1.   In an accident last year in western Japan, a fast-breeder plutonium reactor spewed caustic sodium coolant and overheated.

2.   In the accident, tons of caustic liquid sodium coolant leaked in what scientists called a very serious incident.

3.   The advanced boiling water reactor is of a different design than the plutonium-fueled fast-breeder reactor that spewed caustic sodium coolant and overheated in December.

4.   Tons of caustic sodium coolant was spilled in the accident, and some of which exploded, when a secondary cooling system in the reactor overheated.

5.   Tons of caustic sodium leaked from a plant cooling system in the accident and some of it combusted with the air.