Atomic Bombs would have to be a technology, so if you’re playing with no techs, then no Atomic Bombs.
I see it as being the result of having a strong research program, so here’s a simple way to do it.
After having researched any 4 technologies, a player gains a new research chart called “Atomic Warfare” with 2 technologies in the chart. The chart is below.
Chart 3 – Atomic Warfare
1. Atomic Bomb – You may now produce Atomic Bomb units. These have the following stats.
Atomic Bomb
0 Attack
0 Defense
0 Movement points – may only be moved by bombers, destroyers, cruisers, and/or battleships during the non-combat move phase.
3 IPC cost
2. Atomic Bomber – If it started the turn in a territory containing an Atomic Bomb, then during its combat move phase 1 of your bombers may now perform an “Atomic Bombing Run” on a territory. This may be a regular attack or a SBR attack. Of course if the territory has aa, then aa fires fire as usual.
Regular attack (no other attacking units other than air units may be used when performing a regular Atomic Bombing Run – roll 4 dice which hit at “5”
Atomic SBR attack – roll 4 dice. The total of the dice is the amount of damage which is dealt to the IC. 1 of the damage points dealt is a permanent damage token placed under the IC which permanently reduces the production capacity of the IC. No IC may be reduced in this way to more than half (rounded down) of its original production capacity. (i.e. Japan could have 4 permanent damage tokens on its IC which would mean that it could only produce up to 4 units and could only be SBR’d for up to 8 damage. An Indian IC, on the other hand, could have up to 2 permanent damage tokens on it which would reduce its production capacity to 1 and could only be SBR’d for up to 2 damage.
If the above mentioned Japan with 4 permanent damage tokens on it had Increased Factory Production, then he could produce up to 6 units but could only be SBR’d for up to 8 damage.