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Research Needs for Magnetic Fusion Energy Sciences - US Burning ...

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areas of safety R&d that are common to all envisioned magnetic fusion energy designs, including<br />

tritium retention in irradiated materials, dust generation and entrainment, activation product<br />

mobilization, and dispersal of chemically toxic materials. close correlation to other fusion development<br />

themes exist because of the materials characteristics and configurations required <strong>for</strong><br />

solving the gaps in those themes. The limiting amounts <strong>for</strong> accidental release of these materials<br />

are determined by the adopted safety approach, such as implementation of the no-evacuation criteria.<br />

The effectiveness of release mitigation strategies can only be developed, evaluated, and refined<br />

through safety integration in design.<br />

MatERiaLS LiFE CyCLE ManagEMEnt<br />

materials life-cycle management and environmental needs are broad and certainly influenced by<br />

design configurations, materials selection, and operational per<strong>for</strong>mance. Proper handling of the<br />

activated materials is important to the future of fusion energy. <strong>Fusion</strong> offers salient safety advantages<br />

relative to other sources of energy, but generates a sizable amount of mildly radioactive<br />

materials that tend to rapidly fill the Us low-level waste repositories. all three operational commercial<br />

repositories will be closed by ~2050 be<strong>for</strong>e building the first Us fusion power plant. For<br />

these reasons and to guarantee the environmental potential of fusion, geological disposal should<br />

be avoided. Focus should be placed on more attractive scenarios, such as recycling and reuse of<br />

activated materials within the nuclear industry and clearance or free-release to the commercial<br />

market if materials contain traces of radioactivity.<br />

There is a need <strong>for</strong> a global understanding of the activation levels throughout the fusion power<br />

core to develop an integrated management approach <strong>for</strong> all activated materials. such an approach<br />

should consider the radioactivity levels, remote handling issues, property of recycled materials<br />

and cost. The key technological needs include the development of 3-d activation codes, remote<br />

handling and treatment of tritium-containing materials, separation of materials from complex<br />

components, detritiation and tritium capturing and handling, and refabrication of recyclable and<br />

clearable materials.<br />

This integral approach calls <strong>for</strong> major rethinking, education, and research to make the recycling<br />

and clearance approaches a reality. in the 2000s, these new approaches have become more technically<br />

feasible with the development of advanced radiation-resistant remote handling tools that<br />

can recycle highly irradiated materials and with the introduction of the clearance category <strong>for</strong><br />

slightly radioactive materials by national and international agencies. note that such approaches<br />

are straight<strong>for</strong>ward in application from a technical standpoint, however, a substantial challenge<br />

lies in influencing the policy, regulatory, and public acceptance aspects.<br />

The Us fusion development program should consider implementing this state-of-the-art recycling<br />

and clearance strategy to handle the expected large quantities of fusion-activated materials.<br />

a dedicated R&d program would address the issues identified <strong>for</strong> strategic options. several areas<br />

of scientific advancement underlie sound decisions in restructuring the framework of handling<br />

fusion radioactive materials. examples of specific research needs include development of:<br />

• low-activation materials that optimize alloying elements specifications to maximize<br />

recycling after a short cooling period.<br />

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