ANALYSIS OF UO$sub 2$ DISSOLUTION IN NITRIC ACID SOLUTION

Technical Report · Tue Sep 18 04:00:00 EDT 1962

DOI:https://doi.org/10.2172/4785244· OSTI ID:4785244

Johnson, H. F.

A model assuming a zero-order reaction and dependence of specific area, a, on fraction of pellets dissolved, F, is proposed to explain the dissolution of UO/sub 2/ pellets in nitric acid solution. A Fortran program for the IBM-7090 was developed to calculate the rate coefficient, ka, and F from experimental data for concentration as a function of time obtained in countercurrent stage runs. Application of the Fortran program to data from eight experimental runs led to fairly good agreement between the ka-vs-F relations for all stages of the eight runs. The average relatlon for all runs can be represented by a second-order polynomial. From the ka-vs-F polynomial and the zero-order reaction model, an analog computer representation of the multistage dissolution process was developed and applied for conditions of the eight experimental runs. The concentration profiles thus calculated were in very good agreement with the original experimental profiles. The studies covered conditions of initial acid concentrations from 5.5 to 8.0 M and L/V ratios from 0.126 to 0.223 min/sup -1/. The model described should be tested with other systems. It is desirable that the sampling time interval be decreased relative to the dissolution rate. Thus for rates of the magnitude studied here, more frequent sampling should be used. However for slower rates, the 10-min interval is probably satisfactory. U intervals other than 10 min are used, the Fortran program will have to be modified. (auth)

• Research Organization: Oak Ridge National Lab., Tenn.
• DOE Contract Number: W-7405-ENG-26
• NSA Number: NSA-16-030366
• OSTI ID: 4785244
• Report Number(s): ORNL-3297
• Country of Publication: United States
• Language: English

Related Subjects

CHEMISTRY
COMPUTERS
IBM 7090
MATHEMATICS
NITRIC ACID
PELLETS
POLYNOMIALS
SOLUTIONS
URANIUM DIOXIDE