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Le Clere S.,Sellafield Ltd.
Proceedings of the International Conference on Radioactive Waste Management and Environmental Remediation, ICEM | Year: 2011

The Sellafield Magnox Swarf Storage Silo (MSSS) was constructed to provide an underwater storage facility for irradiated magnox cladding metal swarf, as well as miscellaneous beta-gamma waste from several sources. Liquid effluent arisings from hazard reduction activities at this facility represent the toughest effluent treatment challenge within the company's Legacy Ponds & Silos portfolio. The key requirement for hazard reduction has generated many substantial challenges as the facility is readied for decommissioning. This has demanded the production of carefully thought out strategies for managing, and overcoming, the key difficulties to be encountered as hazard reduction progresses. The complexity associated with preparing for waste retrievals from the Magnox Swarf Storage Silo, has also generated the demand for a mix of creativity and perseverance to meet the challenges and make progress. Copyright © 2011 by ASME. Source


Mackintosh A.,Sellafield Ltd.
Proceedings of the International Conference on Radioactive Waste Management and Environmental Remediation, ICEM | Year: 2011

For over five decades the Sellafield Site has been central to the UK's nuclear programme. Sellafield Ltd is managed by NMP (Nuclear Management Partners), a consortium of URS, AMEC and AREVA and is focussed on the decommissioning of historical facilities. When the activity of Decommissioning commenced in the late 1980's the site focus at that time was on commercial reprocessing and waste management. Now through the implementation of an integrated company change programme, emphasis has shifted towards accelerated risk and hazard reduction of degraded legacy plants with nuclear inventory whilst ensuring value for money for the customer, the Nuclear Decommissioning Authority (NDA). This paper will describe the management approach that is being taken and the planning tools that are being applied by the Site owners in delivering an integrated change programme across the Decommissioning Directorate. The paper will explain how the management approach to change uses Peer Assist, Rapid Improvement Events, Organisational Review Self Evaluation, Value Stream Analysis and Accelerated Improvement Events as improvement tools. Use of these has enabled downsizing of the organisation, driven out hundreds of man day efficiencies within the maintenance and asset management areas, improved the management of spares reducing annual costs by £1000's, improved Commercial practices by fast tracking the preparation of invitations to tender for critical contracts, rolled back radiological control areas and enabled quicker access to the workface at a reduced cost. This paper will explain in detail how the Decommissioning Directorate Programme Office has implemented planning tools such as governance, identification of opportunities, benefit evaluation and prioritisation and sanction of the optimum improvements and how through the use of a balanced scorecard, delivery of the improvements has been measured ensuring that the targets are met. Finally, the paper will discuss how the Performance Improvement Action Plan has proved to be critical for presenting the change plan and its delivery to key stakeholders, Government owners and powerful regulators. Overall, this paper provides an insight into how a massive change programme is being managed within one of the world's highest regulated industries. Copyright © 2011 by ASME. Source


Webborn B.,Sellafield Ltd.
Topical Meeting Held by the ANS Nuclear Criticality Safety Division, NCSD 2013 - Criticality Safety in the Modern Era: Raising the Bar | Year: 2013

There are a number of hazards associated with fire and firefighting on a nuclear site; for example criticality, radiological and conventional hazards. These hazards can impact on a number of areas with varying degrees of risk; including firefighters, personnel in the facility, personnel/public outside the facility, and damage to the facility itself. In the UK, the primary safety requirement is to reduce overall risk to ALARP (As Low As Reasonably Practicable - this is comparable to ALARA). The difficulty with consideration of holistic ALARP is that risks are generally assessed by different disciplines. One can be tempted to take a conservative approach in each assessment, which could increase overall risk; for example, prohibiting the use of water for firefighting purposes may reduce the criticality risk but significantly increase the radiological/conventional risks. At Sellafield a multidisciplinary approach is being developed for fire safety assessment; including criticality, radiological and conventional safety assessors, plant personnel and firefighters. Consideration is given to a common aim for assessment of risk to ensure a balanced approach; for example the use of best estimate assessment rather than a traditional conservative approach. Specifically the following is assessed: identifying the potential locations and nature of a fire, the potential consequences, means of prevention or of reducing likelihood/consequence and the most appropriate way to firefight, should a fire occur. This paper presents a summary of the findings. Source


Denton J.S.,Los Alamos National Laboratory | Denton J.S.,Sellafield Ltd. | Murrell M.T.,Los Alamos National Laboratory | Goldstein S.J.,Los Alamos National Laboratory | And 3 more authors.
Analytical Chemistry | Year: 2013

Recent advances in high-resolution, rapid, in situ microanalytical techniques present numerous opportunities for the analytical community, provided accurately characterized reference materials are available. Here, we present multicollector thermal ionization mass spectrometry (MC-TIMS) and multicollector inductively coupled plasma mass spectrometry (MC-ICP-MS) uranium and thorium concentration and isotopic data obtained by isotope dilution for a suite of newly available Chinese Geological Standard Glasses (CGSG) designed for microanalysis. These glasses exhibit a range of compositions including basalt, syenite, andesite, and a soil. Uranium concentrations for these glasses range from ∼2 to 14 μg g-1, Th/U weight ratios range from ∼4 to 6, 234U/238U activity ratios range from 0.93 to 1.02, and 230Th/238U activity ratios range from 0.98 to 1.12. Uranium and thorium concentration and isotopic data are also presented for a rhyolitic obsidian from Macusani, SE Peru (macusanite). This glass can also be used as a rhyolitic reference material, has a very low Th/U weight ratio (around 0.077), and is approximately in 238U-234U- 230Th secular equilibrium. The U-Th concentration data agree with but are significantly more precise than those previously measured. U-Th concentration and isotopic data agree within estimated errors for the two measurement techniques, providing validation of the two methods. The large 238U-234U-230Th disequilibria for some of the glasses, along with the wide range in their chemical compositions and Th/U ratios should provide useful reference points for the U-series analytical community. © 2013 American Chemical Society. Source


Carlisle D.,Sellafield Ltd.
Proceedings of the International Conference on Radioactive Waste Management and Environmental Remediation, ICEM | Year: 2013

The Pile Fuel Storage Pond (PFSP) was built in 1948/50 to treat materials from the Windscale Piles. Multiple operational regimes over the intervening 60 years have resulted in a complex inventory of spent nuclear fuels, solid and liquid intermediate level wastes. A coordinated programme of work, designed to retrieve and safely dispose of the pond contents, has been implemented to enable the decommissioning of the facility. The long period of passive storage operations which preceded the implementation of the programme meant that the operator was faced with a dual challenge of providing new technical capability and changing a working culture that was inappropriate for the dynamic environment required to successfully deliver the programme. It was recognised that the nature of the programme meant that implementing a standard manufacturing approach to operations would not be appropriate. In order to create a dynamic retrievals focussed working culture, the operator has vigorously embraced change programmes aimed at improving a number of working practices including encouraging innovation, managing integrated but flexible production schedules, and encouraging workface problem solving. The combined impact of beginning to resolve the technical challenges and focussing on the delivery culture has resulted in the facility making a step change towards becoming fully retrievals operations focussed. Copyright © 2013 by ASME. Source

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