scholarly journals Sealing of a Deep Horizontal Borehole Repository for Nuclear Waste

Energies ◽  
2020 ◽  
Vol 14 (1) ◽  
pp. 91
Author(s):  
Stefan Finsterle ◽  
Cal Cooper ◽  
Richard A. Muller ◽  
John Grimsich ◽  
John Apps
Keyword(s):  
Nuclear Waste ◽  
Open Space ◽  
Driving Forces ◽  
Poor Quality ◽  
Advective Transport ◽  
Access Hole ◽  
Borehole Repository ◽  
Backfill Materials ◽  
Isothermal Fluid ◽  
Fast Flow

The depth and layout of a horizontal borehole repository has the potential to offer strong isolation of nuclear waste from the surface. However, the isolation may be compromised by the borehole used to access the repository, as it could provide a direct fast-flow path transporting radionuclides from the disposal section to the accessible environment. Thus, backfilling the disposal section and sealing the access hole are considered essential engineered safety components. To analyze the importance of plugging the open space between canisters and sealing the access hole, we numerically calculate non-isothermal fluid flow and radionuclide transport through the borehole and the surrounding geosphere for a variety of scenarios, which include backfill materials with different sealing properties and configurations that potentially induce strong driving forces along both the horizontal and vertical sections of the borehole. The simulations indicate that the dose contribution of radionuclides released through the access hole is small, even if the backfill material is of poor quality or has deteriorated, and even if considerable horizontal and vertical pressure gradients are imposed by assuming the underlying formation is overpressured and that the disposal section is intersected by faults activated during a seismic event. The modeling also reveals that the low influence of backfill integrity on repository performance partly arises from the very high length-to-diameter ratio of the borehole, which favors the radial diffusion of radionuclides—as well as pressure dissipation and associated advective transport—into the surrounding formation rather than axial transport along the borehole. The integrated modeling approach also exposes the importance of accounting for the connections and feedback mechanisms among the various subcomponents of the repository system.

Materials Interactions Relating to Long-Term Geologic Disposal of Nuclear Waste Glass

1986 ◽  
Vol 84 ◽  
Author(s):  
Ned E. Bibler ◽  
Carol M. Jantzen
Keyword(s):  
Nuclear Waste ◽  
Review Paper ◽  
Waste Glass ◽  
Waste Form ◽  
Glass Waste ◽  
Waste Package ◽  
Geologic Disposal ◽  
Nuclear Waste Glass ◽  
Backfill Materials

AbstractIn the geologic disposal of nuclear waste glass, the glass will eventually interact with groundwater in the repository system. Interactions can also occur between the glass and other waste package materials that are present. These include the steel canister that holds the glass, the metal overpack over the canister, backfill materials that may be used, and the repository host rock. This review paper systematizes the additional interactions that materials in the waste package will impose on the borosilicate glass waste form-groundwater interactions. The repository geologies reviewed are tuff, salt, basalt, and granite. The interactions emphasized are those appropriate to conditions expected after repository closure, e.g. oxic vs. anoxic conditions. Whenever possible, the effect of radiation from the waste form on the interactions is examined. The interactions are evaluated based on their effect on the release and speciation of various elements including radionuclides from the glass. It is noted when further tests of repository interactions are needed before long-term predictions can be made.

Permeability, Swelling and Radionuclide Retardation Properties of Candidate Backfill Materials

1981 ◽  
Vol 6 ◽  
Author(s):  
J. H. Westsik ◽  
L. A. Bray ◽  
F. N. Hodges ◽  
E. J. Wheelwright
Keyword(s):  
Nuclear Waste ◽  
Initial Permeability ◽  
Nuclear Waste Repository ◽  
Dry Density ◽  
Sodium Bentonite ◽  
Backfill Materials ◽  
Waste Repository ◽  
Temperature Radiation ◽  
Bentonite Clays ◽  
Calcium Bentonite

ABSTRACTA backfill placed between a nuclear waste canister and the host geology of a nuclear waste repository can impede the migration of water through the waste package and retard the movement of radionuclides into the geologic formation. Hydraulic conductivities and swelling pressures are being determined as functions of the density of the compacted backfill, temperature, radiation dose, hydraulic head and the chemical composition of the permeating fluid. Bentonite clays and bentonite/sand mixtures have received initial emphasis. Sodium bentonite and calcium bentonite samples compacted to a dry density of 2.1 g/cm3 had hydraulic conductivities in the range of 10−12 to 10−13 cm/s. In addition, batch distribution ratios (Rd) for Sr, Cs, Am, Np, I, U and Tc have been measured for a number of candidatebackfill materials. Both initial permeability and sorption studies have used a synthetic basaltic ground water.

scholarly journals Overview on backfill materials and permeable reactive barriers for nuclear waste disposal facilities.

2003 ◽  
Author(s):  
Robert Charles Moore ◽  
Ahmed Ali Mohamed Hasan ◽  
Kathleen Caroline Holt ◽  
Mahmoud A Hasan
Keyword(s):  
Nuclear Waste ◽  
Waste Disposal ◽  
Nuclear Waste Disposal ◽  
Permeable Reactive Barriers ◽  
Backfill Materials ◽  
Reactive Barriers

scholarly journals Privately-Owned Public Space for Public Use

2017 ◽  
Vol 2 (7) ◽  
pp. 11
Author(s):  
Achmad Delianur Nasution ◽  
Wahyuni Zahrah
Keyword(s):  
Public Space ◽  
Open Space ◽  
Publishing House ◽  
Poor Quality ◽  
Gated Community ◽  
The Public ◽  
Public Open Space ◽  
International Publishing ◽  
Privately Owned ◽  
Open Access Article

The study investigated the using of privately-owned public space (POPS) in two gated communities in Medan, Indonesia. The activities of people during the weekend and the physical setting of the POPS were recorded through observation and visual survey. The research found that most of the visitors were not satisfied with the public open space, but they used it intensively. The study indicated that the better quality public open space was more livable compared to the poor quality. Since the visitors in the two public open spaces were mostly people who live outside the gated community, the private-owned public space contributed to public life.Keywords: privately-owned public space; gated community; Medan.eISSN 2398-4279 © 2017 The Authors. Published for AMER ABRA by e-International Publishing House, Ltd., UK. This is an open access article under the CC BY-NC-ND license (http://creativecommons.org/licenses/by-nc-nd/4.0/). Peer–review under responsibility of AMER (Association of Malaysian Environment-Behaviour Researchers), ABRA (Association of Behavioural Researchers on Asians) and cE-Bs (Centre for Environment-Behaviour Studies), Faculty of Architecture, Planning & Surveying, Universiti Teknologi MARA, Malaysia.

scholarly journals Tackling Root Causes Upstream of Unhealthy Urban Development (TRUUD): Protocol of a five-year prevention research consortium

2021 ◽  
Vol 6 ◽  
pp. 30
Author(s):  
Daniel Black ◽  
Sarah Ayres ◽  
Krista Bondy ◽  
Rachel Brierley ◽  
Rona Campbell ◽  
...  
Keyword(s):  
Decision Making ◽  
Urban Development ◽  
Urban Areas ◽  
Large Scale ◽  
Driving Forces ◽  
Communicable Disease ◽  
Economic Valuation ◽  
Poor Quality ◽  
Urban Environments ◽  
Policy And Practice

Poor quality urban environments substantially increase non-communicable disease. Responsibility for associated decision-making is dispersed across multiple agents and systems: fast growing urban authorities are the primary gatekeepers of new development and change in the UK, yet the driving forces are remote private sector interests supported by a political economy focused on short-termism and consumption-based growth. Economic valuation of externalities is widely thought to be fundamental, yet evidence on how to value and integrate it into urban development decision-making is limited, and it forms only a part of the decision-making landscape. Researchers must find new ways of integrating socio-environmental costs at numerous key leverage points across multiple complex systems. This mixed-methods study comprises of six highly integrated work packages. It aimsto develop and test a multi-action intervention in two urban areas: one on large-scale mixed-use development, the other on major transport. The core intervention is the co-production with key stakeholders through interviews, workshops, and participatory action research, of three areas of evidence: economic valuations of changed health outcomes; community-led media on health inequalities; and routes to potential impact mapped through co-production with key decision-makers, advisors and the lay public. This will be achieved by: mapping system of actors and processes involved in each case study; developing, testing and refining the combined intervention; evaluating the extent to which policy and practice changes amongst our target users, and the likelihood of impact on non-communicable diseases (NCDs) downstream. The integration of such diverse disciplines and sectors presents multiple practical/operational issues. The programme is testing new approaches to research, notably with regards practitioner-researcher integration and transdisciplinary research co-leadership. Other critical risks relate to urban development timescales, uncertainties in upstream-downstream causality, and the demonstration of impact.

Remote data collection methods to inventory COVID-19 interventions in low-income urban settlements

2021 ◽  
Author(s):  
Faith Taylor ◽  
Manshur Talib ◽  
Amos Wandera ◽  
Joseph Mulligan ◽  
Vera Bukachi ◽  
...  
Keyword(s):  
Spatial Distribution ◽  
Low Income ◽  
Open Space ◽  
Informal Settlement ◽  
Smartphone Application ◽  
Poor Quality ◽  
Small Scale ◽  
Round Trip ◽  
Urban Neighbourhoods ◽  
The Impact

<p>In this PICO, we outline methods used to inventory the spatial distribution and characteristics of COVID-19 response activities (‘interventions’) in Kibera (Nairobi, Kenya). About 1/8 of the World’s Population live in slums and informal settlements. For these people, COVID-19 has presented unique challenges for managing health and livelihoods within the constraints of high-density housing and poor-quality infrastructure. In addition, reliable spatial, demographic and health data is often limited for these areas. Between April and July 2020, using the Survey123 smartphone application, combined with social media searches and phone enumeration, we inventoried 270 individual COVID-19 interventions taking place in Kibera, an informal settlement of 2.67 km<sup>2</sup> and an estimated 187,000 to 1 000,000 inhabitants. Results show a large variety in the type of intervention (58 unique types) and organiser (>88 individual organisers), with 39% of interventions led by small scale organisations such as local NGOs and community groups. We found an uneven spatial distribution of interventions within Kibera, with some already underserved neighbourhoods having less access to COVID-19 relief. Many interventions are clustered around the limited open spaces with good accessibility by road, highlighting the need for better coordination between organisers, and the importance of open space for resilience building. Using isochronal service area analysis, we find that 80% of structures are within a 9-minute round trip of a handwashing station. However, 64% of structures have a 24-54 minute round trip to female sanitary supplies, illustrating gender differences in the impact and recovery from COVID-19. Our data is available online in an interactive map dashboard. Our survey results illustrate that rather than being seen as vectors of disease, low income urban neighbourhoods are part of the solution for managing pandemics, and highlight the importance of infrastructure upgrading and planning to build resilience to a range of shocks and stresses.</p>

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