Skip to main content

Measurement and Instrumentation for Cleaning And Decommissioning Operations

Periodic Reporting for period 1 - MICADO (Measurement and Instrumentation for Cleaning And Decommissioning Operations)

Reporting period: 2019-06-01 to 2020-11-30

MICADO goal is to develop a framework that is intended to become a standard referenced to facilitate and harmonize the methodologies for in-field Radioactive Waste Management and D&D operations.
The RCMS DIGIWASTE proposed solution is an expert platform integrating hardware and software technologies to fully characterizes the Radioactive Waste Packages (RWP) reducing time and errors, improving the ALARA, better addressing different waste packages automatically and keeping each single element under control during each phase of the storage process. It integrates RFID tracking technology, data fusion and digitization of measurements with selected radiation detection techniques.
By performing non-destructive analyses to define the characterization protocol, determine the waste category and provide a complete solution for the waste traceability, MICADO is introducing innovations in nuclear waste management to track, from waste packaging and assembling up to long-term monitoring in the final storage, integrating smart technologies and adaptable measurements done using established techniques. RWP and their final disposal remain a controversial topic for the public opinion as testified by what is happening in Italy after the publication of the CNAPI (the National chart of the potentially suitable areas for the Italian nuclear repository), by the violent protest occurred close to the CIGEO future geological disposal site (France) or by the difficulties encountered in Germany to identify a suitable disposal site. Improving public acceptance of radioactive waste repositories and/or disposals may be achieved by pursuing an accurate characterization of RWP followed by a guarantee of safety and integrity in the longer term, that can be achieved by quickly detect potential leaks of radioactive materials from a RWP, contrary to what happened at the WIPP plant (USA) in 2014. MICADO aims to improve the harmonization of the EU methodologies for nuclear waste characterization with a better evaluation of their uncertainties. As a result, there will be a better determination of the waste categories, thus potentially improving the management of the financial resources allocated to Nuclear Waste Management, with a positive impact on the overall cost-benefits.
All activities planned during the period were performed satisfactorily and with significant progress despite some delays related to the COVID-19 pandemic that significantly reduced access to laboratories and other facilities. The entire MICADO team showed an exceptional ability to mitigate the impact as much as possible, and some activities were rescheduled to overcome the impasse due to the restrictions.
One of the first actions was to define the RCMS DigiWaste Platform requirements and propose the design of the structure of the mobile detection stations. In parallel we started to work on the technical integration of all non-destructive gamma characterization techniques. The Preliminary Characterization Phase feeds the segmented gamma scanner helping to drive the selection of the most suitable characterization protocol to be applied.
The neutron measurement station has been designed using Monte Carlo simulations, with the objective to estimate the nuclear material mass in a wide range of drums by passive neutron counting and active neutron interrogation. Performances were estimated by simulation, for a wide range of possible matrices to better understand their effects on the measurements.
The photofission technique task progressed with two measurement setups for different uses: a stationary and a mobile cell based on a based on a 9 MeV and 7 MeV linac. The first measurement campaign was suddenly interrupted, but most of the work continued evaluating performance of the photofission technique on reference cases. Concerning the waste monitoring technology, the foreseen SciFi and SiLiF detectors were built successfully and preliminarily tested with lab sources. As an alternative/complementary solution the Timepix3 detectors are equipped with a range of different sensors and neutron converters. Detectors, electronics, and part of the software are now available and ready for testing.
The low-cost monitoring system task have produced a set of gamma and neutron detectors, which are currently being extensively tested and characterized in house with gamma and neutron sources. Preliminary field tests with real RWPs on other partners’ premises will be started as soon as the travel bans are lifted.
The identification of all sources of uncertainty has been completed and the uncertainty parameters related to the radioactive waste package are harmonized across various techniques. The RCMS software Platform development started with the definition of the communication protocols and data formats, used to determine the status at the starting point of the project and to define the information to be integrated. The software structure has been identified as the logical sequential order to be stored.
The locations for the final tests and demonstration are already defined. Dissemination is ongoing thanks to the new online conferences where available. First articles are already submitted and/or under review.
The D&D process of nuclear infrastructures demands a full traceability of waste material to improve quality management and operational safety. Precise waste management and minimization of procedures provide twofold benefits: the optimization of costs and the exposure reduction of operators. Fundamental aspects are: radiation emitters/isotopes, specific activity of each individual isotope, fissile and fertile mass, hot spot search, waste matrix materials and density distributions alongside with the radioactive content spatial distribution, visual assessment of RWP.
All these elements are addressed by the MICADO project along with the many issues associated to the non-destructive characterization of RWP:
-Methods and operational issues: operations based on manual procedures heavily rely on the operator skills, measurements are performed with different equipment providing separate reports, using different software that makes it compulsory for operators to attend specific trainings. All of this would become obsolete with the MICADO RCMS DigiWaste Platform that can automatically retrieve data from multiple systems.
-Concrete and large volume RWP: the quantification of fissile mass contained in large concrete or high density RWPs. Within MICADO project active and passive neutron measurement and photofission are used to cope these two problems.
-Cost issues: RWP characterization is an expensive process in terms of HR, requiring expert staff, detection systems and their location. These elements can be solved using automated and mobile detection stations in need of limited HR for handling, operations and relocation. The incomplete or inaccurate characterization of a RWP has a significant impact on the storage cost. In those cases, there is a significant risk to assign the package to a wrong category with a significant cost increase. The project is developing a software analysis for the data assessment and the uncertainty reduction based on combination of different measurement outputs and simulations.
-Regulatory issues: a specific issue is the constantly evolving regulatory framework. MICADO defined a step procedure, RWP dependent, to obtain the maximum information taking advantage of the multiple and integrated technologies.
MCNP model of the MICADO neutron system design
Test and MCNP simualtion caried on for RadHand spectroscopic system
ε × Rfis(t) in active neutron interrogation of 235U homogenously distributed in different matrices
SciFi & SiLiF detectors bare & during a tests with AmBe source with thermal & fast neutrons
Top: 500µm Si and 1mm CdTe Tpx3 with chipboards; bottomleft: read-outs bottomRight: calib set-up
Test performed with RadHand in the new configuration with a Mockup drum
MCNP upper views of the different neutron system designs
Evolution of ε × Rfis for 1g of 235U homogeneously distributed in a empty 200l drum
Concept of the Nuclear waste management platform
RCMS DigiWaste RWP characterization procedure
(n,p) reaction rate of the detection blocks for the system shown in Pict1
Calculated 3He(n,p)3H reaction rates in active neutron interrogation mode for 1g of 235U
silicon detectors, 1 SiLiF det. close-up; 1 SiLiF assembly. & HDPe moderator
scintillating fibres, 1 close-up; 2 fibre holders with photosensors & electronics; assembled det.
Gamma Scanner System upgrading process with other RadHand & Gamma camera