The Condition Management and Inspection Challenge
There are thousands of waste containers currently stored on the Sellafield site in west Cumbria, each containing materials and objects which are the result of nuclear reprocessing or decommissioning activities over the past decades.
These cans, drums and mostly boxes (collectively known as packages) filled with various wastes are placed in above ground stores across the Sellafield site and it is anticipated that there could be more than 150,000 packages that will be sent to such stores over the next few decades.
These wastes could be dry, grouted, water covered, heat generating, gas generating, vitrified or any combination of these but, in all cases, some degree of corrosion of the package will occur. The stored waste packages could be in place for many decades, and it is important that during this period, we can confirm that the performance of the packages is as expected, demonstrating control. The behaviour of the waste is also of interest.
At present, the baseline position is to undertake monitoring by either:
- Removing individual, suspect packages into a designated area where they are inspected manually. This is particularly time consuming and difficult.
- Installing in-situ devices, the deployment of which is particularly difficult because of the complexity of the waste forms and the restrictive storage arrangements.
Introducing innovative thinking and technologies into this area of operations will, it is anticipated, bring significant benefits to Sellafield’s decommissioning programme. Game Changers are looking for innovative technologies and instrumentation which could be considered, including developing ‘smart’ packages that monitor themselves, periodically taking devices/technologies to the packages or large area scanning e.g. hydrocarbon detection on oil refineries, atmospheric monitoring.
Sellafield are seeking ideas, innovations and technologies that will deliver game-changing improvements over the current baseline options, which could include:
Identifying improvements over the baseline options could include:
- The development of new ‘smart packages’ that monitor themselves and/or communicate warnings if they are not performing as expected.
- Periodically taking devices/technologies to the packages in their storage locations.
- Large area scanning, such as deploying technologies akin to hydrocarbon detection on oil refineries or atmospheric monitoring.
- Technologies or techniques for visual observation and image analysis.
It is expected that such solutions will bring primary benefits to Sellafield’s decommissioning programme, namely:
- Improved efficiencies through reduced complexity of deployment.
- Reducing human intervention
- Cost savings gained by eliminating over-engineered packages.
- Long-term cost savings
The following constraints need to be considered when developing potential solutions. These include:
- Packages will be stored above ground in dry, often dark stores.
- Expected storage period is up to many decades.
- Poor access – packages will be stored in arrays, with minimal spacing between them – less than tens of centimetres.
- Dose rates could be high with gamma and neutron fluxes.
- Wide range of packages designs, from big boxes, to little cans.
- Wide range of storage configurations including stillages, racks, stacks etc…
For any device installed, it is inconceivable that its energy source would be replaced over its lifetime. Energy harvesting from the waste package would be useful. Any disposable power source shouldn’t themselves cause a potentially significant corrosion risk to the package.
Different timelines and insertion points may be required depending on waste package type.
Functional requirements of solutions
The following functional requirements should be incorporated into concepts presented to the Game Changer initiative.
- Parameters to be measured include (but may not be limited to):
– Temperature of package and contents, which could infer changes in chemical reactions inside the package.
– Pressure inside package, which could be indicative of the evolution of gases.
– Package deformation, possibly caused by increased internal pressure.
– Corrosion of package material, both inside and outside.
– Rate of change of gas evolution.
– Chemical analysis of gases evolved in waste package, which could indicate corrosion mechanisms
- Reliability – the ability to perform over the long term.
- Data transmission and handling.
- Option of retrofitting to existing packages may be desirable.
- Quality of data – in some cases an indication may be enough, in others may need to measure quite precisely. There is a danger we throw ideas out because they are not good enough for some things when they would be adequate for others.
Funding is available through the Game Changers process for new innovations, technologies and approaches which demonstrate commercial potential and may significantly aid Sellafield’s decommissioning programme. This funding starts at £5,000 for business case and poster presentation through to proof of concept and prototype development.