Contrary effects of the water radiolysis product H2O2 upon th dissolution of nuclear fuel in natural ground water and deionized water

2002 ◽  
Vol 90 (7) ◽  
Author(s):  
M. Amme
Keyword(s):  
Radiolysis Product ◽  
Water Radiolysis ◽  
Oxidant Concentration ◽  
Geological Repository ◽  
Influence Of Water ◽  
Leaching Experiments ◽  
High Level Nuclear Waste ◽  
High Level ◽  
Solid Liquid Interface ◽  
Solid Liquid

SummaryRadiolysis of water is a phenomenon which alters the prevailing conditions in the nearfield of a final geological repository for high-level nuclear waste (HLW), because the nominally anoxic conditions in the repository may change due to the production of oxidants close to the solid-liquid interface of the fuel, caused by the alpha radiolysis of water.The influence of water chemistry and oxidant concentration in the liquid phase was tested by experiments which simulate chemical radiolysis effects. Leaching experiments with solutions of de-ionized water (DI) and natural groundwater (GW) containing the water radiolysis product H

scholarly journals Transporting and Storing High-Level Nuclear Waste in the U.S.—Insights from a Mathematical Model

2019 ◽  
Vol 9 (12) ◽  
pp. 2437 ◽  
Author(s):  
Sebastian Wegel ◽  
Victoria Czempinski ◽  
Pao-Yu Oei ◽  
Ben Wealer
Keyword(s):  
Nuclear Waste ◽  
The United States ◽  
Nuclear Industry ◽  
High Level Waste ◽  
Geological Repository ◽  
High Level Nuclear Waste ◽  
High Level ◽  
Interim Storage ◽  
Storage Facilities

The nuclear industry in the United States of America has accumulated about 70,000 metric tons of high-level nuclear waste over the past decades; at present, this waste is temporarily stored close to the nuclear power plants. The industry and the Department of Energy are now facing two related challenges: (i) will a permanent geological repository, e.g., Yucca Mountain, become available in the future, and if yes, when?; (ii) should the high-level waste be transported to interim storage facilities in the meantime, which may be safer and more cost economic? This paper presents a mathematical transportation model that evaluates the economic challenges and costs associated with different scenarios regarding the opening of a long-term geological repository. The model results suggest that any further delay in opening a long-term storage increases cost and consolidated interim storage facilities should be built now. We show that Yucca Mountain’s capacity is insufficient and additional storage is necessary. A sensitivity analysis for the reprocessing of high-level waste finds this uneconomic in all cases. This paper thus emphasizes the urgency of dealing with the high-level nuclear waste and informs the debate between the nuclear industry and policymakers on the basis of objective data and quantitative analysis.

scholarly journals Response of compacted bentonite to hyperalkalinity and thermal history

2021 ◽  
Vol 11 (1) ◽  
Author(s):  
Rohini C. Kale ◽  
Bhanwariwal Kapil ◽  
K. Ravi
Keyword(s):  
Thermal History ◽  
Dry Density ◽  
Distilled Water ◽  
Cement Concrete ◽  
Compacted Bentonite ◽  
Concrete Layer ◽  
Geological Repository ◽  
High Level Nuclear Waste ◽  
High Level ◽  
Swell Pressure

AbstractThe use of compacted bentonite around the high-level nuclear waste canister (HLW) inside the deep geological repository (DGR) ensures the prevention of entry of active radionuclides in the atmosphere due to its noteworthy large swelling ability. In the eventual repository, the waste canister has a high (100 °C–200 °C) temperature initially, and it reduces over a vast period, which induces a thermal history over the compacted bentonite layer. The cement/concrete layer is constructed as a bulkhead or in the vaults or to support the access of galleries between a buffer and the host rock, and it degrades over the period. The hyperalkaline fluid is created when it percolates through the cement/concrete layer and comes in contact with the compacted bentonite. The contact of hyperalkaline fluid to compacted bentonite induced with thermal history can hamper the swell pressure characteristic of the bentonite. Therefore to determine the combined effect of hyperalkalinity to the thermal history induced compacted bentonite, swell pressure testing has been conducted on two compacted Barmer bentonites (B1 and B2) specimens with an initial dry density of 1.5 Mg/m3, 1.75 Mg/m3, and 2.0 Mg/m3 and saturated with distilled water as well as with hyperalkaline cement water (W/C = 1 und pH = 12.5) and heated to 110 °C and 200 °C. When the specimens were saturated with hyperalkaline cement water, the swell pressure exerted by both bentonites was noticeably reduced compared to specimens saturated with distilled water. Nevertheless, the time taken to full saturation was longer than distilled water for samples saturated with hyperalkaline cement water. Also, the decrease in swell pressure was observed in the samples subjected to thermal history than samples, which were tested without inducing thermal history in both the cases of hyperalkaline cement water and distilled water. The microstructural observations through XRD, FESEM and EDX revealed the clogging of pores due to the presence of non-swelling minerals.

Backfill Modification Using Geochemical Principles to Optimize High Level Nuclear Waste Isolation in a Geological Repository

1991 ◽  
Vol 257 ◽  
Author(s):  
Donald Langmuir ◽  
Michael J. Apted
Keyword(s):  
Nuclear Waste ◽  
Diffusion Rate ◽  
Release Rates ◽  
Retardation Coefficient ◽  
Geological Repository ◽  
High Level Nuclear Waste ◽  
Peak Release ◽  
High Level ◽  
Mineral Additives ◽  
Adjacent Rock

ABSTRACTThe clay backfill that will surround a buried high level nuclear waste package in most national repository programs, could be modified to play a greater role as a barrier to radionuclide (RN) releases. The RN steady state release (Mb) rate from a clay backfill to adjacent rock is directly proportional to backfill porosity (ε), RN diffusion rate In the backfill (Ds), and RN solubility at the waste form surface (C*), and Inversely proportional to RN half-life (λ) and RN retardation coefficient (R) in the backfill [1]. We propose ways to reduce ε, Ds and C* and Increase R for important radionuclides, mostly through the addition of reactive minerals to the backfill. Silica, calcite and anhydrite may be added to precipitate and clog porosity. Increased backfill compaction similarly reducesε, Ds and Mb for all the RN's. Strongly sorbent phases can be added to selectively adsorb both cationic and anionic RN's (e.g. 1–129). However, adsorption will not Importantly reduce peak release rates of most long-lived RN's. The backfill can be poised at reducing Eh's with mineral additives to lower Ds and so immobilize radioisotopes of NI, Np, Pa, Pu, Se, Tc and U. Minerals of stable or more stable isotopes of Cs, NI, Se, Sn and U can be added to lower Ds values of the RN's and to coprecipitate them in solid solution. Phosphorite-apatites, which are known to have high selectivities for rare earths and RN's, may be added to coprecipitate Am, Np, Pu, Sr, Th and U.

Laboratory and Modelling Studies of Microbial Activity in the Near Field of a HLW Repository

1985 ◽  
Vol 50 ◽  
Author(s):  
Julia M West ◽  
Ian G McKinley ◽  
Helen A Grogan ◽  
Susan C Arme
Keyword(s):  
Recent Literature ◽  
Near Field ◽  
Deep Geological Repository ◽  
Sampling Studies ◽  
Geological Repository ◽  
Modelling Studies ◽  
High Level Nuclear Waste ◽  
High Level ◽  
Hlw Repository ◽  
Microbial Effects

Microbial effects are one of the possible perturbations to the expect-ed performance of a deep geological repository which must be examined as part of a comprehensive safety analysis. Recent literature surveys (eg [1, 2] ) and reconnaisance sampling studies [3, 4] have concluded that: a) microbial contamination of a repository is inevitable b) even for high level nuclear waste, conditions in the near-field are insufficiently extreme to ensure complete sterilisation.

scholarly journals Ultrasound-based density determination via buffer rod techniques: a review

2013 ◽  
Vol 2 (2) ◽  
pp. 103-125 ◽  
Author(s):  
S. Hoche ◽  
M. A. Hussein ◽  
T. Becker
Keyword(s):  
Industrial Applications ◽  
Temperature Gradients ◽  
Signal Generation ◽  
Temperature Changes ◽  
Density Measurements ◽  
Non Invasive ◽  
Measurement Principle ◽  
High Level ◽  
Solid Liquid Interface ◽  
Solid Liquid

Abstract. The review presents the fundamental ideas, assumptions and methods of non-invasive density measurements via ultrasound at solid–liquid interface. Since the first investigations in the 1970s there has been steady progress with regard to both the technological and methodical aspects. In particular, the technology in electronics has reached such a high level that industrial applications come within reach. In contrast, the accuracies have increased slowly from 1–2% to 0.15% for constant temperatures and to 0.4% for dynamic temperature changes. The actual work reviews all methodical aspects, and highlights the lack of clarity in major parts of the measurement principle: simplifications in the physical basics, signal generation and signal processing. With respect to process application the accuracy of the temperature measurement and the presence of temperature gradients have been identified as a major source of uncertainty. In terms of analytics the main source of uncertainty is the reflection coefficient, and as a consequence of this, the amplitude accuracy in time or frequency domain.

Environmental Risk and the Iron Triangle: The Case of Yucca Mountain

1995 ◽  
Vol 5 (4) ◽  
pp. 753-777 ◽  
Author(s):  
Kristin S. Shrader-Frechette
Keyword(s):  
Ethical Issues ◽  
Yucca Mountain ◽  
Spent Fuel ◽  
Business Climate ◽  
The Public ◽  
Iron Triangle ◽  
Geological Repository ◽  
High Level Nuclear Waste ◽  
High Level ◽  
Public Opposition

Abstract:Despite significant scientific uncertainties and strong public opposition, there appears to be an “iron triangle” of industry, government, and consultants/contractors promoting the siting of the world’s first permanent geological repository for high-level nuclear waste and spent fuel, proposed for Yucca Mountain, Nevada. Arguing that representatives of this iron triangle have ignored important epistemological and ethical difficulties with the proposed facility, I conclude that the business climate surrounding this triangle appears to leave little room for consideration of ethical issues related to public safety, environmental welfare, and citizen consent to risk. If my analysis of the Yucca Mountain case is correct and typical, then some of the most pressing questions of business ethics may concern how to break the iron triangle or, at least, how to expand it into a quadrilateral that includes the public.

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