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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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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.
J. D. Rader, M. S. Greenwood, A. M. Melin, A. J. Wysocki (ORNL), G. M. Borza C. D. Lietwiler (SMR Inventec, LLC)
Proceedings | Nuclear Plant Instrumentation, Control, and Human-Machine Interface Technolgies (NPIC&HMIT 2019) | Orlando, FL, February 9-14, 2019 | Pages 765-775
A cooperative research and development agreement between Oak Ridge National Laboratory (ORNL) and Holtec International subsidiary SMR Inventec, LLC, was crafted to explore the primary flow stability of the SMR-160, a natural circulation-based pressurized-water small modular reactor. It is necessary to investigate the stability of the system at operational power levels when natural circulation is the driver of the primary flow to show that operation of the plant is stable, predictable, and controllable. The first phase of the analysis was a code-to-code benchmarking activity between RELAP5-3D and the Modelica-based, ORNL-developed TRANSFORM library. The benchmarking included both generic comparisons of heated channels and step-change transients of certain plant boundary conditions of interest. Following the benchmarking, a parametric series of linear stability tests was performed using discrete signals applied to one of several boundary conditions. These signals excite the natural harmonics of the system and produce small perturbations in the power of the reactor. Though some resonant behavior was observed, the results indicate stable operation of the SMR-160 at the conditions investigated. The frequency range covered included several octaves on either side of the loop transit frequency. Thus, a reasonable determination of the stability and controllability of the plant can be made over a large range of timescales.
