INITIAL MAR ASSESSMENTS TO ACCESS THE IMPACT OF AL DISSOLUTION ON DWPF OPERATING WINDOWS

Newell, J ; Tommy Edwards, T ; David Peeler, D

Savannah River Site (S.C.)

关键词: Aluminium;    Chemical Composition;    Sludges;    Process Control;    Radioactive Waste Processing;   

DOI  :  10.2172/924155
RP-ID  :  WSRC-STI-2007-00688
RP-ID  :  DE-AC09-96SR18500
RP-ID  :  924155

美国|英语

来源: UNT Digital Library

【 摘 要 】

SRNL was tasked to provide an assessment of the downstream impacts (or lack thereof) to DWPF of decisions regarding the implementation of Al-dissolution to support sludge mass reduction and processing. Based on future sludge batch compositional projections, assessments have been made with respect to the ability to maintain comparable projected operating windows for sludges with high temperature Al-dissolution and without Al-dissolution. In general, paper study assessments indicated that most of the future sludge batches (twelve with and fourteen without high temperature Al-dissolution) had multiple frits available that yielded relatively large operating windows. The projected operating windows were defined by the waste loading (WL) interval over which glasses were classified as acceptable based on current process control models and their related constraints. Although multiple frits were identified, using a 17-point width as a general guide for a reasonable operating window (e.g., 25-41% WL), there generally appeared to be more flexibility in frit selection for the without Al-dissolution flowsheets. This larger frit compositional platform could allow frit development efforts to make more significant adjustments to melt rate. However, based on the general observations of the paper study, there is essentially no clear distinction between the two options with which to drive a decision to implement Al-dissolution. That is, comparable operating windows can be achieved through the frit development and selection process for either process. One could interpret this general summary statement to indicate: given frit development efforts can compensate for the different pretreatment strategies yielding equivalent operating windows or maximum WL targets, the lower sludge mass as a result of Al-dissolution would obviously result in reducing the number of cans produced at DWPF. Although the basic mathematics is technically sound, other factors need to be considered including facility operating times or mission life for the Tank Farm, DWPF and Saltstone. To address some of these questions, candidate frit compositions have been selected to assess melt rate as a function of waste loading for the glass systems representing future sludge batches with and without Al dissolution. The frit selection process was driven by reviewing compositional trends that have historically influenced melt rate as well as identifying systems with relatively large operating windows. With respect to the identification of sludge batches to support the melt rate testing, average compositions representing with and without Al-dissolution 'clusters' were developed using a statistical grouping routine. Ultimately, five frits were identified for each average 'cluster' composition. Melt rate assessments will be performed as a function of waste loading for the five frits selected. The data obtained from the experimental melt rate program can be used in combination with actual DWPF processing data to provide valuable insight into the waste throughput potentials for both flowsheets.