COMPUTER MODELING OF HIGH-LEVEL WASTE GLASS TEMPERATURES WITHIN DWPF CANISTERS DURING POURING AND COOL DOWN

Amoroso, J.

Savannah River Site (S.C.)

关键词: 99 General And Miscellaneous//Mathematics, Computing, And Information Science;    Computers;    Computerized Simulation;    Kinetics;    Simulation;   

DOI  :  10.2172/1027495
RP-ID  :  SRNL-STI-2011-00546
RP-ID  :  DE-AC09-08SR22470
RP-ID  :  1027495

美国|英语

来源: UNT Digital Library

【 摘 要 】

This report describes the results of a computer simulation study to predict the temperature of the glass at any location inside a DWPF canister during pouring and subsequent cooling. These simulations are an integral part of a larger research focus aimed at developing methods to predict, evaluate, and ultimately suppress nepheline formation in HLW glasses. That larger research focus is centered on holistically understanding nepheline formation in HLW glass by exploring the fundamental thermal and chemical driving forces for nepheline crystallization with respect to realistic processing conditions. Through experimental work, the goal is to integrate nepheline crystallization potential in HLW glass with processing capability to ultimately optimize waste loading and throughput while maintaining an acceptable product with respect to durability. The results of this study indicated severe temperature gradients and prolonged temperature dwell times exist throughout different locations in the canister and that the time and temperatures that HLW glass is subjected to during processing is a function of pour rate. The simulations indicate that crystallization driving forces are not uniform throughout the glass volume in a DWPF (or DWPF-like) canister and illustrate the importance of considering overall kinetics (chemical and thermal driving forces) of nepheline formation when developing methods to predict and suppress its formation in HLW glasses. The intended path forward is to use the simulation data both as a driver for future experimental work and, as an investigative tool for evaluating the impact of experimental results. Simulation data will be used to develop laboratory experiments to more acutely evaluate nepheline formation in HLW glass by incorporating the simulated temperatures throughout the canister into the laboratory experiments. Concurrently, laboratory experiments will be performed to identify nepheline crystallization potential in HLW glass as a function of time and temperature, the results of which will be fed back into simulations to evaluate the potential impacts. Through an iterative process involving computer simulations and experimental results, the potential for nepheline crystallization in HLW glass can be predicted, evaluated, and suppressed to maximize waste loading and throughput of canisters.