LLNL, Derek Wapman, program director for weapon technologies and engineering, is the acting principal associate director for weapons complex and integration. The lab spokesperson said LLNL plans to announce the next full-time head of the directorate “soon.”

Lawrence Livermore National Security, a partnership led by the University of California and Bechtel National with industry partners AECOM and BWX Technologies, manages LLNL for the National Nuclear Security Administration. The team’s roughly $2-billion-a-year contract began in 2007 and with options could stretch into 2026. 

Lawrence Livermore, in cooperation with the Sandia National Laboratories in New Mexico and California, maintains the B83 heavy gravity bomb that was slated for retirement until the Donald Trump administration last year announced plans to keep the weapon in the stockpile. The labs also maintain the W87 warhead used on Minuteman III intercontinental ballistic missiles.