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Title: Rheological properties of the product slurry of the Nitrate to Ammonia and Ceramic (NAC) process

Abstract

The Nitrate to Ammonia and Ceramic (NAC) process is an innovative technology for immobilizing the liquid from Low Level radioactive Waste (LLW). An experimental study was conducted to measure the rheological properties of the pipe flow of the NAC product slurry. Test results indicate that the NAC product slurry has a profound rheological behavior. At low solids concentration, the slurry exhibits a typical dilatant fluid (or shear thinning)fluid. The transition from dilatant fluid to pseudo-plastic fluid will occur at between 25% to 30% solids concentration in temperature ranges of 50--80{degree}C. Correlation equations are developed based on the test data.

Authors:
; ;  [1]; ; ;  [2]
  1. Florida International Univ., Miami, FL (United States). Dept. of Mechanical Engineering
  2. Oak Ridge National Lab., TN (United States)
Publication Date:
Research Org.:
Oak Ridge National Lab., TN (United States)
Sponsoring Org.:
USDOE, Washington, DC (United States)
OSTI Identifier:
62623
Report Number(s):
CONF-950828-6
ON: DE95007407
DOE Contract Number:
AC05-84OR21400
Resource Type:
Conference
Resource Relation:
Conference: 1995 National heat transfer conference, Portland, OR (United States), 5-9 Aug 1995; Other Information: PBD: [1995]
Country of Publication:
United States
Language:
English
Subject:
05 NUCLEAR FUELS; LOW-LEVEL RADIOACTIVE WASTES; CONTAINMENT; SLURRIES; RHEOLOGY; RADIOACTIVE WASTE PROCESSING; CERAMICS

Citation Formats

Muguercia, I., Yang, G., Ebadian, M.A., Lee, D.D., Mattus, A.J., and Hunt, R.D.. Rheological properties of the product slurry of the Nitrate to Ammonia and Ceramic (NAC) process. United States: N. p., 1995. Web.
Muguercia, I., Yang, G., Ebadian, M.A., Lee, D.D., Mattus, A.J., & Hunt, R.D.. Rheological properties of the product slurry of the Nitrate to Ammonia and Ceramic (NAC) process. United States.
Muguercia, I., Yang, G., Ebadian, M.A., Lee, D.D., Mattus, A.J., and Hunt, R.D.. Wed . "Rheological properties of the product slurry of the Nitrate to Ammonia and Ceramic (NAC) process". United States. doi:. https://www.osti.gov/servlets/purl/62623.
@article{osti_62623,
title = {Rheological properties of the product slurry of the Nitrate to Ammonia and Ceramic (NAC) process},
author = {Muguercia, I. and Yang, G. and Ebadian, M.A. and Lee, D.D. and Mattus, A.J. and Hunt, R.D.},
abstractNote = {The Nitrate to Ammonia and Ceramic (NAC) process is an innovative technology for immobilizing the liquid from Low Level radioactive Waste (LLW). An experimental study was conducted to measure the rheological properties of the pipe flow of the NAC product slurry. Test results indicate that the NAC product slurry has a profound rheological behavior. At low solids concentration, the slurry exhibits a typical dilatant fluid (or shear thinning)fluid. The transition from dilatant fluid to pseudo-plastic fluid will occur at between 25% to 30% solids concentration in temperature ranges of 50--80{degree}C. Correlation equations are developed based on the test data.},
doi = {},
journal = {},
number = ,
volume = ,
place = {United States},
year = {Wed Mar 01 00:00:00 EST 1995},
month = {Wed Mar 01 00:00:00 EST 1995}
}

Conference:
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  • The Nitrate to Ammonia and Ceramic (NAC) process is an innovative technology for immobilizing liquid form low level radioactive waste (LLW). An experimental study has been conducted to measure the heat transfer properties of the NAC product slurry. The results indicate that the heat transfer coefficient for both concentration slurries is much higher than that of pure water, which may be due to the higher conductivity of the gibbsite powder. For the 20% concentration slurry, the heat transfer coefficient increased as the generalized Reynolds number and slurry temperature increased. The heat transfer coefficient of 40% is a function of themore » Reynolds number only. The test results also indicate that the thermal entrance region can be observed only when the generalized Reynolds number is smaller than 1,000. The correlation equation is also developed based on the experimental data in this paper.« less
  • The Nitrate to Ammonia and Ceramic (NAC) process is an innovative technology for immobilizing liquid form low level radioactive waste (LLW). An experimental study has been conducted to measure the heat transfer properties of the NAC product slurry. The results indicate that the heat transfer coefficient for both concentration slurries is much higher than that of pure water, which may be due to the higher conductivity of the gibbsite powder. For the 20% concentration slurry, the heat transfer coefficient increased as the generalized Reynolds number and slurry temperature increased. The heat transfer coefficient of 40% is a function of themore » Reynolds number only. The test results also indicate that the thermal entrance region can be observed only when the generalized Reynolds number is smaller than 1,000. The correlation equation is also developed based on the experimental data in this paper.« less
  • Recently, a new immobilization technique for LLW, the Nitrate to Ammonia and Ceramic (NAC) process, has been developed. Instead of mixing the liquid waste form directly with the cement to make concrete blocks, the NAC process eliminates the nitrate from the LLW by converting it to ammonia gas. Aluminum particles are used as a reductant to complete this conversion. The final product of the NAC process is gibbsite, which can be further sintered to a ceramic waste form. Experimental tests are conducted to measure the apparent viscosity, the pressure drop, and the heat transfer coefficient of the pipe flow ofmore » the Nitrate to Ammonia and Ceramic (NAC) process product slurry. The tests indicate that the NAC product slurry exhibits a typical pseudoplastic fluid behavior. The pressure drop in the pipe flow is a function of the Reynolds number and the slurry temperature. The results also indicate that at a low slurry temperature, the slurry is uniformly heated peripherally. At a high slurry temperature, however, the slurry may be thermally stratified. In a straight pipe, the Nusselt number is reduced as the slurry temperature increases.« less
  • A process for the conversion of alkaline, aqueous nitrate wastes to ammonia gas at low temperature, based upon the use of the active metal reductant aluminum, has been developed at the Oak Ridge National Laboratory (ORNL). The process is also well suited for the removal of low-level waste (LLW) radioelements and hazardous metals which report to the solid, alumina-based by-product. ne chemistry of the interaction of aluminum powders with nitrate, and other waste stream metals is presented.
  • The nitrate to ammonia and ceramic (NAC) process is an innovative technology for the denitration of radioactive sodium nitrate-based liquid waste found throughout Department of Energy (DOE) facilities in the United States. In the present investigation, two reaction systems were studied. The first utilized only sodium nitrate as the substrate for the aluminum. The second consisted of the multication composition of waste forms located at the Hanford facility. Studies were carried out on the batch reaction at three different starting nitrate ion concentrations, each at three different temperatures. For each of these conditions, the rate of nitrate depletion was determined,more » and rate constants were calculated. The reaction did not demonstrate simple kinetics; rather, it appeared to involve two zero order reactions. Certain generalities were obtained in both the batch reaction and in the continuous process, nonetheless. It was found that the conversion of nitrate to ammonia seemed to be most efficient at the lowest temperature studied, 50{degrees}C. This behavior was more obvious in the case of the unadulterated nitrate solution than with the Hanford simulant. To elaborate a practical, marketable product, it was necessary to develop a process that could be carried out in a continuous matter, whereby reactants were continuously fed into a reactor while the products of the reaction were simultaneously removed. Thus, the objective has been to develop the prototype procedures for carrying out this continuous reaction. As a corollary of this research, it was first necessary to define the characteristics of the reaction with respect to rate, conversion efficiency, and safety. To achieve this end, reactions were run under various batch conditions, and an attempt was made to measure the rates of the depletion of nitrate and the production of ammonia and hydrogen as well as pH and temperature changes.« less