Втрата стійкості і форма можливого вигину напрямних каналів тепловидільних збірок ядерних реакторів ВВЕР-1000

• Дата: 2015
• Автори: Yefimov, A., Maksymov, M., Romashov, Yu.
• Формат: Стаття
• Мова: Ukrainian
• Опубліковано: State Scientific and Technical Center for Nuclear and Radiation Safety 2015
• Онлайн доступ: https://nuclear-journal.com/index.php/journal/article/view/286
• Назва журналу: Nuclear and Radiation Safety

The paper defines the critical value of compressive force and the corresponding possible bending shapes of WWER-1000 fuel assemblies guide tubes resulting from loss of stability during operation. The guide tubes are considered as the long rods that are bent due to the loss of stability under the longitudinal compressive force. The three design schemes of the guide tubes fixations with the fuel assembly top and bottom nozzles corresponding to the motionless and sliding cylindrical joints and rigid fixations are considered in this paper. The minimal values of the guide tubes critical compressive force correspondent to loss of stability are obtained as 1.87 MPa for the both edges cylindrical joints fixing, 3.83 MPa for the cylindrical joint fixing of the one edge and the rigid fixing of the another edge, 7.49 MPa for the both edges rigid fixing. The relatively small values of the critical compressive force show that the shape of guide tube bent due to loss of stability can include several bending points leading to increased time for drop of absorber element cluster to the core bottom and incompliance with reactor normal operation conditions.