CHALLENGE: Surveillance and Maintenance

Transcription

1 CHALLENGE: Surveillance and Maintenance

2 CONTENTS Glovebox Laboratories 7. Cost Table Chemical Processing Plants 14. Cost Table 2

3 1. GLOVEBOX LABORATORIES 3

4 This Challenge Statement seeks innovative ideas to address the costs associated with the surveillance and maintenance of nuclear laboratories containing gloveboxes. Many designs exist, however a glovebox can be thought of as a sealed, but ventilated, container generally comprising a steel frame and panels made from polymers such as Perspex. Long PVC gloves are built into the panels such that operators can place their hands into them and work on hazardous materials within the glovebox, such as plutonium. Conventional laboratory equipment, e.g. microscopes or furnaces, are housed within the gloveboxes and often remain in place after operations. A typical suite ofgloveboxes in a relatively modern lab at Sellafield Front of an older glovebox, note old gloves posted inside and blanking plugs fitted in their places Used gloveboxes are typically contaminated with residues of materials which produce alpha radiation, and may even be capable of further nuclear or chemical reactions. The principal requirement now is to prevent the release, and human inhalation or ingestion, of any remaining process materials. The materials must either be removed or permanently immobilised, otherwise the structural integrity and ventilation of the glovebox must be constantly monitored and preserved until decommissioning (dismantling and disposal) finally takes place. Gloveboxes, and the plants housing them, can be up to 60 years old. As a result, many are degrading and have significant asset care issues. 4

5 KEY FACTS Hazardous Materials The residual nuclear material within the gloveboxes is primarily comprised of oxides of uranium and plutonium, and their associated daughter products. Bulk residues were removed after operations, but the effectiveness of cleaning was limited by constraints such as access and the availability of waste routes. The remaining material is generally in the form of a dry powder, although larger solids and contaminated liquids are sometimes present. The location and exact quantity of material is not always known; it might be spread across all exposed surfaces within the box or held up within specific features or equipment within it, or it may have spread to the ventilation system. Workers at the Sellafield Mixed Oxide (MOX) Fuel Plant Constraints Any work that involves breaking the containment of a glovebox requires operators to wear air-fed suits and the area to be tented, i.e. temporary barriers and containment must be provided. Certain materials cannot be introduced into a glovebox, for example a moderator such as water or graphite (light elements with a low atomic mass), as they could cause a criticality (a nuclear reaction). Dressing for work in an alpha-contaminated laboratory Configuration There are approximately 350 gloveboxes in total on the Sellafield site, mainly concentrated in a half- dozen or so plants. These plants comprise laboratories, each typically tens of metres long and wide, containing suites of interconnected gloveboxes forming process lines. Gloveboxes are generally cuboid and vary in size from one to several cubic metres. Typically, all sides are accessible from the floor or via installed or temporary access platforms. Gloveboxes generally incorporate a posting port, usually 250mm in diameter, and a number of 125mm diameter glove ports as well as other, smaller, ventilation, service and instrumentation connections. Some of the oldest Sellafield gloveboxes, note the almost opaque, aged Perspex windows 5

6 DESIRED OUTCOMES The desired, overall, outcome from this Challenge Statement is the introduction of innovative strategies, methods and technologies which significantly reduce the cost of preserving nuclear plants with gloveboxes in a post-operational state of surveillance and maintenance. The current constraints derive from the presence of residues of hazardous materials that could be released from the gloveboxes, potentially causing harm to those in the immediate vicinity or, in a worst case, to the public outside the site. These constraints mean that high levels of spending are necessary in order to maintain the gloveboxes and their associated plants in a condition which is not that different to when they were actually processing the materials. The cost drivers for the surveillance and maintenance of post-operational glovebox plants thus include: Manual interventions, e.g. inspection, monitoring, maintenance, testing and routine replacements of equipment, all of which expose operators to both nuclear and conventional safety risks Continued operation and upkeep of ventilation, environmental monitoring and security systems Asset care, both in terms of routine maintenance and unique projects to address obsolescence and age Wastes deriving from all of the above, noting the high cost of disposing of any nuclear waste Consumption of energy and raw materials, i.e. electricity, water, steam, etc. Management overhead, including maintenance of the nuclear Safety Case, regulator and stakeholder management, etc. In order to address the primary cost drivers the innovations will have to deliver the removal, or permanent immobilisation, of the material residues. Highly desirable consequences of achieving this are likely to include (some of which are pre-surveillance and maintenance operations): An ability to switch off glovebox and laboratory ventilation systems A reduced requirement for environmental monitoring and security systems A reduced requirement for environmental monitoring and security systems A reduction in waste generation A reduction in the consumption of energy and raw materials A reduction in management overhead. It is also recognised that partial reductions in some of the cost drivers may be achieved through innovations that do not remove or immobilise inventory, e.g. remote monitoring techniques which reduce the requirement for manual interventions or strategies which prolong asset life through limited, or no, additional expense. Such innovations are equally relevant and may be considered in conjunction with those that directly deliver material removal or immobilisation. It is further recognised that an ideal plant status for surveillance and maintenance may exist, where all hazardous materials are either removed or permanently immobilised and the plant requires no further manual interventions, and may even become unmanned, i.e. where the risk to personnel and the consumption of resources are at an absolute minimum. Innovations that move the plant towards such a status, or actually deliver that status, are thus the focus of this Challenge Statement. 6

7 COST TABLE The following table illustrates the key factors which drive surveillance and maintenance requirements, the current means of meeting those requirements and the typical costs, resources utilised and waste generated, for a plant which includes 10 s of gloveboxes. A recent study suggests a saving in the order of 30 million (lifetime) may result from achieving a plant which requires no further manual interventions, and may even become unmanned. 7

8 COST TABLE Driver Requirement Current means of meeting requirement Remaining nuclear materials within gloveboxes Maintain: Containment Environmental monitoring Safety Case Security Provisions Waste routes Operational readiness of ventilation systems, sumps, level monitoring equipment. High-Efficiency Particulate Arrestance (HEPA) filter changes (undertaken every 10 years). Glove and posting port plastic caps changes (undertaken every 3 years) Operator rounds checking glovebox pressure and glove condition Periodic decontamination activities of glovebox and building Waste handling and consignment operations Facility Examination, Inspection Maintenance and Testing (EIM&T) activities on plant and equipment Environmental monitoring & security provisions Waste costs (lifetime, based on volume) Typical Cost Typical Resource Utilised Waste Generated < 50k/10 years Plant personnel Waste filters (in the region of 0.5m 3 /10 years) Plutonium Contaminated Material (PCM) waste, approximately 1m 3 /10 years Low Level Waste (LLW) < 50k/year Plant personnel Waste gloves (in the region of 0.2m 3 /year) PCM waste, approximately < 50k/year Plant personnel N/A < 50k/year Plant personnel In the region of 1m 3 /year PCM waste, approximately 1m 3 /year LLW < 500k/year Plant personnel N/A < 100k/year < 1m/year Plant personnel & site species HP&S personnel & CNC Officers & Guard Force 0.1m 3 /year PCM waste, 1m 3 /year LLW N/A < 500k/year N/A Covers all of above Continued overleaf... 8

9 COST TABLE CONTINUED... Driver Requirement Current means of meeting requirement Age of facility and past level of care Manned occupancy of the facility Nuclear site licence conditions. Asset care projects, ranging from relatively minor (such as roof handrail replacement) to major (such as facility power supply upgrades) Provide electrical power (including some UPS supplies) for ventilation fans, facility instrumentation, lighting and small power Provide steam for heating of the facility Safety Case and documentation changes Maintenance and risk based replacement of required assets. Typical Cost Circa 7m between now and Projects range from 10k to 800k in estimated value. Typical Resource Utilised Project and engineering work delivered by Sellafield Ltd and supply chain resources, the number of which depends upon project size Electricity < 500k/year N/A N/A Steam < 500k/year N/A N/A Short Term (ST) (3-yearly) and Long Term (LT) (10-yearly) Periodic Review (PR) of the Safety Case. Implementation of improvement works as recommended by periodic Safety Case reviews < 50k/STPR < 100k/LTPR Project and engineering work delivered by Sellafield Ltd and supply chain resources, the number of which depends on the scope of the review Waste Generated Dependent on the scope of each individual project N/A Dependent on outcome of periodic reviews but can result in significant project work. 9

10 2. CHEMICAL PROCESSING PLANTS 10

11 This Challenge Statement seeks innovative ideas to address the costs associated with the Surveillance & Maintenance of nuclear chemical process plants. These comprise large, shielded cells containing stainless steel vessels and pipework. Isometric view of a chemical process cell: <50m high, <10m2 footprint, <5m thick reinforced concrete walls, multiple main process vessels, many pipes and ventilation ducts, mild steel supports, <15 minutes human - working time due to radiation and heat The interconnected stainless steel tanks, columns and vessels can be several metres in length or diameter, weighing several tonnes. This equipment was used to undertake chemical reactions and processes on the radioactive feedstock. Fuel reprocessing plants, e.g. ThORP and Magnox, contain tens of cells, linked together to form a complete separation process. Vessels and pipes, and some cells also, can be contaminated with materials which emit radiation. The principal requirements are to guard against the release of these materials and to minimise the radiation dose to operators. The vessels, cells and plants are ventilated by separate, high integrity systems. Cells are provided with sumps to collect and dispose of any spills. The radioactive materials must either be removed or permanently immobilised, otherwise the structural integrity and ventilation of the pipes, vessels and cells must be constantly monitored and preserved until decommissioning (dismantling and disposal) finally takes place. The scrubber cell in the Thermal Oxide Reprocessing Plant (ThORP) during construction. Note access doorway (right), sealed on commissioning. The facilities can be up to 60 years old, with all the attendant condition and asset care issues. 11

12 KEY FACTS Hazardous Materials Residual materials in nuclear chemical plants comprise a broad range of radioactive compounds, principally inorganic. Bulk residues were removed after operations, but the effectiveness of the wash out was limited by constraints such as access and the availability of waste routes. The materials remaining in pipes, vessels and cells will be in a variety of forms ranging from liquors and sludges, to loose dry powders, to fixed, hard, scale-like deposits. Generally, such material cannot be removed using the existing plant processes and chemicals. Constraints Some cells are not man accessible due to prohibitively high dose rates, indeed some have been physically sealed since construction. Access into these cells can be highly constrained; limited to a small number of engineered openings, typically no more than 30cm in diameter, which are usually filled with removable shielding plugs. Man access is possible into most other cells, but radiation dose management is an issue. Working times can be severely limited. Heat stress is another factor that can reduce working times. Gamma image showing radiation hotspots after plant washout Radiation source mapping showing concentration at base of vessel Configuration There are in the region of 200 chemical process cells on the Sellafield site, mainly concentrated in around two dozen plants. The majority of cells allow at least some level of man access, but those which do not represent some of the hardest nuclear challenges anywhere in the world. The location and exact quantity of materials within individual vessels and pipes is not always accurately known. It might be spread across all internal surfaces or held up within specific features or areas. Some vessels contain tubes or stirrers, some hold packing rings. All have bases where materials naturally accumulate. Past incidents have left residual contamination in the cells and sumps. Some cells have a stainless steel lining whereas others do not, resulting in radioactive contaminants leaching into the surface of the concrete structure itself. In a few, extreme cases corrosion has affected the mild steel supports for vessels. 12

13 DESIRED OUTCOMES The desired, overall, outcome from this Challenge Statement is the introduction of innovative strategies, methods and technologies which significantly reduce the cost of preserving nuclear chemical process plants in a post-operational state of Surveillance and Maintenance. The current constraints derive from the presence of residues of hazardous materials that could be released from the pipes, vessels and cells, potentially causing harm to those in the immediate vicinity or, in a worst case, to the public outside the site. These constraints mean that high levels of spending are necessary in order to maintain the plants in a condition which is not that different to when they were actually processing the materials. The cost drivers for the surveillance and maintenance of post-operational nuclear chemical plants thus include: Manual interventions, e.g. inspection, monitoring, maintenance, testing and routine replacements of equipment, all of which expose operators to both nuclear and conventional safety risks Continued operation and upkeep of ventilation, environmental monitoring and security systems Asset care, both in terms of routine maintenance and unique projects to address obsolescence and age Wastes deriving from all of the above, noting the high cost of disposing of any nuclear waste Consumption of energy and raw materials, i.e. electricity, water, steam, etc. Management overhead, including maintenance of the nuclear Safety Case, regulator and stakeholder management, etc. In order to address the primary cost drivers the innovations will have to deliver the removal, or permanent immobilisation, of the material residues. Highly desirable consequences of achieving this are likely to include: An ability to switch off vessel, cell and building ventilation systems A reduced requirement for environmental monitoring and security systems A reduced requirement for manual interventions A reduction in waste generation A reduction in the consumption of energy and raw materials A reduction in management overhead. It is also recognised that partial reductions in some of the cost drivers may be achieved through innovations that do not remove or immobilise inventory, e.g. remote monitoring techniques which reduce the requirement for manual interventions or strategies which prolong asset life through limited, or no, additional expense. Such innovations are equally relevant and may be considered in conjunction with those that directly deliver material removal or immobilisation. It is further recognised that an ideal plant status for surveillance and maintenance may exist, where all hazardous materials are either removed or permanently immobilised and the plant requires no further manual interventions, and may even become unmanned i.e. where the risk to personnel and the consumption of resources are at an absolute minimum. Innovations that move the plant towards such a status, or actually deliver that status, are thus the focus of this Challenge Statement. 13

14 COST TABLE The following table illustrates the key factors which drive surveillance and maintenance requirements, the current means of meeting those requirements and the typical costs, resources utilised and waste generated, for a nuclear chemical process plant containing 10 cells. A recent study suggests a saving in the order of 100 million (lifetime) may result from achieving a plant which requires no further manual interventions, and may even become unmanned. 14

15 COST TABLE Driver Requirement Current means of meeting requirement Remaining nuclear inventory within vessels and pipework Maintain: Containment Environmental monitoring Safety Case Security Provisions Waste routes Operational readiness of ventilation systems, sumps, level monitoring equipment. Examination, Inspection, Maintenance & Testing (EIM&T) tasks including inspection of the cell, sumps instruments and major vessels. Operational tasks, routine monitoring, maintain & balancing ventilation including High- Efficiency Particulate Arrestance (HEPA) filter changes. Environmental monitoring & security provisions Waste costs (lifetime, based on volume) Typical Cost < 5m/year < 5m/year < 1m/year Typical Resource Utilised Plant personnel & site specialists Plant personnel Health, Physics & Safety personnel & Security provisions Waste Generated 0.1m 3 /year Intermediate Level Waste (ILW) 1m 3 / year Low Level Waste (LLW) 0.1m 3 /year ILW 1m 3 /year LLW N/A <50k/year N/A Covers the above Continued overleaf... 15

16 COST TABLE CONTINUED... Driver Requirement Current means of meeting requirement Age of facility and past level of care Manned occupancy of the facility Nuclear site licence conditions. Asset care projects, ranging from relatively minor (such as roof handrail replacement) to major (such as facility power supply upgrades) Provide electrical power (including some UPS supplies) for ventilation fans, facility instrumentation, lighting and small power Provide steam for heating of the facility Safety Case and documentation changes Maintenance and risk based replacement of required assets. Typical Cost Approximately 1m/year. Projects range from 5k to 2m in estimated value Typical Resource Utilised Project and engineering work delivered by Sellafield Ltd and supply chain resources, the number of which depends upon project size Electricity < 500k/year N/A N/A Steam < 1m/year N/A N/A Short Term (ST) (3-yearly) and Long Term (LT) (10-yearly) Periodic Review (PR) of the Safety Case for the cell. Implementation of improvement works as recommended by periodic Safety Case reviews < 500k/STPR < 1m/LTPR Project and engineering work delivered by Sellafield Ltd and supply chain resources, the number of which depends on the scope of the review Waste Generated Dependent on the scope of each individual project N/A Dependent on outcome of periodic reviews but can result in significant project work. 16

17 Get involved. Should any of the challenges presented be of interest to you and your organisation, and you feel that you have the innovative technologies or techniques to help deliver the desired solutions, then we d like to hear from you. Visit to download or complete an application form online, or you can request an application form by at apply@gamechangers.technology The decommissioning of the Sellafield site is anticipated to take over 100 years, cost in excess of 50bn and creates challenges never encountered before. These challenges require investment in innovative technologies, concepts and methods. Sellafield Ltd actively seek to engage with Game Changers - businesses, academia and individuals who can bring their innovations into the nuclear arena and help achieve the goals of accelerating the decommissioning programme whilst also reducing costs and upholding Sellafield s commitment to human and environmental safety. Game Changers could also be technologies and methods which are already used in other industries which could be developed for use in the nuclear sector. Funding for proposals is available to support development of these technologies: we invite proposals which clearly articulate the innovative technology development needed to meet Sellafield s decommissioning challenges. Successful applicants are eligible for an initial 5,000 of funding and commercialisation support to present their innovations to Sellafield Ltd. Further proof of concept and prototype development funding will be made available to any innovations identified by review panels to have significant commercial and operational potential. Information about this initiative is available on the Game Changers website at or you can contact us by at apply@gamechangers.technology Vimeo.com/GCinnovators LinkedIn - Game Changers Innovation Programme