|Nuclear Reactor Robot|
|Relatives||Atomic Power Robot|
|Drops||Super Bomb (16/128 chance)|
|Vulnerable to||PSI Freeze|
|Location||Cave of the Past|
|Drops||Super Bomb (3% chance)|
|Vulnerable to||Siren Beetle, PK Thunder|
|Location||Laboratory Level of the Empire Porky Building|
|In-battle theme||Strong One|
- "Replenishes even more energy than the Atomic Power Robot, but its explosion is all the more powerful, too."
- — Battle Memory (Mother 3)
The Nuclear Reactor Robot is an enemy that appears in EarthBound and Mother 3. As an upgraded version of the Atomic Power Robot, it frequently replenishes the HP of enemies fighting alongside it and itself, causing battles to last a lot longer. However, it will occasionally fire a beam at one of your party members doing a moderate amount of damage.
The Nuclear Reactor Robot is known to explode when it is defeated, causing damage to the characters. However, you will suffer less damage if you try to press A as much as you can to try and get to the "YOU WON!" screen as soon as possible. When it explodes, it has the same effect as PK Fire, being a stronger form of it depending on what version of the enemy you're fighting. However, like its cousin in Mother 3, if the player turns the Robot around by either encountering it from behind or using items (like Duster's Siren Beetle or a Made-You-Look), and then follows up with a physical attack, the robot's explosive device will be destroyed, preventing it from exploding on defeat. Their form in this game differs from that of EarthBound, suggesting a new version was made since the last game.
In Mother 3, its battle sound is Battle Sound 59, a battle sound used only by mushrooms and exploding robots, which falls under Code Numbers 936 for regular attack, 937 for Smaaaash! and 938 for Miss. Like the Atomic Power Robot, Kumatora's Brainshock is required to get it to use its battle sound as it never uses a battle sound inducing regular attack on its own.