what is radioactive nuclear waste
High-Level Waste. High-level radioactive waste primarily is uranium fuel that has been used in a nuclear power reactor and is spent, or no longer efficient in producing electricity. Spent fuel is thermally hot as well as highly radioactive and requires remote handling and shielding.uring the fission process, two things happen to the uranium in the fuel. First, uranium atoms split, creating energy that is used to produce electricity. The fission creates radioactive isotopes of lighter elements such as cesium-137 and strontium-90.