1. (1) Die Kooperation von Forschungszentrum Karlsruhe GmbH und Universität Karlsruhe (TH) 0 | Transient Analysis for the EFIT 3-Zone Core P. Liu, X.-N. Chen, A. Rineiski, S. Wang, M. Flad, W. Maschek Forschungszentrum Karlsruhe, IKET Postfach 3640, D-76021 Karlsruhe IP EUROTRANS DM1 WP1.5 Mtg. Bologna, 28-30 May 2008 IP EUROTRANS DM1

2. (1) Die Kooperation von Forschungszentrum Karlsruhe GmbH und Universität Karlsruhe (TH) 1 | Contents Design base and Some former work; Design base and Some former work; (ULOF, Beam trip, UTOP, UBA already presented in last meeting) (ULOF, Beam trip, UTOP, UBA already presented in last meeting) SIMMER-III new model; SIMMER-III new model; (with a new implemented pump model) (with a new implemented pump model) ULOF (under new pressure drop conditions); ULOF (under new pressure drop conditions); Beam Trip (short term beam trip:1second); Beam Trip (short term beam trip:1second); Unprotected Blockage (first fuel ring totally blocked); Unprotected Blockage (first fuel ring totally blocked); Summaries Summaries

3. (1) Die Kooperation von Forschungszentrum Karlsruhe GmbH und Universität Karlsruhe (TH) 2 | ENEA 384MWth 3Zone Core Design 42 66 72 Output section Hex. wrapper Fuel bundle Central rod Joint section 186 Ø 159 4080 70 2100 485 26 160 1220 Ø 146 Ø 127 4.0 186 13.63 186 Ø 127 186 Ø 12 186 Input tube Conical foot Output section Hex. wrapper Fuel bundle Central rod Joint section 186 Ø 159 186 Ø 159 4080 70 2100 485 26 160 1220 Ø 146 Ø 127 Ø 146 Ø 127 4.0 186 13.63 4.0 186 13.63 186 Ø 127 186 Ø 127 186 Ø 12 186 Ø 12 186 Input tube Conicalfoot

4. (1) Die Kooperation von Forschungszentrum Karlsruhe GmbH und Universität Karlsruhe (TH) 3 | Former work-SIMMER-III simulation of the steady state SIMMER-IIISIMMER-III ENEA

5. (1) Die Kooperation von Forschungszentrum Karlsruhe GmbH und Universität Karlsruhe (TH) 4 | SIMMER-III Calculated Peak Fuel Temperature: 1352.1 ; Peak Clad Temperature: 521.1 Peak Fuel Temperature: 1352.1 ; Peak Clad Temperature: 521.1 SIMMER-III Calculated Peak Fuel Temperature: 1352.1 ; Peak Clad Temperature: 521.1 Peak Fuel Temperature: 1352.1 ; Peak Clad Temperature: 521.1 Limit temperatures at nominal conditions: Fuel 1380, Clad 550 ; (From ENEA Files) Former work-SIMMER-III simulation of the steady state

6. (1) Die Kooperation von Forschungszentrum Karlsruhe GmbH und Universität Karlsruhe (TH) 5 | New geometrical model of EFIT core in SIMMER-III Coolant outlet Coolant inlet Coolant flow pass Pump region Heat exchanger region region New

7. (1) Die Kooperation von Forschungszentrum Karlsruhe GmbH und Universität Karlsruhe (TH) 6 | ULOF analysis Assumptions and conditions: Core - SG midplane distance: 3.7 m; Core - SG midplane distance: 3.7 m; The transient starts at 60 s from a well established steady-state; The transient starts at 60 s from a well established steady-state; Total pressure drop in the primary system Total pressure drop in the primary system 1.1 bar; 1.1 bar; 1.37 bar (two cases); 1.37 bar (two cases); 1.87 bar; 1.87 bar; Pump head becomes zero in 10 s; halving time = 2 s; (Main) Pump head becomes zero in 10 s; halving time = 2 s; (Main) Pump head becomes zero in 5s, halving time =2 s; Pump head becomes zero in 5s, halving time =2 s; (for the 2 nd case of 1.37bar) (for the 2 nd case of 1.37bar) Assumptions and conditions: Core - SG midplane distance: 3.7 m; Core - SG midplane distance: 3.7 m; The transient starts at 60 s from a well established steady-state; The transient starts at 60 s from a well established steady-state; Total pressure drop in the primary system Total pressure drop in the primary system 1.1 bar; 1.1 bar; 1.37 bar (two cases); 1.37 bar (two cases); 1.87 bar; 1.87 bar; Pump head becomes zero in 10 s; halving time = 2 s; (Main) Pump head becomes zero in 10 s; halving time = 2 s; (Main) Pump head becomes zero in 5s, halving time =2 s; Pump head becomes zero in 5s, halving time =2 s; (for the 2 nd case of 1.37bar) (for the 2 nd case of 1.37bar)

8. (1) Die Kooperation von Forschungszentrum Karlsruhe GmbH und Universität Karlsruhe (TH) 7 | ULOF analysis -1.1 bar pressure drop Pump head becomes zero in 10 s, halving time =2 s

9. (1) Die Kooperation von Forschungszentrum Karlsruhe GmbH und Universität Karlsruhe (TH) 8 | ULOF analysis -1.37 bar pressure drop (1 st case) Pump head becomes zero in 10 s, halving time =2 s

10. (1) Die Kooperation von Forschungszentrum Karlsruhe GmbH und Universität Karlsruhe (TH) 9 | ULOF analysis -1.37 bar pressure drop (1st case) Simple view of the Coolant Movement in the system during the pump coast down process.

11. (1) Die Kooperation von Forschungszentrum Karlsruhe GmbH und Universität Karlsruhe (TH) 10 | ULOF analysis -1.37 bar pressure drop (2 nd case) Pump head becomes zero in 5 s, halving time =2 s Pump coast down data needed!!

12. (1) Die Kooperation von Forschungszentrum Karlsruhe GmbH und Universität Karlsruhe (TH) 11 | ULOF analysis -1.87 bar pressure drop Pump head becomes zero in 10 s, halving time =2 s

13. (1) Die Kooperation von Forschungszentrum Karlsruhe GmbH und Universität Karlsruhe (TH) 12 | ULOF-Comparison

14. (1) Die Kooperation von Forschungszentrum Karlsruhe GmbH und Universität Karlsruhe (TH) 13 | Beam trip analysis External beam amplitude being zero for 1 second. Assumption: External beam amplitude being zero for 1 second. Maximum fuel temp. decrease about 554 K ; Maximum fuel temp. decrease about 554 K ; Maximum clad temperature decrease Maximum clad temperature decrease about 14 K; about 14 K; Maximum coolant temperature decrease about 12 K. Maximum coolant temperature decrease about 12 K. Maximum fuel temp. decrease about 554 K ; Maximum fuel temp. decrease about 554 K ; Maximum clad temperature decrease Maximum clad temperature decrease about 14 K; about 14 K; Maximum coolant temperature decrease about 12 K. Maximum coolant temperature decrease about 12 K. Fuel temp. at core mid-plane; Fuel temp. at core mid-plane; Coolant and clad temp. at core outlet Coolant and clad temp. at core outlet Fuel temp. at core mid-plane; Fuel temp. at core mid-plane; Coolant and clad temp. at core outlet Coolant and clad temp. at core outlet

15. (1) Die Kooperation von Forschungszentrum Karlsruhe GmbH und Universität Karlsruhe (TH) 14 | Unprotected blockage Assumptions/Conditions/Parameters: Innermost ring totally blocked Transient starts at 30 s from a well established steady-state; He & fission gas pressure (1MPa BOC initial at gas plenum) Radial heat exchange between SA rings is taken into account; Clad failure and gas release at 1280K; Clad weakening and start of fuel movement at 1513 K Hexcan crack at 1280K; Hexcan weakening at 1513K; Fuel particle size volumetrically equals to one pellet: r = 4.555mm; Steel particle size r = 2.0mm; No-removable upper pin structure; No damage propagation to Target facility;Assumptions/Conditions/Parameters: Innermost ring totally blocked Transient starts at 30 s from a well established steady-state; He & fission gas pressure (1MPa BOC initial at gas plenum) Radial heat exchange between SA rings is taken into account; Clad failure and gas release at 1280K; Clad weakening and start of fuel movement at 1513 K Hexcan crack at 1280K; Hexcan weakening at 1513K; Fuel particle size volumetrically equals to one pellet: r = 4.555mm; Steel particle size r = 2.0mm; No-removable upper pin structure; No damage propagation to Target facility;

16. (1) Die Kooperation von Forschungszentrum Karlsruhe GmbH und Universität Karlsruhe (TH) 15 | Unprotected blockage-Continued Power increased to a maximum of 655 MW; Power increased to a maximum of 655 MW; Fuel pin damage propagation happens, damage spreads to the third fuel ring. Fuel pin damage propagation happens, damage spreads to the third fuel ring. Power increased to a maximum of 655 MW; Power increased to a maximum of 655 MW; Fuel pin damage propagation happens, damage spreads to the third fuel ring. Fuel pin damage propagation happens, damage spreads to the third fuel ring.

17. (1) Die Kooperation von Forschungszentrum Karlsruhe GmbH und Universität Karlsruhe (TH) 16 | Summaries ULOF Analysis New SIMMER modeling on the ULOF has been performed with a pump and heat exchange region and in turn, the three free surface well modeled with the implemented pump model in SIMMER-III; New SIMMER modeling on the ULOF has been performed with a pump and heat exchange region and in turn, the three free surface well modeled with the implemented pump model in SIMMER-III; Under the 1.37 bar total pressure drop and the assumed pump coast down conditions, the current core can survive the ULOF transient; Under the 1.37 bar total pressure drop and the assumed pump coast down conditions, the current core can survive the ULOF transient; Pump coast down data should be well established; Pump coast down data should be well established; Beam Trip Analysis With a 1 seconds beam-off, the maximum fuel temperature decreases about 554 K, the maximum clad temperature transiently decreases 14 K, the maximum coolant temperature decreases 12 K; With a 1 seconds beam-off, the maximum fuel temperature decreases about 554 K, the maximum clad temperature transiently decreases 14 K, the maximum coolant temperature decreases 12 K; UBA Analysis Fuel damage could happen and spread to the third fuel ring if the first fuel ring is completely blocked; Fuel damage could happen and spread to the third fuel ring if the first fuel ring is completely blocked; The power can arrive as high as 655 MW; The power can arrive as high as 655 MW; The power finally decreases due to the inherent fuel sweep-out mechanism. The power finally decreases due to the inherent fuel sweep-out mechanism.