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2027 ANS Winter Conference and Expo
October 31–November 4, 2027
Washington, DC|The Westin Washington, DC Downtown
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Fusion Science and Technology
November 2024
Latest News
Siting of Canadian repository gets support of tribal nation
Canada’s Nuclear Waste Management Organization (NWMO) announced that Wabigoon Lake Ojibway Nation has indicated its willingness to support moving forward to the next phase of the site selection process to host a deep geological repository for Canada’s spent nuclear fuel.
Tim D. Bohm, Edward P. Marriott, Mohamed E. Sawan
Fusion Science and Technology | Volume 72 | Number 4 | November 2017 | Pages 595-600
Technical Paper | doi.org/10.1080/15361055.2017.1350484
Articles are hosted by Taylor and Francis Online.
The ITER vacuum vessel (VV) is a double walled toroidal shaped stainless steel structure divided into nine 40 degree sectors. In the design process for the ITER blanket system (which provides shielding for the VV), determining integrated nuclear heating loads on the VV is important for cooling system sizing and determining localized nuclear heating on the VV is important for assessing thermal stress loads. Further, determining radiation damage, displacements per atom (dpa) on the VV, is important in meeting pressure vessel limits. Near the neutral beam injection (NBI) region of the VV (both sector 2 and sector 3), there are significant gaps and cut-outs in the blanket system to accommodate the 3 heating neutral beam (HNB) ports and the diagnostic neutral beam (DNB) port. These features lead to higher localized radiation loads. Previous analysis indicated high nuclear heating and dpa in the NBI region. The CAD based DAG-MCNP5 transport code was used to perform neutronics calculations in detailed, updated CAD models of the NBI region. For this work, a 40 degree model of sector 2 (which includes the HNB1 port, the DNB port, and the HNB2 port) was analyzed. Three design options were investigated which add shielding in the DNB port region by using port liners. Mesh tally maps of both nuclear heating and dpa are provided for the VV in the BM13-16 region. Peak dpa values ranged from 0.41–0.65 dpa. Two of the 3 design options investigated had peak dpa values near the DNB port within the ITER dpa limit of 0.5 dpa. Peak nuclear heating results ranged from 1.7 W/cm3 to 2.0 W/cm3. The mesh tally maps of nuclear heating have been provided to the ITER Organization for subsequent finite element engineering analysis. Preliminary analysis has shown the thermal stress levels are unacceptable with the added shielding. The results of this work are being used by the ITER Blanket and Tokamak Integration groups to assess the current design and modify blanket module (BM) design where needed if radiation loads are excessive.
