The LOBI Integral System Test Facility Experimental Programme
Table 2
LOBI-MOD1 and LOBI-MOD2 test matrix.
Test
Date
Definition
Objectives
Phenomenologies
LOBI-MOD1: Downcomer width 50 mm
A1-04
12.12.79
Germany
200% CL break LOCA ECC-AIS in CL, first test in power ascension series, 1.8 FPS, PREX test
DNB, early rewet, dryout, final rewet, system performance at low power
A1-01
29.01.80
Germany
200% CL break LOCA ECC-AIS in HL, second test in power ascension series, 3.0 FPS
DNB, early rewet, dryout, final rewet, oscillatory refill behaviour, DEGB partially communicative
A1-02
14.02.80
Germany
200% CL break LOCA ECC-AIS in CL + HL, third test in power ascension series, 8.2 FPS
DNB, early rewet, dryout, final rewet, oscillatory refill behaviour
A1-03
19.03.80
Germany
200% CL break LOCA ECC-AIS in CL + HL, fourth test in power ascension series, 8.8 FPS, power off from 3.2 s to 5 s
DNB, early rewet, dryout, final rewet, oscillatory refill behaviour
A1-04R
17.04.80
Germany
200% CL break LOCA ECC-AIS in CL, Counterpart to A1-04 at nominal power 10.2 FPS, baseline CL LOCA
DNB, early rewet, dryout no final rewet before power shutoff, no sustained oscillation during refill
A1-05
06.05.80
Germany
200% CL break LOCA ECC-AIS in CL + HL Counterpart to A1-04R, namely, AIS mode Enhanced AIS injection, 10.2 FPS
DNB, early rewet, dryout No effective improvement of AIS performance, oscillatory refill behaviour
SD-SL-01
04.06.80
Germany
10% CL break LOCA ECC-AIS in CL, first test of the small break LOCA scoping series, instrumentation response to slow transients Link between small and large break LOCAs
No degradation of core heat transfer
SD-SL-02
04.06.80
Germany
1% CL break LOCA ECC-AIS in CL, second test of the small break LOCA scoping series Secondary 100 K/h cooldown
Flow to break mainly from vessel side, flow from pump side impeded due to closure of break valve, no degradation of core heat transfer
SD-SL-03
24.09.80
Germany
0.4% CL break LOCA, ECC-AIS in CL, third test of the small break LOCA scoping series Secondary 100 K/h cooldown,
No degradation of core heat transfer, natural circulation and reflux condenser heat transport detected
A2-59
27.10.80
Germany
100% CL break LOCA ECC-AIS in CL, first test of interim matrix, system response to communicative break
DNB, early rewet, dryout, final rewet, clear bottom-up rewet trend, response similar to DEGB
B-101
26.11.80
France
2 × 50% CL break LOCA ECC-AIS in CL, second test of the interim matrix, influence of noncommunicative break configuration
DNB, early rewet Comparison of B-101 with A2-59 precluded by difference in power load
A2-55
19.01.81
Germany
50% CL break LOCA ECC-AIS in CL, third test of the interim matrix, system response to intermediate large break sizes
DNB and early rewet only at core upper levels, thereafter, effective core cooling prevailed over the whole core
A2-59R
11.02.81
Germany
100% CL break LOCA ECC-AIS in CL, fourth test of interim matrix, counterpart to A2-59 with respect to reproducibility
A2-59R and A2-59 system thermal-hydraulic response similar, MOD1 reproducibility confirmed
B-R1M
17.03.81
Germany
25% CL break LOCA ECC-AIS in CL, fifth test of the interim matrix, system response to small large break sizes
Core thermal response followed prevailing system saturation temperature, no core thermal excursions tendency to loop seal formation
LOBI MOD1: Downcomer width 12 mm
A1-66
03.07.81
Germany
200% CL break LOCA ECC-AIS in CL, baseline test, counterpart to A1-04R with respect to downcomer width
DNB, early rewet at core bottom and top dryout, no conclusive rewet observed, CCFL and hot wall delay effects in downcomer
A1-07
09.07.81
Germany
200% CL break LOCA ECC-AIS disabled System response with no ECCS Baseline test for ECCS injection mode
DNB, early rewet at core bottom and top ends, dryout, rod temperatures high after power shutoff
A1-06
21.07.81
Germany
00% CL break LOCA ECC-AIS in CL + HL System response to combined ECCS injection, Baseline test with respect to ECC injection mode
DNB, early rewet at core bottom and top ends, dryout, heater rod temperature turnaround after ECC injection starts, no clear definite rewet
A1-67
30.09.81
Germany
25% CL break LOCA ECC-AIS in System response to intermediate break Break size test series
Delayed dryout at core mid and upper elevations, rewet, response tendency towards small break LOCA features, loop seal formation and clearout
A1-68
28.10.81
Germany
50% CL break LOCAECC-AIS in System response to intermediate break Break size test series
DNB, rewet, clear top-down rewet behaviour
A1-10A
25.11.81
Germany
200% HL break LOCA ECC-AIS in System response to hot leg break Break location test series, Low core power
DNB, rewet only at core, mid, and upper elevations, hot leg ECC core penetration hindered by sustained positive core flow, CCFL at core exit
A1-10B
10.12.81
Germany
200% HL break LOCAECC-AIS in HL + CL System response to hot leg break Break location test series Nominal core power
DNB, rewet limited at core upper elevations, higher peak cladding temperatures with respect to A1-10A, CCFL at core exit
A1-70
13.01.82
Germany
200% PS break LOCA ECC-AIS in System response to pump suction break, Break location test series
DNB, rewet, less severe overall core heat transfer degradation with respect to similar cold and hot leg break DEGB-LOCA
A1-73
04.02.82
Germany
25% HL break LOCA AIS in System response to hot leg small large break LOCA Break size and location test series
No core heat transfer degradation, heater rod temperatures at the prevailing system saturation temperature
A1-72
24.03.82
Germany
200% CL break LOCA ECC-AIS in influence of pump operation mode, pump countdown delayed off, pump head simulation
DNB, early rewet, dryout, enhancement of initial recovery of positive core flow, lower peak cladding temperatures with respect to A1-06
A1-69
06.04.82
Germany
100% CL break LOCA ECC-AIS in System response to intermediate break LOCA, break size effect test series
DNB, early rewet, dryout, final rewet, typical DEGB LOCA blowdown features, preferentially top-down rewet observed
A1-74
21.04.82
Germany
200% CL break LOCA ECC-AIS in System response to ECCS injection in both intact and broken loop, counterpart to A1-72
DNB, early rewet, dryout, no discernible impact on overall system response from the addition of ECC injection into broken loop
B-222
05.05.82
France
100% CL break LOCA ECC-AIS in CL Noncommunicative (2 × 50%) CL break configuration, counterpart to B-101 with respect to downcomer size
DNB, early rewet, dryout, limited effectiveness of cold leg ECCS injection
Dryout at core mid and upper elevations, rewet, positive core flow throughout the whole transient, enhanced refill and effective core cooling
LOBI-MOD2: Downcomer width 12 mm, shell and U-tube steam generators
A1-76
12.04.84
Germany
SG performance under primary forced circulation, variation of secondary inventory, and core power: (i) flooding of SG coarse separator at nominal core power (ii) flooding of SG coarse separator at 50% core power and reduced secondary water level (iii) boiloff of SG SS at 10% core power
Data on coarse and fine separator efficiency, variation of recirculation ratios, void distribution in the SG riser region, and degradation of SG heat transfer
A2-81
27.09.84
Germany
1% CL break LOCA ECC- HPIS in CL, AIS off Secondary cooldown at 100 K/h First test of the small break LOCA test series, OECD International Standard problem 18 (ISP 18)
Coupling of primary and secondary systems depressurisation, 2 phase NC and reflux condenser heat transport, flow separation and stratification in horizontal pipes liquid holdup in hot legs and SG U-tubes
A1-82
28.09.84
Germany
1% CL break LOCA ECC-HPIS in HL, AIS in Secondary cooldown at 100 K/h Counterpart to A2-81 relatively to HPIS location
Coupling of primary and secondary systems, 2 phase NC and reflux condenser heat transport, low subcooling in pressure vessel downcomer, reduced ECC bypass to the break
A1-78
24.10.84
Germany
2% CL break LOCA ECC-HPIS in HL, AIS in HL + Cl Secondary cooldown at 100 K/h Test of the break size effect test series
Decoupling of primary and secondary systems, reverse SG heat transfer, voiding in SG U-tubes and liquid holdup in hot legs, loop seal formation, and core liquid level depression
A2-77A
28.11.84
Germany
Characterization of NC and reflux condenser heat transport mechanisms at a primary system pressure of 90 bar and 70 bar, (i) 90 bar: 1 and 2 phase NC and reflux condenser (ii) 70 bar: 2 phase NC and reflux condenser
NC heat transport mechanisms characterized as function of primary system mass inventory, minimum mass inventory of c. 45% at c. 3% of core power to sustain effective reflux heat transport and prevent core heat transfer degradation, oscillatory transition from 2 phase NC to reflux
A1-83
19.12.84
Germany
10% CL break LOCA ECC-HPIS in HL, AIS in HL + CL Secondary cooldown at 100 K/h, larger of the small break size effect test series
Decoupling of primary and secondary systems, early voiding of SG U-tubes and hot legs, initial core dryout and rewet coupled to loop seal formation and clearout, second core dryout, and rewet coupled to mass inventory boiloff and AIS injection
A2-90
27.03.85
Germany
LONOP-ATWS or “SBO” Anticipated transient caused by loss of offsite and normal onsite electrical power with failure to SCRAM (i) boiloff of SG secondary system down to a level of c 1 m above tube plate, (ii) SG refill and cooldown at 100 K/h
Pressure increase in primary and secondary systems, fluid discharge from pressurizer PORV and SG SRV, pressurizer insurge/outsurge, SG heat transfer degradation, recovery of primary to secondary heat transfer, 1 and 2 phase NC
A1-85
07.05.85
Germany
0.4% pressuriser break LOCA ECC-HPIS in HL, AIS in HL + CL Secondary cooldown at 100 K/h, test of the break location effect series
Coupling of primary and secondary systems depressurisation, pressurizer insurge, primary system overfeeding
BL-00
03.07.85
France
0.4% CL break LOCA ECC- HPIS in CL Secondary cooldown at 57 K/h First test of the EC B test matrix
Primary and secondary systems thermally coupled, liquid holdup in SG U-tubes, stratification in horizontal pipework, Thermal nonequilibrium downstream ECC injection points, 2 phase and reflux condenser heat transport, primary overfeeding and refill, no core dryout
A1-84
14.10.85
Germany
10% HL break LOCA ECC-HPIS in HL, AIS in CL + HL Secondary cooldown at 100 K/h Test of the break location effect test series, counterpart to A1-83
Decoupling of primary and secondary systems depressurisation, early voiding of SG U-tubes and hot legs, holdup and CCFL at core exit, ECC penetration and flow channelling
BT-00
30.11.85
UK
LOFW with primary feed and bleed (i) loss of main feedwater and SG boildown to c. 1 m (ii) loss of auxiliary feedwater and SG dryout (iii) long-term cooldown via primary feed and bleed
SG boil-off and heat transfer degradation, PORV and SRV fluid discharge, pressurizer insurge/outsurge, PORV flow compensation via HPIS flow, primary system refill, verification of Feed and Bleed as an accident management procedure
BT-01
24.01.86
Belgium
10% SLB with pressurised thermal shock (PTS) and plant recovery procedure (i) small steam line break transient (ii) establishment of PTS conditions (iii) accident mitigation and recovery
SG secondary blowdown and heat transfer, primary system cooldown rate, pressurizer insurge/outsurge, downcomer temperature stratification, primary depressurization via pressuriser PORV cooling system and mass inventory control via HPIS injection
BL-02
22.03.86
UK
3% CL break LOCA ECC-HPIS in CL, AIS in CL SCS cooldown at 56 K/h Test of the break size effect test series
Primary and secondary systems decoupled, SG heat transfer reversed, formation and clearout of loop seal, no core dryout
A1-79
15.05.86
Germany
1% CL break LOCA HPIS in HL, AIS off Secondary cooldown at 100 K/h Effect of high (4/4) HPIS injection rate
Coupling of primary and secondary systems cooldown, primary system overfeeding, NC heat transport hindered by condensation in hot legs and upper plenum induced by high HPIS rate
A1-88
11.06.86
Germany
0.4% CL break LOCA ECC-HPIS in HL, AIS off SCS cooldown at 100 K/h in IL-SG Asymmetric cooldown of secondary system
Primary system pressure coupled to isolated SG, pressurizing effect of isolated SG, primary system depressurization, break flow compensated by HPIS flow
BL-01
20.09.86
Germany
5% CL break LOCA ECC-HPIS in HL, AIS on secondary cooldown at 100 K/h Test of the break size effect test series
decoupling of primary and secondary systems, SG reverse heat transfer, clearout of intact loop seal, liquid holdup in HL
BC-01
18.10.86
JRC
SG secondary mass inventory determination LOBI-MOD2 characterization test
SG mass inventory determined at various power levels, relationship of SG mass versus downcomer water level determined
BC-02
26.11.86
JRC
SG heat losses determination LOBI-MOD2 characterization test
SG heat losses determined via (i) steady-state method balancing core power (ii) cool-down method SG heat losses unacceptably high: ILSG—24 kW, BLSG—18 kW, need improvement of thermal insulation
BL-21
24.01.87
Italy
steam generator tube rupture (SGTR) break Size 0.4%, ascending side Intentional PCS depressurization through PORV and AIS actuation as recovery procedure
Break and PCS depressurization, natural circulation and reflux condenser heat transport, core uncovery and dryout, PORV discharge, AIS actuation and core rewet
BL-12
19.02.87
France
1% CL break LOCA ECC-HPIS off, AIS in CL SCS cooldown off, system response with degraded safety systems
core uncovery and dryout at high PCS pressure, phase separation and stratification, thermal nonequilibrium downstream AIS location, loop seal formation and clearout, core rewet
BT-02
09.05.87
France
LOFW + LOAF (loss of main and auxiliary feedwater) PCS bleed and feed as recovery procedure
SG boiloff and heat transfer degradation, PCS heatup and pressurization, pressurizer insurge/outsurge, PORV discharge and HPIS compensation, recovery of PCS inventory
BT-12
17.06.87
UK
steam line break (SLB) Break size 100% (orifice limited) SCS break size effect and location test series
Faulted SG depressurization, break flow and steam line carryover, faulted SG heat extraction, reverse heat transfer in unaffected SG, pressurizer behaviour, PCS overcooling and thermal stratification
A1-91
26.09.87
Germany
1% CL break LOCA ECC-HPIS in HL, AIS off Secondary cooldown at 100 K/h Effect of low (1/4) HPIS injection rate
PCS and SCS thermal coupling, core thermal response with reduced HPIS capacity, core liquid level depression, loop seal formation, no core dryout at reduced HPIS capacity
BT-03
24.10.87
Italy
loss of feed water-anticipated transient without SCRAM (LOFW-ATWS) PCS passive recovery procedure
PCS heat up and pressurization, PORV and SRV discharge, voiding and refill of SG, pressurizer insurge/outsurge, intentional PCS depressurization and AIS actuation, core dryout
A1-92
30.11.87
Germany
Characterization of NC and reflux condenser heat transport at a primary pressure of 40 bar, 1 and 2 phase NC and reflux condenser, Counterpart to PKL test AC.1
NC and reflux condenser heat transport mechanisms as function of primary mass inventory, minimum mass inventory to sustain reflux condenser and prevent core heat transfer degradation c. 45%, rather stable transition from 2 phase NC to reflux condenser
BL-16
19.03.88
Germany
0.4% small break LOCA ECC- HPIS in HL, AIS off SCS cooldown in BLSG at 100 K/h, MCPs off and restart
Asymmetric SCS cooldown, pressurizing effect of isolated SG, thermal homogenisation and fluid redistribution following MCPs restart
BC-03
15.04.88
JRC
SG heat losses determination LOBI-MOD2 characterization test
Measurement of SG heat losses after improvement of thermal insulation (ref.: BC-02) ILSG: 6.8 kW, BLSG: 5.0 kW
A1-93
30.04.88
Germany
2% CL break LOCA, HPIS off, AIS on secondary system cooldown at 100 K/h, accident management procedure, pressurizer PORV on high core heater rod temperature
Decoupling of primary and secondary systems, loop seal formation and core level depression, core dryout and AIS injection, enhancement of primary depressurization and AIS actuation through intentional opening of pressurizer PORVs
A1-94
27.05.88
Germany
4% CL break LOCA at 40 bar, HPIS off, AIS on, OBI counterpart to PKL test, secondary system cooldown at 100 K/h, AIS on at high core heater rod temperature
Core uncovery and dryout, AIS injection and core rewetting, verification of PKL-III pressure scaling concept
BC-04
07.02.89
JRC
Core bypass flow measurement LOBI-MOD2 characterization test
Determination of upper plenum to upper downcomer flow bypass: c. 3% of core flow
BL-30
15.04.89
JRC
5% CL break LOCA, HPIS in CL, AIS in CL, SCS cooldown at 100 K/h, test of the break size effect test series
Primary depressurization at a moderate rate, primary and secondary systems thermally decoupled, loop seal formation and clearout
Break flow, overfilling of affected SG and SRV discharge, autostabilizing mechanism for break flow when affected SG level reaches U bend elevation, verification of emergency operating procedures
A1-87
11.11.89
Germany
Cooldown transient, LOBI counterpart to PKL-III test
1 phase NC under saturated conditions, upper head steam bubble formation and propagation, SG heat transfer
BT-04
0.02.90
France
Cooldown transient under asymmetric conditions, BLSG isolated, ILSG cooldown at 56 K/h
Reverse heat transfer in isolated SG, pressurizing effect of isolated SG, flow reversal in secondary of isolated SG
BL-34
22.03.90
JRC
6% CL break LOCA, HPIS off, AIS on at 40 bar, initial conditions scaled to low power (10%), SCS cooldown disabled, counter part test to BETHSY, LSTF and SPES
Sequence of 3 core thermal excursions (1) dryout and rewet due to loop seal formation and clearout, (2) dryout due to boiloff and rewet due to AIS, (3) dryout due to depletion of AIS injection and rewet due to LPIS injection
BL-44
26.04.90
JRC
6% CL Break LOCA, HPIS off, AIS on at 40 bar, initial conditions scaled to full power (100%), SCS cooldown disabled, Counter Part Test to BL-34 (full power-low power)
Phenomenologist similar to BL-34, sequence of 3 core dryout/rewet phases, first dryout less extensive due to less pronounced core liquid level depression
BT-56
03.07.90
UK
Multiple failure transient evolving from an original LOFW: isolation of ILSG, MCP power off, SCRAM failure, PCS blowdown through upper plenum due to rupture of the safety disk
PCS heat up and pressurization, pressurizer insurge/outsurge, primary and secondary systems decoupled, dryout at high pressure, blowdown of the PCS through a relatively large break in upper plenum represented by the rupture disk opening
BT-15/16
22.11.90
UK
LOFW: loss of feed water with MCP on (BT-15), SG boiloff and refill with MCPs off (BT-16)
BT-15: SG boiloff and heat transfer degradation with MCPs on, primary system heat up, reestablishment of SG heat transfer following AFW actuation, BT-16: SG boiloff and heat transfer degradation with MCPs off, natural circulation in PCS, SG refill
BT-17
07.02.91
Germany
LOFW; loss of feed water and secondary feed and bleed recovery procedure Intentional PCS depressurization from upper plenum
SG boiloff, PCS heat up and pressurization, pressurizer insurge and PORV discharge, SCS blowdown and PCS depressurization due to condensation in SG U-tubes, PCS depressurization from upper plenum, pressurizer outsurge, core dryout and partial rewet
BT-06
21.03.91
France
FLB: feed line break (10%) MCPs on, AFW on in ILSG MCPs off and asymmetric natural circulation in PCS with a voided SG
Blowdown and heat transfer from faulted SG, break flow fed from different flow paths, residual heat removal by unaffected SG, pressurizer insurge/outsurge
Break flow, PCS natural circulation, PCS depressurization and control of subcooling margin and pressurizer level cycling PORV and HPIS flow
BL-06
21.06.91
UK/France
1% CL break LOCA, HPIS off, AIS on at 40 bar, SCS cooldown as in BL-12, MCPs on, effect of MCP on/off issue
PCS depressurization with MCPs on, core dryout and rewet, PCS pressure stagnation, termination of AIS injection, depressurization from PORV and actuation of LPIS
ATWS: anticipated transient without scram; AIS: accumulator injection system; BL: broken loop; CL: cold leg; CCFL: counter current flow limitation; DEGB: double ended guillotine break; DNB: departure from nucleate boiling; ECC: emergency core cooling system; FLB: feed line break; FPS: full power seconds; HL: hot leg; HPIS: high pressure injection system; IL: intact loop; LPIS: low pressure injection system; LOCA: loss of coolant accident; LOFW: loss of feed water; LONOP: loss of offsite and normal onsite power; MCP: main coolant pump; NC: natural circulation; PCS: primary cooling system; PORV: power operated relief valve; SCS: secondary cooling system; SRV: safety relief valve; SGTR: steam generator tube rupture; SLB: steam line break; SBO: station break out.
