Thermal and flow analyses of the Nuclear Materials Storage Facility Renovation Title I 60% design

The authors are continuing to use the computational fluid dynamics code CFX-4.2 to evaluate the steady-state thermal-hydraulic conditions in the Nuclear Material Storage Facility Renovation Title 1 60% Design. The analyses build on those performed for the 30% design. They have run an additional 9 cases to investigate both the performance of the passive vault and of an individual drywell. These cases investigated the effect of wind on the inlet tower, the importance of resolving boundary layers in the analyses, and modifications to the porous-medium approach used in the earlier analyses to represent better the temperature fields resulting from the detailed modeling of the boundary layers. The difference between maximum temperatures of the bulk air inside the vault for the two approaches is small. They continued the analyses of the wind effects around the inflector fixture, a canopy and cruciform device, on the inlet tower by running a case with the wind blowing diagonally across the inflector. The earlier analyses had investigated a wind that was blowing parallel to one set of vanes on the inflector. Several subcases for these analyses investigated coupling the analysis to the facility analysis and design changes for the inflector