defusing the bomb、つまり「不発弾の信管を抜く、分離する」です。（EnDough）
WWII bomb removed from Sendai Airport
A bomb disposal squad of the GSDF's Sixth Division, based in Yamagata Prefecture, started the removal work at about 9 a.m. The procedure, including defusing the bomb, took about two hours to complete, after which the bomb was taken away by truck.
The airport's runways were temporarily closed for the disposal work, and at least 32 flights were canceled or delayed until the runways were returned to service at 11:26 a.m.