noun
nuclear force
Refers to a nation's nuclear military capability, including weapons and delivery systems. Often used in geopolitical and defense contexts.
その国は核戦力の近代化を進めている。
That country is modernizing its nuclear forces.
核戦力の均衡が国際安全保障の鍵となる。
The balance of nuclear forces is key to international security.
戦力 means 'military strength' or 'fighting power' in general; 核戦力 specifies nuclear capability.
Compound of 核 (kaku, 'nuclear') and 戦力 (senryoku, 'military strength').