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Nuclear and Hydropower
Published in Roy L. Nersesian, Energy Economics, 2016
Fusion is inherently safe. A hydrogen bomb environment cannot be created because any “runaway” condition stops the fusion process by removing plasma. The trick is knowing how to keep plasma together long enough for fusion to occur. Alternative approaches to magnetic confinement as a means of trapping the hot plasma are lasers or particle beams. If fusion could be perfected, energy would be virtually inexhaustible. Radioactivity is limited to high-energy neutron bombardment of the containment vessel. This radioactivity is short-lived (100 years) compared to the radioactivity of a fission reactor (many thousands of years). An additional health hazard is the possibility of tritium leaking into the environment. Tritium is a radioactive proton with two neutrons and has a half-life of 12.4 years. Tritium can be bound with an oxygen atom and form an isotope of water. The body does not discriminate with water made of hydrogen and oxygen or tritium and oxygen. Once ingested, tritium is easily absorbed by the human body and becomes a constituent part of cells and remains in a human body for a long time, posing a serious threat to human health as it decays. The advantage of the deuterium–deuterium fusion process is that no tritium is involved.
Preliminary Safety Analysis of Tritium Source Term for the CFETR Tritium Plant
Published in Fusion Science and Technology, 2020
Shiping Wei, Xinyu Sun, Haixia Wang, Jiangtao Jia, Zhibin Chen, Shichao Zhang
Tritium generation is mainly in the BZ of the blankets, and tritium produced in the BZ is about 13.89 g per operational day. It is also produced by deuterium-deuterium fusion reaction or neutronic transmutation in beryllium; tritium produced in the above two ways was not considered in this technical note for the much smaller amount than that of breeding zone. The large blanket system with about 400 breeding blankets in the CFETR tokamak, more than in ITER, tritium retention in the BZ pebble beds, the structural material of the pipelines, and the efficient tritium recovery methods of the auxiliary tritium extraction systems will be key issues for generation.21 The evaluation result of tritium retention in the blanket system showed that even with high tritium extraction efficiency (>95%), about 0.14 g of tritium, equivalent to the production of four breeding blankets, still remains in the BZ and will not be used in time.
Activation Analysis and Evaluation of Radionuclide Inventory Decay Heat for EU DEMO Vacuum Vessel Components
Published in Fusion Science and Technology, 2021
Gediminas Stankunas, Simona Breidokaite, Andrius Tidikas
The vacuum vessel (VV) structure is a toroidal metal chamber that encloses two important components: the breeding blanket and the divertor. The torus-shaped D-T plasma source of the neutron radiation is located inside the VV. Neutron production is defined by statistical estimates of the D-T, tritium-tritium, and deuterium-deuterium fusion reactions in low confinement mode. The main difference in the model between the two cases examined is the selection of the breeding blanket type. For HCPB, Li4SiO4 ceramics (with 6Li enriched at 60%) is used as the breeding material, and beryllium is used as the neutron multiplier. For WCLL, Li-Pb eutectic alloy is used for the tritium breeding and the neutron multiplication.10