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Title: YMP: Example of a Scientifically Engineered Radionuclide Multi-barrier System

Authors:
ORCiD logo [1]
  1. Los Alamos National Laboratory
Publication Date:
Research Org.:
Los Alamos National Lab. (LANL), Los Alamos, NM (United States)
Sponsoring Org.:
USDOE Office of Environmental Management (EM)
OSTI Identifier:
1351254
Report Number(s):
LA-UR-17-22604
DOE Contract Number:
AC52-06NA25396
Resource Type:
Conference
Resource Relation:
Conference: NAKAI Visit ; 2017-03-29 - 2017-03-30 ; Los Alamos, New Mexico, United States
Country of Publication:
United States
Language:
English
Subject:
Earth Sciences; Yucca Mountain, Repository Science, Flow and Transport, Engineered and Natural Barriers

Citation Formats

Bussod, Gilles Yves A. YMP: Example of a Scientifically Engineered Radionuclide Multi-barrier System. United States: N. p., 2017. Web.
Bussod, Gilles Yves A. YMP: Example of a Scientifically Engineered Radionuclide Multi-barrier System. United States.
Bussod, Gilles Yves A. Thu . "YMP: Example of a Scientifically Engineered Radionuclide Multi-barrier System". United States. doi:. https://www.osti.gov/servlets/purl/1351254.
@article{osti_1351254,
title = {YMP: Example of a Scientifically Engineered Radionuclide Multi-barrier System},
author = {Bussod, Gilles Yves A.},
abstractNote = {},
doi = {},
journal = {},
number = ,
volume = ,
place = {United States},
year = {Thu Mar 30 00:00:00 EDT 2017},
month = {Thu Mar 30 00:00:00 EDT 2017}
}

Conference:
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  • The main aim of the PEBS project is to evaluate the sealing and barrier performance of the EBS over time, through development of a comprehensive approach involving experiments, model development, and consideration of the potential impacts on long-term safety functions. The experiments and models cover the full range of conditions, from initial emplacement of wastes (high heat generation and EBS re-saturation) through to later stage establishment of near steady state conditions, i.e. full re-saturation and thermal equilibrium with the host rock. These aspects will be integrated in a manner that will lead to greater certainty and thus greater confidence regardingmore » the development from the initial transient state of the EBS to its long-term state, which provides the required isolation of the wastes. The work proposed within the project builds on existing knowledge and experience generated during recent years and supported by ongoing national and EC research programs. The project aims to provide a more complete description of the THM and THMC (thermo-hydro-mechanical- chemical) evolution of the EBS system, a more quantitative basis for relating the evolutionary behavior to the safety functions of the system, and a further clarification of the significance of residual uncertainties for long-term performance assessment. The importance of uncertainties arising from potential disagreement between the process models and the laboratory and in-situ experiments to be performed within PEBS, and their implications for an extrapolation of the results, will be reviewed, with particular emphasis on possible impacts on safety functions. In addition to the scientific-technical aims, the consortium will disseminate the basic findings to the broad scientific community within the EU, China and Japan, use expertise gained for public information purposes, and promote knowledge and technology transfer through training. (authors)« less
  • Yucca Mountain, approximately 100 miles northwest of Las Vegas, Nevada, has been selected as the site for the nation's first geologic repository for high level nuclear waste. The Yucca Mountain Project (YMP) is currently developing the design for the underground facilities. Ventilation is a key component of the design as a way to maintain the desired thermal conditions in the emplacement drifts prior to closure. As a means of determining the effects of continuous ventilation on heat removal from the emplacement drifts two series of scaled ventilation tests have been performed. Both test series were performed in the DOE/North Lasmore » Vegas Atlas facility. The tests provided scaled (nominally 25% of the full scale emplacement drift design) thermal and flow process data that will be used to validate YMP heat and mass transport codes. The Phase I Ventilation Test series evaluated the ability of ambient ventilation air to remove energy under varying flow and input power conditions. The Phase II Ventilation Test series evaluated the ability of pre-conditioned ventilation air to remove energy under varying flow, input temperature and moisture content, and simulated waste package input power conditions. Twenty-two distinct ventilation tests were run.« less
  • A preliminary performance analysis of the engineered barrier system in geological disposal of high-level waste was performed, taking into account the possible degradation of a buffer material caused by intrusion into fissures in the surrounding rock. For the analysis, a program code to calculate radionuclide migration behavior in multi-porous media with time-dependent diffusion/retardation parameters was developed. For the case without buffer degradation, the analysis showed that the maximum normalized hazard was about 0.1 and the predominant nuclides were Cs-135, Am-243 and Th-229 under the conservative zero concentration condition at the outer boundary. The effect of groundwater flow in the surroundingmore » rock and the assumption of very high nuclide solubilities did not drastically change the results. Preliminary calculation of buffer degradation suggests that the loss of the buffer material mass would not markedly increase the release of Cs-135, Tc-99 and Np-237 due to the slow dissolution rate of the glass and the low solubility limits if the groundwater velocity is small.« less
  • The primary rationale for studying the transport behavior of radionuclides through the Engineered Barrier system / Near Field Environment (EBS/NFE) is to ascertain whether the material properties of the introduced and altered host rock can significantly affect the transport of radionuclides from the waste container to the far field. The intent of this report is to present data and modeling results that can be used to assess the importance of canister corrosion products and cementitious materials to transport of radionuclides to the far field.
  • This study, which develops a safety assessment code for radioactive waste disposal, consists of two-dimensional analyses of underground water infiltrated flow and near-field radionuclide migration, one-dimensional analyses of far-field migration, and the dose equivalent. The study takes into account the influence of a finite absorption amount of radionuclides in an engineered barrier system (EBS).The safety assessment code is applied to {sup 14}C migration calculations. The near-field cylindrical model consists of an equally mixed region of wasteforms and backfill, bentonite, and rock. Carbon-14 coexists with 3.1 x 10{sup 6} times as much {sup 12}C in the wasteforms. The distribution coefficient, maximummore » absorption amount, and solubility of CO{sub 3}{sup 2-} against the equally mixed region are assumed to be 2.0 m{sup 3}/kg, 3.06 mol/kg, and 544 mol/m{sup 3}, respectively. Then, the release rate from the wasteforms (10{sup -4} to 10{sup -6}/yr) and underground water detachment period from the wasteforms are examined to lower the dose equivalent by the intake of well water.The {sup 14}C concentration on the EBS boundary is 20 times as large in the case of EBS finite absorption as in the case of infinite absorption. So, the EBS finite absorption leads to absorption saturation and accelerated release of the radionuclides. The influence of the absorption saturation could not be prevented by lowering the release rate. A 3 x 10{sup 4}/yr detachment lowered the dose equivalent to 1/40 of the original case.« less