Letter Report. Defense Waste Processing Facility Pour Spout Heaters - Conceptual Designs and Modeling

The Tanks Focus Area (TFA) identified a major task to address performance limitations and deficiencies of the Defense Waste Processing Facility (DWPF) now in its sixth year of operation. Design, installation, testing, monitoring, operability, and a number of other characteristics were studied by research personnel collaboratively at a number of facilities: Savannah River Technology Center (SRTC), Clemson Environmental Technologies Laboratory (CETL), Pacific Northwest National Laboratory (PNNL), and the Idaho National Engineering and Environmental Laboratory (INEEL). Because the potential limiting feature to the DWPF was identified as the pour spout/riser heater, researches on alternative design concepts originally proposed in the past were revisited. In the original works, finite element modeling was performed to evaluate temperature distribution and stress of the design currently used at the DWPF. Studies were also made to define the requirements of the design and to consider the approaches for remote removal/replacement. Their heater type/location, their remotely replaceable thermocouples, and their capabilities for remote handling characterized the five alternative designs proposed. Review comments on the alternative designs indicated a relatively wide range of advantages and disadvantages of the designs. The present report provides an overview of the design criteria, modeling results, and alternative designs. Based on a review of the past design optimization activities and an assessment of recent experience, recommendations are proposed for future consideration and improvement