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[en] This report presents the analytical data for the 2016 calendar year (CY) (January 1 through December 31, 2016) and an evaluation of the data to ensure that the Sampling Plan’s objectives are met. Special investigations that took place in 2016 that are relevant to the Sampling Plan are also presented.
[en] This report is required by the Underground Test Area (UGTA) Activity Quality Assurance Plan (QAP) (NNSA/NFO, 2015) and identifies the UGTA quality assurance (QA) activities for calendar year (CY) 2017 (January 1, 2017, through December 31, 2017). UGTA organizations—U.S. Department of Energy (DOE) Environmental Management (EM) Nevada Program conduct QA activities throughout the CY. The activities include conducting oversight assessments (OAs) for UGTA Activity QAP compliance, identifying findings and completing corrective actions, evaluating laboratory performance, reviewing technical work, and publishing documents.
[en] Radioactive waste is generated at all stages of the nuclear fuel cycle, including ore mining, processing and enrichment, nuclear fuel production, NPP operation, fuel processing, production of weapon materials, and decommissioning of nuclear facilities. Today, the disposal of radioactive waste in geological formations is the only option for waste isolation accepted worldwide. Here, the hard rock mass if becomes the major safety barrier for the waste containing long-lived radionuclides. For the purpose of objective safety evaluation for this isolation option, it is necessary to obtain the experience, instruments, and methods allowing a long-term prediction of changes in the rock safety properties. Underground laboratories are created for this purpose. The more monitoring is conducted in these facilities, the greater the probability is in obtaining the reliable data needed. Taking into consideration that the processes in the hard rock are moving slowly, the lifetime of a human being will not be enough to run the studies. This paper will outline the examples of investigations on physical processes in the hard rock massif using a heat source that was acting during a 40- year period of facility operation. (author)
[en] The evolution of gas-driven fractures and the associated cavity pressure decay is predicted by a mathematical model which includes opening displacements and stress intensity based on linear-elastic fracture mechanics, laminar and turbulent friction in the driving gas, as well as seepage losses and heat transfer to the porous wall rock. A time-marching solution procedure satisfies the transport equations in a global or integral sense over three control-volume regions: (1) the entire volume of the fracture; (2) a small sub-volume at the leading edge of the flow; and (3) the cavity volume which feeds the fracture. Engineering calculations are typically executed in less than a minute of CPU time. Comparisons with exact analytical and numerical results suggest that accuracy is within 10 pct for a broad range of test problems including laminar and turbulent flows, ideal gases and incompressible liquids, permeable and impermeable media, prescribed inlet pressure, and prescribed flow rates. Calculations of borehole pressure decay and fracture extent are in good agreement with tailored-pulse, well-shooting experiments conducted by Sandia, even in multifracture circumstances. The extent of fracturing is predicted for two hypothetical example problems which are illustrative of decoupled nuclear events. In the first example the cavity pressure is about twice as large as the minimum insitu stress, and the fracture extends slightly beyond 3 cavity radii. In the second case, the cavity pressure is ten-fold greater than the confining stress, and a single fracture could extend as far as 10 radii. Such a fracture would, however, be severely overdriven, suggesting the likelihood of multiple fractures which are two or three times shorter. This multifracture scenario provides a mechanism for prompt pressure decay without excessive fracture extension, in keeping with field observations
[en] The article presents some reasons for the lagging of domestic mining engineering from foreign competitors, substantiates the need to form a new promising technological paradigm in the field of formation and development of underground space. A new systematic approach to the development of geotechnics and geotechnologies is proposed, which allows for creation of prerequisites for formation of a new technological structure and Russia’s breakthrough into leading positions in the field of geotechnology and mining engineering. (paper)
[en] The first phase of the Mine-by Experiment was conducted at the 420 Level of the Underground Research Laboratory (URL) to investigate the response induced in the rock mass by excavating a 3.5-m-diameter circular tunnel using a non-explosive technique. The main objective of the experiment was to study the processes involved in progressive failure and the development of excavation-induced damage around underground openings. To this end, state-of-the-art geomechanical and geophysical instrumentation was used to monitor the excavation of the 46-m-long Mine-by Experiment test tunnel. The results from the experiment show that progressive failure in compressive regions around the tunnel initiates at stresses about 50% of the rock strength measured in uniaxial compression tests in the laboratory. The difference between the laboratory and in situ behaviour is attributed to complex stress changes that occur during excavation of the tunnel, especially in the vicinity of the advancing face. These effects are not simulated in standard laboratory tests. Numerical modelling and in situ characterization studies were conducted to establish the extent and characteristics of the damaged zone around the test tunnel. As part of this study, in situ stresses and material properties were established through back analysis of measured displacements and strains. Using these boundary conditions, it was shown that the damaged zone was limited to within 1 m of the original tunnel perimeter. The characteristics of the damaged zone, however, were found to be highly variable around the tunnel, and were dependent on the nature of the stress concentrations, geology, stress magnitudes and orientations and, to a lesser extent, the excavation method and sequence. (author) 136 refs., 14 tabs., 103 figs
[en] The 25 lectures discuss a variety of problems: problems of subsidence and landfall, including the effects on mines and buildings; geotechnical problems in tunnels and roadways, slopes and open pits; topical problems concerning disposal; underground storage and final storage of radioactive waste. (HP)
[de]Die 25 Vortraege behandeln eine Vielzahl von Fragen: Senkungs- und Erdfallprobleme und deren Bedeutung im Bergbau und fuer Bauwerke, geotechnische Probleme bei Tunnel- und Stollenbauten, Boeschungen und Tagebauen, brennende Fragen der Deponierung, untertaegiger Speicherung und Endlagerung radioaktiver Abfaelle. (HP)
[en] The advantages are briefly listed of siting nuclear power plants and storage areas of nuclear wastes in underground spaces. A prototype of an underground storage area of radioactive waste was built in the FRG xn a salt mine, and an underground storage area in a salt formation is to be built in the USA. Two Swedish designs of an underground storage area with a clay barrier are described. (Ha)
[en] In order to develop a safe geological disposal concept for the HLW from the nuclear power plants in Korea, it is necessary to evaluate the safety of the disposal concept in an underground research tunnel in the same geological formation as the host rock mass. The design concept of a research tunnel depends on the actual disposal concept, repository geometry, experiments to be carried at the tunnel, and geological conditions. In this study, geological investigation had been carried out to develop the basic design of the small scale underground disposal research tunnel in KAERI