According to regulatory requirements, when carrying out handling operations with spent nuclear fuel (SNF), prevention of damage to the spent fuel assemblies (SFA) and especially fuel elements shall be ensured. For this purpose, it is necessary to exclude the risk of SFA falling, SFA uncontrolled displacements, prevent mechanical influences on SFA, at which their damage is possible. Special requirements for handling equipment (in particular, cranes) to exclude these dangerous events, the requirements for equipment strength, resistance to external impacts, reliability, equipment design solutions, manufacturing quality are analyzed in this work. The requirements of Ukrainian and U.S. regulatory documents also are considered. The implementation of these requirements is considered on the example of handling equipment, in particular, spent nuclear fuel storage facilities. This issue is important in view of creation of new SNF storage facilities in Ukraine. These facilities include the storage facility (SFSF) for SNF from water moderated power reactors (WWER): a Сentralized SFSF for storing SNF of Rivne, Khmelnitsky and South-Ukraine Nuclear Power Plants (СSFSF), and SFSF for SNF from high-power channel reactors (RBMK): a dry type SFSF at Chornobyl nuclear power plant (ISF-2). After commissioning of these storage facilities, all spent nuclear fuel from Ukrainian nuclear power plants will be placed for long-term “dry” storage. The safety of handling operations with SNF during its preparation for long-term storage is an important factor.

The paper presents the analysis of dynamic behavior of the reinforced concrete containment of NPP unit under the combined effect of internal pressure shock caused by the accident in the reactor hall and seismic impact of design-basis earthquake using the finite element method (FEM) and DIPROS software. Using the modal analysis and numerical solution of the FEM equations of containment concrete, the stress-strain state of the building structure in the post-accident period was defined. It is shown that the maximum intensity of the stresses in the steel liner of the containment does not exceed the yield strength of the steel liner material. Accordingly, the liner integrity is preserved, the containment remains operable and ensures compliance of radiation safety requirements.

The paper presents the analysis of experience in using mixed fuel loadings at Ukrainian NPPs (those envisaging simultaneous use of fuel assemblies different in design and/or fuel structure in the core). The stated analysis was performed under implementation of the first stage of research program that envisages in-depth consideration of comprehensive safety analysis of mixed loadings in thermohydraulic, neutronic, mechanical and strength aspects of nuclear fuel operation. The paper formulates the tasks that will ensure reaching of the objective of the stated research program.

Розглянуто деякі аспекти щодо вичерпання циклів навантаження тепломеханічного обладнання АЕС і представлено основні положення методики з перепризначення допустимої кількості циклів навантаження та оцінки технічного стану обладнання при циклічних навантаженнях.

Computer analysis of thermomechanical state of the sealing steel lining under relevant extreme hazards has been performed to define the possibility and scope of loss of integrity of sealing steel lining, in particular the possibility of losing of the confining function by the NPP reactor compartment containment under emergency conditions. The study gave an opportunity to obtain functions of stress strain parameter evolution function in reinforced concrete and sealing steel lining depending on changes in emergency temperature and pressure in the reactor compartment. The paper assessed the margin of sealing steel lining bearing capacity.