1. magnetic confinement - ENEA - Fusione

3. FUSION TECHNOLOGY 109
The cooling tubes inside the breeding blanket will be subjected to neutron-induced
sputtering, which is the primary contributor to cooling system maintenance doses.
The total cooling system dose was estimated to be of the order of 290 p-mSv/a.
Therefore, a self-cooled liquid-metal blanket, for example, which eliminates the need
for cooling tubes, would significantly reduce cooling system maintenance doses.
Waste management
3.12 Safety and Environment, Power
Plant Studies and Socio-Economics
[3.81] A. Natalizio, L. Di
Pace, Assessment of
clearance and recycling
from the policy point of
view, in preparation
[3.82] A. Natalizio, L. Di
Pace, Tritium transport
and proliferation issues,
in preparation
Assessment of clearance and recycling from the policy viewpoint [3.81]. A valid
analogy exists between in-vessel components that need to be replaced on a regular
basis and used fission reactor fuel, even if there are significant differences in the type
of waste and radiotoxicity. The fission power industry has followed two basic
strategies for used fuel disposal: the once-through fuel cycle and the closed-fuel
cycle, which includes reprocessing of the used fuel. These two strategies are also
available to the future fusion power industry. The key question is to determine the
technical and economic feasibility of used, in-vessel component (IVC) refurbishment
and reprocessing. Seven scenarios were developed and studied to identify the factors
that are important in the development of a suitable fusion-power waste management
strategy dealing with the interim storage, refurbishment/reprocessing, and final
disposal of waste. The scenarios studied range from doing very little
refurbishment/reprocessing to doing the maximum refurbishing/reprocessing that
is practical, both on-site and off-site. The key criterion in evaluating the various
scenarios was the environmental acceptability of the fusion power plant. More
specifically, the aim was to identify scenarios that would eliminate or reduce the
shipment of radioactive materials to and from centralised fuel reprocessing facilities.
The following conclusions were drawn from the study:
1. Future fusion power plants should be constructed as multi-unit plants with
adjacent in-vessel component refurbishing facilities.
2. Tritium recovery from blanket modules is expected to reduce the cost of IVC
refurbishment.
3. Reprocessing the breeder and neutron multiplier material may not be economical
unless the reprocessing unit cost is significantly lower than a few hundred Euro/kg.
4. Without IVC refurbishing, the operational IVC waste volume will far exceed the
decommissioning waste volume.
Tritium transport and proliferation issues [3.82]. The objective was to analyse the
tritium transport and proliferation issues that could arise from the transport of
considerable quantities of tritium to and from future fusion power plants. These
potential issues were addressed in the context of a mature fusion power industry.
Two aspects were considered: the public safety of tritium shipments (i.e., the
potential for radiation exposure in the event of a shipping accident); and the
proliferation aspects of tritium shipment (i.e., the potential for the hijacking of
tritium shipments by terrorist organisations). Based on simple analyses it was
demonstrated that there will be a need to ship significant quantities of tritium, to and
from a future fusion power plant, on an annual basis. This could be of the order of
10 kg per year.
Tritium has been safely shipped in licensed shipping containers for many years and
without incidents that could constitute a public risk. Current shipping containers in
Canada are designed and licensed to transport 50 g of tritium, but larger containers
have also been considered in past studies, for example for ITER. Considering the
large quantities of tritium to be shipped to and from a future fusion power plant, a