Investigation of the thermal behavior of 2-1/2 ton cylinder protective overpack

Conference · Fri Jan 01 04:00:00 EST 1988

OSTI ID:7052061

Park, S H

UF/sub 6/ cylinders containing reactor grade enriched uranium are transported in protective overpacks. Recently, the design of the 2-1/2 ton UF/sub 6/ cylinder overpack was modified to insure the safety of the cylinder inside the overpack. Modifications include a continuous stainless liner from the outer surface to the inner surface of the overpack and step joints between the upper and lower halves of the overpack. The effects of a continuous stainless steel liner and moisture in the insulation layer of a UF/sub 6/ cylinder protective overpack were investigated with a numerical code. Results were compared with limited available field data. The purpose of comparing the numerical results with field data is to insure the validity of the numerical analysis and the physical properties used in the analysis. The study indicates that the continuous stainless steel liner did not influence the heat transfer rate much from the outer surface of the overpack to the 30B cylinder inside. The effect of step joints was not modeled due to the difficulty of quantifying the leakage rate through the gap. With a continuous stainless steel liner from the outside of the overpack to the inside, the overpack satisfies the thermal design criteria of protecting the cylinder inside for a minimum of 30 minutes when the overpack is exposed to a fire. The effect of moisture inside the insulation layer in the overpack is to reduce the energy to the cylinder with its high thermal capacity. The high pressure steam generated from the moisture will be relieved externally through the vent holes on the outer surface of the overpack. Although these holes are sealed after the overpack is dried, the plug sealing the holes will melt when the overpack is exposed to a fire. 3 refs., 8 figs.

• Research Organization: Oak Ridge Gaseous Diffusion Plant, TN (USA)
• DOE Contract Number: AC05-84OT21400
• OSTI ID: 7052061
• Report Number(s): K/QT-166; CONF-880558-9-Vugraphs; ON: DE88010427
• Country of Publication: United States
• Language: English

Related Subjects

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FIRES
FLUORIDES
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URANIUM HEXAFLUORIDE