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Hydroxylated ceramic waste forms and the absurdity of leach tests

Abstract

The repository pressure and temperature conditions during the thermal period projected in US repositories have been drastically lowered in the last year or two to new values of say 175 +- 50/sup 0/K. Using the argument that the evidence from natural models indicates the most stable mineral (= ceramic) hosts for radionuclides, one finds that under these new repository conditions such crystalline assemblages would be micas, clays, zeolites and other hydrated minerals, plus the tetravalent anhydrous oxide families. A waste form consisting of specific hydroxylated candidate phases can be made via a simple in-can technology (demonstrated by Oak Ridge) by reacting liquid wastes with precursor gels or phyllo or tektosilicates at <200/sup 0/C under modest pressure within the final disposal canister. The data on the rate of reaction of typical oxide materials to yield hydroxylated phases under these conditions show that the typical leach test (at 25 to 100/sup 0/C in deionized water) does not provide a simulation of the reactions which will occur. Hence such tests are not only totally meaningless with respect to qualifying a waste form for its role in a repository, they can be downright misleading.
Authors:
Roy, R; Odoj, R; Merz, E [1] 
  1. eds.
Publication Date:
Jun 01, 1981
Product Type:
Conference
Report Number:
Juel-Conf-42-Vol.2; CONF-810650-Vol.2
Reference Number:
ERA-08-004355; EDB-83-002073
Resource Relation:
Conference: International seminar on chemistry and process engineering for high-level waste solidification, Julich, F.R. Germany, 1 Jun 1981; Related Information: In: Proceedings of the international seminar on chemistry and process engineering for high-level liquid waste solidification.
Subject:
12 MANAGEMENT OF RADIOACTIVE AND NON-RADIOACTIVE WASTES FROM NUCLEAR FACILITIES; 36 MATERIALS SCIENCE; CERAMICS; LEACHING; CESIUM; RADIOACTIVE WASTE PROCESSING; SOLIDIFICATION; STRONTIUM; EVALUATION; MEDIUM TEMPERATURE; SILICATES; TEMPERATURE DEPENDENCE; ALKALI METALS; ALKALINE EARTH METALS; DISSOLUTION; ELEMENTS; MANAGEMENT; METALS; OXYGEN COMPOUNDS; PHASE TRANSFORMATIONS; PROCESSING; SEPARATION PROCESSES; SILICON COMPOUNDS; WASTE MANAGEMENT; WASTE PROCESSING; 052001* - Nuclear Fuels- Waste Processing; 360205 - Ceramics, Cermets, & Refractories- Corrosion & Erosion
OSTI ID:
8432207
Research Organizations:
Pennsylvania State Univ., Universtiy Park
Country of Origin:
Germany
Language:
English
Other Identifying Numbers:
Other: ON: DE82905800
Availability:
NTIS (US Sales Only), PC A21/MF A01.
Submitting Site:
HEDB
Size:
Pages: 576-602
Announcement Date:
Mar 15, 2013

Citation Formats

Roy, R, Odoj, R, and Merz, E. Hydroxylated ceramic waste forms and the absurdity of leach tests. Germany: N. p., 1981. Web.
Roy, R, Odoj, R, & Merz, E. Hydroxylated ceramic waste forms and the absurdity of leach tests. Germany.
Roy, R, Odoj, R, and Merz, E. 1981. "Hydroxylated ceramic waste forms and the absurdity of leach tests." Germany.
@misc{etde_8432207,
title = {Hydroxylated ceramic waste forms and the absurdity of leach tests}
author = {Roy, R, Odoj, R, and Merz, E}
abstractNote = {The repository pressure and temperature conditions during the thermal period projected in US repositories have been drastically lowered in the last year or two to new values of say 175 +- 50/sup 0/K. Using the argument that the evidence from natural models indicates the most stable mineral (= ceramic) hosts for radionuclides, one finds that under these new repository conditions such crystalline assemblages would be micas, clays, zeolites and other hydrated minerals, plus the tetravalent anhydrous oxide families. A waste form consisting of specific hydroxylated candidate phases can be made via a simple in-can technology (demonstrated by Oak Ridge) by reacting liquid wastes with precursor gels or phyllo or tektosilicates at <200/sup 0/C under modest pressure within the final disposal canister. The data on the rate of reaction of typical oxide materials to yield hydroxylated phases under these conditions show that the typical leach test (at 25 to 100/sup 0/C in deionized water) does not provide a simulation of the reactions which will occur. Hence such tests are not only totally meaningless with respect to qualifying a waste form for its role in a repository, they can be downright misleading.}
place = {Germany}
year = {1981}
month = {Jun}
}