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Fusion Science and Technology
Latest News
Norway’s Halden reactor takes first step toward decommissioning
The government of Norway has granted the transfer of the Halden research reactor from the Institute for Energy Technology (IFE) to the state agency Norwegian Nuclear Decommissioning (NND). The 25-MWt Halden boiling water reactor operated from 1958 to 2018 and was used in the research of nuclear fuel, reactor internals, plant procedures and monitoring, and human factors.
Mahmoud Z. Youssef, Neil Morley, Anter El-Azab
Fusion Science and Technology | Volume 34 | Number 3 | November 1998 | Pages 697-705
Neutronics Experiments and Analysis | doi.org/10.13182/FST98-A11963696
Articles are hosted by Taylor and Francis Online.
Innovative concepts are being explored and evaluated in the Advanced Power Extraction (APEX) study to enhance the capability of removing high power density and surface wall load while satisfying all other blanket functional requirements. The minimum surface and neutron wall load considered is ∼1.5 MW/m2 and 7 MW/m2, respectively, with account taken for peaking factors. Liquid first wall is among the concepts considered in which a flowing layer is introduced from the top of the Tokamak. Liquid lithium, Flibe, and Li17Pb83 are among the candidate materials considered. The objectives of the present work are: (a) determination of the spatial range over which X-ray from the plasma deposits its energy across the protective liquid layer under a realistic spectrum, (b) evaluation of the impact of difference in the neutron moderation among the liquid studied on the volumetric heat deposition rate across the layer as well the structured blanket behind it, and (c) assessment of the percentage of tritium bred only in the liquid layer relative to the total tritium bred in the entire system. In this paper, it is shown that X-ray deposits its energy over a finite depth in the layer; contrary to what have been assumed in previous studies. This assessment gives the correct input source for the thermal hydraulic analysis and leads to a large decrease in the liquid surface temperature. It is shown that: (a) still high heat deposition rate is attainable at the layer surface due to the fraction of the Bremsstrahlung spectrum below ∼80 eV (Li) and ∼200 eV (Flibe) which constitutes only ∼0.4% of the incident spectrum, (b) Flibe is more powerful in moderating neutrons than Li, leading to a factor of 2–9 reduction in the volumetric heating rate (and thermal stresses) across the structured blanket, and (c) the fraction of the total breeding ratio, TBR, attributed only to the convective layer is ∼25% although the liquid layer is only ∼9% of the layer/blanket length.
