A STUDY OF THE POLYMERIZATION, DEPOLYMERIZATION, AND PRECIPITATION OF TETRAVALENT PLUTONIUM AS FUNCTIONS OF TEMPERATURE AND ACIDITY BY SPECTROPHOTOMETRIC METHODS: PRELIMINARY REPORT
Studies were made on the kinetics of the polymerization of tetravalent Pu, depolymerization of polymeric Pu(IV), and properties of Pu(IV) poiymer under representative solution conditions of acidity, temperature, and ion concentrations encountered in fuel processing. The polymerization of tetravalent Pu was studied as a function of the Pu concentration, (1 to 8 mg Pu/ml), nitric acid concentration, (0.03 to 0.3 M), and temperature (25 to 95 deg ). Under these conditions, disproportionation and nitrate oxidation of the tetravalent Pu occurred and were also studied. It is clearly indicated that colloidal polymer formation is favored by an increase in the Pu concentration and temperature, or by a decrease in the acidity. Temperature had a pronounced effect on the rate and extent of polymer formation at any particular acidity. The effects of UO/sub 2/(NO/sub 3/)/sub 2/, Al(NO/sub 3/)/sub 3/, NaNO/sub 3/, and F/sup -/ upon the kinetics of polymer formation in acidic nltrate media were also determined at low acidities and elevated temperatures. In the presence of high concentrations of the nitrate salts the colloidal Pu(IV) polymer was observed to precipitate. The precipitation of aged colloidal Pu(IV) polymer by nitratecontaining electrolytes, HNO/sub 3/, Al(NO/sub 3/)/sub 3/, NaNO/sub 3/, and LiNO /sub 3/, was studied at 25 deg C. The Pu(IV) polymer was aged by refluxing for 24 hr at the boiling temperature. The amount of aged polymer precipitated reached a maximum at 2 to 3 M nitrate, and decreased thereafter with an increase in nitrate concentration. Precipitation did not occur above a nitrate concentration of 4 M. The depolymerization reaction kinetics of freshly prepared Pu(IV) polymer at fixed acidity were observed to be first order, depending only upon the concentration of Pu present as polymer. The results show that polymer formation and precipitation can be prevented by the proper control of solution conditions, and that polymer, once formed, can be depolymerized. (P.C.H.)
- Research Organization:
- Oak Ridge National Lab., Tenn.
- DOE Contract Number:
- W-7405-ENG-26
- NSA Number:
- NSA-17-027319
- OSTI ID:
- 4688143
- Report Number(s):
- ORNL-TM-585
- Country of Publication:
- United States
- Language:
- English
Similar Records
Polymerization of Pu(IV) in aqueous nitric acid solutions
Technical Basis for Safe Operations with Pu-239 in NMS and S Facilities (F and H Areas)
Polymerization and Precipitation of Plutonium(IV) in Nitric Acid
Technical Report
·
Wed Oct 01 00:00:00 EDT 1980
·
OSTI ID:711701
Technical Basis for Safe Operations with Pu-239 in NMS and S Facilities (F and H Areas)
Technical Report
·
Wed Mar 17 23:00:00 EST 1999
·
OSTI ID:4769
Polymerization and Precipitation of Plutonium(IV) in Nitric Acid
Journal Article
·
Wed Dec 31 23:00:00 EST 1958
· Industrial and Engineering Chemistry
·
OSTI ID:4280440