ASN Report 2018

4 —  Assessment of the nuclear safety of facilities undergoing decommissioning 4.1  ̶  The licensees’ decommissioning strategies Given that numerous facilities have been shut down for several decades, with partial loss of knowledge of their operating histories, ageing structures and in some cases large quantities of waste still present, the advancement of decommissioning projects is one of the major issues for the safety of shut down facilities. Yet ASN has noted that the majority of the decommissioning projects are falling significantly behind schedule. ASN therefore asks the CEA, EDF and Orano to periodically present their decommissioning and radioactive waste management strategies, thereby providing an integrated view of the decommissioning projects and the disposal routes that are available or to be created for the waste resulting from the decommissioning operations. As far as decommissioning is concerned, the licensees must justify the priority operations, principally through safety analyses. This prioritisation provides a means of checking that even if some projects are substantially behind schedule, the most significant resources will be devoted to operations with higher risk implications. With regard to radioactive waste management, ASN checks for consistency with the regulatory framework and the guidelines of the PNGMDR (French National Radioactive Material and Waste Management Plan). ASN examines with particular attention the defences against unforeseen events on a waste management facility and the plausibility of the time frames announced by the licensees. It ensures that the licensees look ahead to the safety studies of packages and the feasibility of the packaging processes. ASN also checks the availability of the envisaged waste management routes and the support means (transport packages, treatment and storage facilities, etc.) which in practise govern the sustainability of the decommissioning strategy. In 2019, ASN will adopt a position on the decommissioning and waste management strategies of the CEA and Orano and on the file justifying the change of decommissioning strategy for the EDF Gas-Cooled Reactors. The context and the preliminary conclusions of these examinations are detailed below. 4.1.1  –  Assessment of EDF’s decommissioning strategy The first decommissioning strategy for definitively shut down EDF reactors was transmitted in 2001 at the request of ASN. This strategy has been updated regularly, in order, for example, to adjust the decommissioning schedule or incorporate the complementary studies requested by ASN and elements concerning the future decommissioning of the reactor fleet in service. These updates did not call into question either the decommissioning scenarios or the pace of decommissioning. In March 2016, EDF informed ASN of a complete change of decommissioning strategy for its Gas-Cooled Reactors (changing to “in air” instead of “under water” decommissioning, and changing the first reactor to be decommissioned from Bugey 1 to Chinon A2), resulting in their decommissioning being pushed back by several decades. This strategy is now based on the operation of an industrial demonstrator for about ten years to qualify the reactor pressure vessel decommissioning procedure. Once qualification is confirmed, EDF proposes completely decommissioning the pressure vessel of a first reactor (Chinon A2) before starting decommissioning of the pressure vessels of the five other reactors. In June 2016, ASN heard EDF on this strategy and asked that the files justifying this change be submitted. ASN received these files in March 2017 and December 2017, and they have been the subject of substantial technical discussion between EDF and ASN. In December 2017, ASN inspected the organisation and integration of safety and radiation protection in the decommissioning studies and strategy. This inspection shows that the request for proposals process for the Bugey “under water” decommissioning studies was rigorous and effectively took into account the questions of nuclear safety and radiation protection. The inspectors have noted that the decision to change strategy seems to have been taken in order to share the industrial risk with the possible service providers, and for financial reasons. ASN considers that waiting for one reactor to be completely decommissioned before starting all the others, resulting in their decommissioning being pushed back by several decades, is unacceptable and has asked EDF to study possible ways of optimising the GCR decommissioning schedule. 4.1.2  –  Assessment of Orano’s decommissioning strategy Decommissioning the old installations is a major challenge for Orano, which has to manage several large-scale decommissioning projects in the short, medium and long term (UP2-400 facility at La Hague, Eurodif Production plant, individual facilities of the DBNI at Pierrelatte, etc.). Implementation of decommissioning is closely linked to the radioactive waste management strategy, given the quantity and the non-standard and difficult-to-characterise nature of the waste resulting from the decommissioning operations. Furthermore, Orano must carry out special legacy Waste Retrieval and Packaging (WRP) operations in old waste storage facilities. The deadlines for completion have been stipulated by ASN, particularly for the La Hague site. Furthermore, completion of these WRP operations governs the progress of decommissioning on the UP2-400 plant, as WRP is one of the first steps of its decommissioning. The WRP work is of particular importance given the inventory of radioactive substances present and the age of the facilities in which they are stored, which do not meet current safety standards. Moreover, the WRP work is highly complex. In June 2016, at the request of ASN and ASND, Orano submitted its decommissioning and waste management strategy. The file also includes the application of this strategy on the La Hague and Tricastin sites. The Tricastin site accommodates one DBNI, hence the joint oversight of Orano by ASN and ASND. ASN considers that Orano must increase its ability to prioritise the operations according to the risks inherent to the facilities to decommission. Orano’s personnel and technical resources must be increased to meet the deadlines for these projects. ASN and ASND have mobilised substantial expertise to examine this file and will adopt a position on the strategy in 2019. ASN report on the state of nuclear safety and radiation protection in France in 2018  345 13 – DECOMMISSIONING OF BASIC NUCLEAR INSTALLATIONS 13