Perform CFD modeling and heat exchanger evaluation of large mixed nuclear waste tanks at the Department of Energy (DOE) Hanford Site.
The ultimate client, the prime contractor on the DOE-ORP River Protection Project (RPP), asked a pass through broker of engineering services to secure the services of Process Engineering Associates, LLC (PROCESS) to assist with predictive modeling of the underground waste storage tanks.
Computational fluid dynamic (CFD) models can be a useful tool for understanding the migration of the hydroxide ion within the radioactive underground storage tanks at the Hanford site, as well as other problems of interest to the client. Understanding the hydroxide distribution can help guide sampling work and other testing which in turn alerts the site to problems in the corrosion mitigation chemistry control. The first step was to determine what program to use for the tank analysis. A number of computational fluid dynamic programs were reviewed as possible alternatives to the GOTH‑SNF program which was currently being used by contractors to solve the problems of interest. The most potentially viable programs were reviewed in detail with a trial license and sample problem. The programs reviewed in detail were then ranked within a number of categories. The top two programs that seemed most likely to fulfill the objectives of the tank modeling program were STAR-CCM+ and COMSOL. COMSOL was less expensive on a multi-year basis and easier to learn, so it was the recommended software package. Details of the selection process were written into the selection report, “Computational Fluid Dynamic Modeling Software Comparison for Hanford Tank Simulations”.
To enable acquiring software within a nuclear environment for quality effecting projects, a number of things needed to be done. First a Hanford Information Systems Inventory (HISI) form was filled out (HISI ID: 3748, Acronym: COMSOL). This was presented to and approved by the Software Review Board. The Automatic Data Process (ADP) form was filed out and approved for the computer and software. Quality effecting software needs to be purchased with a PO, so a Tank Farm Material Services Systems (TFMSS) form also needed to be completed and approved. Purchasing was not seamless, and the process needed to be monitored to continue the vast array of approvals moving through the system. At the end of the contract both the computer and software had been purchased. The Software management plan for grade D acquired software COMSOL, was written and was routed for phase 1 review.
The main heat exchangers in the 242 A evaporator system, heater E-A-1 and condenser E-C-1, were evaluated. The concept of stall was found to explain the normally low condensate temperature from E-A-1. Both heat exchangers appeared to be generally underutilized and over surfaced. Analysis was presented and a report written which was routed for review explaining the results.
Nuclear Waste Storage and Processing
- Computational fluid dynamics modeling
- Heat exchanger evaluation.