Ukraine has accumulated large amounts of Chernobyl-origin emergency radioactive waste stored in the Chernobyl Exclusion Zone and beyond, as well as legacy radioactive waste in the Radon-type facilities and military sites of the former Soviet Union. Management of such radioactive waste requires the application of a graded approach, in particular, ranking of sites with such radioactive waste by the degree of hazard. Based on the results of ranking, a decision is made on one of the three options: urgent removal of radioactive waste from the site, delayed removal of radioactive waste from the site, and absence of necessity to remove radioactive waste from the site. If it is decided to leave radioactive waste at the site, the graded approach determines the scope of measures to maintain the safety level of that site. This paper presents methodological aspects and experience of the practical application of the graded approach to ensure the safe management of emergency and legacy radioactive waste. In particular, it includes the experience of the Ukrainian State Scientific and Technical Center for Nuclear and Radiation Safety in expert reviews of safety assessments of such sites with emergency and legacy radioactive waste, results of their ranking by degree of hazard, designs for removal of radioactive waste from sites, and establishment of levels for the remediation of territories.
The ROUTES Work Package (WP) is one of the two strategic studies being conducted as part of the European Joint Programme on Radioactive Waste Management (EURAD). ROUTES’ objectives are (i) to provide a framework for European Union’s member states (MS) to share methodologies, experiences, and knowledge in situations in which a waste management strategy is difficult to define as well as to (ii) to compare national approaches and strategies of waste management. The work considers national programmes at different stages of their development and deals with different amounts and types of radioactive waste. The expected output is identifying Research & Development (R&D) needs and opportunities for collaboration between MS, which need not be confined to ROUTES or EURAD frameworks. This work has enabled ROUTES partners to identify key issues such as retrieving poorly characterised legacy waste from a predisposal or disposal facility, implementing specific waste management solutions in the absence of well-defined WAC or developing innovative or shared solutions for MS that have only limited amounts of waste to manage. Discussion of these questions is illustrated through some of the case studies identified and analysed under the ROUTES WP.
Construction of the New Safe Confinement (NSC) above the Shelter over destroyed Chornobyl NPP Unit 4 has been completed. The NSC design is based on boundary conditions for current and potential hazardous impacts of the Shelter. Accordingly, criteria for Shelter safe state have to be established, in particular, criteria for the safe state of fuel-containing material (FCM) accumulations.
The paper presents the results of the development of methodological recommendations for the establishment of acceptance/non-acceptance criteria of FCM accumulations with regard to safety, as well as on the FCM monitoring scope in order to monitor the extent of compliance of FCM state with the established criteria.
Представлено результати аналізів: граничних умов по поточних та потенційних небезпечних впливах об'єкта «Укриття» (викид радіоактивних речовин, вихід іонізуючого випромінювання, гіпотетичні аварійні події з виникненням критичності, обвалення конструкцій, пожежі тощо); факторів, що характеризують стан об'єкта «Укриття» і пов'язані з дотриманням граничних умов (утворення пилу при деградації паливовмісних матеріалів (ПВМ), погіршення стану конструкцій, динаміка змін температурно-вологісного режиму та скупчень води тощо). Указується на потребу проведення додаткових досліджень процесів деградації ПВМ, стану внутрішніх конструкцій об'єкта «Укриття», на яких знаходяться скупчення ПВМ, джерел пожежонебезпеки в зонах із високим рівнем радіаційного забруднення тощо.
In the frameworks of the international Action Plan for the Chornobyl Shelter, the experts analyzed experience in safety regulation of the efforts on overcoming consequences of the accident that occurred 30 years ago at ChNPP-4 and presented achievements under this Plan.
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