Hello everyone, I have a problem about power generation. I have selected small submarine, but it's junction boxes aren't generating power. There isn't any nuclear generators in submarine, too. How can I solve this problem?

The small subs are not designed to generate their own power. They charge the batteries by docking to a sub that is designed to transfer power to the docking ports. The only stable method to generate power is to put in a reactor and scale it down to fit in the shuttle and reduce power output to match the shuttle's average Load. Don't make an object that generates power and slave it to the junction boxes because Load fluctuates constantly and using too little power causes the J-box to blow up and using too much with cause blackouts.