ASN Report 2017

428 ASN report on the state of nuclear safety and radiation protection in France in 2017 Chapter 15  - Decommissioning of Basic Nuclear Installations and packaging of legacy waste at La Hague on the ASN website, www.asn.fr ). ASN issued prescriptions regarding all the legacy waste recovery and packaging programmes in resolution 2014-DC-0472 of 9th December 2014. This resolution defines the priorities regarding the safety of waste retrieval and packaging operations and sets milestones for each of the programmes concerned. At the end of 2016 ASN also carried out an in-depth inspection of the waste retrieval and packaging projects. STE2 sludges The scenario presented in 2010 concerning the recovery and packaging of STE2 sludges is split into three steps: ཛྷ ཛྷ recovery of sludges stored in silos in STE2 (BNI 38); ཛྷ ཛྷ transfer and treatment by drying and compacting in STE3 (BNI 118); ཛྷ ཛྷ packaging of the pellets obtained into C5 packages for deep geological disposal. ASN authorised the first phase of recovery of the STE2 sludges in 2015. During 2017, Areva NC provided additional elements relating to the first phase of the works, along with an authorisation application concerning the procedure for recovering the sludges from STE2 and transferring them to STE3. This file is currently being examined. The Creation Authorisation Decree for the STE3 effluents treatment station was modified by the Decree of 29th January 2016 to allow the installation of the STE2 sludges treatment process. Moreover, in a resolution of 4th January 2011, ASN made production of the C5 package, for which the risk of radiolysis leading to the production of hydrogen must be considered as of the design stage (see chapter 16, point 1.4.2), subject to prior ASN consent. However, at the end of 2016, Areva NC informally notified ASN that the process adopted for the treatment of the sludge in STE3 could lead to more complex equipment operating and maintenance conditions. The licensee confirmed this information in 2017 and presented the alternative scenario it intends implementing along with results of an internal audit of the STE2 sludge recovery and packaging project. This information makes it difficult to conceive that time frame targets defined by the law for packaging the legacy waste can be met. ASN will be particularly vigilant in ensuring that Areva NC does everything in its power to meet the deadlines prescribed for the recovery of the STE2 sludges. Silo 130 Silo 130 is a reinforced concrete underground storage facility, with carbon steel liner, used for dry storage of solid waste from the reprocessing of Gas-Cooled Reactor (GCR) fuels, and the storage of technological waste and contaminated soils and rubble. The silo received waste of this type from 1973 until 1981, when a fire forced the licensee to flood the waste. The tightness of the silo thus filled with water is today ensured by means of a single containment barrier consisting of a steel “skin”. Silo 130 is monitored by a network of piezometers situated nearby. The scenario for retrieving and packaging this waste comprises four stages: ཛྷ ཛྷ retrieval and packaging of the solid GCR waste; ཛྷ ཛྷ retrieval of the liquid effluents; ཛྷ ཛྷ retrieval and packaging of the residual GCR waste and the sludge in the bottom of the silo; ཛྷ ཛྷ retrieval and packaging of the soils and rubble. Areva NC is currently building a retrieval unit above the pit containing the waste and a new building dedicated to the packaging operations. ASN had set 1st July 2016 and 31st December 2023 as the deadline dates for starting and ending of the recovery operations for all the waste. During an inspection in July 2016, ASN found that Areva NC had not actually begun to recover the waste stored in silo 130. In view of the justifications provided by Areva NC concerning the technical difficulties encountered and considering that the final deadline of 31stDecember 2023 was not called into question, ASN pushed back the date of start of retrieval to 30th April 2018. The authorisation applications for the first retrieval phases will be examined in 2018. Old fission product solutions stored in the SPF2 unit in the UP2-400 plant To package fission products from reprocessing of Gas-Cooled Reactor fuel, in particular that containing molybdenum (UMo FP), the licensee has opted for cold crucible vitrification. The package thus produced is a standard UMo vitrified waste package (CSD-U). The use of the cold crucible with legacy solutions was authorised by a resolution of 20th June 2011. The first CSD-U packages were produced in 2013, but the cold crucible experienced a number of technical problems in 2014 and 2015. CSD-U packages were produced during short production campaigns. In view of the technical contingencies, Areva NC was unable to meet the end-of-retrieval deadlines of 31st December 2017 set by ASN resolution 2011-DC-0229 of 14th June 2011 and undertook to complete retrieval by the end of March 2019. Other legacy waste recovery and packaging projects With regard to other lower-priority legacy waste recovery and packaging projects, the following events in 2017 are worthy of note: ཛྷ ཛྷ completion of retrieval of the waste stored in room 107 of the MAPu facility at La Hague (BNI 33); ཛྷ ཛྷ continuation of the R&D studies on the packaging processes for the operational waste from GCR reactors and low granulometry wastes. Final shutdown and decommissioning operations The HAO (High Activity Oxide) Facility (BNI 80) BNI 80 ensured the first stages of the reprocessing of spent oxide nuclear fuels: reception, storage then shearing and dissolution. The dissolution solutions produced in BNI 80 were then transferred to the UP2-400 industrial plant in which the subsequent reprocessing operations took place.