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Title: Interpretation of Actinide-Distribution Data Obtained from Non-Destructive and Destructive Post-Test Analyses of an Intact-Core Column of Culebra Dolomite

Abstract

The US DOE, with technical assistance from Sandia National Laboratories, has successfully received EPA certification and opened the Waste Isolation Pilot Plant (WIPP), a nuclear waste disposal facility located approximately 42 km east of Carlsbad, New Mexico. Performance assessment analyses indicate that human intrusions by inadvertent, intermittent drilling for resources provide the only credible mechanisms for releases of radionuclides from the disposal system. In modeling long-term brine releases, subsequent to a drilling event, potential migration pathways through the permeable layers of rock above the Salado formation were analyzed. Major emphasis is placed on the Culebra Member of the Rustler Formation because this is the most transmissive geologic layer overlying the WIPP site. In order to help quantify parameters for the calculated releases, radionuclide transport experiments have been earned out using intact-core columns obtained from the Culebra dolomite member of the Rustler Formation within the WIPP site. This paper deals primarily with results of analyses for {sup 241}Pu and {sup 241}Am distributions developed during transport experiments in one of these cores. Transport experiments were done using a synthetic brine that simulates Culebra brine at the core recovery location (the WIPP air-intake shaft--AIS). Hydraulic characteristics (i.e., apparent porosity and apparent dispersion coefficient)more » for intact-core columns were obtained via experiments using the conservative tracer {sup 22}Na. Elution experiments carried out over periods of a few days with tracers {sup 232}U and {sup 239}Np indicated that these tracers were weakly retarded as indicated by delayed elution of the species. Elution experiments with tracers {sup 241}Pu and {sup 241}Am were attempted, but no elution of either species has been observed to date, including experiments of many months' duration. In order to quantify retardation of the non-eluted species {sup 241}Pu and {sup 241}Am after a period of brine flow, non-destructive and destructive analyses of one intact-core column were carried out to determine distribution of these actinides in the rock. Analytical results indicate that the majority of the {sup 241}Am remained very near the injection surface of the core (possibly as a precipitate), and that the majority of the {sup 241}Pu was dispersed with a very high apparent retardation value. The {sup 241}Pu distribution is interpreted using a single-porosity advection-dispersion model, and an approximate retardation value is reported.« less

Authors:
;
Publication Date:
Research Org.:
Sandia National Labs., Albuquerque, NM (US); Sandia National Labs., Livermore, CA (US)
Sponsoring Org.:
US Department of Energy (US)
OSTI Identifier:
12664
Report Number(s):
SAND99-2289J
TRN: US0102571
DOE Contract Number:  
AC04-94AL85000
Resource Type:
Journal Article
Resource Relation:
Journal Name: Journal of Contaminant Hydrology; Other Information: Submitted to Journal of Contaminant Hydrology; PBD: 26 Aug 1999
Country of Publication:
United States
Language:
English
Subject:
12 MANAGEMENT OF RADIOACTIVE WASTES, AND NON-RADIOACTIVE WASTES FROM NUCLEAR FACILITIES; ACTINIDES; DOLOMITE; RADIOACTIVE WASTE DISPOSAL; WIPP; RADIONUCLIDE MIGRATION; HYDRAULIC CONDUCTIVITY; PLUTONIUM 241; AMERICIUM 241; DRILL CORES

Citation Formats

LUCERO, DANIEL A, and PERKINS, W GEORGE. Interpretation of Actinide-Distribution Data Obtained from Non-Destructive and Destructive Post-Test Analyses of an Intact-Core Column of Culebra Dolomite. United States: N. p., 1999. Web.
LUCERO, DANIEL A, & PERKINS, W GEORGE. Interpretation of Actinide-Distribution Data Obtained from Non-Destructive and Destructive Post-Test Analyses of an Intact-Core Column of Culebra Dolomite. United States.
LUCERO, DANIEL A, and PERKINS, W GEORGE. Thu . "Interpretation of Actinide-Distribution Data Obtained from Non-Destructive and Destructive Post-Test Analyses of an Intact-Core Column of Culebra Dolomite". United States. doi:. https://www.osti.gov/servlets/purl/12664.
@article{osti_12664,
title = {Interpretation of Actinide-Distribution Data Obtained from Non-Destructive and Destructive Post-Test Analyses of an Intact-Core Column of Culebra Dolomite},
author = {LUCERO, DANIEL A and PERKINS, W GEORGE},
abstractNote = {The US DOE, with technical assistance from Sandia National Laboratories, has successfully received EPA certification and opened the Waste Isolation Pilot Plant (WIPP), a nuclear waste disposal facility located approximately 42 km east of Carlsbad, New Mexico. Performance assessment analyses indicate that human intrusions by inadvertent, intermittent drilling for resources provide the only credible mechanisms for releases of radionuclides from the disposal system. In modeling long-term brine releases, subsequent to a drilling event, potential migration pathways through the permeable layers of rock above the Salado formation were analyzed. Major emphasis is placed on the Culebra Member of the Rustler Formation because this is the most transmissive geologic layer overlying the WIPP site. In order to help quantify parameters for the calculated releases, radionuclide transport experiments have been earned out using intact-core columns obtained from the Culebra dolomite member of the Rustler Formation within the WIPP site. This paper deals primarily with results of analyses for {sup 241}Pu and {sup 241}Am distributions developed during transport experiments in one of these cores. Transport experiments were done using a synthetic brine that simulates Culebra brine at the core recovery location (the WIPP air-intake shaft--AIS). Hydraulic characteristics (i.e., apparent porosity and apparent dispersion coefficient) for intact-core columns were obtained via experiments using the conservative tracer {sup 22}Na. Elution experiments carried out over periods of a few days with tracers {sup 232}U and {sup 239}Np indicated that these tracers were weakly retarded as indicated by delayed elution of the species. Elution experiments with tracers {sup 241}Pu and {sup 241}Am were attempted, but no elution of either species has been observed to date, including experiments of many months' duration. In order to quantify retardation of the non-eluted species {sup 241}Pu and {sup 241}Am after a period of brine flow, non-destructive and destructive analyses of one intact-core column were carried out to determine distribution of these actinides in the rock. Analytical results indicate that the majority of the {sup 241}Am remained very near the injection surface of the core (possibly as a precipitate), and that the majority of the {sup 241}Pu was dispersed with a very high apparent retardation value. The {sup 241}Pu distribution is interpreted using a single-porosity advection-dispersion model, and an approximate retardation value is reported.},
doi = {},
journal = {Journal of Contaminant Hydrology},
number = ,
volume = ,
place = {United States},
year = {Thu Aug 26 00:00:00 EDT 1999},
month = {Thu Aug 26 00:00:00 EDT 1999}
}