Nuclear Research Facility Process Cooling Loops Detailed Simulation and Design, and Utilities Systems Process Design

SPALLATION NEUTRON SOURCE UTILITIES SYSTEMS PROCESS DESIGN

The client contracted Process Engineering Associates, LLC (PROCESS) to perform conceptual and detail process designs for the Spallation Neutron Source (SNS) utilities systems, including cooling water, helium, nitrogen and vacuum, with particular emphasis on design associated with the facility cooling water loops.  The SNS is a neutron scattering research facility.

Initially, PROCESS executed a conceptual process design for the seven facility cooling water loops that included mass and energy balance preparation using commercial computer process simulation software, preparation of preliminary process flow diagrams (PFDs), and development of a conceptual process control system design.  As part of this task, PROCESS developed a unique in-house computer model designed to predict cooling water offgas generation rates and compositions for gases produced in the cooling water by radiation-induced spallation and radiolysis.

The major project task involved full-scale process design of the utilities systems and resulted in the following major project deliverables:

• PFDs and process descriptions
• Process control diagrams (PCDs) and process control descriptions
• Piping and instrumentation diagrams (P&IDs)
• Equipment specifications for the cooling loop primary unit operations and instrumentation including tanks, pumps, cleanup system ion removal elements, valves, and pressure relief devices (PRDs).

Within the realm of the process design project, PROCESS completed the following specific subtasks:

• Development of detailed water cooling loop hydraulic analyses using the pipe simulation package included in the commercial process simulation software.  The analyses allowed PROCESS to determine cooling loop line sizes, cooling water pump requirements, and flow control valve performance requirements.
• Cooling loop tank sizing and design.
• Design of the cooling loop water cleanup systems which included pre-filters for the removal of insoluble ions, ion exchange systems for the removal of soluble ions, and post-filters for the removal of ion exchange system blow-through.  A unique in-house computer program was developed by PROCESS for the purpose of determining ion exchange system unit operation sizes, flow characteristics including ion exchange column pressure drops, and ion exchange resin life.  The program also included radionuclide production, decay, and removal terms for the purpose of determining cleanup system unit operation radiation activity levels and shielding requirements.
• Design of cooling loop offgas water removal and recovery systems, particularly for the recovery of valuable heavy water for one of the cooling loops.
• Preparation of an off-normal operations analysis for the purpose of identifying credible accident scenarios for the cooling water, helium, nitrogen and vacuum systems.
• Performance of cooling loop offgas helium recycle system alternatives technical and economic evaluations.
• Major equipment vendor bid reviews.
• Utilities systems detail design reviews.