From the book "Eradith.Physics"
Note on the fields in the "nuclear reactors" paragraph:
How to build a nuclear reactor? take a large aluminum pot with a volume of liters of etch by 25. Put there 15 kg of enriched to 95% uranium of fine grind. Gradually pouring distilled water, carefully mix the contents of the pot with an aluminum spoon. When the level of the solution reaches the edges of the pot, the homogeneous nuclear reactor is ready! Upon removing the spoon from the pot, the reactor will start. Be Healthy!