Chicade Nuclear Facility: A Technological Platform, Dedicated to the Expertise and Characterisation of Nuclear Wastes - 23125

CHICADE (CHimie CAracterisation DEchets - Chemistry Characterization Wastes - Basic Nuclear Facility N. 156) is one of the nuclear facilities of the Energy Division of the French Alternative Energies and Atomic Energy Commission (CEA/DES). The DES is responsible for the production of low-carbon energy, resource management, global system performance, the functioning of the energy system and, as far as CHICADE is concerned, nuclear clean-up and dismantling, including project management for clean-up, dismantling and operation of nuclear services, innovation and advanced R and D and waste management. CHICADE is located at the CEA Centre in Cadarache, which is one of the CEA's historic centres as it is celebrating its 63. anniversary. This centre was home to the first experimental fission reactors for electricity production but also for naval propulsion. Cadarache is also a platform for fusion, solar energy and life sciences. This site now includes a clean-up and dismantling centre with numerous Nuclear Facilities undergoing clean-up and dismantling. Overall, for all the dismantling sites managed by the Dismantling, Nuclear Service and Waste Management Projects Directorate, the total annual volume of waste generated is 25,000 m³; this flow requires support in terms of expertise and technological development, which is provided by CHICADE and made available to other waste producers. To carry out these assessments, CHICADE is a large Nuclear Facility with more than 6,000 m² including 4,000 m² of hot surfaces including a wide range of equipment from the bench, to the fume hood, Glove Boxes, shielded cell and measurement casemates allowing the expertise of wastes from few mg to several tons. As far as shielded cells are concerned, CHICADE is able to cut through drums under water spray and to drill dry axially or radially through shells and to handle waste packages up to 2 m³, 16 tons and up to 11.1 TBq of activity. CHICADE also has the necessary means and skills to enable expertise on these samples (e.g. slicing of these samples, sampling techniques...) The fifty or so employees of CHICADE contribute to the activities of the 6 laboratories, each with its own field of expertise: operation, characterisation, radiochemistry, imaging, gamma spectrometry and, beyond the activity on nuclear waste, the manufacture of fission chambers. These skills, both technical and human, give CHICADE the opportunity to carry out research and technological development activities making possible supervision of research work of PhD students, teaching activities and meeting the needs of other waste producers such as ITER, ONDRAF, Orano, EdF, etc. The objectives of the assessments and technological development carried out at CHICADE are therefore: -Enabling waste transportation to the appropriate outlet: This objective can be broken down into the following questions and methods of expertise, deployed after the implementation of the necessary innovations. - Will the radionuclides contained in concrete waste packages remain in these packages after several hundred years and under severe conditions? This property is assessed by carrying out leaching tests. - In which extend, a radioactive waste package is able to remove the gases produced by radiolysis (such as H₂, CO ...)? These Gas analysis are carried out either on individual packages or in storage wells, and the technique used is either gas air flush measurements or gas accumulation measurements. In this latter case, the basic tool is an airtight container in which the released gases are accumulated and then sampled for identification and measurement (gas chromatography, β liquid scintillation method...). - Is the assessed waste assigned to the right waste outlet or is there a more suitable waste outlet (e.g. reallocation of a waste that was originally ILW-LL to the LILW-SL stream)? This objective is achieved in CHICADE either by destructive characterisation of the package (cutting or coring) or by imaging (Xray, γ Spectrometries and CT scans, passive and active neutron measurements, γ spectrometry after neutron/photon activation). - Does the mechanical strength of the waste packaging comply with the storage requirements, in particular with regard to the stacking of waste packaging? This question is answered by carrying out compression tests. -The development of waste conditioning methods; this is to say, for new waste, what are the methods for blocking (i.e. with mortar) the package to meet the storage requirements? - One example is the cementing of incinerator ash: the formulation of hydraulic binder has been developed in cold conditions on dummy ashes and is currently being tested in hot conditions on the basis of aliquots of real ashes. The parameters studied are the incorporation rate and compliance with technical tests. -The sample controls of waste assigned to existing outlets. - This activity consists of taking an inventory of non-blocked waste to certify its compliance In conclusion, CHICADE is a nuclear facility with unique equipment, allowing complete expertise to be carried out in a single location, for greater efficiency, benefiting from crossed, complementary and innovative methods. (authors)