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[Display omitted] • Estimation of radionuclides formed in core components of TRIGA 2000 Bandung reactor. • This study focuses on the predominant aluminum components in the reactor core. • The numerical calculation uses MCNP 6.1 and ORIGEN 2.1 software. • Aluminum-27 is found to be the most prevalent stable isotope for all components. • Zinc-65 is the most significant radioactivity up to 6 years after decommissioning. This paper presents estimates of the radionuclides formed in the core components of the TRIGA 2000 Bandung reactor. This research is crucial for updating decommissioning programs and predicting the quantity and activity levels of radioactive wastes. This study primarily focused on the predominant aluminum components in the reactor core. MCNP 6.1 was utilized to calculate the neutron flux during the reactor operation, whereas ORIGEN 2.1 determined the radionuclides resulting from neutron activation. The calculations span over six years, with 2021 as the base year. The nine modelled components include the reflector wall, Lazy Susan, thermal column, thermalizing column, core wall and safety plate, shim wall, top grid plate, bottom grid plate, and beam port. The findings indicate that Aluminum-27 (Al-27) is the most prevalent stable isotope across all components, with mass percentages ranging between 97.89% and 97.93%. Aluminum exhibits low activation, and the radionuclides produced primarily stem from other elements present in 6061-type aluminum. Among the radionuclides, Zinc-65 (Zn-65) displayed the most significant radioactivity, with percentages varying from 81.6% to 99.82% in the initial year and diminishing over six years due to radioactive decay. By the sixth year, a notable reduction in the radioactivity was observed. Decommissioning nuclear facilities requires a holistic approach that encompasses cost, risk, potential environmental impacts, human safety, regulatory compliance, and the chosen technical strategy. Such planning is vital for adhering to the safety and security standards of the national regulatory body, BAPETEN. [ABSTRACT FROM AUTHOR]

The decommissioning of manmade structures in the marine environment causes large volumes of greenhouse gas (GHG) emissions to be released. Current GHG emissions calculation methods for decommissioning offshore oil and gas industry infrastructure leave large sources of GHG emissions unaccounted for. The results presented here show that these consequential decommissioning GHG emissions are underreported by 50%. Until now, no study has looked at the cumulative impact of decommissioning, but this study shows that globally offshore oil and gas infrastructure decommissioning has produced 25 MtCO2e to date, around 0.5% of annual global GHG emissions. Importantly, this study also shows that due to the growth of the offshore wind industry, increasing numbers of manmade structures will be emplaced in the marine environment, and GHG emissions from decommissioning will increase 200-fold to 5 GtCO2e by 2067. Crucially, this growth of GHG emissions is not compatible with the Paris Agreement, and new decommissioning methods will be required to meet this challenge.

• The trend of radiological dose for an offsite receptor living near the proposed Ninh Thuan 1 Nuclear Power Plant (NPP) site in Vietnam is assessed by using the RESRAD-OFFSITE v4.0 code. • DCGL values and the dose contribution fractions for nine target radionuclides are derived under site-specific conditions. • The fish ingestion pathway is determined to be the most dominant contributor affecting the offsite receptor's exposure dose, followed by the plant ingestion pathway. • The equilibrium solubility transfer model estimates a more conservative radiological dose than the equilibrium desorption transfer model. • The sensitive analysis reveals the change of distribution coefficients significantly influences the output dose results. The potential radiation exposure for an offsite receptor living near the proposed Ninh Thuan 1 Nuclear Power Plant (NPP) site in Vietnam is assessed using the RESRAD-OFFSITE v4.0 code. Radioactive contamination is assumed to occur on 23 ha of surface soil in the Ninh Thuan 1 NPP's protected core site due to residual radioactive inventory resulting from operation or decommissioning activities. Nine radionuclides of concern in this work are selected based on the previous decommissioning experience of typical VVER, the same Russian reactor type intended for the Ninh Thuan 1 NPP project, and those of typical PWRs in the United States. The radionuclide migration through the aqueous and air medium is modeled based on the geological and physical characteristics of the specific site gathered through the feasibility safety report for the Ninh Thuan 1 NPP project and the related literature. Identifying the dose contribution fraction of each radionuclide to the annual dose limit through individual DCGL values can assist in weighting the influence faction of each radionuclide to the final total exposure dose. The results show that the total offsite exposure dose from nine radionuclides considered in the present work under a given contamination condition (1 pCi/g) is relatively lower than the annual dose limit (0.1 mSv/yr) for the public in Vietnam. In addition, the dominant exposure pathway for an offsite receptor is determined to be fish ingestion due to the remarkably high transfer factors, followed by plant ingestion. Consequently, observation of the sensitivity analysis for the solubilities and distribution coefficients of the radionuclides shows that while the change of distribution coefficients significantly influences the output dose, the impact of the solubility variation is relatively minor according to the small concentration inventory of each radionuclide in the survey area. [ABSTRACT FROM AUTHOR]

• A prototype for automatized building surface contamination measurements was created. • Detector displacement with a cable driven robot offers large flexibility. • A contamination monitor offers easy integration and qualification. The final stage in the life cycle of any nuclear installation is its decommissioning, where after decontamination and dismantling of all systems and equipment, one is left with demonstrating the absence of residual contamination on building structures above applicable clearance limits. Given the huge surfaces involved, this is often a costly and lengthy endeavor. In this paper we give an introduction into the regulatory framework for building clearance and present a prototype developed at Tractebel's Innovation Lab to demonstrate the feasibility of automatizing such surface contamination measurements with a cable driven robot. [ABSTRACT FROM AUTHOR]

Many Oil and Gas (O&G) fields in the North Sea have produced their economically recoverable reserves and have entered the decommissioning phase or are close to cessation of production. The subsequent O&G decommissioning process involves a range of stakeholders with specific interests and priorities. This range of inputs to the process highlights the necessity for the development of multi-criteria decision frameworks to help guide the decision-making process. This study presents bottom-up formulations for the economic, environmental, and safety risk criteria to support the multi-criteria decision analysis within the Comparative Assessment (CA) of O&G pipeline decommissioning projects in the North Sea. The approach adapts current guidelines in the O&G industry and considers a range of parameters to provide estimations for the costs, energy usage, greenhouse gas emissions, and safety risks. To verify the effectiveness of the proposed bottom-up formulations, the longest oil export pipeline in the Brent field, PL001/N0501 is selected as a case study. The numerical results revealed the consistency of the results obtained from the proposed approach with those reported in the technical documents by industry. In most cases, the formulations provide estimates with less than 10% differences for the costs, energy usage, emissions, and safety risks. Based on the proposed multi-criteria formulations, the study also presents the use of an immersive decision-making environment within a marine simulator system to help inform the decision-making process by stakeholders. • Decision-making process for O&G decommissioning involves a range of stakeholders. • Bottom-up formulations for decommissioning multi-criteria analysis are developed. • Oil export pipeline in the Brent field, PL001/N0501, is investigated as case study. • Numerical results revealed good consistency with those reported by the O&G industry. • An immersive decision-making environment is developed for stakeholder engagement. [ABSTRACT FROM AUTHOR]

Over the past thirty years, European offshore wind farm development surged, yet end-of-life and decommissioning considerations were overshadowed by initial climate and energy security objectives during design and construction. As the first major projects near their final decade, numerous unanswered questions persist. Through a comprehensive literature review, this study identifies, maps, and evaluates challenges across technical, economic, environmental, social, and policy dimensions spanning five end-of-life phases: planning, dismantling, transport and logistics, waste management, and site recovery. Examining 42 publications reveals 46 distinct challenges affecting stakeholders such as the end-of-life supply chain, policy makers, and society. While 33 % of the challenges manifested in the technical dimension, 48 % of the challenges covered the planning phase. Notably, the economic challenge of vessel cost and availability was raised most often. Less-explored challenges underscore the importance of consideration before the end-of-life phase intensifies. The study illustrates the complex interconnection of numerous end-of-life challenges across phases, dimensions, and disciplines, emphasizing the imperative of addressing bottlenecks in a comprehensive and integrated manner. The results of this study help steering future research, while also improving awareness of challenges for stakeholders, emphasizing the need for collaborative efforts between governmental bodies and industry stakeholders to address imminent challenges through transparent guidelines, data exchange, and circular design principles. The novelty of this study lies in its holistic, multidisciplinary approach, systematic framework for identifying challenges, and critical perspective unveiling interconnectedness. [Display omitted] • Identification and mapping of 46 distinct challenges. • Many obstacles in planning phase and of technical nature. • Economic challenge of cost and availability vessels most prevalent in literature. • The different challenges are highly interconnected. • Less-explored challenges demand greater focus from stakeholders. [ABSTRACT FROM AUTHOR]

In this study, a novel ultrasound-assisted removal/decontamination process using ultrafine bubbles (UFBs) of 1 μm or less diameter gas bubbles is proposed to reduce secondary radioactive waste for decommissioning of nuclear installations. The removal/decontamination technique does not require abrasive media for abrasive-blasting decontamination or chemical reagents for chemical decontamination. The removal experiments with simulated contaminants (Co oxides) on the surface of a stainless steel 316 (SUS316) plate were conducted, and the removal performance was confirmed using UFB water via ultrasonic irradiation at 1.6 MHz. The experimental results indicate that the UFBs adhere to the contaminants and move into the cracked Co oxides and the gap between the contaminants and the SUS316 plate. The vibration of UFBs and the impact due to the collapse of cavitation bubbles emitting ultrasound will exfoliate the contaminants. Decontamination experiments using fuel pin end plugs contaminated with radioactive materials, such as 60Co, were performed to evaluate the decontamination performance of various kinds of contaminants. The decontamination performance of 60Co in the fuel pin end plugs was different from that of non-radioactive Co oxides in the removal experiments, and the difference in the chemical states of Co affects the removal/decontamination behavior in the N 2 -UFB water. Therefore, understanding the properties of contaminants before the decontamination operation is necessary to maximize the decontamination performance with UFBs. [ABSTRACT FROM AUTHOR]

Quantifying impacts on marine ecosystems remains pivotal in estimating risks associated with offshore industry practices. Cuttings piles, formed during drilling operations, are commonly abandoned in situ , and left to attenuate on the seabed. In the present work, the presence and lability of mercury in samples obtained from drill cuttings piles of two decommissioned North Sea oil platforms (bp Miller and bp North West Hutton) and the surrounding sediment were investigated. Maximum concentrations of total mercury were measured at 0.23 and 0.37 μg/g dry weight (dw) for bp Miller and bp North West Hutton, respectively. Background concentrations of 3.6 and 8.3 ng/g dw were measured at reference sites at 3200 metre distance. Thermofractionation and DGT-analysis of the samples to assess the effective environmental impact of the measured mercury suggests that although total mercury concentrations are increased in the proximity of the cuttings pile, the effective environmental impact may be limited. [Display omitted] • Legacy offshore cuttings piles are contaminated with mercury. • Mercury contamination exceeds OSPAR Estimated Acceptable Concentrations. • Reactivity and leaching of deposited mercury are considered low. [ABSTRACT FROM AUTHOR]

The purpose of the Creative Robot Contest for Decommissioning is to raise students' interest in decommissioning through robotics, contribute to the cultivation of students' creativity, and develop not only their problem-solving ability but also their problem-finding ability. The contest assumes fuel debris removal from the lower part of the pedestal at the Fukushima Daiichi Nuclear Power Plant. This paper describes the activities of our college in the Creative Robot Contest for Decommissioning and the robot design to overcome the challenges of the 4th and 5th contests. Whereas the 4th contest was held on site, the 5th contest was held online. To evaluate the robot that we have developed, we prepared a mock-up of the contest field at our school and conducted a demonstration. In the 4th contest, our team was the only one among the participating teams to complete the task and won the award from the Ministry of Education, Culture, Sports, Science and Technology (MEXT). In the 5th contest, we won the award from the Governor of Fukushima prefecture. The educational effects of the Creative Robot Contest for Decommissioning were great. The students who participated in the contest became more interested in decommissioning and were able to develop problem-solving skills, the ability to study independently, schedule management, and so on. [ABSTRACT FROM AUTHOR]

This paper presents a robot developed for reconnaissance at a nuclear power plant that had an accident. When an accident occurs, such as the Fukushima Daiichi Nuclear Power Plant disaster, rubble is scattered on the premises, increasing the radiation dose. Consequently, it is nearly impossible for humans to enter the plant and assess the situation. Therefore, a robot that performs reconnaissance is required. In this study, we designed and fabricated a reconnaissance robot to be used in a nuclear power plant that has undergone an accident. The inaccessibility of the scattered on-site rubble and high radiation dose can be addressed by employing an airship-type design that does not use electronic devices. [ABSTRACT FROM AUTHOR]

Following the demands established by the current Ukrainian legislation, the Decommissioning Concept for the WWR-M research reactor was recently approved. The Concept envisages a strategy of immediate dismantling; it identifies and justifies the main technical and organizational measures for the preparation and implementation of decommissioning, the sequence of planned works and activities, as well as the necessary conditions and infrastructure. Decommissioning requires proper planning and demonstration that all planned dismantling works will be carried out safely. Presented safety assessment is a mandatory component of the Concept and the most important element of the overarching technological scheme. The purpose of the safety analysis is to provide input for detailed planning on how to ensure safety during decommissioning. Based on the results of the safety analysis, the measures to ensure radiation protection are defined while justifying their necessity and sufficiency. [ABSTRACT FROM AUTHOR]

Plutonium containing fluorine compounds significantly increases the neutron flux due to the nuclear reactions between alpha particles (α) emitted from the radioactive decay of Pu and the 19F nuclei. As a result, this introduces significant measurement challenges in passive thermal-neutron coincidence counting. To address this, an innovative non-destructive assay technique was developed by Cavendish Nuclear, in collaboration with Sellafield Ltd., using high-resolution gamma-ray spectrometry (HRGS) to account for the presence of fluorine so that a more accurate estimate of the plutonium mass can be calculated. The fluoride correction technique measures the fraction of the Pu that exists in fluoride form using several key gamma rays: the 583 keV, 891 keV, 1236 keV, and 1275 keV emissions. In addition, a Pu and 241Am isotopic abundance calculation algorithm is performed using the same gamma-ray spectrum, as part of the fluoride correction technique. From this information, a more accurate estimate of the Pu-specific neutron emission rate can be calculated, which when combined with the passive thermal-neutron totals count rate, which has a much smaller statistical uncertainty and less influence from self-multiplication compared to the passive thermal-neutron "reals" coincidence count rate, yields more accurate Pu mass estimates. This work has been applied "offline" to high α-radioactive transuranic (TRU) waste drums, residue containers and packages generated from the nuclear decommissioning and clean-up of legacy nuclear facilities on the Sellafield site. The technique was also used on HRGS in-situ surveys performed in Pu oxide finishing lines; unexpected evidence of significant fluorine contamination in the held-up Pu in oxide plant equipment was discovered for the first time at Sellafield. The results and benefits from applying this technique are summarized and discussed. A new independent complimentary method of fluoride quantification in the Pu using passive fast-neutron spectroscopy methods is currently under development and is showcased here. [ABSTRACT FROM AUTHOR]

A preliminary derived concentration guideline level (DCGL) was calculated for the soil of the Wolsong nuclear power plant (NPP) (the first commercial pressurized heavy water reactor in South Korea) site using the RESRAD-ONSITE computational code. In total, fourteen selected radionuclides were analyzed after considering the preliminary evaluation information of radionuclides observed in the pressure tube specimen in the Wolsong Unit 1 heavy water reactor and previous NPP decommissioning cases. Furthermore, a geological structure model of the Wolsong NPP site was established according to the safety analysis report of the Wolsong NPP. In addition, the distribution coefficients (Kd) of various radionuclides were derived using the JAEA-SDB and the pH information of the groundwater around the Wolsong NPP site. The DCGL for surface soil of the Wolsong NPP site was derived via the application of criteria for the site release to facilitate unrestricted reuse. Moreover, preliminary dose evaluation and relevant analysis were performed according to the Wolsong NPP site resident scenario. The novelty of this study lies in the first calculation of the preliminary DCGL values for the case of the pressurized heavy water reactor (Wolsong NPP) site. It is expected that further reliable DCGL results might be achievable if more precise radionuclide information and site-specific parameters with respect to the Wolsong NPP site are secured and applied in the future. [ABSTRACT FROM AUTHOR]

Man-made marine structures (MMS) are commonly used to describe any artificial structure in the marine environment, encompassing oil and gas infrastructure and pipelines, artificial reefs, jetties, piers and shipwrecks. MMS are increasingly proposed to address issues facing marine planners, including augmenting fish stocks through the creation of artificial reefs and the repurposing of redundant offshore oil and gas infrastructure ('rigs to reefs'). Marine spatial planning is a highly contested process, characterised by multiple stakeholders with often divergent priorities due to competing objectives and values. Understanding stakeholder perspectives in relation to MMS is therefore critical in formulating appropriate policies. This review presents the first systematic and comprehensive integration of information from academic journals and 'grey' literature relating to social and economic values and perceptions of MMS. The review identifies that, despite advocacy for research on social and economic values of MMS, there are significant gaps in knowledge, in particular relating to comparative assessments of stakeholder values across different types of MMS. Priority areas for future research are highlighted. • Understanding user perspectives of MMS is critical in marine management. • Knowledge gaps include multi-stakeholder and integrated social-economic research. • Existing research is predominantly from the global north. • A model of the social value of man-made marine structures is developed. • Priority areas for future research are outlined. [ABSTRACT FROM AUTHOR]

Due to the Taiwan national policy “nuclear-free homeland by 2025”. As a result, Taiwan nation’s three operating Nuclear Power Plants (NPPs) are being decommissioned. Decommissioning is a representative stage in back-end cycle of NPP. There has been several NPP decommissioning indicated Global Warming Potential (GWP) could also be reduced by reducing the volume of waste and increasing recycling of material and steel. The Taiwan nation’s three operating nuclear NPPs are to be decommissioned and has progressed the strategy determination and Research and Design (R&D) for the decommissioning. Decommissioning waste, components, system and structure is one of the most important elements. Decommissioning waste quantity is calculated based on Piping and Instrumentation Diagram Piping (P&ID) and completion report with activation and contamination data. Due to the largest portion of waste management and disposal in decommissioning, it is necessary to exactly evaluate waste quantity (applying the regulation, guideline, and site-specific characterization) for economic viability. The purposes of this paper are to provide an overview of useful as an important information in establishing the waste inventory and quantity for Boiling Water Reactors (BWR) are mainly described. [ABSTRACT FROM AUTHOR]

This study applied the Lotka-Volterra model to energy consumption and carbon dioxide (CO2) emissions from 1965 to 2017 in the United States to explore the feasibility of replacing fossil fuels with nuclear energy. Parameter estimations suggested that the consumption of nuclear energy increases the consumption of fossil fuels, thereby increasing CO2 emissions. Consistent with the arguments in Sovacool (2008) and Lenzen (2008), our results suggested that the mining, milling, conversion, enrichment, fuel fabrication, construction of nuclear plants, nuclear waste treatment, and decommissioning increase the consumption of fossil fuels and hence CO2 emissions. Utilization of nuclear energy fails to reduce fossil fuel consumption and CO2 emissions to achieve the environmental protection goals in the United States. By applying the Lyapunov functions to conduct equilibrium analysis, our investigation verified that the consumption of fossil fuels will ultimately be ten-fold the consumption of nuclear energy in the long term. Furthermore, the results of forecast accuracy show that the predictive ability of our proposed LotkaVolterra model is superior to that of Bass model both in forecasting energy consumption and CO2 emissions because the Lotka-Volterra model considers how nuclear energy affects the consumption and CO2 emissions of fossil fuels, while the Bass model does not. [ABSTRACT FROM AUTHOR]

The decommissioning of offshore oil and gas platforms typically involves removing some or all of the associated infrastructure and the consequent destruction of the associated marine ecosystem that has developed over decades. There is increasing evidence of the important ecological role played by offshore platforms. Concepts such as novel ecosystems allow stakeholders to consider the ecological role played by each platform in the decommissioning process. This study focused on the Wandoo field in Northwest Australia as a case study for the application of the novel ecosystem concept to the decommissioning of offshore platforms. Stereo‐baited remote underwater video systems were used to assess the habitat composition and fish communities at Wandoo, as well as two control sites: a sandy one that resembled the Wandoo site pre‐installation, and one characterized by a natural reef as a control for natural hard substrate and vertical relief. We found denser macrobenthos habitat at the Wandoo site than at either of the control sites, which we attributed to the exclusion of seabed trawling around the Wandoo infrastructure. We also found that the demersal and pelagic taxonomic assemblages at Wandoo more closely resemble those at a natural reef than those which would likely have been present pre‐installation, but these assemblages are still unique in a regional context. The demersal assemblage is characterized by reef‐associated species with higher diversity than those at the sand control and natural reef control sites, with the pelagic community characterized by species associated with oil platforms in other regions. These findings suggest that a novel ecosystem has emerged in the Wandoo field. It is likely that many of the novel qualities of this ecosystem would be lost under decommissioning scenarios that involve partial or complete removal. This study provides an example for classifying offshore platforms as novel ecosystems. [ABSTRACT FROM AUTHOR]

It is essential to clarify the characteristics of the material activation in cyclotron-type proton therapy facilities for future decommissioning. In particular, concrete occupies the largest volume among object materials, but its activation characteristics of activity level and distribution are unknown. We investigated concrete radioactivation in cyclotron-type proton therapy facilities at the National Cancer Center Hospital East and Aizawa Hospital. The in situ 24Na measurement method, which is easy and high sensitivity, was applied for the investigation. Using the in situ 24Na measurement method, we obtained the thermal neutron fluence rates in concrete with high sensitivity. Based on these fluence rates, the sum of the 152Eu and 60Co specific activities in the concrete were predicted for an operation duration of 30 years. The study aims to predict general 152Eu and 60Co (which are major radionuclides) specific activities for cyclotron-type proton therapy facilities, and we found the following common characteristics in the investigation results. In the accelerator room, neutrons were mainly produced at the degrader and/or objects surrounding it and diffused over the room. As a result, the sum of the ratios of the concrete floor's specific activities of 152Eu and 60Co for their respective clearance level (0.1 Bq/g) was estimated to be close to 1. On the other hand, the production of neutrons both in the treatment and beam transport line rooms was low, and the sum of the ratios of the 152Eu and 60Co specific activities for their respective clearance level was estimated to be below 1. [ABSTRACT FROM AUTHOR]

Abstract To obtain the necessary information on fuel debris and water leakages during the decommissioning task of the Fukushima Daiichi Nuclear Power Plant, an ultrasonic-based method was proposed for future internal investigation of the primary containment vessel (PCV). In this article, we describe the rotatable winch mechanism and visual localization method, which were used to aid the investigation. We used the rotatable winch mechanism to adjust the height and orientation of the ultrasonic sensor and localized the robot with cameras to localize the sensor, to provide assisting information for data combination. We studied the feasibility of the conventional visual odometry method for application to the situation and performed localizing accuracy evaluation experiments with a mobile robotic platform prototype. The results showed that the visual odometry method could generate intuitive bird’s-eye-view maps, and provided an average error rate of 35 mm/1500 mm, which met the required maximum error rate of 100 mm/1500 mm for the grating movement. Experiments were also conducted with adjustable parameter ranges that could provide the required accuracy.

The Kori Unit 1 will be decommissioned after a permanent shutdown in June 2017. South Korea has a 0.1 mSv/yr exposure limit standard for limited or unlimited site release. This is South Korea's first commercial NPP; therefore, if the containment building is reused as a memorial hall, it will contribute to the improvement of public understanding and enhance the public's acceptance of NPPs. Also, existing Kori Unit 1 nuclear power plant manpower resources can be reused after decommissioning and resident staff and memorial hall visitors can activate nearby commercial areas. Therefore, such a reuse scenario may also prevent an economic recession. The exposure dose was calculated using the following scenarios: worker in the containment building, visitor in the containment building, and worker in buildings other than the containment building. The exposure dose in the buildings was calculated by the RESRAD-BUILD developed by the Argonne National Laboratory (ANL). The preliminary exposure dose and derived concentration guideline level (DCGL) were derived.

Abstract Background Drawing on the literature on cutback management, this article deals with healthcare decommissioning in times of austerity. Politicians and decision-makers are typically reluctant to decommission healthcare, and if they do, the public generally reacts strongly towards reductions in service supply. Despite this, comprehensive decommissioning does take place, though empirical knowledge about its effects and economic sustainability is limited. To further the understanding of healthcare decommissioning, this paper aims to introduce the concepts of cutback management into the research on healthcare decommissioning, and apply its components to an empirical case of comprehensive decommissioning. In doing so, the study analyses whether decommissioning measures can be expected to generate long- or short-term economic payoff, and considers what other effects they might have on the healthcare system. Method We developed a theoretical framework that enabled us to investigate the measures through which a local healthcare system in Sweden, region Dalarna, responded to an acute fiscal crisis in 2014, and what effects these measures are likely to generate. The method used was a deductive content analysis of Dalarna’s decommissioning program, containing 122 austerity measures for saving 700 million Swedish Krona (SEK). Results Dalarna’s local decision-makers responded to the fiscal crisis through a combination of operational cuts (20% of undertaken measures), programme cuts (42% of undertaken measures), and structural reforms (38% of undertaken measures). The instruments most commonly used were increased patient fees and the merger of service facilities. By relying foremost on programme cuts and structural reforms, Dalarna adopted the measures most plausible to have moderate or long-term economic payoffs. Successful implementation, however, may be challenging and difficult to evaluate. Conclusions Healthcare politicians and decision makers have better potential to stabilize their long-term economic situation if they rely on responses such as operational cuts, programme cuts and structural reforms, as opposed to across-the-board cuts and cuts in investment and capital expenditures. However, with economics being only one important factor for sustainable healthcare systems, further studies should investigate how these measures affect important principles, such as equal healthcare distribution and access. Trial registration Not applicable.

The article provides a brief description of organizational and technical measures aimed at ensuring radiation safety during the decommissioning of the heavy-water research nuclear reactor of Institute for Theoretical and Experimental Physics after A.I. Alikhanov of National Research Centre «Kurchatov Institute». Information is provided on the history and features of the operation of the reactor, including parameters and characteristics that are significant for planning and conducting work. The peculiarities of legal regulation in the field of ensuring radiation safety are given; regulatory acts and rules accompanying other activities during decommissioning and directly related to radiation safety are also considered. The paper describes the work done in preparation for dismantling, the initial and current state of the installation, forthcoming work with examples of dismantled equipment. Methods for handling radioactive waste arising during decommissioning are considered, including methods for fragmentation of large structural elements (examples of mechanical devices are given), methods for sorting according to different specific activity (high activity, low activity), radionuclide composition and physical properties (solid, metallic, non-metallic, liquid). A special method for handling liquid radioactive waste is described, which includes the collection and temporary storage system. To assess the radiation situation at workplaces during the dismantling of the reactor structures, calculations of radiation transfer were carried out on the running and shutdown reactor, during which it was established that the expected dose to the personnel when performing activities on decommissioning of TBR is much lower than the limit values, established by regulatory documents. In accordance with the estimated radiation doses, rules and instructions for personnel were determined, including the procedure for using personal protective equipment, the necessary measures for surface decontamination, etc. Information is given on the procedure for radiation monitoring at all stages of dismantling and at the final stages of decommissioning including control of premises, personnel, equipment, waste of various types, atmospheric air.

Interpretation for the two-week long Unit 3 ex-vessel debris cooling behavior was conducted based on the Fukushima-Daiichi Nuclear Power Plant (1F) data and the site data such as pressure, temperature, gamma ray level and live camera pictures. It was estimated that the debris relocated to the pedestal was in partial contact with liquid water for about initial two days. With the reduction of the sea water injection flowrate, the debris, existed mainly in the pedestal region, became “dry”, in which the debris was only weakly cooled by vapor and this condition lasted for about four days until the increase of the sea water injection. During this dry period, the pedestal debris was heated up and it took further days to re-flood the heated up debris.

Biofouling in the marine environment refers to an unwanted build-up of marine organisms on subsea surfaces including harbor docks, hulls of ships and offshore installations. The first stage of marine fouling occurs as a microbial biofilm which forms via the aggregation of bacterial, algal, and fungal cells. This biofilm provides a favorable substrate for the larval settlement of larger organisms such as mussels, barnacles and hard corals which accumulate to uncontrollable extents, causing issues for the maritime industries. Since the ban of tributyltin (TBT) in 2008 by the International Maritime Organisation, alternative antifouling agents have been used such as algaecides and copper-based coatings. Recent studies are showing that these can accumulate in the marine environment and have toxic effects against non-target species. Marine microbes and invertebrates are known to be prolific producers of bioactive molecules, including antifouling active compounds. These compounds are often produced by marine organisms as a means of chemical defense to deter predators and prevent fouling of their own surfaces, making them a promising source of new antifouling agents. This article discusses the effects of biofouling on the maritime industries, the environmental dangers of currently used antifouling compounds and why natural products from marine organisms could be a source of environmentally friendly antifouling agents.

Abstract The decommissioning of offshore oil and gas platforms typically involves removing some or all of the associated infrastructure and the consequent destruction of the associated marine ecosystem that has developed over decades. There is increasing evidence of the important ecological role played by offshore platforms. Concepts such as novel ecosystems allow stakeholders to consider the ecological role played by each platform in the decommissioning process. This study focused on the Wandoo field in Northwest Australia as a case study for the application of the novel ecosystem concept to the decommissioning of offshore platforms. Stereo‐baited remote underwater video systems were used to assess the habitat composition and fish communities at Wandoo, as well as two control sites: a sandy one that resembled the Wandoo site pre‐installation, and one characterized by a natural reef as a control for natural hard substrate and vertical relief. We found denser macrobenthos habitat at the Wandoo site than at either of the control sites, which we attributed to the exclusion of seabed trawling around the Wandoo infrastructure. We also found that the demersal and pelagic taxonomic assemblages at Wandoo more closely resemble those at a natural reef than those which would likely have been present pre‐installation, but these assemblages are still unique in a regional context. The demersal assemblage is characterized by reef‐associated species with higher diversity than those at the sand control and natural reef control sites, with the pelagic community characterized by species associated with oil platforms in other regions. These findings suggest that a novel ecosystem has emerged in the Wandoo field. It is likely that many of the novel qualities of this ecosystem would be lost under decommissioning scenarios that involve partial or complete removal. This study provides an example for classifying offshore platforms as novel ecosystems.

Companies are striving to optimize the decommissioning process of oil and gas facilities in order to reduce overall costs. Various options and criteria for making decisions on the liquidation of objects are considered, which are based on a multicriteria approach that allows optimizing this complex process. The most important characteristics of a reliable model for optimizing options for decommissioning oil and gas facilities are defined as follows: the option should take into account qualitative and quantitative criteria. To minimize the subjectivity of human judgment, a systematic poll of skilled performers should be conducted using a well-structured technique. It is shown that multicriteria decision analysis can be considered as an adequate model for choosing options for decommissioning oil and gas assets. Based on a test case that reflects the practice of decommissioning offshore platforms in the state of California (USA), the logic and algorithm of calculations are reproduced when choosing the best options for decommissioning facilities. The presented calculation scheme is quite universal and can be used at other facilities, including Russian ones. In order to determine the optimal choice, three options for the project model for the decommissioning of oil and gas facilities of offshore structures (platforms) were considered: complete liquidation, partial liquidation, and leaving in place.

The operating license of Kori units 3 and 4 are to be expired in 2024 and 2025. If the plants are decided to be decommissioned, the spent nuclear fuels in the spent fuel storage pool (SFP) have to be removed from the site. However, no proper storage facility is currently available in Korea. To overcome the difficulty, this study proposes application of an independent temporary SFP cooling system. It is expected to safely isolate the SFP from the plant. The case study conducted showed this concept is achievable and technically mature. Moreover, the installation cost per unit is USD 9.51 million obtained from an analogous estimating. This is much lower cost than the dry cask options. Then, system requirements and applicable design are developed. Maximum heat generation of unit 4 is estimated as 1.67 MW, through fuel characteristics categorizations and ORIGEN calculations. To remove the decay heat, installation of an indirect air-cooled method is selected by evaluating three cooling methods. The modification includes new heat exchanger, secondary cooling pumps, and chillers. Furthermore, two single failures are considered; cooling pump and normal power. This can be covered by two redundant trains and a back-up diesel generator provided.

A huge amount of radioactive soil has been generated through decommissioning of nuclear facilities around the world. This review focuses on the difficulties and complexities associated with the remediation of radioactive soils at the site level; therefore, laboratory studies were excluded from this review. The problems faced while remediating radioactive soils using techniques based on strategies such as dry separation, soil washing, flotation separation, thermal desorption, electrokinetic remediation, and phytoremediation are discussed, along with appropriate examples. Various factors such as soil type, particle size, the fraction of fine particles, and radionuclide characteristics that strongly influence radioactive soil decontamination processes are highlighted. In this review, we also survey and compare the pool of available technologies currently being used for the remediation of radionuclide-contaminated soils, as well as the economic aspects of soil remediation using different techniques. This review demonstrates the importance of the integrated role of various factors in determining the effectiveness of the radioactive soil decontamination process. [ABSTRACT FROM AUTHOR]

The decommissioning Concept for WWR-M research reactor is developed to meet the requirements of the current Ukrainian legislation. The main goal of the Concept is to provide a strategic stage of the work planning, including all the required justifications with a sufficient level of detail. It will allow during the next planning stage to develop the decommissioning project and other documents required to obtain the decommissioning license. The Concept is the institutional and technical document, which defines and substantiates the basic administrative, organizational, and technical measures for the preparation and implementation of the reactor decommissioning. It also describes the main activities and works, defines the procedure, conditions for their implementation and provision, and planned deadlines. [ABSTRACT FROM AUTHOR]

Over 1400 km of oil and gas pipeline infrastructure exists within the boundaries of the Pilbara Trap Managed Fishery (PTMF) operating on the North West Shelf of Australia. Some of this infrastructure has reached the end of its operational life and requires decommissioning. Location and speed data collected from 2008 to 2018 using vessel monitoring systems onboard all trap fishing vessels (n = 3) operating in the PTMF were used to understand how fishing activity near pipelines has changed through time, and to identify the best predictive variables to explain hours spent fishing km−2 week−1. The proportion of fishing activity within 200 m of a pipeline increased over the survey decade and averaged 4.2% across all years. Hours spent fishing km−2 within 200 m of any pipeline was found to be 8.0 h km−2, ~ 11.4 times more than that recorded, on average, for the remaining area of the PTMF (0.7 h km−2), and ~ 4.6 times more than the western portion of the PTMP (1.7 h km−2) where all pipeline infrastructure exists. Fishing activity within 1 km of pipelines increased after their installation, and hence time since installation was the best predictor of fishing. This study demonstrated that trap fishers in the PTMF allocate a small proportion of their time targeting pipeline infrastructure, with the area close to a pipeline experiencing a relatively greater magnitude of fishing than that elsewhere in the PTMF. As such, the results of this study provide decision makers with an understanding of the intrinsic value of this infrastructure to trap fishers. [ABSTRACT FROM AUTHOR]

Scientific issues that draw international attention from the public and experts during the last 10 years after the Fukushima accident are discussed. An assessment of current severe accident analysis methodology, impact on the views of nuclear reactor safety, dispute on the safety of fishery products, discharge of radioactive water to the ocean, status of decommissioning, and needs for long-term monitoring of the environment are discussed. [ABSTRACT FROM AUTHOR]

Following the permanent shutdown of Kori Unit 1 in June 2017, the Republic of Korea has been preparing for full‐scale decommissioning work. In addition, the design life of 12 units will expire by 2030. If decommissioning begins without initially extending the lifespan of nuclear reactors, massive amounts of decommissioning wastes will be generated in a short period. The total amount of radioactive wastes generated during the dismantling of a pressurized water reactor is estimated as 6200 tons, and approximately 70% of the total radioactive wastes are classified as metal wastes. Self‐disposal through the decontamination of contaminated metals can contribute to the economic feasibility of decommissioning nuclear power plants because it can reduce the disposal cost of medium‐ and low‐level radioactive wastes. Therefore, this study evaluated the possibility of self‐disposal of steam generators that may occur during future decommissioning. The radioactivity analysis data on transferring the replaced steam generator of Hanul Unit 1 were used as the source term. The decontamination factor was calculated by applying 200 units from 1200 to 2000, and the radiation dose was evaluated using the RESRAD‐RECYCLE code. Consequently, the single‐nuclide concentration and sum of the allowable concentration fraction for mixed radionuclides at a decontamination factor of 1400 were below the regulatory requirements; however, the dose evaluation results exceeded the allowable dose in some scenarios. The decontamination factor was 2000, when the dose evaluation results for all scenarios met the regulatory requirements. [ABSTRACT FROM AUTHOR]

A simple underwater noise model suitable for use with explosive severance of well conductors and piles during the decommissioning of oil and gas subsea structures is introduced and evaluated against data from five projects in the US. This study focuses on a novel model for the determination of sound exposure levels. The model has been developed to enable determination of impact areas for marine mammals and fish. Simulated received underwater sound exposure levels were significantly correlated with measurements for all scenarios. The maximum total error achieved between simulations and measurements was 2.6%, suggesting that predictions are accurate to within 3% of the average measurement. A low relative bias was observed in the simulations when compared to measured values, suggesting only a small systematic underestimate (≤0.5% of average measurement) for most severance operations and a small overestimate (0.14%) for open water blasts. [ABSTRACT FROM AUTHOR]

A simple underwater noise model suitable for use with explosives in the decommissioning of oil and gas subsea structures is introduced and evaluated against data from five projects in the US. The performance of the model is compared to four existing models for open water blasts, and for the severance of well conductors and piles. Simulated received underwater sound pressure levels were significantly correlated with measurements for all scenarios. The maximum total error achieved between simulations and measurements was 3.5%, suggesting that predictions are accurate to within 4% of the average measurement. A low relative bias was observed in the simulations when compared to measured values, suggesting only a small systematic underestimate (≤1% of average measurement) for most severance operations and a small overestimate (1.34%) for open water blasts. [ABSTRACT FROM AUTHOR]

To retrieve the fuel debris in Fukushima Daiichi Nuclear Power Plants (1F), it is essential to infer the fuel debris distribution. In particular, the molten metal spreading behavior is one of the vital phenomena in nuclear severe accidents because it determines the initial condition for further accident scenarios such as molten core concrete interaction (MCCI). In this study, the fundamental molten metal spreading experiments were performed with different outlet diameters and sample amounts to investigate the effect of the outlet for spreading-solidification behavior. In the numerical analysis, the moving particle full-implicit method (MPFI), which is one of the particle methods, was applied to simulate the spreading experiments. In the MPFI framework, the melting-solidification model including heat transfer, radiation heat loss, phase change, and solid fraction-dependent viscosity was developed and implemented. In addition, the difference in the spreading and solidification behavior due to the outlet diameters was reproduced in the calculation. The simulation results reveal the detailed solidification procedure during the molten metal spreading. It is found that the viscosity change and the solid fraction change during the spreading are key factors for the free surface condition and solidified materials. Overall, it is suggested that the MPFI method has the potential to simulate the actual nuclear melt-down phenomena in the future. [ABSTRACT FROM AUTHOR]

Mechanical circulatory support using left ventricular assist devices (LVADs) has transformed management of patients with end-stage heart failure with more patients on LVAD therapy surviving long enough to necessitate either device explantation or decommissioning. Usually, there is foreign material retained following these procedures that requires maintaining antiplatelet and/or anticoagulant therapy. However, there is no consensus on optimal management of antiplatelet and anticoagulant therapy following LVAD explantation or decommissioning. We conducted a scoping review of antiplatelet and anticoagulation strategies, searching EMBASE, PubMed and CENTRAL. A total of 15 case reports and series encompassing 38 patient cases were found that met inclusion criteria. There was a heterogeneity of LVAD types and techniques used for explantation and decommissioning. Most reports identified in our review maintained patients on a vitamin K antagonist for at least 3 months post-explantation or decommissioning with or without concomitant antiplatelet therapy with low-dose aspirin. However, there was no single agreed-upon optimal strategy for antiplatelet and anticoagulant use post-procedure. Factors such as the degree of foreign material retained following device explantation or decommissioning and whether there is another indication for anticoagulation or antiplatelet use must be considered. A lack of overall consensus indicates that more studies are needed in this area to establish definitive guidelines around antiplatelet and anticoagulant therapy following LVAD explantation or decommissioning. [ABSTRACT FROM AUTHOR]

Although nuclear power generation has stopped in 1990 and the decision has been taken to accelerate the process towards an "immediate dismantling" of the Enrico Fermi plant, the people of Trino (Po plain, Piedmont) find it difficult to imagine and plan a post-nuclear territory. This contribution tries to explain why the post-nuclear phase is not so obvious and the reasons that are largely holding it back. From a diachronic perspective, this article shows how the various actors and social groups of this territory went through the phase of decline in nuclear production (referendum of 1987 decreeing a moratorium on the construction of new plants), the uncertain phase of the shutdown of nuclear power plants production (1990), and then passive safety (1990-2003) and dismantling (since 2003) to settle in the lasting uncertainty of dismantling and waste management, waiting for a national repository that, in Italy, has still not been realized. Despite projects and initiatives to imagine and build post-nuclear territories through the development of green and quality tourism or renewable energies, most of the actors involved at the local scale remain in rhetoric and actions tending to confirm the continuity and legitimacy of nuclear power on its territory, sometimes against their own beliefs. In view of the demographic decline and the process of the deindustrialization of its territory, nuclear power, with, on the one hand, jobs in dismantling and, on the other hand, the state compensation funds paid to municipalities for the hosting of radioactive waste, remains an essential sector of this territory.

According to common sense, the abrogative anti-nuclear referendum of 1987 and the cessation of nuclear power production in 1990 would certify Italy's "exit from nuclear power". However, the decommissioning of sites shows that phasing out nuclear power is a long and complex process. The Italian case is interesting because it is one of the nuclear countries among the first to stop its production by confirming again by referendum in 2011 its willingness to give up this energy. This contribution focuses more particularly on the rhetoric of critics and denunciation used by local environmental associations concerning the nuclear sector, in general, and the decommissioning at the Saluggia site in Piedmont, in particular. We show that, despite their stated desire to “end with nuclear power” in Italy and free their territories from radioactive waste, these local ecologists remain entangled in a logic of hand-to-hand struggle with the nuclear industry and, of the same time, of dependence vis-à-vis this same industry. We thus observe an evolution of these environmental activists rhetorics of denunciations and critics of politico-ideological nuclear power articulating different scales of analysis (local, national, international) expressed in the 1980s by elected officials and environmental activists and from the Italian far left, in the years 2000 and 2010, we shifted to rhetoric of depoliticized denunciations, very concentrated at the local level of the Saluggia site and targeting almost exclusively the decommissioning agency.

By following the work of organizing and temporalizing the action, this article traces the development in the 2000s of a new dismantling policy; then its implementation within an operator, the French Atomic Energy Commission (CEA). In 2015, in response to criticism from safety authorities for recurrent delays, the CEA developed a new temporal strategy, differentiating between priority projects and mothballed projects: this makes it possible to respect the principle of immediate dismantling enshrined in the law while putting less urgent projects on hold. This new strategy, negotiated between safety authorities and operators, reconfigures their relations and their respective roles in developing this nuclear policy.