In real life, the Second World War saw the first development and deployment of nuclear bombs, so they are available as a gameplay option.
Deploying nuclear bombs needs the right technologies from Engineering technology, special resource, and specific aircraft to deliver the bombs.
The second technology, Nuclear Reactor , unlocks the state level building titled "Nuclear Reactor" which can be found in the Construction screen. Built nuclear reactors provide the state with enriched uranium for use in nuclear weapons, but have no effect without the requisite technology to make nuclear bombs.
The final technology, Nuclear Bombs , allows the country to produce and stockpile nuclear bombs. Each reactor will provide approximately 1 bomb per year. The bomb production progress can be seen via a slowly progressing percentile bar.
It is possible to speed up research by:
- Employing a theorist with either the Nuclear Scientist or Nuclear Enthusiast trait.
- Finishing certain focuses.
Nuclear Bombs are deployed onto specific provinces. In order to deploy a bomb, the following requirements must be met:
- at least 1 bomb must be available (it is depicted as the "radioactive" icon at the top of the game's main screen)
- hostile with the province controller
- at least 75% Air superiority in the region
- a Strategic Bomber should be in range of the province (despite having the strategic bombing mission, tactical bombers cannot deliver nuclear bombs)
How to drop a nuclear bomb
Once you have completed the prerequisites listed above then:
- Select the Default map mode (F1)
- Click the province you wish to bomb
- Click the nuclear bomb symbol at the bottom of the province window
- Once ordered, it will take 12 hours for the nuclear bomb to detonate, however multiple nuclear bombs can be dropped in parallel
- As of patch 1.9 several nuclear bombs can not be dropped on the same province at once
- units in the province take a random percentage between 10% and 90% of their current strength and organisation as damage
- all province buildings get reduced to 0 HP
- all state buildings are reduced to a random level below their current undamaged level (damaging airports also destroys airplanes located there)
- the controller of the target province loses up to 20% war support. If the largest victory point in the state is smaller than 3 or the undamaged infrastructure is lower than level 10, the effect is proportionately lower respectively.
- The first use, as well as uses on specific (capital) cities, will result in news messages, however those are purely informational
- After the 2nd nuclear bomb has been dropped on a Japanese core state, Japan has a special decision for surrender