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Title: ADVANCED MODELING AND EXPERIMENTAL VALIDATION OF COMPLEX NUCLEAR MATERIAL WASTE FORMS OF POTENTIAL TRANSPORTATION CONCERN

Abstract

No abstract prepared.

Authors:
;
Publication Date:
Research Org.:
Los Alamos National Lab., NM (US)
Sponsoring Org.:
US Department of Energy (US)
OSTI Identifier:
789413
Report Number(s):
LA-UR-01-6654
TRN: US0302179
DOE Contract Number:
W-7405-ENG-36
Resource Type:
Conference
Resource Relation:
Conference: Conference title not supplied, Conference location not supplied, Conference dates not supplied; Other Information: PBD: 1 Dec 2001
Country of Publication:
United States
Language:
English
Subject:
12 MANAGEMENT OF RADIOACTIVE WASTES, AND NON-RADIOACTIVE WASTES FROM NUCLEAR FACILITIES; SIMULATION; VALIDATION; WASTE FORMS

Citation Formats

D. KELLY, and M. T. PAFFETT. ADVANCED MODELING AND EXPERIMENTAL VALIDATION OF COMPLEX NUCLEAR MATERIAL WASTE FORMS OF POTENTIAL TRANSPORTATION CONCERN. United States: N. p., 2001. Web.
D. KELLY, & M. T. PAFFETT. ADVANCED MODELING AND EXPERIMENTAL VALIDATION OF COMPLEX NUCLEAR MATERIAL WASTE FORMS OF POTENTIAL TRANSPORTATION CONCERN. United States.
D. KELLY, and M. T. PAFFETT. Sat . "ADVANCED MODELING AND EXPERIMENTAL VALIDATION OF COMPLEX NUCLEAR MATERIAL WASTE FORMS OF POTENTIAL TRANSPORTATION CONCERN". United States. doi:. https://www.osti.gov/servlets/purl/789413.
@article{osti_789413,
title = {ADVANCED MODELING AND EXPERIMENTAL VALIDATION OF COMPLEX NUCLEAR MATERIAL WASTE FORMS OF POTENTIAL TRANSPORTATION CONCERN},
author = {D. KELLY and M. T. PAFFETT},
abstractNote = {No abstract prepared.},
doi = {},
journal = {},
number = ,
volume = ,
place = {United States},
year = {Sat Dec 01 00:00:00 EST 2001},
month = {Sat Dec 01 00:00:00 EST 2001}
}

Conference:
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  • We present here computer modeling efforts to describe the time-dependent pressurization and gas-phase mole fractions inside sealed canisters containing actinide materials packaged with small (0.12 - 0.5 wt. %) amounts of water. The model is run using Chemkin software, and the chemical reaction mechanism includes gas generation due to radiolysis of adsorbed water, interfacial chemical reactions, and adsorption/desorption kinetics of water on PuO2 materials. The ultimate goal is to provide a verifiable computer model that can be used to predict problematic gas generation in storage forms and assure design criteria for short-term storage and transportation of less than well-characterized (withmore » respect to gas generation) material classes. Our initial efforts are intended to assess pressurization and gas-phase mole fractions using well-defined 3013 container test cases. We have modeled gas generation on PuO2 with water loading up to 0.5 wt. %, at 300 and 525 K, for time frames of 3 years. Estimates of the initial H2 generation rates were determined using RadCalc and employed in the Chemkin model to assess time- and coverage-dependent system behavior. Results indicate that canister pressurization due to radiolysis is a relatively slow process, with pressure increases at 300 K of approximately 1.5 atm. for 5000 g of PuO2 packaged with 0.5 wt. % water. At higher temperatures (> 400 K), desorption of water into the gas phase largely dictates pressurization and the gas-phase mole fractions. These modeling efforts provide a predictive capability for potential gas generation behavior that when augmented and validated by surveillance information will provide a technical basis for safe storage and transportation.« less
  • We present here computer modeling efforts to describe the time-dependent pressurization and gas-phase mole fractions inside sealed canisters containing actinide materials packaged with small (0.12 - 0.5 wt. %) amounts of water. The model is run using Chemkin software, and the chemical reaction mechanism includes gas generation due to radiolysis of adsorbed water, interfacial chemical reactions, and adsorption/desorption kinetics of water on PuO2 materials. The ultimate goal is to provide a verifiable computer model that can be used to predict problematic gas generation in storage forms and assure design criteria for short-term storage and transportation of less than well-characterized (withmore » respect to gas generation) material classes. Our initial efforts are intended to assess pressurization and gas-phase mole fractions using well-defined 3013 container test cases. We have modeled gas generation on PuO2 with water loading up to 0.5 wt. %, at 300 and 525 K, for time frames of 3 years. Estimates of the initial H2 generation rates were determined using RadCalc and employed in the Chemkin model to assess time- and coverage-dependent system behavior. Results indicate that canister pressurization due to radiolysis is a relatively slow process, with pressure increases at 300 K of approximately 1.5 atm. for 5000 g of PuO2 packaged with 0.5 wt. % water. At higher temperatures (> 400 K), desorption of water into the gas phase largely dictates pressurization and the gas-phase mole fractions. These modeling efforts provide a predictive capability for potential gas generation behavior that when augmented and validated by surveillance information will provide a technical basis for safe storage and transportation.« less
  • The mechanisms of radiation induced degradation of soda glass were investigated via low-energy (5-120 eV) electron-stimulated desorption (ESD) studies. The major ionic desorption products observed are H{sup +}, Na{sup +}, O{sup +} and Si{sup +}. The primary thresholds for H{sup +}, O{sup +} and Na{sup +} are approximately 25, 30 and 90 eV. These thresholds correlate to deep valence holes which Auger decay. The inter-atomic and intra-atomic Auger processes result in a reversal of the Madelung potential and cation desorption due to Coulomb repulsion. This is one of the main mechanisms of radiation damage of glass surfaces and is typicalmore » of wide band-gap materials.« less
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