constitutes the objective of the present section. This can be achieved by combining the reactor descriptions given in Annexes I to XX and the passive systems identified in Sections 2 and 3.
Furthermore, the ‘passive’ thermal-hydraulic phenomena characterized in Section 4 can be cross-correlated with the reactor configurations.
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TABLE 2. CROSS LISTING OF THE PASSIVE SAFETY SYSTEM WITH PHENOMENA Type of Passive Safety
System Passive Safety Systems of Advanced Designs Related Phenomena
Standby liquid control system (ESBWR) Accumulator (AHWR)
Emergency core coolant tanks (SMART)
8,2,5
Core flooding system (SWR 1000) IRWST injection (AP-1000)
ECCS tank subsystem – Elevated hydro-accumulators open to the containment (WWER-640/V-407)
Gravity-driven cooling system (SBWR and ESBWR) Suppression pool injection (SBWR and ESBWR) Gravity-driven core cooling system (LSBWR)
Gravity-driven water pool (GDWP) injection (AHWR) Reserve water system (ACR-1000)
Reserve water system (SCWR-CANDU) Containment suppression pool injection (IRIS)
8,5
Passively Cooled Steam Generator Natural Circulation (water cooled)
- Section 2.4 -
SG passive heat removal system (WWER-640/V-407) Passive residual heat removal system (SMART) Emergency decay heat removal system (PSRD) Stand-alone direct heat removal system (IMR) Passive emergency heat removal system (IRIS)
13,1,6
Passively Cooled Steam Generator Natural Circulation (air cooled)
- Section 2.4 -
Passive residual heat removal system via SG (WWER-1000/V-392)
Passive core cooling system using SG - open loop (APWR+) Stand-alone direct heat removal system – late phase (IMR)
6,4
Passive Residual Heat Removal Heat Exchangers - Section 2.5 -
Passive residual heat removal system (AP-1000)
Passive moderator cooling system – inside insulated PT without CT (SCWR-CANDU)
Residual heat removal system on primary circuit (SCOR)
13,6,2,1
1 Accumulators constitute the design practices of the operating water cooled reactors.
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Passively Cooled Core Isolation Condensers - Section 2.6 -
Emergency condensers (SWR 1000)
Isolation condenser system (SBWR and ESBWR) Passive reactor cooling system (ABWR-II) Isolation condenser (RMWR)
Isolation condenser (AHWR)
Residual heat removal system (CAREM)
13,6,1
Sump Natural Circulation - Section 2.7 -
Lower containment sump recirculation (AP-1000)
Primary circuit un-tightening subsystem (WWER-640/V-407)
ADS-steam vent valves and submerged blow-down nozzles (MASLWR)
6,1
Containment Pressure Suppression Pools - Section 3.1 -
ADS 1-3 steam vent into IRWST (AP-1000)
Automatic depressurization through safety relief valves – vent into suppression pool (SBWR and ESBWR)
Steam vent into suppression pool through SRV and DPV (LSBWR)
Steam vent into suppression pool through safety valves (CAREM)
Steam dump pool (SCOR)
Containment pressure suppression system (SCOR) Steam vent into suppression pool through ADS (IRIS)
1,7,3
Containment cooling condensers (SWR 1000) Passive containment cooling system (AHWR)
4,1,2,3
Containment passive heat removal system (WWER-640/V-407)
Containment water cooling system (PSRD)
4,1,2,3
Passive containment cooling system (SBWR and ESBWR) Passive containment cooling system (ABWR-II)
Passive containment cooling system (RMWR)
4,1,2,3
Passive Containment Spray Systems
- Section 3.3 -
Passive containment cooling system (AP-1000) Passive containment cooling system (LSBWR) Containment cooling spray (ACR-1000) Containment cooling spray (SCWR-CANDU)
3,2,4
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All of these is achieved by Tables 3 and 4 that make reference to two reactor categories, respectively:
(a) PWR, BWR and SCWR (Super Critical Water Cooled Reactor) systems, Annexes I to XIII;
(b) Integral Reactor Systems, Annexes XIV to XX.
The main information in Tables 3 and 4 connects the reactor type with the passive safety systems, e.g.
column 1 and 4. Thermal-hydraulic phenomena are cross-connected with specific passive safety systems in columns 4 and 5. Finally columns 2 and 3 provide elements, as an example, namely the thermal power and the ‘boiling’ or ‘pressurized’ feature, that characterize the reactor system.
‘Proven’ technology reactors, i.e. with final design already scrutinized in a formal safety review process, or under construction, or with an already built and operated prototype, are listed in Table 3, with a few exceptions constituted by the RMWR, the LSBWR and the SCWR that are at different levels of early design stages.
TABLE 3. PWR, BWR AND SCWR SYSTEMS AND TYPES OF PASSIVE SAFETY SYSTEMS
Reactor System Reactor
Type
Power (MW•th)
Passive Safety Systems Related Phenomena2 Emergency Condenser System 13,6,1 Core Flooding System 8,5 SWR 1000 Core Make-up Tanks 8,6,9,5,15 Automatic Depressurization
System 1-3 Steam Vent into IRWST ECCS Accumulator Subsystem 8,2,5 ECCS Tank Subsystem 8,5 Primary Circuit Un-tightening
2 See Section 4 for characterization of the phenomena influencing natural circulation.
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Passive Core Cooling System Gravity Driven Cooling System 8,5 Suppression Pool Injection 8,5 Isolation Condenser System 13,6,1 Passive Containment Cooling Gravity Driven Cooling System 8,5 Suppression Pool Injection 8,5 Isolation Condenser System 13,6,1 Standby Liquid Control System 8,2,5 Passive Containment Cooling (TEPCO), General Electric, Hitachi and Toshiba, Japan
BWR 4960
Passive Containment Cooling System
4,1,2,3
Isolation Condenser System 13,6,1 Reduced-Moderation Water Reactor
(RMWR)
Japan Atomic Energy Agency (JAEA), Japan Isolation Condenser System 13,6,1
Accumulator 8,2,5 Advanced Heavy Water Reactor
(AHWR)
Bhabha Atomic Research Centre, India
HWR 750
Passive Containment Cooling System
4,1,2,3 Core Make-up Tanks 8,6,9,5,15 Reserve Water System (RWS) 8,5 Advanced CANDU Reactor
(ACR 1000)
Atomic Energy of Canada Ltd, Canada
HWR 3180
Containment Cooling Spray 3,2,4 Gravity Driven Core Cooling Pool through SRV and DPV
1,7,3 Core Make-up Tanks 8,6,9,5,15 Reserve Water System 8,5 Passive Moderator Cooling
System
13,6,2,1 SCWR-CANDU
Atomic Energy of Canada Ltd, Canada
SCWR 2540
Containment Cooling Spray 3,2,4
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Integral type reactors are considered in Table 4. All of these are of PWR type, second column, and can be assumed to constitute a special class of Light Water Reactors (LWR). In integral PWR, the major components of the nuclear steam supply system (NSSS) such as the core, steam generators, main coolant pumps, and pressurizer are integrated into a reactor vessel without any pipe connections between those components. This makes integral PWR systems relatively compact.
As a difference from the reactors listed in Table 3, all the integral reactor systems in Table 4 are in a design stage and no-one of such design has undergone a comprehensive safety scrutiny process (i.e.
the licensing). However, in some cases, e.g. CAREM and to a lower extent IRIS, the reactor systems are under design since couple of decades, thus testifying the technological difficulties encountered for the exploitation of the integral nuclear reactor configuration idea.
TABLE 4. INTEGRAL REACTOR SYSTEMS AND TYPES OF PASSIVE SAFETY SYSTEMS Integral Reactor System Reactor
Type
Power (MW•th)
Passive Safety Systems Related Phenomena3 Passive Residual Heat Removal System 13,1,6 System-Integrated Modular
Emergency Core Coolant Tank 8,2,5
Residual Heat Removal System – Emergency Condenser
Steam Vent into Suppression Pool through Safety Valves
PWR 150 ADS-Steam Vent Valves and Submerged Blow-down Nozzles
Containment Water-Cooling System 4,1,2,3
Stand-alone Direct Heat Removal Residual Heat Removal System on
Primary Circuit RRP Emergency Boration Tanks (EBT) 8,6,9,5,15 Containment Suppression Pool Injection 8,5 IRIS
Westinghouse Electric, USA
PWR 1000
Steam Vent into Suppression Pool through ADS
1,7,3
3 See Section 4 for characterization of the phenomena influencing natural circulation
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