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N.S. Savannah: Bridging the gap between decommissioning and historic preservation
It’s safe to say that readers of Nuclear News are familiar with decommissioning. It’s even safe to assume that experienced decommissioning practitioners are familiar with the National Historic Preservation Act (NHPA) and how it applies to typical projects. What’s different about the N.S. Savannah is that the entire project site is a historic property—and in fact, is a federally owned National Historic Landmark (NHL), a status that confers the highest level of protection under law. Federal owners of NHLs are obligated to minimize harm in both planning and actions. Distilled to its salient point, no federal owner of an NHL should destroy it if there’s a reasonable alternative. That level of preservation is not what we normally associate with nuclear decommissioning. This perfectly summarizes the challenges, and opportunities, that decommissioning Savannah offered. The story of how the Maritime Administration (MARAD) managed these two otherwise contradictory processes showcases how historic preservation and decommissioning can positively intersect, provides a pathway for other historic facilities, and further adds to the already illustrious history of one of our nation’s significant 20th century landmarks.
A. R. Wazzan, A. Villalobos, D. Okrent
Nuclear Technology | Volume 70 | Number 2 | August 1985 | Pages 285-289
Technical Note | Fission Reactor | doi.org/10.13182/NT85-A33654
Articles are hosted by Taylor and Francis Online.
A computer code developed earlier by Villalobos et al. to predict fission gas behavior in uranium oxide fuel under steady-state irradiation conditions and where bubble gas resolution is represented with the single knock-on model (SKO) is modified to replace the SKO model with the complete bubble destruction model (CBD). The CBD model required that bubble nucleation be included in the present analysis. The revised code is used to compute gas release and total swelling. Both are found to be insensitive to whether they are obtained with the CBD or the SKO option. This is mainly because at low atomic percent of burnup, total swelling is dominated by the grain-edge bubble gas contribution, and release is dependent on the formation of a complete grainface/grain-edge tunnel network—factors that are not much affected by either the SKO or CBD models. At higher atomic percent of burnup, intragranular swelling, which can be sensitive to the resolution model, contributes more to swelling. But even then, computations at 1.0 at.% burnup suggest total swelling will continue to be dominated by grain-edge gas. These results suggest that in modeling swelling and release in irradiated uranium dioxide fuel, the simpler SKO resolution model is satisfactory.