Challenges of nuclear fuel development for efficiency of electricity production of Russian NPPs

Transcription

1 1 Challenges of nuclear fuel development for efficiency of electricity production of Russian NPPs V. Novikov (JSC «VNIINM») IAEA meeting of the Technical Working Group on Fuel Performance and Tecnology Vienna, April 2013.

2 2 Experience of operation of nuclear fuel and advanced fuel cycles at NPPs with VVER For VVER reactors Rosenergoatom main tasks are: Ensuring the safety of NPPs; Improvement of technical and economical indicators of NPP cores; Improvement of fuel load performance; Improvement of capacity factor. We can point out the following main directions to solve the tasks above: Ensuring geometric stability of the fuel assembly; Raising safety of fuel assembly performance; Increasing capacity of uranium and introduction of fuel assembly with high enrichment of Uran-235; Realization of perspective and economically effective fuel cycles, including: increasing fuel burnup (improvement of fuel efficiency); Forming fuel loads with low level of neutron leak (reactor vessel life extension); Raising thermal efficiency of fuel loading extension (increase of energy output). Anufriev D. Experience of operation of nuclear fuel and advanced fuel cycles at NPPs with VVER // 9th International Conference on WWER Fuel Performance, Modelling and Experimental Support, Helena Resort, Burgas, Bulgaria, september 2011.

3 3 Fuel prime tasks 1. Development of FA design, which meets requirements of reliable, safe and economic efficiency operation. 2. Modernization of structural materials. 3. Improvement of technology of structural materials, manufacturing and FA fabrication. 4. Development of models and codes.

4 10 NPP, 33 units, Nуст. = MWt 4

5 5 Increase of the electricity production on the VVER nuclear power plants VVER-1000 Power increase up to 104% (110% in prospective) from the nominal value and transition to the 18 months fuel cycle (3 x 1.5 year) VVER-440 Power increase up to 107% from the nominal value and transition to the 6-yaer fuel cycle

6 Transition to the 18-months cycle for the NPPs with VVER-1000 From 2008 JSC Concern Energoatom conducts the works for the transition of the VVER-1000 units for 18-months fuel cycle operation. 6 NPP Safety justification is developed, including the justification of the equipment servicability during the increased operation period At the moment there are 8 NPP units are operating in the transition fuel loadings with cycles more then 12 months At 2015 NPP units will be operated with the stationary regimes of 18-months fuel cycle with duration about 500 effective days

7 7 Nuclear fuel for VVER-1000 FA basic design TVSA-PLUS and TVS-2М have idendtical technical-economical parameters that provide: possibility to increase the power up to 104 % of nominal power 18-month fuel cycle (with 66 FAs.) fuel road burnup - 72 MW day/kgu possibility of operation in maneuver regime mode ( % Nel) debris filter repairability in the NPP conditions ТВСА-PLUS TVS-2М

8 8 VVER-1000/1200 fuel evolution Increased geometric stability and repairability of FA, unification of structures Unification of spacing grids namber (12 pcs) in assembly for TVSA and TVS-2M Usage of universal top nozzle for TVSA-PLUS Development of FA (based on TVSA and TVS-2) with fuel rods not fixed to the bottom nozzle Increased thermal engineering reliability Introduction to commercial operation of FA with mixing grids (TVSA-PLUS with 12 spacer grids and 3 mixing grids and universal top nozzle will be delivered to Kalinin NPP in 2014) Increased uranium load in FA Introduction to experimental operation of 4-th generation FA with maximum fuel Increased fuel enrichment Validation of introduction of uranium-erbium fuel with increased enrichment (more than 5% at VVER-1200 and VVER-TOI

9 New VVER units under construction 9 Rostovskaya - 3, 4 2-nd Novovoronezhskaya 1,2 2-nd Leningradskaya 1, 2 Beloyarskaya 4 (BN) Baltiyskaya 1, 2

10 10 New VVER units under construction Нововоронежская АЭС-2 Novovoronezhskaya NPP-2 Leningradskaya NPP-2 Rostovskaya NPP, un. 3 Baltiyskaya NPP

11 11 Fuel cycles of WWER-1000 based on assemblies with increased fuel mass If we take a glance at the history of WWER-1000 fuel cycles development it will become clear that in recent years enhancement of fuel usage efficiency has been reached by increasing the average fuel enrichment. The highest enrichment in uranium-gadolinium fuel cycle with 48 feeding FAs was 4.1 %, a four-year fuel cycle being applied using FA with rigid skeleton with maximum fuel enrichment of 4.4 %. The fuel rod column height of these FAs was 3530 mm, the fuel pellet diameter mm and the central hole mm. The highest fuel enrichment of the TVS-2M being used today in Russian WWER units has been increased to 4.95 %. Additionally the energy potential of such FA was enhanced using increased fuel weight (by about 8 %) that was reached because of the fuel column extension to 3680 mm, an increase of the fuel pellet diameter to 7.6 mm and a decrease of central hole diameter to 1.2 mm. This upgrade, combined with the use of a low leakage arrangement, makes it possible to reduce the number of feeding FAs to 36 units in 12- month fuel cycles and apply 18-month fuel cycle with 66 feeding FAs. Research in the field of modernization, safety justification and licensing of equipment for fuel manufacture, storage and transportation are required for further fuel enrichment increase (above 5 %). So in the nearest future an improvement of technical and economic characteristics of fuel cycles is possible if assembly fuel mass is increased. E. Kosourov, A. Pavlovichev, A. Shcherenko Fuel cycles of WWER-1000 are based on assemblies with increased fuel mass // 9th International Conference on WWER Fuel Performance, Modelling and Experimental Support, Helena Resort, Burgas, Bulgaria, september 2011.

12 12 Nuclear fuel for VVER th generation FA Development stages Preliminary design 2012 Experimental operation 2015 Commercial operation 2017

13 13 VVER-440 Fuel Operation experience of FA 3rd generation on the unit 4 from 2010 Kolskaya NPP Units 1 and 2: FA with Vibration resistant design, enrichment 3,82% Units 3 and 4: FA of 2 nd generation, enrichment 4,25 % (107% Nnom.) Novovoronezhskaya NPP Units 3 and 4: FA with enrichment 3,82%.

14 14 Experience of operation of nuclear fuel and advanced fuel cycles at NPPs with VVER At units 1-2 of Kola NPP fuel assemblies of vibration resistant design of 3,82% enrichment have been launched into operation in a 4-year fuel cycle. At units 3-4 there are II generation fuel assemblies of 4,25% enrichment and TVS ARK of 3,82% enrichment. Fuel assemblies of 4,87% enrichment in a 5-year fuel cycle are now being loaded. Unit 4 of Kola NPP will be loaded with trial III generation fuel assemblies without case of 3,82% enrichment with a view to transition to a 6-year fuel cycle. Anufriev D. Experience of operation of nuclear fuel and advanced fuel cycles at NPPs with VVER // 9th International Conference on WWER Fuel Performance, Modelling and Experimental Support, Helena Resort, Burgas, Bulgaria, september 2011.

15 15 VVER-440 Fuel development stages : 3 rd generation fuel (without wrapper design) 2 nd generation fuel (increased fuel load) 1 st generation fuel (standard design) 15

16 16 Features of 3 rd generation FA Wrappers were replaced with angle elements; Usage of fuel pellets without central hole; Increased fuel rod step distance to optimize U/H 2 O

17 Main characteristics of fuel cycles based on 2 nd generation fuel and PK-3 fuel assembly 17

18 18 VVER-440 fuel VVER-440 fuel modernization allows: - to increase average fuel burnup from 45 MW. day/kgu (1 st generation) up to 57 MW. day/kgu (2 nd generation) and 65 MW. day/kgu (3 rd generation); - to low amount of zirconium in active core.

19 19 The development of the nuclear fuel and materials of BN reactors BN-350 Fuel: 7-8 % h.a. Materials: 70 dpa BN-600 Fuel: 9-11 % h.a. Materials: 82 dpa BN-800 Fuel: % h.a. Materials: up to 140 dpa Demonstration of closed fuel cycle

20 20 Fuel of the fast neutron reactor Unit 3 of Beloyarskaya NPP with BN-600 reactor High enriched nuclear fuel provision goes as scheduled Prospectives: Burnup increase from 10,5% (at the moment) up to 14-14,5% Formation of hybrid zone (UO 2 +UPuO 2 ) Unit 4 of Beloyarskaya NPP with BN-800 reactor Initial fuel load in the hybrid active zone (25% MOX and 75% UO 2 ) Building of the MOX-fuel plant and transition of the active zone to the complete MOX-fuel load at the end of 2017

21 LOCA 21

22 22 RIA Reactor BIGR

23 23 Driving To Zero Leakage Design Manufacture NPP

24 Zirconium alloys 24 VVER Zr-alloys RBMK Icebreaker

25 25 VVER-1000 nuclear fuel New construction materials Development of alloys E110M, E125opt, E635M is aimed at solving such problems as: Improving resistance to radiation creep and growth while maintaining corrosion resistance; To confirm the characteristics of cladding made from these materials three TVS-2M fuel assemblies were installed in 2012 at Balakovo NPP for operation with experimental fuel rods. 25

26 26 Testing new cladding materials in commercial reactor Alloys E110M, E635M, E125

27 27 Zirconium alloys research program BOR-60 NPP with VVER reactors KhPTI ESUVI accelerator, Ukraine 27

28 Accelerated methods for R and D of new zirconium materials 28 Source of radiation Dose rate, dpa/s Time to get 1 dpa Years VVER reactor 1х10-7 ~ 2000 hours BOR-60 reactor 5х10-7 ~ 400 hours Hours Accelerator 1х10-2 1х10-3 < 0,1 hour

29 C-loops Диаметр diameter, с-петель, nm нм 29 E110 Evolution of c-loops in zirconium alloys irradiated with Zr ions at 390 С E Э Э125 Э110М E110M 50 Э635 E Doze, Доза, dpa сна Dose, dpa 29

30 30 Conclusion To increase power and duration of operating cycle new high uranium content FAs which provide increased geometric stability and thermal reliability of the reactor cores were developed and are now in operation.

31 Thank you! 31