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

at the time when the demo design is initiated, there should be a well-defined set of design requirements
and a well-documented, low-risk design approach based on a complete set of validated
and qualified components and processes to be integrated into an acceptable-risk demonstration
power plant.
3. Addressing safety and environmental aspects. of the many integrated design, modeling,
and simulation aspects important for fusion power development, comprehensive safety and
environmental evaluations in the context of advanced design studies are essential for proving the
key benefits of fusion power relative to other energy systems. Fusion power is being developed
under the very restrictive “no-evacuation criteria,” very little decay heat, recyclable and clearable
materials, and no long-lived waste products, to name a few.
simulation tools are necessary to provide the protective assurances for the regulators, power producers
and the general public. These tools must be developed, refined, and validated specifically
for fusion developmental facilities and eventual power systems (as needed for licensing). The
tools include robust computational models considering integrated thermal, chemical, and electromagnetic
phenomena possible during postulated events, single-effects and integral experimentation
to validate the physical models, a consistent method for interfacing safety analyses with
the system design processes, and a suitable framework for safety assurance and regulation within
parties considering fusion power deployment. For example, scientific understanding is presently
incomplete and simulation tools are subsequently inadequate for evaluating the magnetic energy
interaction, or arcing, during material failure. The behavior of tritium in irradiated structural,
plasma facing, and functional materials is not well understood at present. This issue is closely related
to similar issues examined in the ReneW Theme “taming the Plasma-material interface.”
The safety relevance is found in the potential, and presently uncertain, estimates of tritium, dust,
and other dispersible materials released in postulated accident scenarios. simulation tools for
safety analysis and materials performance must be integrated to address this issue.
There is a need to establish an integrated management strategy that could handle the sizable
amount of mildly activated materials anticipated for fusion power plants. because of concerns
about the environment, limited capacity of existing repositories, high disposal cost, and political
difficulty of constructing new repositories, the geological disposal option should be avoided and
more attractive scenarios should be considered:
• Recycling and reuse of activated materials within the nuclear industry.
• clearance or free release to the commercial market, if materials contain traces of
radioactivity.
There is a growing international effort in support of this new trend and several fusion studies
indicated recycling and clearance are technically feasible. The Us fusion program should accommodate
this new strategy. a dedicated R&d program could address the issues identified for each
option. Fusion designers must minimize the radioactive waste volume by clever designs, and the
materials community should continue developing low-activation materials and accurately measure
and reduce impurities that deter the free release of in-vessel components.
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