Transmutation and ADS Safety Forschungszentrum Karlsruhe in der Helmholtz-Gemeinschaft Transient Analysis for EFIT (ENEA 384MWth 3-Zone core) Safety and Transient Analysis for EFIT (ENEA 384MWth 3-Zone core) P. Liu, X. Chen, A. Rineiski, C. Matzerath Boccaccini, F. Gabrielli, W. Maschek (FZK) Forschungszentrum Karlsruhe, IKET Postfach 3640, D Karlsruhe IP EUROTRANS DM1 WP1.5 Mtg. Madrid, Nov.13-14, 2007 IP EUROTRANS DM1

Transmutation and ADS Safety Forschungszentrum Karlsruhe in der Helmholtz-Gemeinschaft All calculations are performed taking into account radial heat transfer between subassemblies ContentsContents Analysis of the 3-Zone ENEA 384MWth core  Steady state analysis of the 3-zone core Power, Temperatures, Void worth, Doppler etc. Power, Temperatures, Void worth, Doppler etc.  Unprotected Loss of Flow (ULOF)  Unprotected Blockage Accident (UBA) Flow area reduced to 2.5% Flow area reduced to 2.5%  UTOP (1000pcm jump in a 0.1s period in reactivity at HFP)  Beam Trip (5s beam trip case)

Transmutation and ADS Safety Forschungszentrum Karlsruhe in der Helmholtz-Gemeinschaft From Carlo Artioli, DM1-CC meeting-Orsay, Sept.26,2007 ENEA 384MWth 3Zone Core Design

Transmutation and ADS Safety Forschungszentrum Karlsruhe in der Helmholtz-Gemeinschaft ENEA 3-Zone core SIMMER-III Geometrical Model of the EFIT Core SIMMER-III Geometrical Model of the EFIT Core Coolant outlet to the heat exchanger Coolant outlet to the heat exchanger Coolant inlet Core View and SIMMER-III Geometrical Model

Transmutation and ADS Safety Forschungszentrum Karlsruhe in der Helmholtz-Gemeinschaft Steady-state Analysis

Transmutation and ADS Safety Forschungszentrum Karlsruhe in der Helmholtz-Gemeinschaft Steady-state Analysis Parameter Inner zone Middle zone Out zone Reflector-dummy + by-pass Total Nominal Temperature ℃ 400 ℃ (inlet), 480 ℃ (outlet) - Power SIMMER MW ENEA-Power (BOC) MW Pb mass flow rate kg/s β eff pcm 159 (SIMMER-III) 148 (ENEA) WholeActive-Core Void Worth pcm 7133 (SIMMER-III) 6670 (ENEA) Doppler effect pcm/K 0-1 pcm (SIMMER-III) 0-1 pcm (SIMMER-III)

Transmutation and ADS Safety Forschungszentrum Karlsruhe in der Helmholtz-Gemeinschaft Steady-state Analysis – Continued SIMMER-III Calculated Peak Fuel Temperature: ℃ ; Peak Clad Temperature: ℃ Peak Fuel Temperature: ℃ ; Peak Clad Temperature: ℃ SIMMER-III Calculated Peak Fuel Temperature: ℃ ; Peak Clad Temperature: ℃ Peak Fuel Temperature: ℃ ; Peak Clad Temperature: ℃ ℃℃ Limit temperatures: Fuel 1380 ℃, Clad 550 ℃ ; (From ENEA Files)

Transmutation and ADS Safety Forschungszentrum Karlsruhe in der Helmholtz-Gemeinschaft Void Worth Calculations Active-core void worth LibrariesENEApcm6670 MCNPX & JEFF 3.1 FZK : ERANOS calculational procedure (ENEA) pcm5463 RZ geometry, ERALIB HEX-Z geometry, ERALIB 1 FZK : SIMMER - III pcm7133 FZK XS FZK : C4P/DANTSYSpcm7030 JEFF JEFF ENDF/B-7

Transmutation and ADS Safety Forschungszentrum Karlsruhe in der Helmholtz-Gemeinschaft ENEA SIMMER-IIISIMMER-III In the inner core, SIMMER-III void worth in good agreement with ENEA; In outer core ring ~ 20% difference Steady-state analysis – Continued

Transmutation and ADS Safety Forschungszentrum Karlsruhe in der Helmholtz-Gemeinschaft ULOF Analysis Assumptions:  Core - SG height difference 3.7 m;  Fast ULOF with 5 s pump halving time;  No structural thermal expansion taken into account (need for data);  The coolant inlet temperature kept constant at 400 ℃. Assumptions:  Core - SG height difference 3.7 m;  Fast ULOF with 5 s pump halving time;  No structural thermal expansion taken into account (need for data);  The coolant inlet temperature kept constant at 400 ℃.

Transmutation and ADS Safety Forschungszentrum Karlsruhe in der Helmholtz-Gemeinschaft ULOF Analysis During ULOF, Power Power finally stabilized at about 1% higher than operational power. Reactivity Reactivity finally stabilized at about pcm higher than operation condition.

Transmutation and ADS Safety Forschungszentrum Karlsruhe in der Helmholtz-Gemeinschaft During ULOF, The coolant velocity decreases as shown in the left side figures. coolant In turn, the coolant mass flow rate mass flow rate decreases, which finally stabilizes at 40% around 40% due to the natural convection flow. Because of the remaining coolant flow rate, the coolant maximum temperature (TLK3) finally stabilizes at about 640 ℃ (913K). During ULOF, The coolant velocity decreases as shown in the left side figures. coolant In turn, the coolant mass flow rate mass flow rate decreases, which finally stabilizes at 40% around 40% due to the natural convection flow. Because of the remaining coolant flow rate, the coolant maximum temperature (TLK3) finally stabilizes at about 640 ℃ (913K).

Transmutation and ADS Safety Forschungszentrum Karlsruhe in der Helmholtz-Gemeinschaft ULOF Analysis –Continued  Final Pb flow rate stabilized at about 40%;  Maximum Pb temperature (at outer fuel ring) stabilized at about 640 ℃ (913K);  Maximum fuel temperature (at inner fuel ring) stabilized at about 1510 ℃ (1783K) (DBC-I limit 1750K,1477 ℃ );  Maximum clad temperature (at inner fuel ring) stabilized at about 672 ℃ (945K). 672 ℃ (945K).  Final Pb flow rate stabilized at about 40%;  Maximum Pb temperature (at outer fuel ring) stabilized at about 640 ℃ (913K);  Maximum fuel temperature (at inner fuel ring) stabilized at about 1510 ℃ (1783K) (DBC-I limit 1750K,1477 ℃ );  Maximum clad temperature (at inner fuel ring) stabilized at about 672 ℃ (945K). 672 ℃ (945K).

Transmutation and ADS Safety Forschungszentrum Karlsruhe in der Helmholtz-Gemeinschaft UBA Analysis Assumptions:  First fuel ring blocked and its flow area reduced to 2.5%;  Fuel pellets break up into particles after clad melting or clad failure;  In SIMMER-III, the fuel solidus temperature is defined as 2130K (MgO matrix evaporation limit), and the fuel liquidus temperature is defined as 2450K (melting of TRU);  UBA consequences depend on large parameter field (clad failure conditions, fuel failure conditions, above core structure behavior, hexcan failure conditions etc.). Assumptions:  First fuel ring blocked and its flow area reduced to 2.5%;  Fuel pellets break up into particles after clad melting or clad failure;  In SIMMER-III, the fuel solidus temperature is defined as 2130K (MgO matrix evaporation limit), and the fuel liquidus temperature is defined as 2450K (melting of TRU);  UBA consequences depend on large parameter field (clad failure conditions, fuel failure conditions, above core structure behavior, hexcan failure conditions etc.).

Transmutation and ADS Safety Forschungszentrum Karlsruhe in der Helmholtz-Gemeinschaft UBA Analysis Power and reactivity transients during UBA Power and reactivity transients during UBA

Transmutation and ADS Safety Forschungszentrum Karlsruhe in der Helmholtz-Gemeinschaft  Pin failure after the clad looses its mechanical strength;  Gas blow-down and local voiding  Rewetting  Local fuel pellet ‘melting’;  Local Pb boiling;  Fuel sweep-out, reactivity and power reduction (25 %);  Beam shut-down necessary;  Pin failure after the clad looses its mechanical strength;  Gas blow-down and local voiding  Rewetting  Local fuel pellet ‘melting’;  Local Pb boiling;  Fuel sweep-out, reactivity and power reduction (25 %);  Beam shut-down necessary; UBA Analysis-Continued

Transmutation and ADS Safety Forschungszentrum Karlsruhe in der Helmholtz-Gemeinschaft

Transmutation and ADS Safety Forschungszentrum Karlsruhe in der Helmholtz-Gemeinschaft UTOP Analysis Assumptions:  During 0.1s period, 1000pcm increase in reactivity  During 0.1s period, 1000pcm increase in reactivity (according to WP1.5 ad hoc definition) Assumptions:  During 0.1s period, 1000pcm increase in reactivity  During 0.1s period, 1000pcm increase in reactivity (according to WP1.5 ad hoc definition)

Transmutation and ADS Safety Forschungszentrum Karlsruhe in der Helmholtz-Gemeinschaft Increase of 1000 pcm in reactivity during 0.1s period: Power Power finally stabilizes at about 40 % higher than operational power. Reactivity Reactivity finally stabilizes at about 1040 pcm higher than operational condition. UTOP analysis

Transmutation and ADS Safety Forschungszentrum Karlsruhe in der Helmholtz-Gemeinschaft  Maximum fuel temp. stabilizes at around 1750 ℃ (2023K) 1750 ℃ (2023K)  Maximum fuel temp. above DBC-IV limit (1680 ℃ ). below DEC limit (1860 ℃ )  Maximum clad temp. stabilizes at around 572 ℃ (845K); 572 ℃ (845K);  Maximum coolant temp. stabilizes at around 549 ℃ (822K). 549 ℃ (822K).  Maximum fuel temp. stabilizes at around 1750 ℃ (2023K) 1750 ℃ (2023K)  Maximum fuel temp. above DBC-IV limit (1680 ℃ ). below DEC limit (1860 ℃ )  Maximum clad temp. stabilizes at around 572 ℃ (845K); 572 ℃ (845K);  Maximum coolant temp. stabilizes at around 549 ℃ (822K). 549 ℃ (822K).

Transmutation and ADS Safety Forschungszentrum Karlsruhe in der Helmholtz-Gemeinschaft Beam Trip Analysis Assumptions:  External beam amplitude being zero for 5 seconds.  External beam amplitude being zero for 5 seconds (according to WP1.5 ad hoc definition). Assumptions:  External beam amplitude being zero for 5 seconds.  External beam amplitude being zero for 5 seconds (according to WP1.5 ad hoc definition).

Transmutation and ADS Safety Forschungszentrum Karlsruhe in der Helmholtz-Gemeinschaft Beam Trip Analysis With 5 seconds’ beam- off: Power Power decreases immediately and sharply; Reactivity Reactivity nearly unchanged (small neutron flux shape and the coolant temperature reactivity effect).

Transmutation and ADS Safety Forschungszentrum Karlsruhe in der Helmholtz-Gemeinschaft Beam Trip Analysis-Continued  Maximum fuel temp. decreases about 720 ℃ ; 720 ℃ ;  Maximum clad temperature decreases about 54 ℃ ; about 54 ℃ ;  Maximum coolant temperature decreases about 35 ℃.  Maximum fuel temp. decreases about 720 ℃ ; 720 ℃ ;  Maximum clad temperature decreases about 54 ℃ ; about 54 ℃ ;  Maximum coolant temperature decreases about 35 ℃.  Fuel temp. at core mid-plane;  Coolant and clad temp. at core outlet  Fuel temp. at core mid-plane;  Coolant and clad temp. at core outlet

Transmutation and ADS Safety Forschungszentrum Karlsruhe in der Helmholtz-Gemeinschaft Beam Trip Analysis-Continued  Temperature development at core mid-plane of first fuel ring.

Transmutation and ADS Safety Forschungszentrum Karlsruhe in der Helmholtz-Gemeinschaft SummarySummary Steady State Analysis  SIMMER simulated results are in agreement with the design data;  The EFIT core has a void worth larger than the sub-criticality;  The Doppler effect in EFIT core is about zero; ULOF Analysis  Conservative assumptions  The power and reactivity increase is small;  The clad and coolant temp. are below their safety limits;  The fuel peak temperature is about 1510 ℃ (1783K), which is between 1480 ℃ (DBC-I limit,1750K) and 1580 ℃ (DBC-II limit,1850K);

Transmutation and ADS Safety Forschungszentrum Karlsruhe in der Helmholtz-Gemeinschaft UBA Analysis  The power and reactivity increase is small; (Power increase less 5%)  Pin failure happens when the clad looses its mechanical strength; local Pb voiding possible, fuel stack disintegration;  No serious damage happens to neighbor fuel rings due to the inherent fuel sweep-out mechanism;  UBA, a transient with the potential of local core damage and damage propagation;  Outcome of UBA scenario dependent on many parameters;  UBA outcome connected with uncertainty band;  Special efforts needed and under way for improved understanding and simulation. Summary - Continued

Transmutation and ADS Safety Forschungszentrum Karlsruhe in der Helmholtz-Gemeinschaft UTOP Analysis  The power increases 40% due to 1000pcm jump of the reactivity;  No pin failure happens;  The maximum fuel temp. is around 1750 ℃ (2023K) (higher than DBC-IV limit 1680 ℃,1950K ), clad 572 ℃ (845K), coolant 549 ℃ (822K) ; Summary - Continued Beam Trip Analysis  With a 5 seconds beam-off, the maximum fuel temperature decreases about 720 ℃, the maximum clad temperature transiently decreases 54 ℃, the maximum coolant temperature decreases 35 ℃.  Fuel behaviour after multiple beam trips

Transmutation and ADS Safety Forschungszentrum Karlsruhe in der Helmholtz-Gemeinschaft The End Thank you for your attention

Transmutation and ADS Safety Forschungszentrum Karlsruhe in der Helmholtz-Gemeinschaft