A improvement of BrickedKeyboard watercooled redpower 2 reactor:
When properly cooled with water buckets its a mk1 else you better run for your live. My relative compact water cooling system can be seen in the screenshots. Based on Brickedkeyboard reactor but improved alot :). Requires no maintenance except refueling once setup.
1 nuclear reactor
4 reactor chambers
Glassfiber/HV cable to transport the eu (not shown in screenshots but can be easily added).
Redpower 2 components:
And some red alloy wires and pneumatic pipes
A ton of buckets for the cooling system
Bedrock (which i used for testing purposes here but normally use obsidian)
Thats pretty much all you need