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1. 17th Symposium of AER on VVER Reactor Physics and Reactor Safety September 24-29, 2007, Yalta, Crimea, Ukraine ADVANCED FUEL CYCLES FOR VVER-1000 REACTORS Semchenkov Y.M., Pavlovichev A.M., Pavlov V.I., Spirkin E.I., Styrin Y.A. and Kosourov E.K. RRC “Kurchatov Institute” Moscow, Russia Reduced leakage RRC KI 1

2. Introduction In the present report following themes are discussed: • Stages of development of the Russian uranium fuel from the point of view of increase of safety and profitability of fuel loadings operation • Neutron-physical and economic characteristics of present-day and perspective uranium fuel cycles • Potential of uranium-plutonium regenerate use in VVER-1000 reactors • Potential of weapon-grade plutonium disposition in VVER-1000 reactors Reduced leakage RRC KI 2

3. Evolution of VVER-1000 fuel cycles

4. Average burnup versus number of loaded FAs, FA enrichment and cycle length Reduced leakage RRC KI 4

5. Natural uranium consumption versus number of loaded FAs, FA enrichment and cycle length Reduced leakage RRC KI 5

6. Cost of electricity generation versus number of loaded FAs, FA enrichment and cycle length (cost of fuel-20%, reloading – 65 days) Reduced leakage RRC KI 6

7. Cost of electricity generation versus number of loaded FAs, FA enrichment and cycle length (cost of fuel-30%, reloading – 65 days) Reduced leakage RRC KI 7

8. Cost of electricity generation versus number of loaded FAs, FA enrichment and cycle length (cost of fuel-20%, reloading – 40 days) Reduced leakage RRC KI 8

9. Average burnup versus number of loaded FAs, FA enrichment and cycle length Reduced leakage RRC KI 9

10. Loading patterns of advanced equilibrium cyclesHeight of core – 3680 mm, fuel pellet diameter -7,6 mm, central hole - 1,2 mm 12-month cycle (36 FAs) Average enrichment – 4,83% Cycle length – 324 EFPD FA operational time – 4 or 5 cycles 18-month cycle (60 FAs) Average enrichment – 4,88% Cycle length – 478 EFPD FA operational time – 2 or 3 cycles Reduced leakage RRC KI 10

11. Main neutronic characteristics of advanced equilibrium cycles 11

12. Uranium-plutonium regenerate in VVER-1000 It was proposed to use uranium-plutonium regenerate in thermal reactors by using spent fuel of these reactors cleaned from other actinides and fission products, and by following mixing of cleaned fuel with enriched uranium Weight fraction of uranium-plutonium regenerate and highly enriched uranium at their mixing is 0,8 and 0,2 correspondingly Enrichment of highly enriched uranium has been defined from a set of calculations under condition that the equilibrium cycle of VVER-1000 with feed by 42 fresh FAs has the same cycle length as the design uranium cycle. The enrichment of highly enriched uranium for uranium-plutonium fuel was 17,1% Reduced leakage RRC KI 12

13. Isotopic content of regenerated fuel (kg/tHM) Reduced leakage RRC KI 13

14. Main neutronic characteristics of equilibrium cycles with regenerated uranium-plutonium fuel Reduced leakage RRC KI 14

15. Weapon Plutonium MOX FA in VVER-1000 core Preliminary researches with participation of US, French and German experts have shown possibility of use of W-МОХ fuel in existing VVER-1000. Reduced leakage Fuel rod with high plutonium content Fuel rod with medium plutonium content Fuel rod with low plutonium content UGBA rod Guide tube Instrumental tube Low leakage The pattern of the typical MOX FA RRC KI 15

16. Loading patterns of equilibrium cycles with MOX FAs Reduced leakage MOX FAs- 30, UOX FAs-24 MOX FAs- 36, UOX FAs- 36 307 EFPD 465 EFPD 684 UGBA 1188 UGBA RRC KI 16

17. Main characteristics of equilibrium cycles with MOX fuel Reduced leakage * CR CPS boron is enriched by the isotope boron-10 up to 80% RRC KI 17

18. Conclusion • Advanced uranium fuel cycles for VVER-1000 ensure under meeting safety requirements: • effective use of natural uranium;  • possibility of cycle length variation in a wide interval and consequently possibility of NPP power production adaptation to demands of power net and to eventual changes in relations between components of electricity generation cost;  • reducing of neutron fluence on reactor vessel in view of its service life prolongation. • Expanding of fuel raw material nomenclature is possible for VVER-1000 by using regenerated uranium and uranium-plutonium fuel. • VVER-1000 reactors could ensure a high rate of weapon-grade plutonium disposition at effective using of plutonium power potential. Reduced leakage RRC KI 18