Performance Assessment with Realistic Data for a Hypothetical High-Level Waste Repository in A Salt Dome

1988 ◽  
Vol 127 ◽  
Author(s):  
R.-P. Hirsekorn ◽  
R. Storck
Keyword(s):  
Salt Dome ◽  
High Level Waste ◽  
Model Parameters ◽  
Dose Rates ◽  
Best Estimate ◽  
Time Histories ◽  
Sensitivity Studies ◽  
High Level ◽  
Physical And Chemical ◽  
Realistic Data

ABSTRACTIn the frame of the European R&D program on “Management and Storage of Radioactive Waste” assessments for HLW repositories in different geological formations have been performed with realistic data. Part of this action was the discussion of altered evolution scenarios for a repository in a salt dome.For the considered HLW repository a combined altered evolution scenario with brine intrusion via the main anhydrite vein and brine intrusion from undetected brine pockets has been considered. For this scenario limited intrusions of brine at very early times are assumed, which inundate boreholes and parts of the repository. Radionuclides are leached out of the waste forms and contaminate the brine. At later times brine intrusion via the main anhydrite is assumed to take place. Under certain conditions contact between both amounts of brine is possible, and contaminated brine reaches the overburden. Here, the radionuclides are swept away with the groundwater flow.Decisive for the transport of radionuclides from the repository to the geosphere are several interacting effects (e.g. convergence, permeability, pressure) which determine the movement of brine through the drifts and seal-ings. For the parameters involved in the modelling of physical and chemical effects as realistic data as available (best estimate) were used. Local sensitivity studies show that with the best estimate values for some parameters the combined intrusion scenario is just at the transition point between release and no release.Results are obtained showing time histories for the decrease of the voids in the repository, release rates for relevant nuclides injected into the overburden, and for dose rates. Dependences on the model parameters are discussed and most relevant parameters are identified.

Performance Assessment of a High-Level-Waste Repository in Clay

1988 ◽  
Vol 127 ◽  
Author(s):  
Jan L. Marivoet ◽  
Geert Volckaert ◽  
Arnold A. Bonne
Keyword(s):  
Performance Assessment ◽  
Maximum Dose ◽  
High Level Waste ◽  
Clay Layer ◽  
Geological Disposal ◽  
Dose Rates ◽  
Consequence Analysis ◽  
Calculated Dose ◽  
Order Of Magnitude ◽  
High Level

ABSTRACTPerformance assessment studies have been undertaken on the geological disposal of high-level waste in a clay layer in the framework of the CEC project PAGIS. The methodology applied consists of two consecutive steps : a scenario and a consequence analysis. The scenario analysis has indicated that scenarios of normal evolution, of human intrusion, of climatic change, of secondary glaciation effects and of faulting should be evaluated. For the consequence analysis as well deterministic “best estimate” as stochastic calculations, including uncertainty, risk and sensitivity analyses, have been elaborated.The calculations performed show that most radionuclides decay to negligible levels within the first fewjneters of the clay barrier. Just a few radionuclides, 99Tc, 135Cs and 237Np with its daughter nuclides 233U and 229Th can eventually reach the biosphere. The maximum dose rates arising from the geological disposal of HLW, as evaluated by the “best-estimate” approach are about 10−11 Sv/y for river pathways. If the sinking of a water well into the 150 m deep aquifer layer in the vicinity of the repository is considered together with a climatic change, the maximum calculated dose rate rises to a value of 3×10−7 Sv/y. The maximum dose rates evaluated by stochastic calculations are about one order of magnitude higher due to the considerable uncertainties in the model parameters. In the case of the Boom clay the estimated consequences of a fault scenario are of the same order of magnitude as the results obtained for the normal evolution scenario. The maximum risk is estimated from the results obtained through stochastic calculations to be about 5×10−8 per year. The sensitivity analysis has shown that the effective thickness of the clay layer, the retention factors of Tc, Cs and Np, and the Darcy velocity in the aquifer are parameters which strongly influence the calculated dose rates.

scholarly journals Spent Fuel as a Waste Form - Data Needs to Allow Long Term Performance Assessment Under Repository Disposal Conditions.

1986 ◽  
Vol 84 ◽  
Author(s):  
V. M. Oversby
Keyword(s):  
Performance Assessment ◽  
Waste Form ◽  
High Level Waste ◽  
Detailed Knowledge ◽  
Spent Fuel ◽  
Expected Performance ◽  
High Level ◽  
Term Performance ◽  
Physical And Chemical ◽  
Waste Repositories

AbstractPerformance assessment calculations are required for high level waste repositories for a period of 10,000 years under NRC and EPA regulations. In addition, the Siting Guidelines (IOCFR960) require a comparison of sites following site characterization and prior to final site selection to be made over a 100,000 year period. In order to perform the required calculations, a detailed knowledge of the physical and chemical processes that affect waste form performance will be needed for each site. While bounding calculations might be sufficient to show compliance with the requirements of IOCFR60 and 40CFRI91, the site comparison for 100,000 years will need to be based on expected performance under site specific conditions. The only case where detailed knowledge of waste form characteristics in the repository would not be needed would be where radionuclide travel times to the accessible environment can be shown to exceed 100,000 years. This paper will review the factors that affect the release of radionuclides from spemt fuel under repository conditions, summarize our present state of knowledge, and suggest areas where more work is needed in order to support the performance assessment calculations.

scholarly journals Uranium(VI) and neptunium(V) transport through fractured, hydrothermally altered concrete

2000 ◽  
Vol 88 (9-11) ◽  
Author(s):  
S.L. Matzen ◽  
J.M. Beiriger ◽  
P.C. Torretto ◽  
P. Zhao ◽  
B.E. Viani
Keyword(s):  
Chemical Properties ◽  
High Level Waste ◽  
Physical And Chemical Properties ◽  
Hydrothermal Conditions ◽  
Concrete Core ◽  
The Core ◽  
Waste Repository ◽  
High Level ◽  
Physical And Chemical ◽  
And Chemical Properties

In a high level waste repository in which temperatures are elevated due to waste decay, concrete structures will be subjected to hydrothermal conditions that will alter their physical and chemical properties. Virtually no studies have examined the interaction of hydrothermally altered concrete with radionuclides. We present the results of experiments in which soluble and colloid-associated U and Np, were eluted into a fractured, hydrothermally altered concrete core. Although the fluid residence time in the fracture was estimated to be on the order of 1 minute, U and Np in the effluent from the core were below detection (10

Long-Term Radioactivity Release from Solidified High-Level Waste - Part II Parametric Study of Waste form Properties, Temperature and Time

1982 ◽  
Vol 15 ◽  
Author(s):  
Friedrich K. Altenhein ◽  
Werner Lutze ◽  
Rodney C. Ewing
Keyword(s):  
Parametric Study ◽  
Computer Code ◽  
Salt Dome ◽  
Waste Form ◽  
Glass Block ◽  
High Level Waste ◽  
Surface Layers ◽  
History Of ◽  
High Level

The computer code QTERM has been used to calculate the total released activity from a single glass block when in contact with brine in a salt dome repository as a function of: (1) waste form properties, (2) leaching mechanisms, (3) retention or precipitation of specific radionuclides in surface layers, (4) thermal history of the repository and (5) decreasing activity as a function of time.

scholarly journals The Influence of Zeolite (Sokyrnytsya Deposit) on the Physical and Chemical Resistance of a Magnesium Potassium Phosphate Compound for the Immobilization of High-Level Waste

Molecules ◽  
2019 ◽  
Vol 24 (19) ◽  
pp. 3421 ◽  
Author(s):  
Svetlana A. Kulikova ◽  
Sergey E. Vinokurov
Keyword(s):  
Compressive Strength ◽  
Hydrolytic Stability ◽  
Potassium Phosphate ◽  
High Level Waste ◽  
Leaching Rate ◽  
New Material ◽  
Hydrolytic Resistance ◽  
Main Component ◽  
High Level ◽  
Physical And Chemical

The manuscript presents the results of the development of new material for high-level waste (HLW) management: the magnesium potassium phosphate (MKP) compound. The possibility of using zeolite (Sokyrnytsya deposit) to increase the mechanical, thermal, and hydrolytic resistance of this compound with immobilized HLW was studied. The main component of the used natural zeolite is a mineral of the clinoptilolite–heulandite series, and quartz, microcline, and clay minerals (illite, sepiolite, and smectite) are present as impurities. The compressive strength of the compound, containing at least 4.2 wt % zeolite, is about 25 MPa. Compound containing 28.6 wt % zeolite retains high compressive strength (at least 9.0 MPa), even after heat treatment at 450 °C. The adding of zeolite to the composition of the compound increases its hydrolytic stability, while the leaching rate of the mobile nuclides 137Cs and 90Sr decreases up to one order of values. Differential leaching rate of radionuclides from the compound containing 28.6 wt % zeolite is 2.6 × 10−7 for 137Cs, 2.9 × 10−6 for 90Sr, 1.7 × 10−9 for 239Pu, and 2.9 × 10−9 g/(cm2∙day) for 241Am. Thus, the properties of the resulting compound correspond to the requirements for solidified HLW in Russia.

The Isolation Capability of a Salt Dome Utilized for High-Level Waste Disposal

1981 ◽  
Vol 11 ◽  
Author(s):  
J. Hamstra
Keyword(s):  
Waste Disposal ◽  
Salt Dome ◽  
High Level Waste ◽  
High Level

The overall objective of disposal of high-level and alpha bearing wastes in deep geologic formations is to isolate these wastes from the biosphere for such a period of time that a subsequent future release of radionuclides from the buried wastes will not result in undue radiation exposures to man.

scholarly journals Radiation resistance of borosilicate glass to beta and gamma radiation evaluated using the accelerated proton method

2021 ◽  
Vol 14 (1) ◽  
pp. 8-18
Author(s):  
A. S. Aloy ◽  
◽  
N. V. Kovalev ◽  
A. M. Prokoshin ◽  
N. F. Karpovich ◽  
...  
Keyword(s):  
Gamma Radiation ◽  
Borosilicate Glass ◽  
Chemical Properties ◽  
High Level Waste ◽  
Time Period ◽  
Long Time ◽  
Radiation Induced ◽  
Intermediate Storage ◽  
High Level ◽  
Physical And Chemical

Preservation of the main physical and chemical properties of vitrified high-level waste over a long-time period under the influence of heavy radiation exposure is considered as an essential criterion for its quality assessment used to demonstrate the safety of intermediate storage under controlled conditions and subsequent final disposal of the waste. Earlier calculations covering a time period of up to 104 years allowed to identify the maximum beta- and gamma-radiation induced dose loads for borosilicate glass (BSS) of a basic composition specifically designed to vitrify liquid HLW from ODC MCC [1]. This study evaluates potential feasibility of applying an accelerated proton beam to simulate radiation damage according to the type of beta-gamma effects produced on the BSS and investigates the consequences of such effects on its properties which is seen as a distinctive feature of this research.

Repository performance assessment and advanced fuel cycle models for input to decision making of options for nuclear waste and resource management

2006 ◽  
Vol 932 ◽  
Author(s):  
J.S. Small ◽  
C.H. Zimmerman ◽  
D.R. Parker ◽  
C. Robbins ◽  
A.E. Bond ◽  
...  
Keyword(s):  
Nuclear Fuel ◽  
Fuel Cycle ◽  
Computer Software ◽  
Nuclear Fuel Cycle ◽  
Dose Assessment ◽  
High Level Waste ◽  
Process Step ◽  
Advanced Fuel ◽  
High Level ◽  
Physical And Chemical

ABSTRACTA methodology and computer software is described which can be used to track the inventory of radionuclides as they are affected by various nuclear, physical and chemical processes during reactor, storage, effluent and disposal phases of the nuclear fuel cycle. Such a model is required to provide an assessment of economic, environmental and societal performance indicators which underpin decisions regarding options for the use and management and nuclear materials. An example generic deep repository model is described which can be used to provide an indicator of environmental performance of vitrified high level waste and UO2 and mixed oxide (MOX) spent fuels. The assessment models highlight the significance of the I-129 fission product which necessitates the use of appropriate dose assessment models to be considered for each process step of the nuclear fuel cycle in order that a complete environmental assessment of process options can be determined.

Numerical and Experimental Investigations on the Time Dependent Behaviour of a Salt Dome With a High-Level Waste Repository

1983 ◽  
Vol 26 ◽  
Author(s):  
Jan Prij ◽  
Leo H. Vons
Keyword(s):  
Elevated Temperatures ◽  
Salt Dome ◽  
Time Dependent ◽  
High Level Waste ◽  
Experimental Investigations ◽  
Time Dependent Behaviour ◽  
High Level ◽  
Hlw Repository ◽  
Dependent Behaviour

ABSTRACTResults are presented of in-situ measurements, performed in a 300 m deep dry-drilled borehole, in the ASSEmine. Convergence measurements at ambient as well as elevated temperatures and pressure measurements at elevated temperatures are discussed. Creep equations derived from these experiments are used for the numerical analysis of the time dependent behaviour of a salt dome with a HLW repository. The analyses show that the total stresses in the salt remain compressive with deviatoric components smaller than 3 MPa.

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