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Decommissioning & Environmental Sciences
The mission of the Decommissioning and Environmental Sciences (DES) Division is to promote the development and use of those skills and technologies associated with the use of nuclear energy and the optimal management and stewardship of the environment, sustainable development, decommissioning, remediation, reutilization, and long-term surveillance and maintenance of nuclear-related installations, and sites. The target audience for this effort is the membership of the Division, the Society, and the public at large.
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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.
Young Min Kim, Moon Sung Cho
Nuclear Technology | Volume 170 | Number 1 | April 2010 | Pages 231-243
Technical Paper | Special Issue on the 2008 International Congress on Advances in Nuclear Power Plants / Fuel Cycle and Management | doi.org/10.13182/NT10-A9461
Articles are hosted by Taylor and Francis Online.
The COPA-FPREL computer code has been developed to estimate the releases of gaseous and metallic fission products (FPs) from high-temperature gas-cooled reactor (HTGR) fuel into coolant. The COPA-FPREL code treats FP release from a coated fuel particle (CFP), diffusion in a fuel element, and leakage into the coolant considering the temperature distribution within a CFP and a fuel element. The code uses a finite difference method to calculate FP migration and heat transfer. In the finite difference method, the kernel, buffer, and coating layers of a CFP and the fuel element are divided into small finite difference intervals. A steady-state heat transfer equation and the Fickian diffusion equation are applied to these intervals. A relatively high diffusion coefficient is assigned to the buffer and the broken coating layers to describe fast diffusion in those regions. Sorption equilibrium is set up between the concentration at the fuel element surface facing the coolant and the vapor pressure at the graphite side of the boundary layer that forms on the fuel element surface. Mass transfer occurs through the boundary layer into the bulk coolant. In a prismatic HTGR, sorption equilibrium is assumed to form between the concentrations at the compact and structural graphite surfaces and the vapor pressure in the gap between the compact and the structural graphite. For 137Cs, 90Sr, 110mAg, and 85Kr isotopes, the fractional releases from a CFP, a pebble, and a fuel block during simulated heating processes and reactor operations were calculated using COPA-FPREL.
