Equilibrium Leach Testing of Intermediate Level Waste

1988 ◽  
Vol 127 ◽  
Author(s):  
W Heafield ◽  
P Barlow ◽  
A Hunt
Keyword(s):  
Near Field ◽  
Intermediate Level ◽  
Degree Of Protection ◽  
Leach Test ◽  
Additional Protection ◽  
Chemical States ◽  
Equilibrium Concentrations ◽  
The Uk ◽  
Static Conditions ◽  
High Degree

ABSTRACTExperiments examining the leach characteristics of encapsulated Intermediate Level Wastes in repository near-field conditions have been undertaken in the UK since 1982. The Equilibrium Leach Test was developed in order to provide a realistic static leach test for the measurement of equilibrium concentrations and chemical states of individual nuclides within a particular waste, or combination of wastes, and the components of the near-field barriers of a repository, after water has ingressed into the system. The significant components of the near-field ie waste material, waste matrix and repository backfill are equilibrated with water under static conditions.Results illustrate the high degree of protection afforded by the near-field, which under repository conditions will be complemented by the additional protection of the far-field and the biosphere. Analytical results show that a cement based matrix and cementitious backfill provide the lowest radionuclide concentrations, for long lived radionuclides.

Modelling of the Evolution of Porewater Chemistry in a Cementitious Repository

1989 ◽  
Vol 176 ◽  
Author(s):  
A. Haworth ◽  
S.M. Sharland ◽  
C.J. Tweed
Keyword(s):  
Nuclear Waste ◽  
Transport Model ◽  
Near Field ◽  
Intermediate Level ◽  
Current Concept ◽  
Release Rates ◽  
Chemistry Transport Model ◽  
Porewater Chemistry ◽  
The Uk ◽  
Cement Formulation

ABSTRACTThe current concept for disposal of low- or intermediate-level nuclear waste in the UK includes a largely cementitious backfill. An important factor in determining nuclide release rates from the repository is the pH in the near-field. In this paper, we describe development of a coupled chemistry/transport model of cement degradation and its application in determining the evolution of the chemistry within the repository. In particular, the effect of the cement formulation and interaction with groundwater species on the evolution of the pH is examined. The model is sufficiently flexible to consider a number of different repository scenarios.

scholarly journals Novel droplet near-field transducer for heat-assisted magnetic recording

Nanophotonics ◽  
2015 ◽  
Vol 4 (4) ◽  
pp. 503-510 ◽  
Author(s):  
Jacek Gosciniak ◽  
Marcus Mooney ◽  
Mark Gubbins ◽  
Brian Corbett
Keyword(s):  
Surface Plasmon ◽  
Magnetic Recording ◽  
Near Field ◽  
Metal Structure ◽  
Spot Size ◽  
Impedance Match ◽  
Localized Surface Plasmon ◽  
Heat Assisted Magnetic Recording ◽  
Localized Surface Plasmon Resonances ◽  
High Degree

AbstractTwo main ingredients of plasmonics are surface plasmon polaritons (SPP) and localized surface plasmon resonances (LSPR) as they provide a high degree of concentration of electromagnetic fields in the vicinity of metal surfaces, which is well beyond that allowed by the diffraction limit of optics. Those properties have been used in the new technique of heat assisted magnetic recording (HAMR) to overcome an existing limit of conventional magnetic recording by utilizing a near-field transducer (NFT). The NFT designs are based on excitation of surface plasmons on a metal structure, which re-radiate with a subdiffraction limited light spot confined in the near field. In this paper, we propose a novel “droplet”-shaped NFT, which takes full advantage of a recenltly proposed Mach–Zehnder Interferometer (MZI), a coupling arrangement that allows optimal coupling of light to the transducer. The droplet design ensures better impedance match with the recording media and, consequently, better coupling of power. The droplet design results in very high enhancement of the electric field and allows the confinement of light in a spot size much smaller than the present stateof- the-art lollipop transducer.

scholarly journals Problems and Prospects for the Development of the UK Banking System in the Process of New Industrialization and Digitalization

2021 ◽  
Vol 93 ◽  
pp. 05017
Author(s):  
Olga Sokolova ◽  
Nadezhda Goncharova ◽  
Pavel Letov
Keyword(s):  
Capital Market ◽  
Global Financial Crisis ◽  
Banking System ◽  
The European Union ◽  
Important Trend ◽  
The Subject ◽  
The Global Financial Crisis ◽  
The Uk ◽  
High Degree ◽  
New Industrialization

The gist of this article boils down to the development of British banking system in the conditions of new industrialization and digitalization. The banking system of Great Britain is characterized by a high degree of concentration and specialization of banking, a well-developed banking infrastructure, and a close connection with the international loan capital market. London is the world's oldest financial center. The English banking system has the world's widest network of overseas branches. The UK banking system is relatively independent from the credit systems of the European Union. Nevertheless, banking legislation is focused on the unification of banking law within the European Community and supervision of banking activities. In the context of the global financial crisis, the UK banking system, as in other countries, has been severely tested. The most important trend in the development of the UK banking system is the blurring of boundaries between certain types of credit institutions. The subject of the research is the UK banking system in the context of new industrialization and digitalization.

scholarly journals Effectiveness of COVID-19 vaccines against delta variant (B.1.617.2): A meta-analysis

2021 ◽  
Author(s):  
Rashidul Alam Mahumud ◽  
Mohammad Afshar Ali ◽  
Satyajit Kundu ◽  
Md Ashfikur Rahman ◽  
Joseph Kihika Kamara ◽  
...  
Keyword(s):  
Risk Ratio ◽  
Vaccine Coverage ◽  
Meta Analysis ◽  
Random Effect ◽  
Herd Immunity ◽  
Case Control Studies ◽  
Health Crisis ◽  
Degree Of Protection ◽  
Study Designs ◽  
High Degree

Abstract ObjectivesThe highly transmissible COVID-19 delta variant (DV) has contributed to the surge in cases and has now been exacerbated the worldwide public health crisis. Several COVID-19 vaccines play a significant role in a high degree of protection against DV. The primary purpose of this meta-analysis is to estimate the pooled effectiveness of the COVID-19 vaccines against DV in terms of risk ratio (RR) among fully vaccinated, compared to unvaccinated populations.MethodsWe carried out a systematic review with meta-analysis of original studies focused on COVID-19 vaccines effectiveness of COVID-19 vaccines against B.1.617.2 clinical perspective among fully COVID-19 vaccinated populations, compared to placebo (unvaccinated populations), published before September 30, 2021. Eleven studies containing data of 17.2 million participants were identified and included in our study. Pooled estimates of COVID-19 vaccines effectiveness (i.e., risk ratio, RR) against delta variant with 95% confidence intervals were assessed using random-effect models. Publication bias was assessed using Egger's regression test and funnel plot to investigate potential sources of heterogeneity and identify any differences in study design.ResultsA total population of 17.2 million (17,200,341 peoples) were screened for the COVID-19 vaccines' effectiveness against delta variant. We found 61.13% of study population were fully vaccinated with 2-dose of COVID-19 vaccines. Weighted pooled incidence of COVID-19 infection was more than double (20.07%) among unvaccinated populations, compared to the fully vaccinated population (8.16%). Overall, the effectiveness of COVID-19 vaccine against DV was 85% (RR = 0.15, 95% CI: 0.07-0.31). The effectiveness of COVID-19 vaccines varied slidably by study designs, 87% (RR = 0.13, 95% CI: 0.06-0.30) and 84% (RR = 0.16, 95% CI:0.02, 1.64) for cohort and case-control studies, respectively. ConclusionEffectiveness COVID-19 vaccines were noted to offer higher protection against delta variant among populations who received two vaccine doses compared with unvaccinated populations. This finding would help efforts to maximise vaccine coverage (i.e., at least 60 to 70% of the population) with two doses among vulnerable populations to have herd immunity to breat the chain of transmission and gain greater overall population protection more rapidly.

Effectiveness of Vancomycin Against Gaffkemia, the Bacterial Disease of Lobsters (Genus Homarus)

1974 ◽  
Vol 31 (12) ◽  
pp. 1873-1879 ◽  
Author(s):  
James E. Stewart ◽  
B. Arie
Keyword(s):  
Body Weight ◽  
Penicillin G ◽  
Bacterial Disease ◽  
Infection Rates ◽  
Complete Protection ◽  
Degree Of Protection ◽  
Aerococcus Viridans ◽  
High Degree ◽  
Established Infection

The antibiotics vancomycin, penicillin G, novobiocin, and oxytetracycline were examined for in vivo effectiveness against gaffkemia, the fatal bacterial infection of lobsters (genus Homarus) caused by Aerococcus viridans (var.) homari (formerly Gaffkya homari). Only vancomycin was truly effective against an established infection and then only when given at high levels (25 mg/kg lobster body weight) in the early stages of infection, prior to development of hemolymph bacterial numbers in excess of 3 × 104/ml or coincident hepatopancreatic bacterial levels of 1 × 107/g. Even massive cumulative doses (500 mg vancomycin/kg body weight), when given after establishment of maximum bacterial numbers, failed to impede the infection. Rates for the clearance of vancomycin from lobsters, established by using three different concentrations (25, 10, and 5 mg/kg body weight, respectively), were extremely slow and markedly concentration dependent. Twenty-five milligrams vancomycin/kg body weight injected prior to infection still gave a high degree of protection against challenge with the pathogen 50 days later in lobsters held at 15 C. One milligram vancomycin/kg body weight administered prior to infection gave complete protection against gaffkemia for 15 days after the antibiotic had been administered.

scholarly journals The dissolution of simulant vitrified intermediate level nuclear waste in young cement water

MRS Advances ◽  
2020 ◽  
Vol 5 (3-4) ◽  
pp. 131-140
Author(s):  
Colleen Mann ◽  
Jeremy R. Eskelsen ◽  
Donovan N. Leonard ◽  
Eric Pierce ◽  
Claire L Corkhill
Keyword(s):  
Nuclear Waste ◽  
Alkaline Earth ◽  
Water Solution ◽  
Cementitious Materials ◽  
Intermediate Level ◽  
Short Term ◽  
Alkaline Earth Elements ◽  
Altered Layer ◽  
Safety Case ◽  
The Uk

AbstractIt is pertinent to the safety case for geological disposal in the UK that the behaviour of vitrified wastes in proximity to cementitious materials is understood. In this study, vitrified simulant intermediate level nuclear waste (ILW) was subject to dissolution in a synthetic cement water solution to simulate disposal conditions. Results show that the presence of alkali / alkaline earth elements in the cementitious solution can be favourable, at least in the short-term, leading to lower dissolution rates associated with incorporation of these elements into the altered layer of the glass.

scholarly journals A High-Isolation Dual-Polarization Substrate-Integrated Fabry-Pérot Cavity Antenna

2015 ◽  
Vol 2015 ◽  
pp. 1-6 ◽  
Author(s):  
Chang Chen ◽  
Bo-Liang Liu ◽  
Ling Ji ◽  
Wei-Dong Chen
Keyword(s):  
Near Field ◽  
Ground Plane ◽  
Cross Polarization ◽  
Dual Polarization ◽  
High Isolation ◽  
Fabry Perot ◽  
Feeding Structure ◽  
Operating Bandwidth ◽  
High Degree ◽  
Polarization Level

A dual-polarization substrate-integrated Fabry-Pérot cavity (SI-FPC) antenna is presented in this paper. The patch embedded in SI-FPC is excited with a near-field coupled feeding structure for V-polarization and with a slot-coupled feeding structure for H-polarization. The feeding structures are separated by a ground plane to improve the isolation between the ports. As a design example, an antenna operating at 10.0 GHz is fabricated and measured. A high degree of port isolation (<−40 dB) over the whole operating bandwidth (9.5–10.2 GHz) and good cross-polarization level (>25 dB) can be achieved.

Assessment of Redox Conditions in the Near Field of Nuclear Waste Repositories: Application to the Swiss high-level and intermediate level waste disposal concept

2003 ◽  
Vol 807 ◽  
Author(s):  
Paul Wersin ◽  
Lawrence H. Johnson ◽  
Bernhard Schwyn
Keyword(s):  
Solid Phase ◽  
Near Field ◽  
Intermediate Level ◽  
Redox Conditions ◽  
High Level Waste ◽  
Redox Potentials ◽  
Spent Fuel ◽  
Reducing Conditions ◽  
High Level ◽  
Waste Repositories

ABSTRACTRedox conditions were assessed for a spent fuel and high-level waste (SF/HLW) and an intermediate-level waste (ILW) repository. For both cases our analysis indicates permanently reducing conditions after a relatively short oxic period. The canister-bentonite near field in the HLW case displays a high redox buffering capacity because of expected high activity of dissolved and surface-bound Fe(II). This is contrary to the cementitious near field in the ILW case where concentrations of dissolved reduced species are low and redox reactions occur primarily via solid phase transformation processes.For the bentonite-canister near field, redox potentials of about -100 to -300 mV (SHE) are estimated, which is supported by recent kinetic data on U, Tc and Se interaction with reduced iron systems. For the cementitious near field, redox potentials of about -200 to -800 mV are estimated, which reflects the large uncertainties related to this alkaline environment.

Assessment of Package Performance During Long-Term Storage of Intermediate-Level Radioactive Waste

2003 ◽  
Author(s):  
A. V. Chambers ◽  
W. R. Rodwell ◽  
M. Kelly ◽  
A. R. Hoch ◽  
A. J. Baker
Keyword(s):  
Extended Period ◽  
Intermediate Level ◽  
Passive Safety ◽  
Long Term Storage ◽  
Waste Storage ◽  
Disposal Option ◽  
Intermediate Level Radioactive Waste ◽  
The Uk ◽  
The Impact

In the UK, the need for the long-term management of intermediate-level radioactive wastes arises from the absence of an established deep disposal option. As a consequence there is a requirement to demonstrate the ‘passive safety’ of waste packages in stores over a necessarily lengthy period (perhaps 150 years or more). ‘Passive safety’ is taken here to imply that the waste packages themselves would remain safe without intervention; it is assumed however, that the store building and associated infrastructure would need to be actively maintained and that the store may need to be ventilated. Importantly, methods for waste storage also need to ensure that possible future options for disposal are not foreclosed. An extended period of storage suggests that emphasis will need to be placed by waste producers on understanding a number of issues such as: • the impact of corrosion on container integrity; • the assessment of container vents and other features as a pathway for the release of radioactivity; • the extent to which wastes are conditioned for storage and the selection of appropriate methods; • the generation and behaviour of toxic or flammable gases in the storage facility; and the mitigating steps that might be needed to address adverse impacts (e.g. the type of ventilation that the store requires). In this paper, we review the requirements and current state of knowledge relevant to the assessment of operational releases of radioactive, flammable and toxic gases from wastes in long-term interim storage.

The Britannia Field, Blocks 15/29, 15/30, 16/26 and 16/27, UK North Sea

2020 ◽  
Vol 52 (1) ◽  
pp. 664-678 ◽  
Author(s):  
M. Camm ◽  
L. E. Armstrong ◽  
A. Patel
Keyword(s):  
Continental Shelf ◽  
Development Strategy ◽  
North Sea ◽  
Lower Cretaceous ◽  
Near Field ◽  
Field Development ◽  
Infill Drilling ◽  
To Come ◽  
The Uk

AbstractThe Lower Cretaceous Britannia Field development is one of the largest and most significant undertaken on the UK Continental Shelf. Production started in 1998 via 17 pre-drilled development wells and was followed by a decade of intensive drilling, whereby a further 40 wells were added. In 2000 Britannia's plateau production of 800 MMscfgd supplied 8% of the UK's domestic gas requirements.As the field has matured, so too has its development strategy. Initial near-field development drilling targeting optimal reservoir thickness was followed by extended reach wells into the stratigraphic pinchout region. In 2014 a further strategy shift was made, moving from infill drilling to a long-term compression project to maximize existing production. During its 20-year history the Britannia Platform has undergone numerous changes. In addition to compression, production from five satellite fields has been routed through the facility: Caledonia (2003), Callanish and Brodgar (2008), Enochdhu (2015) and Alder (2016). A new field, Finlaggan, is due to be brought through Britannia's facilities in 2020, helping to maximize value from the asset for years to come.As Britannia marks 20 years of production it has produced c. 600 MMboe – surpassing the original ultimate recoverable estimate of c. 570 MMboe – and is still going strong today.

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