1. 1 Hee cheon NO Nuclear System/Hydrogen Lab. KAIST Chapter1: Nuclear Reactor Heat Transport System

2. 2 Contents Chapter 1 Nuclear reactor heat transport system 1.1 Nuclear fuel 1.2 Reactor vessel 1.3 Reactor core and fuel assembly 1.4 Rod cluster control assembly

3. 3  Fuel rod 1.1 Nuclear fuel

4. 4  Pellet hourglassing and Pellet-Cladding Mechanical Interaction(PCMI) 1.1 Nuclear fuel dish/chamfer

5. 5  Fuel cracking 1.1 Nuclear fuel

6. 6  Example of fuel failure mechanisms 1.1 Nuclear fuel

7. 7  Intergranular SCC 1.1 Nuclear fuel: Intergranular SCC

8. 8  Transient cladding ballooning: LOCA 1.1 Nuclear fuel: Cladding Ballooning & rupture stress strain ultimate tensile stress

9. 9 1.1 Nuclear fuel: Cladding rupture  Post-CHF operation: Non-LOCA Reactivity-Initiated Accident(RIA)

10. 10  PCMI 1.1 Nuclear fuel

11. 11 APR1400 Typical 4 loop Rx vessel 1.2 Reactor vessel RCB: Rx Containment Building; TGB: Turbine/Generator Building; AB: Auxiliary Building; CB: Compound Building NSSS upper core plate Lower plenum Upper head Upper plenum

12. 12 1.2 Reactor vessel

13. 13 1.2 Reactor vessel Estimation of core mass flow rate: Flow paths APR1400 설계값 Vessel flow rate 20,991.2kg/sec Guide tube 154.9 kg/sec Core shroud annulus 84.2 kg/sec Outlet nozzle gap 288.9 kg/sec Alignment key 101.9 kg/sec APR Bypass overall 629.9 kg/sec3.0% UK EPR: 5.5%

14. 14 1.2 Reactor vessel

15. 15 1.2 Reactor vessel: irradiation specimen (Nil-ductility transition T)

16. 16 Typical 4-Loop core 1.3 Reactor core and fuel assembly APR cladding volume(m^3)3.72Zr mass in fuel(Kg)Zr mass in struc(kg) Zr total mass(kg)29647241975450

17. 17 core and fuel 1.3 Reactor core and fuel assembly

18. 18 Assembly 1.3 Reactor core and fuel assembly

19. 19 1.3 Reactor core and fuel assembly

20. 20 Assembly(PLUS7) 1.3 Reactor core and fuel assembly

21. 21 Assembly(PLUS7) 1.3 Reactor core and fuel assembly

22. 22 Assembly 1.3 Reactor core and fuel assembly

23. 23 Spacer grid 1.3 Reactor core and fuel assembly

24. 24 1.3 Reactor core and fuel assembly

25. 25 1.4 Rod cluster control assembly