1. EUROTRANS: WP1.5 Technical meeting, Karlsruhe, November 27 – 28, 2008 1 XT-ADS DHR Conceptual Design L. Mansani luigi.mansani@ann.ansaldo.it

2. EUROTRANS: WP1.5 Technical meeting, Karlsruhe, November 27 – 28, 2008 2 1. PHX (2X2) 2. Safety Vessel 3. Reactor Vessel 4. Inner Vessel 5. Core Barrel 6. Support 7. Reactor Cover 8. Primary Pumps (2X1) 9. Spallation loop XT-ADS Reactor Assembly

3. EUROTRANS: WP1.5 Technical meeting, Karlsruhe, November 27 – 28, 2008 3 XT-ADS Secondary and Tertiary Systems DHR System

4. EUROTRANS: WP1.5 Technical meeting, Karlsruhe, November 27 – 28, 2008 4 XT-ADS Decay Heat

5. EUROTRANS: WP1.5 Technical meeting, Karlsruhe, November 27 – 28, 2008 5 XT-ADS Primary System Main Characteristics

6. EUROTRANS: WP1.5 Technical meeting, Karlsruhe, November 27 – 28, 2008 6 XT-ADS Secondary System Main Characteristics

7. EUROTRANS: WP1.5 Technical meeting, Karlsruhe, November 27 – 28, 2008 7 Spurious Trip After reactor trip the following events are postulated  Primary Pumps continue to operate  Air Fans stop  Louvers remain in their actual position  Large condenser isolated in 60 seconds  Small condenser remains in operation

8. EUROTRANS: WP1.5 Technical meeting, Karlsruhe, November 27 – 28, 2008 8 Spurious Trip Power LBE Flowrates

9. EUROTRANS: WP1.5 Technical meeting, Karlsruhe, November 27 – 28, 2008 9 Spurious Trip Temperatures Secondary System Pressure

10. EUROTRANS: WP1.5 Technical meeting, Karlsruhe, November 27 – 28, 2008 10 Protected Loss of Flow 1 Primary Pumps Inertia 20 kg m 2 After reactor trip the following events are postulated  Primary Pumps stop  Air Fans stop  Louvers remain in their actual position  Large condenser isolated in 60 seconds  Small condenser remains in operation

11. EUROTRANS: WP1.5 Technical meeting, Karlsruhe, November 27 – 28, 2008 11 Protected Loss of Flow 1 Power Primary Pump Velocity

12. EUROTRANS: WP1.5 Technical meeting, Karlsruhe, November 27 – 28, 2008 12 Protected Loss of Flow 1 LBE Levels LBE Flowrates

13. EUROTRANS: WP1.5 Technical meeting, Karlsruhe, November 27 – 28, 2008 13 Protected Loss of Flow 1 Secondary System Pressure Temperatures

14. EUROTRANS: WP1.5 Technical meeting, Karlsruhe, November 27 – 28, 2008 14 Protected Loss of Flow 2 Primary Pumps Inertia 100 kg m 2 After reactor trip the following events are postulated  Primary Pumps stop  Air Fans stop  Louvers remain in their actual position  Large condenser isolated in 60 seconds  Small condenser remains in operation

15. EUROTRANS: WP1.5 Technical meeting, Karlsruhe, November 27 – 28, 2008 15 Protected Loss of Flow 2 Primary Pump Velocity LBE Levels

16. EUROTRANS: WP1.5 Technical meeting, Karlsruhe, November 27 – 28, 2008 16 Protected Loss of Flow 2 Temperatures LBE Flowrates

17. EUROTRANS: WP1.5 Technical meeting, Karlsruhe, November 27 – 28, 2008 17 Protected Loss of Flow 2

18. EUROTRANS: WP1.5 Technical meeting, Karlsruhe, November 27 – 28, 2008 18 Protected Loss of Flow 3 Only 1 out of 2 DHR LOOP Credited Primary Pumps Inertia 100 kg m 2 After reactor trip the following events are postulated  Primary Pumps stop  Air Fans stop  Louvers remain in their actual position  Large condenser isolated in 60 seconds  Small condenser remains in operation

19. EUROTRANS: WP1.5 Technical meeting, Karlsruhe, November 27 – 28, 2008 19 Protected Loss of Flow 3 Power LBE Flowrates

20. EUROTRANS: WP1.5 Technical meeting, Karlsruhe, November 27 – 28, 2008 20 Protected Loss of Flow 3 Secondary System Pressure Temperatures

21. EUROTRANS: WP1.5 Technical meeting, Karlsruhe, November 27 – 28, 2008 21 Spurious Trip with No Isolation of the Large Condenser After reactor trip the following events are postulated  Primary Pumps continue to operate  Air Fans stop  Louvers remain in their actual position  Large condenser remains in operation  Small condenser remains in operation

22. EUROTRANS: WP1.5 Technical meeting, Karlsruhe, November 27 – 28, 2008 22 Spurious Trip with No Isolation of the Large Condenser Power Temperatures

23. EUROTRANS: WP1.5 Technical meeting, Karlsruhe, November 27 – 28, 2008 23 XT-ADS RVACS Evacuated Power Vs Reactor Vessel Temperature Emissivity 0.5 Emissivity 0.6

24. EUROTRANS: WP1.5 Technical meeting, Karlsruhe, November 27 – 28, 2008 24 XT-ADS RVACS Performances Emissivity 0.5 Emissivity 0.6

25. EUROTRANS: WP1.5 Technical meeting, Karlsruhe, November 27 – 28, 2008 25 XT-ADS 3D Model and Temperature Field at Nominal Power

26. EUROTRANS: WP1.5 Technical meeting, Karlsruhe, November 27 – 28, 2008 26 XT-ADS Velocity Field at Nominal Power

27. EUROTRANS: WP1.5 Technical meeting, Karlsruhe, November 27 – 28, 2008 27 XT-ADS Temperature and Velocity Field with RVACS Operation After 50 seconds After 5.54 hours After 5.54 hours

28. EUROTRANS: WP1.5 Technical meeting, Karlsruhe, November 27 – 28, 2008 28 XT-ADS RVACS Reactor Vessel Temperature 3D and Simplified Calculation Comparison

29. EUROTRANS: WP1.5 Technical meeting, Karlsruhe, November 27 – 28, 2008 29 XT-ADS RVACS Performance with Primary Forced Circulation Restored Emissivity 0.5Emissivity 0.6

30. EUROTRANS: WP1.5 Technical meeting, Karlsruhe, November 27 – 28, 2008 30 Conclusions 1/2  Normal Decay Heat Removal Function is performed by forced/natural convection through the Primary Heat Exchanger cooled by the secondary system water/steam in natural circulation and by the tertiary system air in forced circulation (the normal path to evacuate the reactor power)  Emergency Decay Heat Removal Function is performed by:  Natural convection through the Primary Heat Exchanger cooled by the secondary system water/steam in natural circulation and by the tertiary system air in natural circulation (DHR number 1)  Reactor Vessel Air Cooling systems by irradiation from the Reactor Vessel wall to the Safety Vessel wall and to the wall of dedicate pipes and by air in natural convection inside the pipes (DHR number 2)

31. EUROTRANS: WP1.5 Technical meeting, Karlsruhe, November 27 – 28, 2008 31 Conclusions 2/2  No actuation is required to start to operate both DHR systems  DHR Systems are already in operation during normal operating conditions  DHR number 1 needs:  after the reactor trip an automatic shutdown of the tertiary system fan and the automatic isolation of a portion of the air cooler to prevent LBE freezing  In the medium term an operator action (not required within the first 30 minutes from the accident) to reduce the system capability to prevent LBE freezing  DHR number 2 needs:  an operator action, within the first 12 hours from the accident, to restart at least one primary pump to avoid exceeding the temperature limit on the Reactor Vessel wall

32. EUROTRANS: WP1.5 Technical meeting, Karlsruhe, November 27 – 28, 2008 32