Europe is facing an immediate and major challenge: the enormous costs of decommissioning many old nuclear facilities. Nuclear decommissioning is the final step in the lifecycle of a nuclear installation, and it covers all activities from shutdown and removal of fissile material to the environmental restoration of the site. A significant reduction in the enormous decommissioning costs by development and implementation of new measurement techniques is necessary.
The JRP delivers research addressing all aspects of the decommissioning process, i.e. the characterisation of solid wastes, pre-selection, free release and repositories’ monitoring, measurement of thermal power prior to repository storage, and monitoring of wastes and repositories in the long term. A collaborative multi-disciplinary approach will ensure that regulators’ and industrial stakeholders’ requirements across Europe are met, guaranteeing the integrity and cost-effectiveness of the clearance and disposal processes and improving safety and accuracy.
The JRP addresses the needs of the decommissioning process by the development and implementation of new measurement techniques, instruments, st andards and reference materials, and by ensuring knowledge transfer to stakeholders.
Need for the Project
The decommissioning process is not only very costly but is being carried out in the context of low public confidence in both the safety of nuclear technology and the comprehensive clearance of sites and the safe disposal of radioactive waste. The restoration of public trust can come about only if strict and precise measurement criteria are set and ensured via reliable measurements with traceability to national st andards. Cost reduction requires the adoption of st andardised and traceable methods and devices to make it possible to discriminate between the various waste categories precisely and rapidly, thus allowing for the safe release of waste into the environment, or its recycling or volume reduction, or its long-term storage in repositories.
By underpinning harmonised methods and developing an infrastructure it is expected that legislation contained in a series of EU Directives will be enabled and effectively implemented.
The specific needs may be summarised:
- Rapid radionuclide characterisation of different types of materials is needed so that nuclides not directly measurable can be included in measurement results.
- For the segregation of materials, a facility must be designed to ensure that at least 95% of the materials selected for subsequent free release measurement satisfy the criteria provided by nuclear regulators.
- The new industrial prototype of the high-capacity spectrometric free release measurement facility needs to be constructed, implemented and tested on site.
- New sensors for monitoring of changes in temperature and stress inside repository infrastructures over decades or centuries are needed in order to ensure that wastes are safely contained. The thermal power of waste packages must be known prior to storage so that a suitable storage mode can be selected. A new system for the monitoring of gaseous emissions from packages stored in repositories must be constructed, implemented, and tested on site.
- New reference materials and st andard sources must be developed to increase the accuracy, traceability, and stability of the above measurement devices.
Scientific and technical objectives
- Development of methods for the radionuclide characterisation of different types of materials present on the site being decommissioned. This will include remote mapping of contamination inside nuclear facilities, statistically valid sampling methods and automated in situ radiochemical analysis.
- Development of traceable methods for the pre-selection of waste materials prior to measurement for repository acceptance or possible free release. This will include segregation of wastes for potential free release in the environment or storage in repository, development of automated facility design, measurement and calibration procedures and software.
- Development and implementation of free release measurement facility (FRMF) on a decommissioning site. This will include the implementation and testing of large-scale industrial prototype eco-friendly shielded FRMF, measurement software improvement, scanning of wastes with heterogeneous density, passive neutron counting.
- Development and implementation of methods for monitoring in radioactive waste repositories. (WP4). This will involve the construction and field-trial of gas monitoring systems including prototype of radiocarbon monitoring mid-infrared spectroscope, development of sensors for repository sites integrity monitoring, construction of acoustic thermometry testing facility for temperature monitoring, design of calorimeter for direct measurement of radioactive waste packages thermal power.
- Development of reference materials and st andard sources for calibration, validation and testing of devices, instruments and procedures developed in the above objectives.
Expected results and potential impact
The outputs of this JRP will enable decommissioning measurements to be carried out using st andard methods with traceability to national st andards of radionuclide activity. This will enable uniformity and accuracy of measurements across the EU that meet the criteria and conditions of all EU regulators. In turn, this will have a positive impact on the environment, minimising radiation doses to the EU population. Also, greater measurement precision (i.e. with uncertainties reduced potentially by factors of up to ten) and st andardised measurements will enable the conditional or unconditional safe release of greater quantities of recyclable expensive materials.
This JRP will address other aspects of the nuclear cycle; technologies for monitoring the structural integrity of waste repositories and their internal temperatures (potentially over timescales of one hundred years), and for measuring the thermal power of waste packages prior to emplacement.
During the lifetime of the project stakeholders will use the results from the JRP nd test them on site both at nuclear facilities and in radioactive waste repositories. For example, a large scale free release measurement facility beyond the current state-of-the-art produced in conjunction with an industrial stakeholder will be implemented on a decommissioning site. Moreover, the utilisation of novel prototype devices and methods in real conditions will ensure their verification and enable training of operational staff.
The contribution to European and international st andards and directives will be assured through the contacts of the JRP-Partners on expert, st andards and technical committees and working groups. Good practice guides will be developed for the characterisation of materials on decommissioning sites, and for free release measurement. JRP results will be presented at conferences and project workshops; this will aid their dissemination to the wider community of stakeholders such as legal authorities, radiation protection and st andardisation bodies, radioactive waste agencies, and producers of measurement devices.