Nuclear Decommissioning Authority

This paper explores strategies for decarbonising the upstream activities of oil and gas platforms in the North Sea through the integration of offshore wind energy and the repurposing of existing infrastructure for green hydrogen production. This study develops a net-zero energy transition scenario for a platform projected to reach its economic limit by the mid-2030s. The proposed energy transition pathway targets a 75% reduction in CO<inf xmlns:mml="http://www.w3.org/1998/Math/MathML" xmlns:xlink="http://www.w3.org/1999/xlink">2</inf> emissions by 2025, a 90% reduction by 2027, and net-zero operation by 2030 through a 95% reduction in emissions while offsetting the remaining 5% with the production of 930 tonnes of green hydrogen annually, and negative emissions by 2035, shifting to 2,000 tonnes of hydrogen. Design optimisation software MOHRES is used to find the best configuration, size, and dispatch strategy for each system associated with the transition milestones. The design considers various configurations, including a wind-heat pump-battery system for 2025 and 2027, and a more complex wind-heat pump-battery-electrolyser-hydrogen storage-fuel cell system for 2030. Evaluation criteria include techno-economic performance measures and environmental impact metrics, with a focus on minimising initial investment. It is found that the integration of optimal solutions necessitates a total investment of $218.5 million over ten years, with most of it needed in the initial transition years of 2025 and 2027 due to ambitious emissions reduction targets.

Abstract A growing and increasingly globalised human population, requiring the movement of goods and commodities, is placing increasing demands on the maritime industry, resulting in a concurrent increase in global shipping activities. This has consequences for the marine environment, particularly for species vulnerable to the impacts of vessel traffic. For example, vessel collisions can result in sub‐lethal or fatal injuries for marine mammals, whilst vessel noise can cause acoustic masking that effectively reduces an animal's listening space, potentially impacting their communication, navigation and foraging capacity. While a number of parallel approaches to mapping collision risk to large whales have arisen, these methods vary in their focus, usually on either co‐occurrence, collision probability, or probability of mortality. However, little attention has been given to the implications of methodological choice and data selection on subsequent risk predictions. To assess differences between these approaches, we used a standardised input dataset comprised of telemetry‐point data from tagged bowhead whales, and satellite‐based Automated Identification System (AIS) data of spatial vessel movements covering the Davis‐Baffin Arctic Marine Area. We applied this data to eight different, previously published analyses for deriving areas of vessel risk. We found that the choice of risk mapping approach affected the location, and total area, identified as ‘high risk’, and that more computationally complex approaches did not necessarily equate to different predictions. There was considerable variation in the total area of ‘high risk’ predicted within each map (range = 20–42,246 km2). Synthesis and Applications. The results underscore the importance of methodological transparency, informed data selection and careful interpretation when predicting collision risk. We provide practical recommendations for enhancing transparency when predicting risk, and discuss choice of approach suitable for different situations or management applications. It is critical that managers and policy makers are aware of the implications of applying different approaches when interpreting risk evaluation outputs.

This paper focuses on the evaluation of scanning devices for in-pile radiation measurement of the shut-down uranium–graphite reactors. The description of several generations of scanning devices is presented cause their design and configuration has been constantly improved in the light of experience and new objectives. Approaches and results of determining the metrological characteristics of γ- and neutron detectors of various types directly in reactor designs in which mixed radiation (α-, β-, γ-, and neutron radiation) prevails are considered. Estimates of the influence of the energy dependence of the sensitivity on the γ-detectors readings of different types, as well as the neutron detectors noise-immunity to γ-radiation, are presented.

The wind energy sector has experienced a significant expansion during the past two decades. With the current global appetite for the further expansion of offshore wind farms (OWFs) as one of the main renewable energy resources, a vast number of OWFs are expected to enter the decommissioning stage in the near future which may potentially create serious environmental and economic challenges to different countries. Hence, effective decision-making procedures are required to protect the environment, taxpayers, and local communities against the potential economic and environmental impacts of OWF assets at the end of their lifetime. The main contribution of this study is to develop a new approach for the economic and environmental assessments of OWF decommissioning projects based on a bottom-up model. The approach formulates the costs and emissions based on the available data and experience in the field and tries to provide appropriate assumptions to predict the costs and emissions caused by the different decommissioning activities. To validate and show the applicability of the approach, the economic and environmental assessments of two OWF decommissioning case studies in the UK continental shelf are investigated; the Lincs and Gunfleet Sands OWFs. A cost sensitivity analysis is also performed for different duration and vessel/equipment leasing parameters to identify the most sensitive parameters in the OWF decommissioning projects. The study suggests a set of interesting conclusions on the economic and environmental assessments of OWF decommissioning projects that may be beneficial for policymakers, operators, and local communities in the wind energy sector.

The number of decommissioned oil and gas platforms will increase over the coming decades. In the tropics and sub-tropics, platforms may operate near biodiverse natural habitats, such as coral reefs. Abundant and diverse fish communities often aggregate around platforms, with different decommissioning options posing variable ecological effects on these assemblages. One decommissioning option is to repurpose platforms into artificial reefs, a process commonly termed “Rigs-To-Reefs” (RTRs). Many RTR programs attempt to retain or enhance habitat availability and associated fish assemblages. To help demonstrate the importance of RTR projects, the fish habitat value of RTRs can be estimated by comparing the fish communities of RTRs to those of adjacent natural habitats. Surveying fish habitats in turbid waters necessitates the use of methods that can quantify the abundance, biomass, and length of fishes irrespective of visibility. Using an imaging sonar (1.2. MHz) and implementing a novel, pixel-based approach analogous to echo-integration, this study estimated the relative biomass density and length distribution of fishes at seven toppled oil and gas platform jackets in a Reefed Jacket Zone (RJZ) in the nearshore western Gulf of Thailand in comparison with a nearby coral reef. Biomass density was comparable at each habitat, despite extreme variability across the RJZ, attributed to the spatiotemporal stochasticity of larger, schooling fishes. However, fishes were larger at the RJZ, a trend supported by simultaneous stereo-video footage. The relative benefits and drawbacks of imaging sonar encountered in this study are also described.

Marine biofouling is the undesired accumulation of organic molecules, microorganisms, macroalgae, marine invertebrates, and their by-products on submerged surfaces. It is a serious challenge for marine vessels and the oil, gas, and renewable energy industries, as biofouling can cause economic losses for these industries. Natural products have been an abundant source of therapeutics since the start of civilisation. Their use as novel anti-fouling agents is a promising approach for replacing currently used, harmful anti-fouling agents. Anthraquinones (AQs) have been used for centuries in the food, pharmaceutical, cosmetics, and paint industries. Citreorosein and emodin are typical additives used in the anti-fouling paint industry to help improve the global problem of biofouling. This study is based on our previous study, in which we presented the promising activity of structurally related anthraquinone compounds against biofilm-forming marine bacteria. To help uncover the anti-fouling potential of other AQ-related structures, 2194 compounds from the COCONUT natural products database were analysed. Molecular docking analysis was performed to assess the binding strength of these compounds to the LuxP protein in Vibrio carchariae. The LuxP protein is a vital binding protein responsible for the movements of autoinducers within the quorum sensing system; hence, interrupting the process at an early stage could be an effective strategy. Seventy-six AQ structures were found to be highly docked, and eight of these structures were used in structure-based pharmacophore modelling, resulting in six unique pharmacophore features.

This modelling study uses the ERICA Tool and Bateman's equation to derive sediment threshold values for radiation protection of the marine environment relevant to NORM-contaminated products (radium-contaminated scales, 210Pb films and 210Po films) found in subsea oil and gas infrastructure. Threshold values are calculated as the activity concentration of the NORM-contaminated products' head of chain radionuclide (i.e., 226Ra + 228Ra, 210Pb, or 210Po) that will increase radiation dose rates in sediments by 10 μGy/h to the most exposed organism at a given release time. The minimum threshold value (corresponding to peak radiation dose rates from the ingrowth of progeny) were for radium-contaminated scales, 0.009 Bq/g of 226Ra, 0.029 Bq/g of 228Ra (in the absence of 226Ra) or 0.14 Bq/g of 228Ra (in the presence of 226Ra), followed by 0.015 Bq/g for 210Pb films, and 1.6 Bq/g for 210Po films. These may be used as default threshold values. Added activity concentrations of the NORM-contaminated products to marine sediments below these threshold values implies a low radiological risk to organisms while exceedances imply that further investigation is necessary. Using contaminated product specific parameterisations, such as Kd values derived for Ra from a BaSO4 matrix in seawater, could greatly affect threshold values. Strong consideration should be given to deriving such data as part of specific radiological risk assessments for these products.

Anais do Congresso Internacional de Engenharia Mecânica e Industrial (2764-4294) - Análise Da Dinâmica Vertical De Um Veículo Utv, A Partir De Um Modelo Com 7 Graus De Liberdade Em Obstáculos Idealizados

Abstract To study the feasibility of deploying a novel type of anchor with variable buoyancy for mooring floating offshore wind turbines, a set of detailed modelling studies was performed in the state-of-the-art, Marine Simulator at the National Decommissioning Centre (NDC). The aim of the multi-physics simulations is to fully assess the proposed deployment method using a small tugboat fitted with a simple winch, thereby simplifying the process and reducing installation costs. The anchor has a 10 m square base, 4.5 m height and weight of 163 tonnes. The anchor is subjected to irregular waves with a JONSWAP spectrum with a significant wave height up to 5 m and peak period of 10 s. The analysis is divided in three sections: characterisation of the anchor buoyancy, positioning the anchor under the stern of the vessel and the controlled descent of the anchor to the seabed. An ideal winch speed of 0.35 m/s is identified, at which working load range on the winch cable decreases from 80 kN at the lowest winch speeds to about 30 kN. The sinking trajectory is similar at all winch speeds, however, the slower the descent, the further the anchor drifts. At this winch velocity, the descent from the resting position under the stern to the seabed takes roughly 5 min. In addition, the anchor’s yaw range during the descent is below \(10^{\circ }\) at the optimal conditions.KeywordsOffshore windAnchor dynamicsVirtual prototyping