1. 1 State Scientific and Technical Center on Nuclear and Radiation Safety THE THERMAL-MECHANICAL BEHAVIOR OF FUEL PINS DURING POWER'S MANEUVERING REGIME AT STATIONARY CORE LOADING ON 2ND UNIT OF KHNPP M. Ieremenko, Y.Ovdiyenko, V.Khalimonchuk 17th SYMPOSIUM of AER on VVER Reactor Physics and Reactor Safety, September 24-29, 2007, Yalta, Crimea, Ukraine

2. 2 State Scientific and Technical Center on Nuclear and Radiation Safety THE THERMAL-MECHANICAL BEHAVIOR OF FUEL PINS DURING POWER'S MANEUVERING REGIME AT STATIONARY CORE LOADING ON 2ND UNIT OF KHNPP 17th SYMPOSIUM of AER on VVER Reactor Physics and Reactor Safety, September 24-29, 2007, Yalta, Crimea, Ukraine Goal M. Ieremenko, Y.Ovdiyenko, V.Khalimonchuk ASSESSMENT OF THE THERMAL-MECHANICAL BEHAVIOR OF FUEL PINS DURING POWER'S MANEUVERING REGIME ON 2ND UNIT OF KHNPP. 16 th Symposium of AER on VVER Reactor Physics and Reactor Safety, 25-29 September 2006, Bratislava, Slovakia. It should be noted that the experiment on maneuvering is carried out during campaign №2, in which there is not a high-burnt fuel. As example of core with hihg-burnup fuel all calculations for design cycle #7 was repeated. It is the design variant of the campaign and reactor core containes the high burnup fuel and there is very high probability to reach interaction between the cladding of a fuel rod and uranium pellet.

3. 3 State Scientific and Technical Center on Nuclear and Radiation Safety THE THERMAL-MECHANICAL BEHAVIOR OF FUEL PINS DURING POWER'S MANEUVERING REGIME AT STATIONARY CORE LOADING ON 2ND UNIT OF KHNPP 17th SYMPOSIUM of AER on VVER Reactor Physics and Reactor Safety, September 24-29, 2007, Yalta, Crimea, Ukraine Loading schedule of the unit during power maneuvering The main macro-characteristics of the reactor core (Kq, Kv) during power maneuvering are obtained by the DYN3D code (FZR, Germany). The simulation of these transient regimes was fulfilled for two moments of campaign - 100 fpd, 160 fpd and for two types of regulation. In the first type (#1) is using boron in the moderator and group of CR №10 for maintaining axial offset. For the second regime (#2) the central rod is dropped. The second regime is characterized by lower change of concentration of boric acid and higher change of the fuel rod power. In the moment of campaign 100 fpd was planned to perform 4 cycles of power's maneuvering, in the moment of campaign 160 fpd - 6 cycles of power's maneuvering.

4. 4 State Scientific and Technical Center on Nuclear and Radiation Safety THE THERMAL-MECHANICAL BEHAVIOR OF FUEL PINS DURING POWER'S MANEUVERING REGIME AT STATIONARY CORE LOADING ON 2ND UNIT OF KHNPP 17th SYMPOSIUM of AER on VVER Reactor Physics and Reactor Safety, September 24-29, 2007, Yalta, Crimea, Ukraine Development of the schedule of control rod’s movement for the reactor power’s decrease or increase was based on following requirements defined by normative documents: minimal deformation of axial power distribution (offset) for allowable peaking factors and fuel rod's linear power compliance for “frame” safety parameters (efficiency of emergency protection system without most effective rod, rate of positive reactivity’s insertion and efficiency of ejected control rod) for any transient’s condition compliance for allowable rate of reactor power’s change parameter’s keeping accuracy and acceptance of boron acid concentration change’s rate from the point of view of equipment’s and technological system’s functioning

5. 5 State Scientific and Technical Center on Nuclear and Radiation Safety THE THERMAL-MECHANICAL BEHAVIOR OF FUEL PINS DURING POWER'S MANEUVERING REGIME AT STATIONARY CORE LOADING ON 2ND UNIT OF KHNPP 17th SYMPOSIUM of AER on VVER Reactor Physics and Reactor Safety, September 24-29, 2007, Yalta, Crimea, Ukraine

6. 6 State Scientific and Technical Center on Nuclear and Radiation Safety THE THERMAL-MECHANICAL BEHAVIOR OF FUEL PINS DURING POWER'S MANEUVERING REGIME AT STATIONARY CORE LOADING ON 2ND UNIT OF KHNPP 17th SYMPOSIUM of AER on VVER Reactor Physics and Reactor Safety, September 24-29, 2007, Yalta, Crimea, Ukraine

7. 7 State Scientific and Technical Center on Nuclear and Radiation Safety THE THERMAL-MECHANICAL BEHAVIOR OF FUEL PINS DURING POWER'S MANEUVERING REGIME AT STATIONARY CORE LOADING ON 2ND UNIT OF KHNPP 17th SYMPOSIUM of AER on VVER Reactor Physics and Reactor Safety, September 24-29, 2007, Yalta, Crimea, Ukraine

8. 8 State Scientific and Technical Center on Nuclear and Radiation Safety THE THERMAL-MECHANICAL BEHAVIOR OF FUEL PINS DURING POWER'S MANEUVERING REGIME AT STATIONARY CORE LOADING ON 2ND UNIT OF KHNPP 17th SYMPOSIUM of AER on VVER Reactor Physics and Reactor Safety, September 24-29, 2007, Yalta, Crimea, Ukraine

9. 9 State Scientific and Technical Center on Nuclear and Radiation Safety THE THERMAL-MECHANICAL BEHAVIOR OF FUEL PINS DURING POWER'S MANEUVERING REGIME AT STATIONARY CORE LOADING ON 2ND UNIT OF KHNPP 17th SYMPOSIUM of AER on VVER Reactor Physics and Reactor Safety, September 24-29, 2007, Yalta, Crimea, Ukraine

10. 10 State Scientific and Technical Center on Nuclear and Radiation Safety THE THERMAL-MECHANICAL BEHAVIOR OF FUEL PINS DURING POWER'S MANEUVERING REGIME AT STATIONARY CORE LOADING ON 2ND UNIT OF KHNPP 17th SYMPOSIUM of AER on VVER Reactor Physics and Reactor Safety, September 24-29, 2007, Yalta, Crimea, Ukraine

11. 11 State Scientific and Technical Center on Nuclear and Radiation Safety THE THERMAL-MECHANICAL BEHAVIOR OF FUEL PINS DURING POWER'S MANEUVERING REGIME AT STATIONARY CORE LOADING ON 2ND UNIT OF KHNPP 17th SYMPOSIUM of AER on VVER Reactor Physics and Reactor Safety, September 24-29, 2007, Yalta, Crimea, Ukraine

12. 12 State Scientific and Technical Center on Nuclear and Radiation Safety THE THERMAL-MECHANICAL BEHAVIOR OF FUEL PINS DURING POWER'S MANEUVERING REGIME AT STATIONARY CORE LOADING ON 2ND UNIT OF KHNPP 17th SYMPOSIUM of AER on VVER Reactor Physics and Reactor Safety, September 24-29, 2007, Yalta, Crimea, Ukraine

13. 13 State Scientific and Technical Center on Nuclear and Radiation Safety THE THERMAL-MECHANICAL BEHAVIOR OF FUEL PINS DURING POWER'S MANEUVERING REGIME AT STATIONARY CORE LOADING ON 2ND UNIT OF KHNPP 17th SYMPOSIUM of AER on VVER Reactor Physics and Reactor Safety, September 24-29, 2007, Yalta, Crimea, Ukraine Common model of thermal-mechanical calculation

14. 14 State Scientific and Technical Center on Nuclear and Radiation Safety THE THERMAL-MECHANICAL BEHAVIOR OF FUEL PINS DURING POWER'S MANEUVERING REGIME AT STATIONARY CORE LOADING ON 2ND UNIT OF KHNPP 17th SYMPOSIUM of AER on VVER Reactor Physics and Reactor Safety, September 24-29, 2007, Yalta, Crimea, Ukraine Results of calculations a thermal-mechanical behaviour of fuel pins. Campaign №7 For the following thermal-mechanical analysis were selected 4 types of fuel rods: 1. Fuel rod with the maximal burnup level; 2. Fuel rod with the maximal power; 3. Fuel rod with the maximal change linear and average power concerning a beginning of power’s maneuvering regime; 4. Fuel rod with the maximal change linear and average power concerning a previous step of power’s maneuvering regime.

15. 15 State Scientific and Technical Center on Nuclear and Radiation Safety THE THERMAL-MECHANICAL BEHAVIOR OF FUEL PINS DURING POWER'S MANEUVERING REGIME AT STATIONARY CORE LOADING ON 2ND UNIT OF KHNPP 17th SYMPOSIUM of AER on VVER Reactor Physics and Reactor Safety, September 24-29, 2007, Yalta, Crimea, Ukraine

16. 16 State Scientific and Technical Center on Nuclear and Radiation Safety THE THERMAL-MECHANICAL BEHAVIOR OF FUEL PINS DURING POWER'S MANEUVERING REGIME AT STATIONARY CORE LOADING ON 2ND UNIT OF KHNPP 17th SYMPOSIUM of AER on VVER Reactor Physics and Reactor Safety, September 24-29, 2007, Yalta, Crimea, Ukraine

17. 17 State Scientific and Technical Center on Nuclear and Radiation Safety THE THERMAL-MECHANICAL BEHAVIOR OF FUEL PINS DURING POWER'S MANEUVERING REGIME AT STATIONARY CORE LOADING ON 2ND UNIT OF KHNPP 17th SYMPOSIUM of AER on VVER Reactor Physics and Reactor Safety, September 24-29, 2007, Yalta, Crimea, Ukraine

18. 18 State Scientific and Technical Center on Nuclear and Radiation Safety THE THERMAL-MECHANICAL BEHAVIOR OF FUEL PINS DURING POWER'S MANEUVERING REGIME AT STATIONARY CORE LOADING ON 2ND UNIT OF KHNPP 17th SYMPOSIUM of AER on VVER Reactor Physics and Reactor Safety, September 24-29, 2007, Yalta, Crimea, Ukraine

19. 19 State Scientific and Technical Center on Nuclear and Radiation Safety THE THERMAL-MECHANICAL BEHAVIOR OF FUEL PINS DURING POWER'S MANEUVERING REGIME AT STATIONARY CORE LOADING ON 2ND UNIT OF KHNPP 17th SYMPOSIUM of AER on VVER Reactor Physics and Reactor Safety, September 24-29, 2007, Yalta, Crimea, Ukraine

20. 20 State Scientific and Technical Center on Nuclear and Radiation Safety THE THERMAL-MECHANICAL BEHAVIOR OF FUEL PINS DURING POWER'S MANEUVERING REGIME AT STATIONARY CORE LOADING ON 2ND UNIT OF KHNPP 17th SYMPOSIUM of AER on VVER Reactor Physics and Reactor Safety, September 24-29, 2007, Yalta, Crimea, Ukraine

21. 21 State Scientific and Technical Center on Nuclear and Radiation Safety THE THERMAL-MECHANICAL BEHAVIOR OF FUEL PINS DURING POWER'S MANEUVERING REGIME AT STATIONARY CORE LOADING ON 2ND UNIT OF KHNPP 17th SYMPOSIUM of AER on VVER Reactor Physics and Reactor Safety, September 24-29, 2007, Yalta, Crimea, Ukraine

22. 22 State Scientific and Technical Center on Nuclear and Radiation Safety THE THERMAL-MECHANICAL BEHAVIOR OF FUEL PINS DURING POWER'S MANEUVERING REGIME AT STATIONARY CORE LOADING ON 2ND UNIT OF KHNPP 17th SYMPOSIUM of AER on VVER Reactor Physics and Reactor Safety, September 24-29, 2007, Yalta, Crimea, Ukraine

23. 23 State Scientific and Technical Center on Nuclear and Radiation Safety THE THERMAL-MECHANICAL BEHAVIOR OF FUEL PINS DURING POWER'S MANEUVERING REGIME AT STATIONARY CORE LOADING ON 2ND UNIT OF KHNPP 17th SYMPOSIUM of AER on VVER Reactor Physics and Reactor Safety, September 24-29, 2007, Yalta, Crimea, Ukraine

24. 24 State Scientific and Technical Center on Nuclear and Radiation Safety THE THERMAL-MECHANICAL BEHAVIOR OF FUEL PINS DURING POWER'S MANEUVERING REGIME AT STATIONARY CORE LOADING ON 2ND UNIT OF KHNPP 17th SYMPOSIUM of AER on VVER Reactor Physics and Reactor Safety, September 24-29, 2007, Yalta, Crimea, Ukraine Conclusions In the design variant of the campaign a reactor core containes the high burnup fuel and interaction between the cladding of a fuel rod and uranium pellet was reached. It is possible to mark a more loaded regime of fuel pins operations during a regime of regulation with additional inserted central rod. On the other hand, this regime is characterized by lower change of boric acid density in moderator, that is favorably reflected in economic indexes of unit operation. For regime of regulation with additional inserted central rod for core with the high burnup fuel is possible to recommend not to use the high burnup FAs in central place of core.