Periodic Reporting for period 1 - INNO4GRAPH (INNOvative tools FOR dismantling of GRAPHite moderated nuclear reactors)
Okres sprawozdawczy: 2020-09-01 do 2022-02-28
Decommissioning is a normal stage in the life of a graphite-moderated nuclear power plant (NPP). However, considerable industrial and technical challenges related to the dimension and complexity of the structure as well as costs for decommissioning require novel, more performant, safer and cost-efficient solutions for dismantling operations.
The three-year EU-funded project INNO4GRAPH is a first step to address the huge challenge of dismantling these graphite-moderated nuclear reactors with such impressive dimensions. Decommissioning these reactors is essential to leave a cleaner and safer world for the next generations. To face the challenge, INNO4GRAPH has been built around 5 main topics:
- Building a database of existing physical properties and radiological inventory on graphite, development of technology or methodology to improve knowledge of the graphite core state in terms on cracks and corrosion.
- Sharing the existing dismantling scenarios of NPP operators of the consortium with their regulatory requirements and building of a multicriteria analysis grid to challenge the scenarios
- Performing 3D simulations of dismantling scenarios.
- Elaboration of innovative tools for dismantling of these reactors and design of a representative mock-up of graphite stack of Chinon A2 NPP.
- Defining a training programme in areas of interest for graphite reactor decommissioning.
The three-year EU-funded project INNO4GRAPH is a first step to address the huge challenge of dismantling these graphite-moderated nuclear reactors with such impressive dimensions. Decommissioning these reactors is essential to leave a cleaner and safer world for the next generations. To face the challenge, INNO4GRAPH has been built around 5 main topics:
- Building a database of existing physical properties and radiological inventory on graphite, development of technology or methodology to improve knowledge of the graphite core state in terms on cracks and corrosion.
- Sharing the existing dismantling scenarios of NPP operators of the consortium with their regulatory requirements and building of a multicriteria analysis grid to challenge the scenarios
- Performing 3D simulations of dismantling scenarios.
- Elaboration of innovative tools for dismantling of these reactors and design of a representative mock-up of graphite stack of Chinon A2 NPP.
- Defining a training programme in areas of interest for graphite reactor decommissioning.
During the first period, technical and environmental dismantling requirements of the European operators were shared. This provided a good overview of the graphite reactor decommissioning situation as well as an understanding of similarities and differences. It also allowed to identify discrepancies to be considered in R&I during and after the INNO4GRAPH lifetime and to build a common development roadmap for future developments.
Improved knowledge of graphite properties was achieved by data sharing between graphite NPP operators (radiological and physical inventories collection) and identifying the most relevant graphite properties needed to conduct a successful dismantling.
The DEMplus® for Nuclear software, a digital tool which allows to simulate scenarios in a 3D virtual environment, is upgraded with a new module dedicated to Graphite reactors which will allow graphite core data to be capitalised, to use external calculation models and to perform sensitivity studies on the decommissioning scenario.
The appropriate experimental setups to measure mechanical properties of graphite have been identified with easy-to-fabricate samples of small dimensions.
Technical specifications of inspection equipment for detection of graphite cracks using Eddy current were defined for an application to Latina reactor. The state of the art of different Non-Destructive Testing methods to measure corrosion has been defined.
A multi-criteria grid analysis was developed which allows graphite NPP operators to decide about their best dismantling scenario based on an objective evaluation of existing options taking into consideration risks and opportunities on different items.
A representative full scale Chinon A2 mock-up of the graphite stack has been designed considering the graphite core characteristics and the risk analysis of the graphite extraction scenario.
A test methodology to assess the risk of bulk-oxidation of the graphite during cutting operations has been defined.
3D models of each reactor (Latina, Chinon A2, G1, Ignalina, Vandellos 1) have been integrated in the DEMplus® software.
Regarding training, a methodology was set up to be followed along the project for knowledge collection and the first specifications defined to produce an example of educational digital resource from an interactive viewer.
Improved knowledge of graphite properties was achieved by data sharing between graphite NPP operators (radiological and physical inventories collection) and identifying the most relevant graphite properties needed to conduct a successful dismantling.
The DEMplus® for Nuclear software, a digital tool which allows to simulate scenarios in a 3D virtual environment, is upgraded with a new module dedicated to Graphite reactors which will allow graphite core data to be capitalised, to use external calculation models and to perform sensitivity studies on the decommissioning scenario.
The appropriate experimental setups to measure mechanical properties of graphite have been identified with easy-to-fabricate samples of small dimensions.
Technical specifications of inspection equipment for detection of graphite cracks using Eddy current were defined for an application to Latina reactor. The state of the art of different Non-Destructive Testing methods to measure corrosion has been defined.
A multi-criteria grid analysis was developed which allows graphite NPP operators to decide about their best dismantling scenario based on an objective evaluation of existing options taking into consideration risks and opportunities on different items.
A representative full scale Chinon A2 mock-up of the graphite stack has been designed considering the graphite core characteristics and the risk analysis of the graphite extraction scenario.
A test methodology to assess the risk of bulk-oxidation of the graphite during cutting operations has been defined.
3D models of each reactor (Latina, Chinon A2, G1, Ignalina, Vandellos 1) have been integrated in the DEMplus® software.
Regarding training, a methodology was set up to be followed along the project for knowledge collection and the first specifications defined to produce an example of educational digital resource from an interactive viewer.
The project will carry on with the developments, evaluation of tools and methodologies in laboratory or representative environments: 3D modelling or physical demonstrator. Knowledge of graphite properties will be further improved by novel techniques of graphite properties prediction.
From the technical specifications defined on in-situ crack detections, a prototype will be set up and tested. From the state of the art established, the most suitable Non-Destructive Testing method to measure corrosion that should be selected on reactor cases will be defined.
The representative mock-up of the graphite stack designed will be manufactured. It will be available in the Industrial Demonstrator commissioned by EDF in Chinon to perform tests on the operational graphite retrieval tools and the way to remotely operate them.
From the test methodology defined to assess the risk of bulk-oxidation of the graphite during cutting operations, data about the oxidation behaviour of different graphite samples will be collected.
Innovative tools will be developed with the aim to make them available during the dismantling operations.
In particular, a proper coating painting will be investigated in order to reduce the contamination risk during graphite extraction and handling and coated samples tested in order to assess structural, thermal and mechanical properties.
Laser cutting tests will be carried out on graphite samples to study the applicability of laser cutting technology on graphite blocks.
Studies regarding the specific needs for the multi-joint manipulator in graphite reactors will be performed to select, model in a virtual environment and test characteristics for a future development.
A deployment system will be developed for graphite retrieval tools. Its aim is to deploy and operate the different tools necessary to dismantle the graphite stack from a mobile dismantling platform set up above the reactor. The system designed will then be manufactured to be tested in the Industrial Demonstrator beyond the Project.
Using DEMplus® software, 3D simulation will be used during the tool developments to better understand the physical environment and constrains. 3D simulation of graphite bricks retrieval will also be performed allowing to evaluate feasibility of operations, in terms of accessibility, cost, duration, collective dose and wastes generated.
By developing tools which will provide more in-depth information about the graphite mechanical properties and tools that will decrease the risk of handling radioactive material, the safety and cost-efficiency of the dismantling operations will be increased.
Moreover, the development of new techniques and the expertise gained within the project will generate knowledge. A training programme will be developed to define the methodology. Areas of learning for graphite reactor decommissioning training and innovative module using interactive viewer will be developed as an example of training module.
INNO4GRAPH, is a first step towards mutualisation of methodologies, tools and cost-effective decision in terms of strategy. It will have an economic impact both through the development of common tools that can be used more than once and by more than one operator and by allowing new tools and methods that will be more effective, in line with operators’ needs.
At the end of the project, a roadmap will be delivered which will include tools and methodologies available to define new or alternative dismantling scenarios, but also further possible developments.
EDF’s graphite industrial demonstrator will facilitate further development of these tools. It will also be the place where worldwide operators will be able to test them, train themselves and share experiences.
From the technical specifications defined on in-situ crack detections, a prototype will be set up and tested. From the state of the art established, the most suitable Non-Destructive Testing method to measure corrosion that should be selected on reactor cases will be defined.
The representative mock-up of the graphite stack designed will be manufactured. It will be available in the Industrial Demonstrator commissioned by EDF in Chinon to perform tests on the operational graphite retrieval tools and the way to remotely operate them.
From the test methodology defined to assess the risk of bulk-oxidation of the graphite during cutting operations, data about the oxidation behaviour of different graphite samples will be collected.
Innovative tools will be developed with the aim to make them available during the dismantling operations.
In particular, a proper coating painting will be investigated in order to reduce the contamination risk during graphite extraction and handling and coated samples tested in order to assess structural, thermal and mechanical properties.
Laser cutting tests will be carried out on graphite samples to study the applicability of laser cutting technology on graphite blocks.
Studies regarding the specific needs for the multi-joint manipulator in graphite reactors will be performed to select, model in a virtual environment and test characteristics for a future development.
A deployment system will be developed for graphite retrieval tools. Its aim is to deploy and operate the different tools necessary to dismantle the graphite stack from a mobile dismantling platform set up above the reactor. The system designed will then be manufactured to be tested in the Industrial Demonstrator beyond the Project.
Using DEMplus® software, 3D simulation will be used during the tool developments to better understand the physical environment and constrains. 3D simulation of graphite bricks retrieval will also be performed allowing to evaluate feasibility of operations, in terms of accessibility, cost, duration, collective dose and wastes generated.
By developing tools which will provide more in-depth information about the graphite mechanical properties and tools that will decrease the risk of handling radioactive material, the safety and cost-efficiency of the dismantling operations will be increased.
Moreover, the development of new techniques and the expertise gained within the project will generate knowledge. A training programme will be developed to define the methodology. Areas of learning for graphite reactor decommissioning training and innovative module using interactive viewer will be developed as an example of training module.
INNO4GRAPH, is a first step towards mutualisation of methodologies, tools and cost-effective decision in terms of strategy. It will have an economic impact both through the development of common tools that can be used more than once and by more than one operator and by allowing new tools and methods that will be more effective, in line with operators’ needs.
At the end of the project, a roadmap will be delivered which will include tools and methodologies available to define new or alternative dismantling scenarios, but also further possible developments.
EDF’s graphite industrial demonstrator will facilitate further development of these tools. It will also be the place where worldwide operators will be able to test them, train themselves and share experiences.