ASN Report 2018

The French waste management policy does not provide for release thresholds for very low level radioactive waste, but requires that it be managed via a specific route to guarantee grouping and traceability. This policy is based on the zoning of the waste from the installations, which is often established conservatively by the licensees for operational reasons. Consequently, the decommissioning of the old installations of the CEA and the first-generation plants of Orano (especially the plants that played a role in the French deterrence policy, such as the gaseous diffusion plants of the Pierrelatte Defence Basic Nuclear Installation (DBNI) at Tricastin and the UP1 plant of the Marcoule DBNI) is going to produce extremely large quantities of Very Low Level (VLL) waste. This massive production of waste in the decades to come, which was not anticipated and which is incompatible with the current capacities of the Cires, was addressed by a PNGMDR working group resulting in several lines of reflection, including the creation of a new centralised repository, the possible recycling of some of the waste or its disposal on site (see chapter 14). 1.2  ̶  The ASN decommissioning doctrine 1.2.1  –  Immediate dismantling Many factors can influence the choice of one decommissioning strategy rather than another: national regulations, social and economic factors, financing of the operations, availability of waste disposal routes, decommissioning techniques, qualified personnel, personnel present during the operating phase, exposure of the personnel and the public to ionising radiation resulting from the decommissioning operations, etc. Consequently, practices and regulations differ from one country to another. Decommissioning in the shortest time frame possible is a core principle in the regulations applicable to BNIs (Order of 7 February 2012 setting the general rules relative to basic nuclear installations). It has been included in the doctrine established by ASN for BNI decommissioning and delicensing since 2009 and has been taken up at legislative level in Act 2015-992 of 17 August 2015 relative to Energy Transition for Green Growth. This strategy moreover avoids placing the technical and financial burden of decommissioning on future generations. It also provides the benefit of retaining the knowledge and skills of the personnel present during operation of the installation, which are vital during the first decommissioning operations. The aim of the strategy adopted in France is that: ∙ ∙ The licensee prepares the decommissioning of its installation from the design stage. ∙ ∙ The licensee anticipates decommissioning and sends its decommissioning application file before it stops operating the installation. ∙ ∙ The licensee has financial resources to finance decommissioning, covering its anticipated expenses by dedicated assets. ∙ ∙ The decommissioning operations are carried out “in as short a time as possible” after shutting down the installation, a time frame which can vary from a few years to a few decades, depending on the complexity of the installation. 1.2.2  –  Complete clean-out The decommissioning and post-operational clean-out operations for a nuclear installation must lead to the elimination of any radioactive substances resulting from the activation or deposition phenomena, and any migration of contamination in the structures of the installation premises or the ground of the site. The structure clean-out operations are defined on the basis of the prior updating of the facility’s waste zoning plan which identifies the areas in which the waste produced is, or could be, contaminated or activated. As work progresses (for example after cleaning the surfaces of a room using appropriate methods), the “possible nuclear waste production areas” are downgraded to “conventional waste areas”. ASN promotes the French decommissioning doctrine on the international scene Since 2014, the International Atomic Energy Agency (IAEA) recognises two possible decommissioning strategies for nuclear facilities following final shutdown: ཛྷ ཛྷ Deferred dismantling: the parts of the installation containing radioactive materials are maintained or placed in a safe state for several decades before actual decommissioning operations begin (the “conventional” parts of the installation can be decommissioned as soon as the installation is shut down). ཛྷ ཛྷ Immediate dismantling: decommissioning is started as soon as the installation is shut down, without a waiting period, although the decommissioning operations can extend over a long period of time. The IAEA considers that immediate dismantling should be favoured. A third strategy called “safe enclosure” (or entombment), which consists in placing the parts of the installation containing radioactive substances in a reinforced containment structure for a period that enables a sufficiently low level of radiological activity to be reached with a view to releasing the site, is no longer considered acceptable by the IAEA, but may be justified in exceptional circumstances. Today, in accordance with the IAEA position, French policy aims to ensure that BNI licensees adopt a strategy of decommissioning in the shortest possible time frame. ASN observes that some western countries recognise deferred dismantling as the reference strategy. ASN observes more recently that the IAEA position of not accepting “safe enclosure” is called into question by some countries, essentially for financial reasons. ASN internationally promotes - in its bilateral relations and in the international and European working groups - the French approach which fosters decommissioning through to complete clean-out, within as short a time frame as possible, in order to not place the financial burden on future generations. ASN report on the state of nuclear safety and radiation protection in France in 2018  337 13 – DECOMMISSIONING OF BASIC NUCLEAR INSTALLATIONS 13