Studsvik is a supplier of nuclear analysis software and specialised services to the international nuclear industry. The company is headquartered in Nyköping, Sweden, and has five divisions: Sweden, United Kingdom, Germany, the United States, and Global Services. There are 1,100 employees in 8 countries. The company's shares are listed on the Nasdaq OMX Stockholm.Studsvik offers advanced technical services to the international nuclear power industry in areas including fuel analysis software, waste treatment, decommissioning, engineering and services, and operating efficiency.The company was founded in Stockholm in 1947, as AB Atomenergi, to develop and operate nuclear power stations in Sweden. Originally it was 57% government-owned; during the 1960s, the government acquired the entirety of the shares, but then in the 1970s, government funding was reduced and the company became entirely industry-owned and changed its name to Studsvik Energiteknik AB. Studsvik is the name of the property east of Nyköping, where the business had moved during the 1960s.In 2005, Studsvik's two research reactors, R2 (50 MW) and R2-0 (1 MW), were decommissioned. There was also a third research reactor in Studsvik called FR-0, which was a zero-power fast reactor with low power output. It was operated 1964–1971 and is now dismantled.In the 1990s and 2000s, the company acquired the German SINA Industrieservice GmbH; the nuclear power division of the Norwegian Scandpower AS; the German Industrieanlagen Fritz & Marx; the British Environmental Remediation Services Ltd.; the ISS international health physics group; the American RACE LLC; the German Dr Fary GmbH & Co KG and the English Alpha Engineering Ltd.Studsvik has a radioactive waste processing facility in Erwin, Tennessee in the US, which opened in 2000. The facility operates in partnership with Waste Control Specialists in Andrews County, Texas. With Washington Group Inc., Studsvik co-owns THOR Treatment Technologies, LLC. Studsvik also operates a facility in Memphis, TN on President's Island, which is in the Mississippi River. In January 2008, Studsvik obtained a licence for a radioactive metal recycling plant near Sellafield in England. Studsvik's metal-recycling facility, designed to assist the Nuclear Decommissioning Authority's National LLW Strategy, opened in September 2009. Decontaminating metallic waste both greatly reduces the quantity of waste requiring to be disposed of at the LLW Repository, and recovers valuable metal.Studsvik is the global leader in fuel vendor-independent software for reactor analysis. Studsvik software has been used throughout the world for light water reactor core design, analysis, and operational support.In April 2011, Studsvik praised defeat of a bill in the US State of Tennessee legislature that would have prohibited dumping low-level nuclear waste in landfills. Both of Studsvik's US processing facilities are in Tennessee. Tennessee is one of the few states that allows dumping of low-level nuclear waste in landfills and the only state that allows dumping of nuclear waste on a single-license, rather than seek government approval for each shipment of waste.
Irradiation assisted stress-corrosion cracking (IASCC) is a form of intergranular stress corrosion cracking that occurs in irradiated austenitic alloys. It requires an irradiated microstructure along with high temperature water and stress. The process is ubiquitous in that it occurs in a wide range of austenitic alloys and water chemistries, but only when the alloy is irradiated. Despite evidence of this degradation mode that dates back to the 1960s, the mechanism by which it occurs has remained elusive. Here, using high resolution electron backscattering detection to analyze local stress-strain states, high resolution transmission electron microscopy to identify grain boundary phases at crack tips, and decoupling the roles of stress and grain boundary oxidation, we are able to unfold the complexities of the phenomenon to reveal the mechanism by which IASCC occurs. The significance of the findings impacts the mechanical integrity of core components of both current and advanced nuclear reactor designs worldwide.
This paper presents simulations of the xM3 power ramp with the fuel performance code ALCYONE performed during an international simulation exercise organized within the Organisation for Economic Co-operation and Development/Nuclear Energy Agency Power to Melt and Maneuverability project. The xM3 test involved a large-grain UO2 fuel from Mitsubishi Heavy Industries cladded with Zirlo and pre-irradiated in a Spanish pressurized water reactor up to an average burnup of 27 GWd/tU-1. It was then submitted to a staircase ramp protocol in the R2 reactor at Studsvik (Sweden) with 10 successive steps of 5 kW center dot m-1 up to a ramp terminal level of 70 kW center dot m-1. The fuel rodlet did not fail, and detailed post irradiation examinations performed during the Studsvik Cladding Integrity Project II evidenced recrystallization of the pellet center around a central hole, interpreted as signs of fuel melting.In this paper, simulations with ALCYONE of the xM3 power ramp, including an advanced model for fuel melting based on thermodynamic equilibrium calculations, are detailed. The model relies on the determination of the liquid fuel fraction evolution with temperature that is used to obtain a continuous description of the material properties during phase change. In consequence of the incorporation of rare earths and actinides in the bulk of the fuel, distinct solidus and liquidus temperatures are estimated. It is shown that the observed central hole and recrystallized central part of the pellet could be the consequence of totally melted fuel (liquidus is reached), partially melted fuel (solidus is reached), or pore migration only.
The 3-year Euratom project, “HARPERS: HARmonised PracticEs, Regulations and Standards in waste management and decommissioning,” aims to establish and clarify the benefits and added value of more aligned practices, methodologies, and approaches in decommissioning and radioactive waste management, including possibilities for shared processing, storage and disposal facilities between Member States (MS). HARPERS aims to reinforce the activities of the European Joint Programme on Radioactive Waste Management (EURAD), Pre-disposal Treatment of European Radioactive Waste Streams (PREDIS) and Stakeholder-based Analysis of Research for Decommissioning (SHARE) projects. HARPERS will also connect with the wider European Community through, e.g., SNETP, DigiDECOM, NEA, IGDTP, IAEA, ENSREG, ERDO and will encourage interaction between different national programmes. The project will evaluate the Strengths, Weaknesses, Opportunities and Threats, identify the obstacles & issues preventing implementation of a more common regulatory approach, covering e.g., nuclear, industrial safety, occupational health, environmental, ... aspects. A TECOP analysis will identify a multitude of potential changes, which will be reviewed further in terms of strategic impacts for stakeholders. The high-level benefits of more aligned practices, methodologies and approaches are related to 1) greater business opportunities 2) better understanding between diverse groups serving wider markets 3) improved cost efficiency 4) waste minimisation and 5) improved final disposability of waste. This paper gives a general overview on HARPERS and presents results of the two on-line workshops on WP5 Advanced Technologies.
The Euratom HARPERS (HARmonised PracticEs, Regulations and Standards in waste management and decommissioning) project aims to establish and clarify the benefits and added value of a more aligned practices, methodologies and approaches for prioritised topics related to decommissioning and initial phases of radioactive waste handling, including shared processing facilities between Member States (MS). The HARPERS project has a two-phase approach: the first phase involves engaging with Stakeholders to assess needs and pros/cons for harmonisation and to identify priority areas for deeper analysis. The second phase will pursue deeper engagement with Stakeholders to further assess the highest ranked priority areas in the three technical Work Packages. In Phase 2 the industry and business impacts resulting from the project findings will be also evaluated. Work Package 4 (WP4) of HARPERS project is focused on addressing the most important conditions and opportunities for promoting Circular Economy approaches when managing materials and waste arising from nuclear decommissioning across Europe. For the prioritisation of needs and opportunities for Circular Economy considerations, a detailed list of topics (challenges/needs - related to alignment of practices and approaches) has been developed. Topics were clustered into 7 main categories and discussed with interested external stakeholders during dedicated on-line workshops conducted in January and February 2023. Criteria for the prioritisation of topics, based on drivers relating to societal impacts, actor-specific impacts, scientific impacts and financial impacts, have been developed and discussed during the workshops too. This work presents the preliminary outcomes of the two online workshops.
Collimated Gamma Transmission Micro-Densitometry (GTMD) is a novel technique proposed to investigate local density variations of nuclear fuel in PIE, with a high spatial resolution. In this work, the first experimental tests of a gamma micro-densitometer are presented and the performance is characterized. The experimental procedures are described, including the aligning process and the calibration methodology. The results demonstrated that for the calibration samples with a thickness above 5 mm, a local density was obtained with a maximum discrepancy of about 2% and a spatial resolution of about 280 µm. The setup was used for the first test on an irradiated ADOPTTM fuel pellet slice. From the measurement, an average bulk density of about 9.58 g/cm3 was calculated and local density features were observed, possibly related to rim effects or the presence of local cracks. The information acquired also presented valuable information for possible improvements in the setup’s performance.
