skip to main content
OSTI.GOV title logo U.S. Department of Energy
Office of Scientific and Technical Information

Title: DEVELOPMENT OF MONOSODIUM TITANATE (MST) PURCHASE SPECIFICATIONS

Abstract

Savannah River National Laboratory (SRNL) evaluated the previous monosodium titanate (MST) purchase specifications for particle size and strontium decontamination factor. Based on the measured particle size and filtration performance characteristics of several MST samples with simulated waste solutions and various filter membranes we recommend changing the particle size specification as follows. The recommended specification varies with the size and manufacturer of the filter membrane as shown below. We recommend that future batches of MST received at SRS be tested for particle size and filtration performance. This will increase the available database and provide increased confidence that particle size parameters are an accurate prediction of filtration performance. Testing demonstrated the feasibility of a non-radiochemical method for evaluating strontium removal performance of MST samples. Using this analytical methodology we recommend that the purchase specification include the requirement that the MST exhibits a strontium DF factor of >1.79 upon contact with a simulated waste solution with composition as reported for simulated waste solution SWS-7-2005-1 in Table 1 and containing 5.2 to 5.7 mg L{sup -1} strontium with 0.1 g L{sup -1} of the MST. We also recommend performing additional tests with these simulants and MST samples and, if available, new MST samples, tomore » determine the reproducibility and increase the available database for the measurements by the ICP-ES instrument. These measurements will provide increased confidence that the non-radiological method provides a reliable method for evaluating the strontium and actinide removal performance for MST samples.« less

Authors:
Publication Date:
Research Org.:
SRS
Sponsoring Org.:
USDOE
OSTI Identifier:
890211
Report Number(s):
WSRC-TR-2006-00039
TRN: US0604621
DOE Contract Number:
DE-AC09-96SR18500
Resource Type:
Technical Report
Country of Publication:
United States
Language:
English
Subject:
12 MANAGEMENT OF RADIOACTIVE WASTES, AND NON-RADIOACTIVE WASTES FROM NUCLEAR FACILITIES; 36 MATERIALS SCIENCE; SODIUM COMPOUNDS; TITANATES; SPECIFICATIONS; PROCUREMENT; SAVANNAH RIVER PLANT; RADIOACTIVE WASTE FACILITIES; PARTICLE SIZE; ACTINIDES; REMOVAL; STRONTIUM

Citation Formats

Hobbs, D. DEVELOPMENT OF MONOSODIUM TITANATE (MST) PURCHASE SPECIFICATIONS. United States: N. p., 2006. Web. doi:10.2172/890211.
Hobbs, D. DEVELOPMENT OF MONOSODIUM TITANATE (MST) PURCHASE SPECIFICATIONS. United States. doi:10.2172/890211.
Hobbs, D. Sun . "DEVELOPMENT OF MONOSODIUM TITANATE (MST) PURCHASE SPECIFICATIONS". United States. doi:10.2172/890211. https://www.osti.gov/servlets/purl/890211.
@article{osti_890211,
title = {DEVELOPMENT OF MONOSODIUM TITANATE (MST) PURCHASE SPECIFICATIONS},
author = {Hobbs, D},
abstractNote = {Savannah River National Laboratory (SRNL) evaluated the previous monosodium titanate (MST) purchase specifications for particle size and strontium decontamination factor. Based on the measured particle size and filtration performance characteristics of several MST samples with simulated waste solutions and various filter membranes we recommend changing the particle size specification as follows. The recommended specification varies with the size and manufacturer of the filter membrane as shown below. We recommend that future batches of MST received at SRS be tested for particle size and filtration performance. This will increase the available database and provide increased confidence that particle size parameters are an accurate prediction of filtration performance. Testing demonstrated the feasibility of a non-radiochemical method for evaluating strontium removal performance of MST samples. Using this analytical methodology we recommend that the purchase specification include the requirement that the MST exhibits a strontium DF factor of >1.79 upon contact with a simulated waste solution with composition as reported for simulated waste solution SWS-7-2005-1 in Table 1 and containing 5.2 to 5.7 mg L{sup -1} strontium with 0.1 g L{sup -1} of the MST. We also recommend performing additional tests with these simulants and MST samples and, if available, new MST samples, to determine the reproducibility and increase the available database for the measurements by the ICP-ES instrument. These measurements will provide increased confidence that the non-radiological method provides a reliable method for evaluating the strontium and actinide removal performance for MST samples.},
doi = {10.2172/890211},
journal = {},
number = ,
volume = ,
place = {United States},
year = {Sun Apr 30 00:00:00 EDT 2006},
month = {Sun Apr 30 00:00:00 EDT 2006}
}

Technical Report:

Save / Share:
  • A series of tests were planned to examine the removal of Ra and Th by monosodium titanate (MST) and modified monosodium titanate (mMST). Simulated waste solutions were prepared containing Ra and Th, along with Sr, Np, Pu, and U. Following simulant preparation the simulants were filtered through 0.45-m filters. Analysis of the simulants indicated no Th in the filtered solution. This is due to the very low solubility of Th in alkaline solutions. Based on the reported detection limits for {sup 228}Th by gamma analyses, the solubility of Th in the simulant solutions is < 3.0E-10 g/L or < 1.3E-12more » M. Therefore, data could not be obtained regarding the removal of Th by MST and mMST; however, testing proceeded to examine the removal of Ra. Sorption testing indicated that Ra, like Sr, is very rapidly removed from solution by both MST and mMST. The Ra concentration in solution fell below the method detection limit (MDL) within 30 minutes of contact with MST, and within 2 hours of contact with mMST, when tested at 25 C using a 5.6 M Na simulant. Additional testing examined the effects of ionic strength and temperature on the MST and mMST performance. Results from these tests showed that the majority of samples still reached a Ra concentration below the MDL, indicating excellent removal. For the highest ionic strength solution (6.6 M Na), there did appear to be a slight decrease in the Ra removal by mMST, as indicated by a larger number of samples just above the MDL. The effect of temperature on {sup 226}Ra removal is indeterminate for either MST or mMST in the temperature range (25-60 C) and concentrations studied since the final soluble concentration of Ra remained at or below the detection limits for all tests. Desorption testing was also performed using decontaminated salt solution (DSS) diluted to sodium concentrations of 2 M and 0.5 M, to represent the intermediate and final stages of washing. Results from these tests indicated no desorption of any sorbents, with the exception of Pu from mMST, which desorbed slightly (0.02%). Rather, the testing showed additional sorption of sorbates, likely due to the higher sorbent concentrations in these tests compared to the concentrations used for loading (i.e. 13 g/L vs. 0.4 g/L). SRNL recommends additional testing to confirm the low solubility of Th in a range of simulants representing SRS HLW. We also recommend additional sorption testing with simulants containing a higher concentration of {sup 226}Ra, to allow for the determination of actual DF values, rather than the minimum DF values reported here.« less
  • The Savannah River National Laboratory performed measurements of the rheology of suspensions and settled layers of treated material applicable to the Savannah River Site Salt Waste Processing Facility. Suspended solids mixtures included monosodium titanate (MST) or modified MST (mMST) at various solid concentrations and soluble ion concentrations with and without the inclusion of kaolin clay or simulated sludge. Layers of settled solids were MST/sludge or mMST/sludge mixtures, either with or without sorbed strontium, over a range of initial solids concentrations, soluble ion concentrations, and settling times.
  • The DA isotherm parameters for U, Pu, Sr and Np have been updated to include additional data obtained since the original derivation. The DA isotherms were modified to include a kinetic function derived by Rahn to describe sorbate loading from the beginning of sorption up to equilibrium. The final functions describe both kinetic and thermodynamic sorption. We selected the Rahn function to describe radionuclide sorption because it originates from diffusion and absorption controlled sorption. An investigation of the thermal behavior of radionuclide sorption on MST as shown by this data revealed the sorption process is diffusion (or transport) controlled (inmore » solution). Transport in solution can in theory be accelerated by vigorous mixing but the range of available mixing speed in the facility design will probably not be sufficient to markedly increase radionuclide sorption rate on MST from diffusion-controlled sorption. The laboratory studies included mixing energies hydraulically-scaled to match those of the Actinide Removal Process and these likely approximate the range of energies available in the Salt Waste Processing Facility.« less
  • This report describes the results of an experimental study to measure the sorption of fissile actinides on monosodium titanate (MST) at conditions relevant to operation of the Actinide Removal Process (ARP). The study examined the effect of a single contact of a large volume of radionuclide-spiked simulant solution with a small mass of MST. The volume of simulant to MST (8.5 L to 0.2 g of MST solids) was designed to mimic the maximum phase ratio that occurs between the multiple contacts of MST and waste solution and washing of the accumulated solids cycle of ARP. This work provides themore » following results. (1) After a contact time of {approx}2 weeks, we measured the following actinide loadings on the MST (average of solution and solids data), Pu: 2.79 {+-} 0.197 wt %, U: 14.0 {+-} 1.04 wt %, and Np: 0.839 {+-} 0.0178 wt %. (2) The plutonium and uranium loadings reported above are considerably higher than previously reported values. The higher loading result from the very high phase ratio and the high initial mass concentrations of uranium and plutonium. A separate upcoming document details the predicted values for this system versus the results. (3) The strontium DF values measured in these tests proved much lower than those reported previously with simulants having the same bulk chemical composition. The low strontium DF values reflect the very low initial mass concentration of strontium in this simulant (<100 {micro}g/L) compared to that in previous testing (> 600 {micro}g/L).« less
  • A possible disposition pathway for the residue from the abandoned In-Tank Precipitation (ITP) sends the material from Tank 48H in increments to Saltstone via aggregation in Tank 50H. After entering Tank 50H, the amount of fissile material sorbed on MST may increase as a result of contacting waste solutions with dissolved uranium and plutonium. SRNL recommends that nuclear criticality safety evaluations use uranium and plutonium loadings onto MST of 14.0 {+-} 1.04 weight percent (wt %) for uranium and 2.79 {+-} 0.197 wt % for plutonium given the assumed streams defined in this report. These values derive from recently measuredmore » for conditions relevant to the Actinide Removal Process (ARP) and serve as conservative upper bounds for uranium and plutonium loadings during the proposed transfers of MST from Tank 48H into Tank 50H.« less