Analysis of the heat exchanger tube rupture accident in the XT-ADS reactor with the SIMMER-III code Abstract ACTINIDE AND FISSION PRODUCT PARTITIONING AND TRANSMUTATION, ISBN 97-9--9917-3, OECD 1 1
Introduction XT-ADS design and operating conditions Figure 1: HX design and its arrangement in the primary system of XT-ADS reactor INLET m 1 m ISOLATION VALVES INLET OUTLET ACTINIDE AND FISSION PRODUCT PARTITIONING AND TRANSMUTATION, ISBN 97-9--9917-3, OECD 1
Table 1: Main XT-ADS operating parameters Parameter Unit Value Core power at BOL MW 7 LBE cold temperature C 3 LBE hot temperature C 39 Core mass flow rate kg/s 77 Core bypass mass flow rate kg/s LBE mass flow rate in one HX kg/s 1 75 Feedwater pressure bar 3.3 Feedwater temperature C 33 Secondary pressure at HX outlet bar 9.7 Equilibrium quality at HX outlet. SIMMER-III simulation of postulated accidents ACTINIDE AND FISSION PRODUCT PARTITIONING AND TRANSMUTATION, ISBN 97-9--9917-3, OECD 1 3
Figure : XT-ADS model used in the SIMMER-III transient analysis a) Primary system b) Safety valves and lines Safety valves Reactor cover SV lines Cover gas HX Pump Hot plenum c) HX and pump compartment By-pass Core Cold zone Tube Break Cold plenum ACTINIDE AND FISSION PRODUCT PARTITIONING AND TRANSMUTATION, ISBN 97-9--9917-3, OECD 1
HX water inventory by RELAP5 code Table : HX water inventory Component Volume Mean void Liquid Steam Total H O [m 3 ] fraction mass [kg] mass [kg] mass [kg] Inlet pipe.1 1. 133 133 Cold collector. 1. 71 71 Tube bundle..5 3 1 33 Hot collector + tube outlet 1.3.77 55 15 7 Total 1. 91 1 57 Cover gas circuit and safety valve simulation Table 3: Main cover gas circuit and safety valve parameters Parameter Unit Value Safety valves number Opening pressure set-point bar Valve cross-flow area m.39 Valve capacity (saturated steam) kg/s Inner diameter of line to SV M.15 Length of line to SV above reactor cover M 1 In-vessel cover gas volume m 3 3 Cover gas pressure bar 1 Out-of-vessel cover gas circuit volume Neglected ACTINIDE AND FISSION PRODUCT PARTITIONING AND TRANSMUTATION, ISBN 97-9--9917-3, OECD 1 5
Analysis of accident scenarios Table : Break characteristics in the analysed HX tube rupture events Event Single tube rupture Multiple tube rupture Break type Guillotine break of 1 tube at the inlet Guillotine break of 5 tubes at the inlet Diameter [m] Flow area [m ].137.95.137.175 Initial leakage flow rate [kg/s].3 (by RELAP5 [1]) 11.5 (by RELAP5 [1]) Single tube rupture ACTINIDE AND FISSION PRODUCT PARTITIONING AND TRANSMUTATION, ISBN 97-9--9917-3, OECD 1
Flowrate (kg/s) Mass (kg) ANALYSIS OF THE HEAT EXCHANGER TUBE RUPTURE ACCIDENT IN THE XT-ADS REACTOR WITH THE SIMMER-III CODE Figure 3: Material fractions and gas velocity field during the transient phase a) t = s (1 s after break opening) b) t = 3 s (1 s after SV opening) Figure : Main results of the single tube rupture simulation 5 a) Break flowrate and cumulated value b) Cover gas pressure 1 HO flowrate Cumulated value 3 1 SV1 inlet SV inlet In-vessel 3. 7 1 1 35 7 1 1 35 c) HX secondary pressure d) HX Pump compartment pressure 1 9. Tube inlet Tube bundle pump comp. HX bundle 9.. ACTINIDE AND FISSION PRODUCT PARTITIONING AND TRANSMUTATION, ISBN 97-9--9917-3, OECD 1 7. 7 1 1 35 1. 1. 1. 1. 1.. e) Steam release through safety valves f) Active core voiding 1..
Flowrate (kg/s) Flowrate (kg/s) Mass (kg) Void fraction (%) 3 1 ANALYSIS OF THE HEAT EXCHANGER TUBE RUPTURE ACCIDENT IN THE XT-ADS REACTOR WITH THE SIMMER-III CODE SV1 inlet SV inlet In-vessel 7 1 1 35 7 1 1 35 Figure : Main results of the single tube rupture simulation (cont.) c) HX secondary pressure d) HX Pump compartment pressure 3. 1 9. Tube inlet Tube bundle pump comp. HX bundle 9... 1. 7 1 1 35 1. 1. 1. 1. 1.. e) Steam release through safety valves f) Active core voiding. 1.. SV1 flowrate SV flowrate.3 Active core.....1. 7 1 1 35. 7 1 1 35 Multiple tube rupture ACTINIDE AND FISSION PRODUCT PARTITIONING AND TRANSMUTATION, ISBN 97-9--9917-3, OECD 1
Flowrate (kg/s) Mass (kg) ANALYSIS OF THE HEAT EXCHANGER TUBE RUPTURE ACCIDENT IN THE XT-ADS REACTOR WITH THE SIMMER-III CODE Figure 5: Material fractions and gas velocity field during the transient phase a) t = s (1 s after break opening) b) t = s (13 s after SV opening) Figure : Main results of the multiple tube rupture simulation a) HX Pump compartment pressure b) Break flowrate and cumulated value 15 5 1 pump comp. HX bundle 1 1 9 3 3 HO flowrate Cumulated value 1 3 1. 1.1 1. 1.3 1. 1.5 1 3 5 c) HX secondary pressure d) Cover gas pressure 5 15 Tube inlet 1 SV1 inlet Tube bundle SV inlet 5 In-vessel ACTINIDE AND FISSION PRODUCT PARTITIONING AND TRANSMUTATION, ISBN 97-9--9917-3, OECD 1 9 1 3 5 1 3 5 e) Steam release through safety valves f) Active core voiding.3
Flowrate (kg/s) Void fraction (%) Flowrate (kg/s) Mass (kg) 1 9 3 3 HO flowrate ANALYSIS OF THE HEAT EXCHANGER TUBE RUPTURE ACCIDENT IN THE XT-ADS REACTOR WITH THE SIMMER-III CODE Cumulated value 1 1. 1.1 1. 1.3 1. 1.5 1 3 5 Figure : Main results of the multiple tube rupture simulation (cont.) c) HX secondary pressure d) Cover gas pressure 3 5 15 1 5 Tube inlet Tube bundle SV1 inlet SV inlet In-vessel 1 3 5 1 3 5 e) Steam release through safety valves f) Active core voiding.3 5.5 Active core. 3 1 SV1 flowrate SV flowrate.15.1.5 1 3 5. 1 3 5 Conclusions 1 ACTINIDE AND FISSION PRODUCT PARTITIONING AND TRANSMUTATION, ISBN 97-9--9917-3, OECD 1
References ACTINIDE AND FISSION PRODUCT PARTITIONING AND TRANSMUTATION, ISBN 97-9--9917-3, OECD 1 11