Provide process engineering services to assist in engineering activities geared towards processing a variety of radioactive wastes, cleaning the existing storage tanks and performing decontamination and decommissioning.
RADIOACTIVE LIQUID WASTE HANDLING FACILITIES DESIGN ENGINEERING
In a staff augmentation role to the client’s Project Management, Design and Construction Department, Process Engineering Associates, LLC (PROCESS) supported development of facilities design for radioactive liquid waste processing facilities in an effort to clean and decommission large waste storage tanks. Large quantities of waste by-products from the processing of nuclear materials for national defense, research, and medical programs currently reside in large storage tanks. Sludge and salt solids and solutions containing plutonium, americium, strontium, and cesium must be removed from the tanks to separate the high-activity materials from the voluminous low-activity materials. Emptied tanks must be cleaned to acceptable contamination levels prior to separation from service utilities and decommissioning by filling with grout. Various chemical compositions and tank configuration dictate the application of numerous processes/equipment for the safe and effective waste removal and subsequent decommissioning.
Specifically, PROCESS’ tasks included:
- Provide technical interface between the client and the technology provider for innovative enhanced chemical cleaning technology during the conceptual and preliminary design activities to implement the technology at the site. This technology specifically focused on reacting with the components of the tank sludge for removal followed by conditioning the resulting material for downstream actinide separation processing. PROCESS directed the review of design documents to help ensure all site system requirements were addressed and proper integration with site-provided services were incorporated. This task included such documents as design basis, P&IDs, mass & energy balances, equipment sizing and layout, site interface documents, instrumentation design and specifications, design support to meet natural hazard requirement, etc.
- Develop detailed design documents for the necessary facilities modifications for the removal of a salt mound within a specific waste tank. Salt mounds have been created over the years of storage by the evaporation and cooling of the salt solution contained in the various tanks. Work scope included preparation of revised P&IDs to capture configuration changes, hydraulic calculations necessary for the salt removal (including piping and pumping facilities), and leading the interface with civil, structural, electrical, and instrumentation engineering disciplines required to develop the design package.
- Develop detailed design documents for the necessary facilities modifications for the removal of residue and liquid within the annulus of a specific waste tank. The annulus materials included both liquid salt solution and solid salt cake on the floor of the annulus. Evaluated alternative methods for removing residual water from the tank in preparation of closure activities following annulus cleaning. Other work scope included preparation of revised P&IDs to capture configuration changes, hydraulic calculations necessary for the residual removal (including piping and pumping facilities), and leading the interface with civil, structural, electrical, and instrumentation required to develop the design package.
- Prepare preliminary heat flow and ventilation air movement requirements for a storage container to be used to contain vitrified radioactive waste canisters. This effort was in support of a consideration to use a storage method similar to spent nuclear fuel dry storage. Sizing of ventilation passages for natural convection cooling of the container to prevent degradation of the storage container was required. Simplified convective heat flow and fluid flow methods where utilized for this preliminary evaluation.
- Provide a review of heat exchange surface failure modes for vessels within the salt waste processing facilities. Using heat transfer design calculations for each of the vessels and the process heat loads for each of the steps, evaluated the production loss from a heat transfer surface failure. Evaluated the interaction of the heat transfer surfaces of the various process steps to determine acceptable methods to minimize processing production rate. Made recommendation for modifications to mitigate process production rate impacts of critical failure points.
- Nuclear Waste Storage and Processing
- Radioactive waste process design
- Preliminary process design
- Technology alternatives evaluation
- Detailed process design
- Heat transfer analysis
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