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Fan Coolers
The Project
One of the long-term strategies for storage of high-level radioactive liquid waste, is to vitrify it, i.e. essentially to turn it into a glass product. For the DOE's "West Valley Nuclear " vitrfication project, the vitrified waste was put into canisters that were placed into a hot-cell for interim storage of up to 40 years. As the canisters generate heat during this period, there must be adequate cooling available to ensure that there is not unwanted heat buildup. The hot-cell used was part of an existing structure; its size and layout offered some unique challenges for the heat transfer equipment that Numet provided for this application.
The Solution
The air delivery system to the canisters is a lengthy ductwork system that creates a significant pressure drop for the Fan Cooler to overcome. The cooler that Numet supplied provides 300,000 BTU's / hour of heat transfer to 10,000 cfm of circulation air using a 34" vane axial type fans and eight rows of fin tube coils. Numet developed its own nuclear qualified fan for the application and seismically qualified the entire assembly.
As is typical for many similar contracts for DOE installations, Numet designed and fabricated the fan coolers to an ASME NQA-1 quality standard.
Numet's Project Responsibilities
- Heat transfer analysis to determine the optimum heat exchange geometry, water side flow rates, air side flow rates and pressure drops
- Analysis of the fan cooler air circuit to determine the operating parameters of the fan
- Layout and packaging of the fan and heat exchanger assembly into the tight spatial constraints of the existing air distribution system
- Upgrading of commercial fan units to meet specific materials requirements and radiation tolerance (environmental qualification)
- Static analysis of the fan cooler assembly, including shielding, to verify structural integrity during seismic events
- Extensive performance testing to verify the heat exchanger duty and the air delivery pressure and flow rate
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