reprocessing it.
Nobody is even sure how long wastes must be stored before they are safe, notes Zurer, a Chemical & Engineering News reporter. The U.S. En- vironmental Protection Agency says 10,000 years; the National Acad- emy of Sciences' estimate is 20,000 years. Until that question is settled, scientists cannot accurately judge the merits of various underground sites: The possibility of earthquakes or volcanic activity, the likelihood of groundwater contamination, and the characteristics...