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ANS Student Conference 2025
April 3–5, 2025
Albuquerque, NM|The University of New Mexico
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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.
Edwin M. Larsen, S. I. Abdel-Khalik, Mark S. Ortman
Nuclear Technology | Volume 41 | Number 1 | November 1978 | Pages 12-26
Technical Paper | Reactor | doi.org/10.13182/NT78-A32129
Articles are hosted by Taylor and Francis Online.
The 1000-MW(electric) laser fusion reactor design of the University of Wisconsin, SOLASE, is fueled by inserting cryogenic deuterium-tritium pellets containing a milligram of fuel into a spherical cavity having a 6-m radius at a rate of 20 Hz. The cavity is surrounded by a honeycomb graphite structure divided into 16 longitudinal segments through which lithium oxide particles (100 to 200 µm in diameter and with a pore length of 1 µm) flow by gravity. The total oxide inventory is 1 mg. The lithium oxide, which contains 0.1 wt% water, serves as both a tritium breeder and a heat transport medium. The oxide enters the blanket at 673 K and exits at 873 K except for a 2% side stream exiting at 1123 K, from which the tritium is recovered. At this temperature, a residence time of 300 s at a flow rate of 163 kg/s is required to condense the daily tritium supply as HTO on a cold surface. The 873 K lithium oxide is transported to a steam generator fabricated from Croloy tubes. In addition to the fuel, the container, either borosilicate glass or polyvinylalcohol (PVA), and a polymer ablator, the pellets contain a high-Z material, here xenon. Also, ∼30 mg of neon are frozen on the outside surface to ensure cryogenic conditions during flight. Some pellet constituents will react with the wall, resulting in erosion. Unburned hydrogen species will react with graphite to form acetylene at a rate estimated to be 63 pm/s (2 mm/yr) for glass and PVA shells at pumping speeds of 6.4 and 8.4 Pa · m3/s (4.8 × 104 and 6.3 × 104 Torr · ℓ/s) at 300 K, respectively. The oxygen debris will erode the graphite by carbon monoxide formation at maximum rates of 6.3 and 25.4 pm/s, respectively, for glass and PVA shells. The total erosion rate is within the expected lifetime of the blanket (1 yr) based on radiation damage studies. The reactor exhaust is predominantly neon, so that hydrogen isotope recovery and recycle is essentially a neon purification process. The fill time for glass pellets is estimated to be 5 days and for PVA pellets, 1 day. This results in a total tritium inventory of 26 and 11 kg, respectively, for a lithium oxide blanket containing 1 kg of tritium. Anticipated tritium losses include 1.5 to 2.2 kBq/kg H2O (40 to 60 nCi/ℓ H2O) of tritium to the water in the reheaters and steam generators and <400 kBq/s (1 Ci/day) for atmospheric losses. This study shows the necessity for experimental work on the thermodynamic properties of well-characterized lithium oxide.