Geological Disposal of Radioactive Waste in Situ Experiments in Granite

1986 ◽  
Vol 73 (1) ◽  
pp. 127-128
Author(s):  
Jaak J. K. Daemen
Keyword(s):  
Radioactive Waste ◽  
Geological Disposal ◽  
In Situ Experiments

Methodology in Corrosion Testing of Container Materials for Radioactive Waste Disposal in a Geological Clay Repository

2001 ◽  
Author(s):  
Bruno Kursten ◽  
Frank Druyts ◽  
Pierre Van Iseghem
Keyword(s):  
Radioactive Waste ◽  
Corrosion Behaviour ◽  
Open Circuit ◽  
Geological Disposal ◽  
Boom Clay ◽  
Engineered Barriers ◽  
High Level ◽  
Aerobic And Anaerobic

Abstract The current worldwide trend for the final disposal of conditioned high-level, medium-level and long-lived alpha-bearing radioactive waste focuses on deep geological disposal. During the geological disposal, the isolation between the radioactive waste and the environment (biosphere) is realised by the multibarrier principle, which is based on the complementary nature of the various natural and engineered barriers. One of the main engineered barriers is the metallic container (overpack) that encloses the conditioned waste. In Belgium, the Boom Clay sediment is being studied as a potential host rock formation for the final disposal of conditioned high-level radioactive waste (HLW) and spent fuel. Since the mid 1980’s, SCK•CEN has developed an extensive research programme aimed at evaluating the suitability of a wide variety of metallic materials as candidate overpack material for the disposal of HLW. A multiple experimental approach is applied consisting of i) in situ corrosion experiments, ii) electrochemical experiments (cyclic potentiodynamic polarisation measurements and monitoring the evolution of ECORR as a function of time), and iii) immersion experiments. The in situ corrosion experiments were performed in the underground research facility, the High Activity Disposal Experimental Site, or HADES, located in the Boom clay layer at a depth of 225 metres below ground level. These experiments aimed at predicting the long-term corrosion behaviour of various candidate container materials. It was believed that this could be realised by investigating the medium-term interactions between the container materials and the host formation. These experiments resulted in a change of reasoning at the national authorities concerning the choice of over-pack material from the corrosion-allowance material carbon steel towards corrosion-resistant materials such as stainless steels. The main arguments being the severe pitting corrosion during the aerobic period and the large amount of hydrogen gas generated during the subsequent anaerobic period. The in situ corrosion experiments however, did not allow to unequivocally quantify the corrosion of the various investigated candidate overpack materials. The main shortcoming was that they did not allow to experimentally separate the aerobic and anaerobic phase. This resulted in the elaboration of a new laboratory programme. Electrochemical corrosion experiments were designed to investigate the effect of a wide variety of parameters on the localised corrosion behaviour of candidate overpack materials: temperature, SO42−, Cl−, S2O32−, oxygen content (aerobic - anaerobic),… Three characteristic potentials can be derived from the cyclic potentiodynamic polarisation (CPP) curves: i) the open circuit potential, OCP, ii) the critical potential for pit nucleation, ENP, and iii) the protection potential, EPP. Monitoring the open circuit potential as a function of time in clay slurries, representative for the underground environment, provides us with a more reliable value for the corrosion potential, ECORR, under disposal conditions. The long-term corrosion behaviour of the candidate overpack materials can be established by comparing the value of ECORR relative to ENP and EPP (determined from the CPP-curves). The immersion tests were developed to complement the in situ experiments. These experiments aimed at determining the corrosion rate and to identify the corrosion processes that can occur during the aerobic and anaerobic period of the geological disposal. Also, some experiments were elaborated to study the effect of graphite on the corrosion behaviour of the candidate overpack materials.

scholarly journals Use of in-vitro experimental results to model in-situ experiments: bio-denitrification under geological disposal conditions

SpringerPlus ◽  
2013 ◽  
Vol 2 (1) ◽  
Author(s):  
Kaoru Masuda ◽  
Hiroshi Murakami ◽  
Yoshitaka Kurimoto ◽  
Osamu Kato ◽  
Ko Kato ◽  
...  
Keyword(s):  
Experimental Results ◽  
Geological Disposal ◽  
In Situ Experiments

scholarly journals Development of a MEMS Sensor System for In-Situ Monitoring of the Engineered Barrier in a Geological Disposal Facility

2017 ◽  
Author(s):  
Wenbin Yang ◽  
Rebecca J Lunn ◽  
Alessandro Tarantino ◽  
Gráinne El Mountassir
Keyword(s):  
Relative Humidity ◽  
Radioactive Waste ◽  
Swelling Pressure ◽  
Geological Disposal ◽  
Sensing System ◽  
Mems Sensor ◽  
Polyurethane Resin ◽  
Disposal Facility ◽  
Engineered Barriers

Geological disposal facilities for radioactive waste pose significant challenges for robust monitoring of environmental conditions within the engineered barriers that surround the waste canister. Temperatures are elevated, due to the presence of heat generating waste, relative humidity varies from 20% to 100%, and swelling pressures within the bentonite barrier can typically be 2-10 MPa. Here, we test the robustness of a bespoke design MEMS sensor-based monitoring system, which we encapsulate in polyurethane resin. We place the sensor within an oedometer cell and show that despite a rise in swelling pressure to 2 MPa, our relative humidity (RH) measurements are unaffected. We then test the sensing system against a traditional RH sensor, using saturated bentonite with a range of RH values between 50% and 100%. Measurements differ, on average, by 2.87% RH, and a particularly far apart for high values of RH. However, bespoke calibration of the MEMS sensing system using saturated solutions of known RH, reduces the measurement difference to an average of 1.97% RH, greatly increasing the accuracy for RH values close to 100%.

Flow and Tracer Experiments in Crystalline Rocks: Results from Several Swedish in Situ Experiments

1985 ◽  
Vol 50 ◽  
Author(s):  
H. Abelin ◽  
L. Birgersson ◽  
J. Gidlund ◽  
L. Moreno ◽  
I. Neretnieks ◽  
...  
Keyword(s):  
Radioactive Waste ◽  
Crystalline Rock ◽  
Crystalline Rocks ◽  
Flow And Transport ◽  
In Situ Experiments ◽  
Tracer Experiments

In a final repository for radioactive waste in crystalline rock, water flowing in the fractures may transport the radionuclides eventually leached from the waste. To be able to predict the migration of the radionuclides the processes involved must be understood. To quantify the processes, data from flow and transport in real fractures under realistic conditions are needed. Models used for prediction must include descriptions of the important processes and mechanisms.

ÚJV Řež, a.s. Research Programme Supporting Development of Deep Geological Repository in the Czech Republic

2014 ◽  
Author(s):  
Václava Havlová
Keyword(s):  
Czech Republic ◽  
Radioactive Waste ◽  
Research Programme ◽  
Deep Geological Repository ◽  
The Czech Republic ◽  
Reducing Conditions ◽  
In Situ Experiments ◽  
Geological Repository

ÚJV Řež, a.s. as a company with a long term experience in radioactive waste management (RWM) has been running a comprehensive research programme, supporting development of deep geological repository (DGR) in the Czech Republic. Recently ÚJV Řež, a.s. research has focused on the different aspects of safety functions that DGR barriers should provide. Moreover, the research has also recently paid strong attention to real conditions that can be present in DGR (anaerobic reducing conditions, increased T due to heat generation by radioactive waste, contact of different materials within repository, real scale of the rock massive etc.). Both types of experiments, laboratory and in-situ experiments in underground laboratories, were included in the research programme. The presentation gives a brief overview of experimental trends, being conducted for materials and conditions, concerned in Czech repository concept.

Mechanical and SCC Behavior of an API5L Steel Casing Within the Context of Deep Geological Repositories for Radioactive Waste

2015 ◽  
Author(s):  
F. Bumbieler ◽  
S. Necib ◽  
J. Morel ◽  
D. Crusset ◽  
G. Armand
Keyword(s):  
Radioactive Waste ◽  
Host Rock ◽  
Mechanical Load ◽  
Early Stage ◽  
High Yield ◽  
General Corrosion ◽  
Short Term ◽  
In Situ Experiments ◽  
Deep Geological Repositories

Andra, the French national radioactive waste management agency, is in charge of studying the possibility of disposal of High Level activity Wastes (HLW) in deep geological repositories. The concept of HLW cells consists of horizontal micro-tunnels of about 0.7 m in diameter, equipped with a steel casing. In order to ensure the reliability of the casing, particularly with respect to Stress Corrosion Cracking (SCC), several in-situ experiments dedicated to the analysis of its short term mechanical and corrosion behavior have been performed at Andra’s Underground Research Laboratory (URL) as well as in surface laboratory. Reduced and full scale in-situ experiments consisting of equipping boreholes parallel to the major horizontal stress (σH) with instrumented steel tubing, have been performed to analyze the mechanisms involved in the casing/rock interface. The main characteristics of the short term mechanical load applied by the rock have been determined from local strain and convergence measurements. Although in-situ stress is isotropic in the section of boreholes parallel to σH, measurements exhibit a strongly anisotropic load. SCC experiments conducted on different steel grades, in contact with the clay host rock containing CO2/H2 revealed that general corrosion is the main type of corrosion expected for steel casings. However, the selected steel casing must have a sufficiently high yield strength (above 400 MPa) to reduce the risk of early stage plasticity due to host rock anisotropic convergence and thus to overcome SCC. API5LX65 steel seems to meet both mechanical and corrosion requirements, therefore being likely the appropriate material for the manufacture of the casing.

Research of Rock Mass Gas Conductivity with respect to Geological Disposal and the EDZ

2012 ◽  
Vol 1475 ◽  
Author(s):  
Jiri Svoboda ◽  
Jan Smutek
Keyword(s):  
Rock Mass ◽  
Radioactive Waste ◽  
Gas Migration ◽  
In Situ Testing ◽  
Geological Disposal ◽  
Future Design ◽  
Viable Solution ◽  
Waste Container ◽  
Mass Classification

ABSTRACTThe geological disposal of radioactive waste, based on a multi-barrier concept wherein the first barrier consists of the metal waste container and the final barrier the host rock, is widely considered the only viable solution.Following disposal the risk will remain of the formation of gases due to corrosion and other processes. Research being carried out at the Czech Technical University in Prague (CTU), Centre of Experimental Geotechnics (CEG), the Josef underground laboratory as part of FORGE and other projects focuses on gas migration in underground areas and especially within the EDZ.The research consists of several stages including the design of gas conductivity equipment destined for in-situ testing and the gas conductivity tests proper. An important part of the research involves the evaluation of a potential correlation between rock mass classification parameters and gas conductivity; a certain degree of correlation was identified in earlier research projects. The discovery of such a correlation would greatly assist in the future design of underground gas storage and deep radioactive waste facilities.

Sign in / Sign up

Export Citation Format

Share Document