Radioactive waste management should be recognized as an issue that is significant not only to the fusion community, but also to the global environment. As fusion energy becomes a contributor to the world's energy supply by the mid 21st century, managing the many thousand cubic meters of active materials after plant decommissioning represents a real challenge to the fusion industry and cannot be relegated to the back-end as only a disposal issue. Scenarios for radwaste management include disposal in geological repositories, recycling and reuse within the nuclear industry, and clearance or release to the commercial market if the materials contain traces of radioactivity. Most fusion plants generate Class-C low-level waste, requiring near-surface burial.

The wealth of experience accumulated over the past 30-40 years of fusion power plant studies must be forged in a new strategy to reshape all aspects of handling the continual stream of radioactive materials during operation and after plant decommissioning. With tighter environmental controls and the political difficulty of building new repositories worldwide, the disposal option should be replaced with more environmentally attractive scenarios, such as:

1. Recycle and reuse within the nuclear industry
2. Clear or release to the commercial market if materials contain traces of radioactivity.

There is a growing international effort in support of this new trend. The introduction of the clearance category for slightly radioactive materials is an important recent development to accommodate most decommissioned waste at a cost much lower than that for traditional low-level waste produced by the majority of U.S. power plants.

In the late 1990s, we introduced the clearance option to various design concepts. The majority of the in-vessel components cannot be cleared from regulatory control even after an extended storage of 100-500 y, according to the clearance guidelines by the IAEA and the U.S. NRC. The bioshield, cryostat, and individual magnet constituents qualify for clearance. Representing 75-80% of the total waste volume, the cleared materials save a substantial disposal cost and, more importantly, free ample space in the repositories for other radwaste.

Just recently, we applied the recycling approach to the non-clearable in-vessel components (blanket, shield, and vacuum vessel). All components can potentially be recycled using conventional and advanced remote handling equipment. The online removal of specific radionuclides during recycling prolongs the reusability of materials. Transmutation of these byproducts in fusion devices is one of the means being explored to avoid their geological burial.

As an important goal for U.S. power plant studies, the national ARIES project is committed to radwaste minimization. The focus on compact devices with radwaste reduction mechanisms (such as blanket segmentation and well-optimized components) contributed most significantly to the factor of 2-4 difference in radwaste volume between recent ARIES plants and previous designs developed prior to 1995.

To make fusion a viable energy source with minimal environmental impact, we highly recommend minimizing the radwaste by design, and recycling/clearing all fusion components, if economically and technologically feasible, avoiding the disposal approach, meaning no long-term radwaste burden on future generations.

Our recent activity placed UW as the leading U.S. institute for radwaste management assessments. This activity drew the attention of our colleagues in Europe, Russia, Japan, and S. Korea, requesting collaboration with UW in this unique area of research.