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Latest News
Take steps on SNF and HLW disposal
Matt Bowen
With a new administration and Congress, it is time once again to ponder what will happen—if anything—on U.S. spent nuclear fuel and high-level waste management policy over the next few years. One element of the forthcoming discussion seems clear: The executive and legislative branches are eager to talk about recycling commercial SNF. Whatever the merits of doing so, it does not obviate the need for one or more facilities for disposal of remaining long-lived radionuclides. For that reason, making progress on U.S. disposal capabilities remains urgent, lest the associated radionuclide inventories simply be left for future generations to deal with.
In March, Rick Perry, who was secretary of energy during President Trump’s first administration, observed that during his tenure at the Department of Energy it became clear to him that any plan to move SNF “required some practical consent of the receiving state and local community.”1
M. Z. Youssef, M. A. Abdou, A. Kumar, Li Zhang, K. Kosako, Y. Oyama, F. Maekawa, Y. Ikeda, C. Konno, H. Maekawa
Fusion Science and Technology | Volume 28 | Number 2 | September 1995 | Pages 320-346
Technical Paper | Fusion Neutronics Integral Experiments — Part II / Blanket Engineering | doi.org/10.13182/FST95-A30649
Articles are hosted by Taylor and Francis Online.
Experimental simulation to a line source has been realized at the Japan Atomic Energy Research Institute (JAERI) Fusion Neutronics Source within the U.S. Department of Energy/JAERI collaborative program on fusion neutronics. This simulation, achieved by cyclic movement of an annular Li2O test assembly relative to a stationary point source, was a step forward in better simulation of the energy and angular distributions of the incident neutron source found in tokamak plasmas. Thus, compared with other experiments previously performed with a stationary point source, the uncertainties (that are system dependent) in calculating important neutronics parameters, such as tritium production rate (TPR), will be more representative of those anticipated in a fusion reactor. The rectangular annular assembly used is 1.3 × 1.3 m and 2.04 m long with a square cavity of 0.42 × 0.42 m cross section where the simulated line source (2 m long) is located axially at the center. To characterize the incident neutron source, flux mapping with foil activation measurements was performed in the axial direction (Z = −100 cm to Z = 100 cm) at the front surface of the assembly in the cavity with the annular blanket in place, and comparison was made to the bare line-source case (without annular blanket). Three phases of experiments were performed. In Phase-IIIA, a 1.5-cm-thick stainless steel first wall was used. An additional 2.45-cm-thick carbon layer was added in Phase-IIIB, and a large opening (42.55 × 37.6 cm) was made at one side at the center of the annular assembly in Phase-IIIC. Calculations were performed independently by the United States and JAERI for many measured items that included TPR from 6Li(T6), 7Li(T7), in-system spectrum measurements, and various activation measurements. In this paper, the calculated-to-measured values for the aforementioned measured items are given, as obtained separately by the United States and JAERI. In addition, the mean value of the prediction uncertainties of the local and line-integrated TPR and the associated standard deviations are given based on the calculational and experimental results obtained in all the experiments.
