PBMR OPERATIONAL MODES AND STATES

1

PBMROPERATIONAL MODES

AND STATES30 November 2001

Willem KrielManager Module Dynamics and Control Group(PBMR PTY LTD)

2

Objective

• Inform and educate the NRC regarding the operationof the PBMR

• Demonstrate the application of analytical codes usedby PBMR to evaluate plant operation

3

Topics

• Quick overview of the PBMR Main Power System(MPS) components and control functions• Description of Codes used by PBMR to evaluate plant operations• PBMR Definitions used to describe plant operations• Description of the Modes, States, Transitions and Transients• Examples of analyses used to evaluate plantoperation

4

Reactor

HP turboUnit

LP TurboUnit Power

TurbineGenerator

Start-UPBlowerSystem

RecuperatorPre-

cooler

CoreConditioning

System

Inter-cooler

Main Power System (MPS)

5

Schematic of the PBMR and Temperature – entropydiagram FOR 100% MCR

High Pressure TurboCompressor

(HPT)

Low Pressure TurboCompressor

(LPT)

Generator

HPT BypassValve

LPT BypassValve

By-passValve x 8

Inter-Cooler Pre-Cooler

Power Turbine

Start-Up BlowerShut-off Valve

Reactor Vessel

TO REACTOR

SBS - Blower

FROM PCU

Core Conditioning SystemCCS

Reactor Pressure Vessel Conditioning

SystemRPVCS

Pressure Boundary

Start-Up Blower System

SBS

Start-Up BlowerInline Valve

2000 3000 4000 5000 6000 7000 8000 90000

100

200

300

400

500

600

700

800

900

1000

Specific entropy in kJ/kg

Tem

pera

ture

in °

C

V501 T-s diagram for 100% MCR

7.0 MPa

5.7 MPa

2.6 MPa

4.3 MPa

4.7 MPa33 °C

130 °C

33 °C

900 °C

800 °C

690 °C

100 °C 150 °C

520 °C500 °C

6

Control Overview

• Reactor outlet temperature control

• Inventory power control

• Speed control

• Rapid load reduction

• Recuperator inlet temperature control

• Start-up Blower System (SBS) control

• Reactor inlet temperature control

Main control functions:

7

MPS Schematic Showing the Control Elements

HPT LPT

PT

Recuperator

Pre-coolerIntercooler

Generator

HPC LPC

Core

HCV LCV

RBP

SBSVSBS

SIV

SBP

SBPC

GBP

HPBHPBC

LPBLPBC

HPHelium injection and removal

LPHelium injection

ContinuousResistor Bank

(CRB)

PeakBrakingSystem(PRB)

HICS HICS

8

Codes Used To EvaluatePBMR Operation

� Flownet Nuclear� Simulink� State Flow

9

Flownet Verification & Validation• QA in accordance to ISO9001 & ANSI/ANS-

10.4 & NQA-1– Version control– Source code control– Discrepancy reports– Change requests– Design reviews

• Verification and Validation– Comparison with Analytical Data– Comparison with Experimental Data– Comparison with other Thermo-hydraulic

codes� RELAP 5� Flowmaster� Explicit code

– Plant comparisons� HTTR Japan: Transients during loss of off-site

power� Physical model of a three-shaft recuperative Brayton

cycle

-600.00

-400.00

-200.00

0.00

200.00

400.00

600.00

800.00

0.00 10.00 20.00 30.00 40.00 50.00 60.00

Time (sec)

Mas

s Fl

ow [k

g/s]

Flownet Benchmark

322

324

326

328

330

332

334

336

338

340

342

0 50 100 150 200 250 300 350 400 450 500

Time [s]

Tem

pera

ture

[K]

Bench Node 1 Bench Node 2 Bench Node 3FN Node 1 FN Node 3 FN Node 3

-200

-150

-100

-50

0

50

100

1500 25 50 75 100 125 150 175 200 225

Time (sec)

Mas

s Fl

ow th

roug

h di

ffuse

r

Benchmark solution Flownet solution

10

Flownet Nuclear Features and Attributes):

• Flownet Nuclear is PBMR Intellectual Property• Flownet Nuclear is based on First Principles• Analysis Tool (Loading Catalogues)• Simulation Tool (Operator Training)• Implicit Solving Techniques (Capable of time step variation)• Industrial Code• Multi Fluid Capability• Compressible and Incompressible Fluids• Gravitational Effects• Object Orientated Coding• Relational Data Base

Flownet Nuclear is the “RELAP” for PBMRtechnology

11

1Reactor_Core (R)

3

Reactor_Outlet_Connection_to_Core_Outlet_Pi

pe (FP)

7 Core_Outlet_Pipe (FP)

9CM

11

HPT_Diffuser (FP)

13

HPT_Outlet_Pipe (FP)

17

Low_Pressure_Turbine (T)

CM19

LPT_Diffuser (FP)

21LPT_Outlet_Pipe (FP)

27PT_Intake (FP)

29

Power_Turbine (T)

31PT_Diffuser (FP)

35

PT_Outlet_Contraction (FP)

39

Recuperator_LP (H)RX

41

Pre-cooler_outer_bundle (H)CX

43

Pre-cooler_inner_bundle (H)CX

47

PC_Outlet_Contraction (FP)

51

LPC_Intake (FP)

53CM

55

LPC_Diffuser (FP)

57

LPC_Outlet_Pipe (FP)

61

Intercooler_outer_bundle (H)CX

63

Intercooler_inner_bundle (H)CX

67

IC_Outlet_ducting(FP)

71

HPC_Intake (FP)

73CM

75

HPC_Diffuser (FP)

77HPCe_Holes_to_Manifold (FP)

79

Maintanence_Valve (V)RD

83 RX(HP)_Inlet_Pipes (FP)

85RX

87 RX(HP)_Outlet_Pipes(a) (FP)

89

Core_Inlet_Pipes(e) (FP)

91

Reactor_Annular_Pipes (FP)

93

Reactor_Gas_Inlet_Plenum_Holes (FP)

95Control_Rod_Cooling_flow_connection (FP)

102CX

104CX

109CX

111CX

78P

113

Manifold_to_HPTe_Leakage (L)RD

78P

116RD

119HPC_Bypass_Valve_(HPB) (V)

120

LPC_Bypass_Valve_1_(LPB1) (V)

121

Gas_Cycle_Bypass_Valve_1_(GBP1) (V)

78P

133

Manifold_to_HPTi_Leakage (L)RD

78P

135

RX_bypass_valve_(1 TO 4)_(RBP1) (V)

136Reactor_Plenum_Reduction_Area (FP)

137 Reactor_Outlet_Slots (FP)

138

Control_Rod_Bypass(filled) (FP)

140

Control_Rod_Bypass(empty) (FP)

142

Leakflow_from_Control_Rod_to_Outlet_Manifold (FP)

RD

144

Inside_Cavity_Slots_to_Core (FP)RD

146Reactor_Outside_

Cavity (FP)

148 Reactor_Leak_into_Manifold (FP)

RL

150HPT_Intake (FP)

152

LPT_Intake (FP)

158

RX(LP)_to_PC_connection (FP)

160

Annular_flow_path_to_IC (FP)

162

Annular_flow_path_. . ._to_IC_core (FP)

163

Recuperator_Outlet_Pipe (FP)

165

Core_Inlet_Pipes(a) (FP)

167Core_Inlet_Pipes(b) (FP)

169

Core_Inlet_Pipes(c) (FP)

171

Core_Inlet_Pipes(d) (FP)

174

175

LPC_Bypass_Valve_Pipe2 (FP)

178

LPC_Bypass_Valve_Pipe1 (FP)

180Bypass_Valve_Pipe (FP)

181 HPCe_to_HPCi_Leakage (L)RD

78P

182

Manifold_to_LPTi_Leakage (L)

RD

183

LPCe_to_LPCi_Leakage (L)RD

184 Casing_cooling_flow (L)RD

56185

LPCe_to_PT_casing_flow (FP)

186

PTi_to_Basket_leak (L)RD

188

188 25%_casing_cooling_flow (L)

RD190

190 75%_casing_cooling_flow (L)

RD

192

Basket_to_PTe_leak (L)RD

194

PT_internal_fp2 (FP)

RD

196

196 Buffer_to_gaspath_leak (L)

197

197 ECLS_upper (L)

198

ECLS_lower (L)

300

ECLS_to_PToutlet (L)RD

301

dummy

303

HPS_supply_line (FP)RD

305

PTG_Shaft_Labyrinth_Seal(a) (L)

307

307 PTG_Shaft_Labyrinth_Seal(b) (L)

309

PT_top_volume_to_PTe

(FP)

78P

310

Shaft_valve (V)RD

153312

Pipe_RXe_to_SBSi_2 (FP)

314

SBS_Isolation_valve_2(SBSV2) (V)

316

SBS_Blower2 (CM)

M

CM327 318

Pipe_SBSe2_to_RX_manifold (FP)

153319

Pipe_RXe_to_SBSi_1 (FP)

321

SBS_Isolation_valve_1(SBSV1) (V)

323

SBS_Blower1 (CM)

M

CM327 325

Pipe_SBSe1_to_RX_manifold (FP)

326

SBS_Inline_valve_1_(SIV1) (V)

78P

329

HP_coolant_valve_1_(HCV1) (V)78

P330

LP_coolant_valve_1_(LCV1) (V)

332SBS_Labyrinth_Seal2 (L)

334SBS_Labyrinth_Seal1 (L)

336

RX(HP)_Outlet_Pipes

(b) (FP)

338 RX_inlet_header_pipe (FP)

340

PC_Impingement_plate(FP)

341HPC_Bypass_Control_Valve_(HPBC) (V)

342

LPC_Bypass_Control_Valve[LPBC] (V)

343

SBS_Bypass_valve_(SBP) (V)

344

SBS_Bypass_Control_Valve_(SBPC) (V)

345


346


347

348

349

350

351

352

353 Gas_Cycle_Bypass_Valve_8_(GBP8)(V)

78P

354

HP_coolant_valve_2_(HCV2) (V)

78P

355

LP_coolant_valve_2_(LCV2) (V)

356


357


78P

361

78P

362

78P

363

364

HPC_Bypass_Control_Valve_Pipe (FP)

365LPC_Bypass_Control_Valve

_Pipe2 (FP)

366

LPC_Bypass_Control_Valve_Pipe1 (FP)

368

PT_1st_stg_stator (FP)

370

370 PT_1st_stg_rotor_inlet (FP)

371

371 Inlet_1st_stg_throat (FP)

373

373 25%_rim_cooling_flow (L)

RD

375

375 75%_rim_cooling_flow (L)

RD

376

Rim_cooling_flow (L)RD

377

OD_u_ECLS_backup_lab (L)

380

380 ID_u_ECLS_backup_lab (L)56 381

PT_internals_cooling flow

(FP)

383

PT_internal_fp1 (FP)

RD

387

Inlet_to_SBS_Blower1 (FP)

388

SBS_Blower1_Outlet_Diffuser (FP)

390

Outlet_From_SBS_Blower1 (FP)

393

Inlet_to_SBS_Blower2 (FP)

394

SBS_Blower2_Outlet_Diffuser (FP)

396

Outlet_From_SBS_Blower2 (FP)

78P

1702

Basket_ventilation_flow (L)RD

1703Reactor_Outlet_Pipe_to_CCS (FP)

1705

CCS_Splitting_Restrictor (FP)RD

1707

CCS_Outlet_Pipe_to_Reactor (FP)

2Reactor_Core_Outlet

H

4

6

Reactor_Outlet_Manifold

8 10 12

HPT_Diffuser_Volume

16 18 20

LPT_Diffuser_Volume

26

PT_Inlet_Volume

28 30

34

PT_Diffuser_Volume

38RX(LP)_Inner_Vess

el_Volume40PC_Inlet_Volume

42

46

PC_Outlet_Volume

5052545658

IC_Inlet_Volume

62

66

IC_Outlet_Volume

707274

76HPC_Diffuser_Volume

78

Manifold

P82

RX(HP)_Inlet_Plenum

84RX(HP)_Core_Inlet

86

88 RX(HP)_Outlet_Plenum

90

Reactor_Inlet_Manifold

92

Reactor_Gas_Inlet_Plenum_Volume1

94Reactor_Gas_Inlet_Plenum_Volume2

96

98

Void_above_the_Reactor_Core

H

99IC_Waterside_Inlet

PT

103

105

IC_Waterside_OutletM

106

PC_Waterside_Inlet

PT110 112

PC_Waterside_Outlet

M

139141

143

Reactor_Inside_Cavity

T

145

Reactor_Upper_Volume

T

147

Reactor_Lower_Volume

T

149HPT_Intake_Volume

151

LPT_Intake_Volume

153

RX_Outer_Volume

159161

164

166

168

170172

173

176 177

179

187

187 Turbine_casing_temp

T

189PT_casing_volume

191

PT_basket_volume

195

PT_Inner_Volume

199

302

HPS_outlet_purified

MT304

Generator_Volume

306

308

308 Volume_on_top_of_PT

311

HPS Extraction

M

313315

Inlet_Volume_To_SBS_Blower2

317

320322

Inlet_Volume_To_SBS_Blower1

324

327RX_Outer_Annulus_Volume

328

333SBS_Motor_Casing_Volume2

335

SBS_Motor_Casing_Volume1

337Inlet to RX(HP)_Outlet_Pipes(b)

339

367

369

372 374

374 Turbine_rim_temp

T

378

378 u_ECLS_OD_volume

379

379 u_ECLS_ID_volume382 384

386389

SBS_Blower1_Dump_Volume

391


392395


397


398

1700 1701

1704CCS_Volume1

1706

MPS Flownet Model

Reactor

HP turboUnit

LP TurboUnit

PowerTurbine

Start-UPBlowerSystem

Pre-cooler

Intercooler

Recuperator

Flownet Model

12

0 50 100 150 200 250 300 350 400 450 50030

40

50

60

70

80

90

100

110

Time [s]

Perc

enta

ge M

CR

[%]

Grid power

Power setpointGrid power

Control System

Interactive controlsystem designusing the FlownetNuclear simulator

System Identification• System response tests• Identification ofactuators

Control System design• Controller design• Control interaction• Controller performance testing

Process Simulation

Control System Design

13

Primary frequency support (PFS)

14

Automatic generation control (AGC)

15

Main Mode diagram

Reactor Ready (3a)

Synchronisation

Controlledgrid separation

MPS Startupand

Synchronisation

PCU Trip

Control rodSCRAM/Reverse

.NOT.ConditionedConditioning

ReactorStartup (a)

Insert shut downrods

PowerOperation (5)

ReactorSCRAM

MPS Ready (3b)

Intermediateshutdown (2b)

Normalpower

operation (5b)

Reduced-capabilityoperation (5a)

Partial shutdown(2c)

Shutdown (2)

PCU Operational (4)

DefuelledMaintenance (0) Open Maintenance

(1a)Closed maintenance

(1b)

4

3(b)

De-fuel

Insert maintenance valve gates

4

3(b)

3(a)

Close-down

Insert Controlrods

De-pressurise PPB

Removemaintenancevalve gates

2(c)

3(a)

Loss of load

Increasecapability

Reducecapability

FuelledMaintenance

(1)

4

Full shutdown (2a)

Pressurise PPB

Re-FuelC

C

ReactorStartup (b)

ReactorStartup (c)

S

PCU Disengage

Insert RSS

Standby (3)

Synchronised

Critical

16

PBMR Abbreviations

List of abbreviations:Abbreviation Description

AGC Automatic generation controlC Reactor critical

CCS Core conditioning systemCRB Continuous resistor bankGBP Gas cycle bypass valve. (Referred to as a single valve although it consists of set of 8 valves)HCV High-pressure coolant valveHICS Helium inventory control systemHP High pressure

HPB High-pressure compressor bypass valve.HPBC High-pressure compressor bypass control valve.HPC High-pressure compressorHPT High pressure turbineHV High voltageICS Inventory control system (Part of HICS)LCV Low pressure coolant valve

LOEL Loss of electrical loadLP Low pressure

LPB Low-pressure compressor bypass valve. (Referred to as a single valve although it consists of a set of 3 valves)LPBC Low-pressure compressor bypass control valvesLPC Low-pressure compressorLPT Low-pressure turbineMCR Maximum continuous rating (Usually applicable to power delivered to the grid)MCRI Maximum continuous rating inventory

17

List of abbreviations:Abbreviation Description

MPS Main power systemPBMR Pebble bed modular reactorPCU Power conversion unitPFS Primary frequency support

PLICS Primary loop initial clean-up systemPPB Primary pressure boundaryPRB Peak Resistor BankPT Power turbine

PTG Power turbine generatorRBP Recuperator bypass valve

RCSS Reactivity control & shutdown systemRCS Reactivity control systemROT Average reactor outlet temperatureRSS Reserve shutdown systemRU Reactor unitS Synchronized with national grid

SAS Small absorber spheresSBP Start-up blower system bypass valve

SBPC Start-up blower system bypass control valveSBS Start-up blower system

SBSV Start-up blower system isolation valveSIV Start-up blower system inline valve (Referred to as a single valve although it consists of a set of 3 valves)

PBMR Abbreviations

18

PBMR :Definitions

• TransitionsNormal operations taking the plant from one mode or state tothe next.

• TransientsMode or state transitions that should be avoided, but theplant must still be designed to accommodate thesetransients. The transients result due to faults that ariseexternally or internally to the plant.

19

TransitionMain

PowerOperation

Mode / State

Mode / State

Mode / State

Mode / State

TransitionLess frequent

S

Level 0: Main mode/state

Level 1: Mode / state

Transition: Mainly used

Transition: Designed for, but less frequently used

Transient

S Synchronized with national grid

C Reactor critical

Transient 1

Transient 2

SYMBOLOGY

20

Main Mode diagram

Reactor Ready (3a)

Synchronisation


MPS Startupand

Synchronisation

PCU Trip



ReactorStartup (a)


PowerOperation (5)

ReactorSCRAM

MPS Ready (3b)


Normalpower

operation (5b)



Shutdown (2)

PCU Operational (4)



(1b)

4

3(b)

De-fuel


4

3(b)

3(a)

Close-down

Insert Controlrods

De-pressurise PPB


2(c)

3(a)

Loss of load

Increasecapability

Reducecapability

FuelledMaintenance

(1)

4

Full shutdown (2a)

Pressurise PPB

Re-FuelC

C

ReactorStartup (b)

ReactorStartup (c)

S

PCU Disengage

Insert RSS

Standby (3)

Synchronised

Critical

21

Main Mode diagram

Reactor Ready (3a)

PowerOperation

(5)

MPS Ready (3b)


Normalpower

operation (5b)



Shutdown (2)

PCU Operational (4)


(1a)Closed

maintenance (1b)

FuelledMaintenance

(1)

Full shutdown (2a)

C

S

MPS Shutdown

Standby (3)

Synchronised

Critical

22

De-fuelled maintenance (0)

DefuelledMaintenance (0)

De-fuelRe-Fuel

C

Shutdown (2)

Open Maintenance(1a)

Closed maintenance(1b)


De-pressurise

PPB


FuelledMaintenance

(1)

Pressurise PPB

23

De-fuelled maintenance

Mode• Maintenance activities requiring a de-fuelled reactor

States• The reactor is de-fuelled

24

Fuelled Maintenance (1)


Closedmaintenance (1b)

Insert maintenance valvegates

De-pressurise PPB


FuelledMaintenance

(1)

Pressurise PPB

Shutdown (2)

DefuelledMaintenance

(0)

De-fuelCRe-Fuel

25

Fuelled Maintenance

ModeMaintenance activities performed while the reactor is fuelledThe Core Conditioning System (CCS) is in operationThe Start-up Blower System (SBS) is not operational(To avoid water ingress, the water pressure in the coolers exceedthe helium pressure in the system)

States• The reactor is sub-critical and CCS operational• Brayton cycle is not self-sustaining• The reactor outlet temperature is kept below 400 �C• PPB pressure is atmospheric (or very close to)

26

Open maintenance (1a)

Mode• Scheduled maintenance done on a six-yearly basisAir ingress into the PPB is allowed with the exception of coreinternals

States• The maintenance valve gates are inserted

27

Closed maintenance (1b)

ModeUnscheduled maintenance is done on a number of specific sub-systems

StatesPPB pressure just above atmospheric

28

Shutdown (2)

ReactorStartup (a)



Partial shutdown(2c) Shutdown (2)

De-pressurise PPB

FuelledMaintenance

(1)

Full shutdown (2a)

Pressurise PPB

ReactorStartup (b)

ReactorStartup (c)

Insert RSS

Standby (3)

29

Shutdown

ModeThree reactivity control devices keep the reactor sub-criticalThe SBS is operational �decay heat removal.

States• The reactor is sub-critical and SBS operational• The Brayton cycle is not self-sustaining• The PPB is pressurized (no water ingress)

30

Shutdown Sub-modes (2a,b,c)

External Reactivity

Reactivity duetemperature<550 °C >550 °C >750 °C

Reactivity due Xenon0 0 0

+ + +

+ + +

Sub-criticalSub-critical Sub-critical

FullShutdown

IntermediateShutdown

PartialShutdown

SAS

Res

erve

shu

tdow

n sy

stem

Shut

dow

n R

ods

Con

trol

Rod

s

31

Standby (3)

Reactor Ready (3a)

PCU Startupand

Synchronisation


MPS Ready (3b)

Shutdown (2)

PCU Operational (4)

Close-down

Insert Controlrods

CReactor

Startup (a,b,c)

Standby(3)

Critical

Poweroperation (5)

PCU Disengage

32

Standby

ModeThe reactor outlet temperature is controlled with the control rodsAdjustment of the reactor outlet temperature, reactor neutronicand fluidic power and power turbine power will be possible in thismode by using the SBS, the Reactivity Control System (RCS)and gas cycle valves

States• The reactor is critical• The Brayton cycle is not self-sustaining

33

Reactor Ready (3a)

ModeThis mode or state would occur after reactor start-up transitionsor not conditioned transition

States• The MPS is NOT conditioned as a whole

34

MPS Ready (3b)

ModePCU start-up and synchronisation transition can be initiated,since the plant is within the start-up margins ("conditioned")Entered after a PCU trip transient or Close-down and PCUdisengage transitions.

States• The reactor is critical• The MPS is conditioned. If all the plant parameters remainwithin the “conditioned” margins, the plant will remain in thismode/state.

35

Power operation (5)

Synchronisation


PCU Startupand

Synchronisation

PowerOperation

(5)

Normalpower

operation (5b)

Reduced-capability

operation (5a)

PCU Operational (4)

Increasecapability

Reducecapability

S

PCUdisengage

Synchronised

Standby(3)

36

Power operation

ModeThe plant grid power can be automatically adjusted to a powerset point

States• Supplying power and synchronised to grid.• The Braking System (both the CRB and the PRB) is not inoperation.• Helium PPB inventory level > 40% MCRI

37

Reduced-capability operation (5a)

ModeEntered via the PCU start-up and synchronisation transition orthe Synchronisation transitionThe base-load power controller will be operational (No AGC)Reactor outlet temperature controller will operate in one of thefollowing two sub-modes

• Normal reactor outlet temperature controller mode• Floating reactor outlet temperature controller mode (Xenoneffects)

States• The reactor outlet temperature below or equal to 900 �C .

38

Normal power operation (5b)

ModeProvide power to the gridSupporting ancillary services:

• Load following• Automatic Generation Control (AGC) also known asRegulation or Secondary frequency support. Load “ramping”.• Primary frequency support, also known as governing

States• The reactor outlet temperature will be controlled to 900�C• The power delivered to grid will be between 40% and 100%Maximum Continuous Rating (MCR)

39

PCU operational (4)

Synchronisation


PCU Startupand

Synchronisation

Power operation (5)

PCU Operational(4)

Close-down

Loss of load

S

PCUdisengage

Standby (3)

Synchronised

40

PCU operational

ModeThe mode/state is entered via the Loss of load transient or theControlled grid separation transition.Stable Brayton, low power, high helium inventories, between 40%and 100 % Maximum Continuous Rating Inventory (MCRI).No power is exported to the grid because the plant is notconnected to the grid

41

PCU operational

States

• Generator breaker closed - house load is supplied by thegenerator

• Generator breaker open - house load is supplied from anexternal source

• The reactor temperature outlet temperature between 750�Cand 900 �C

42

Yes/No Yes or No

States Sub-States No ReactorControl Rods

Shut-down Rods RSS

Brayton Self Sus-taining SBS CCS

Power Gene-rated

Synchro-nized

Primary Pressure Boundary

Average Reactor Outlet

Temperature

MPS Helium

Pressure [kPa]

MPS Helium

Inventory [%MCRI]

Power Operation 5 Normal Power Operation 5b Critical Operational Out Out Yes Off Off Yes Yes Closed 900 NA >=40Reduced-Capability Operation 5a Critical Operational Out Out Yes Off Off Yes Yes Closed 750 to 900 NA >=40

PCU Operational 4 PCU Operational 4 Critical Operational Out Out Yes Off Off Yes No Closed 750 to 900 NA >=40Standby 3 MPS Ready 3b Critical Operational Out Out No On Off Yes No Closed 750 to 900 =>2400 >=40

Reactor Ready 3a Critical Operational Out Out No On Off Yes No Closed =<900 *** =>2400 >=40Shutdown 2 Partial Shutdown 2c Sub-Critical Inserted Out Out No On Off No No Closed 750 to 900 =>2400 >=40

Intermediate Shutdown 2b Sub-Critical Inserted Inserted Out No On Off No No Closed 550 to 900 =>2400 >=40Full Shutdown 2a Sub-Critical Inserted Inserted Inserted No On Off No No Closed =<550 ** =>2400 >=40

Fuelled Maintenance 1 Closed Maintenance 1b Sub-Critical Inserted Inserted Inserted No Off On No No Closed =<400°C * Atm. NAOpen Maintenance 1a Sub-Critical Inserted Inserted Inserted No Off On No No Open =<400°C * Atm. NA

Defuelled Maintenance 0 Defuelled Maintenance 0 NA NA NA NA No NA NA No No No NA NA NA

NA=Off/On/Available/Unavailable

MPS StateMatrix

MPS State Matrix

43

Time fraction

Time fraction per mode

Time Fraction Prediction %Description Days per year per year for 40 year plant life

De-fuelled Maintenance (0) * *Open maintenance (1a) 9 2.5

Closed maintenance (1b) 3 0.8Shutdown (2) 3 0.8

Reactor ready (3a) 3 0.8MPS ready (3b) 2 0.5

PCU operational (4) 1 0.3Reduced-capability operation (5a) 20 5.5

Normal power operation (5b) 324 88.8365 100 Total

18 Days / year average planned and unplanned i t 347 Days => 95 % Availability

* The plant will be fuelled and d f ll d at the beginning and end of the plant

lifetime unless special unplanned maintenance requiring a defuelled

t l t reactor is encountered.

44

Transitions

45

De-fuel


De-fuel

Full shutdown (2a)

Re-fuelC

Shutdown(2)

46

Re-fuel


De-fuel

Full shutdown (2a)

Re-fuelC

Shutdown(2)

47




Insert maintenance valvegates


FuelledMaintenance

(1)

48


Stepwise procedure� Maintenance valve gates are positioned in the pipingbetween the PCU and reactor unit (RU).They stop airentering the fuelled reactor� A temporary tent is erected� Before lids are opened, the PCU internal pressure(now filled with dry air) is lowered to slightly belowatmospheric pressure (30 Pa / 0.3mbar)

49

Remove maintenance valve gates





FuelledMaintenance

(1)

50

Remove maintenance valves

Stepwise procedure• Remove the dry air in the PCU by drawing a vacuum in thePCU.• The extracted air & helium mixture is removed via the PrimaryLoop Initial Clean Up System (PLICS) filters.• The helium leaks from the Reactor Unit (RU) into the PCUvolume until a vacuum is drawn over both the RU and PCU.• Once a vacuum has been established, helium is re-introducedinto the RU and leaks into the PCU.• This cycle is repeated until the allowable level of impurities isachieved

51

Pressurise PPB

Shutdown (2)


De-pressurise PPB

FuelledMaintenance

(1)

Full shutdown (2a)

Pressurise PPB

52

Pressurise PPB

Stepwise procedure� Fill PPB with helium to 40% MCRI� Start the main closed circuit pumps that supplycooling water to the inter- and pre-coolers.� Switch on SBS and decay heat controllers� Switch off CCS

53

De-pressurise PPB

Shutdown (2)


De-pressurise PPB

FuelledMaintenance

(1)

Full shutdown (2a)

Pressurise PPB

54

De-pressurise PPB

Stepwise procedure� Using the SBS reduce reactor outlet temperature(ROT) until 200°C is reached. (2 days)� Switch the SBS off and the CCS on� Switch off the main closed circuit pumps that supplycooling water to the inter- and pre-coolers.� The helium content of the PCU is flushed with dry air.

55

Reactor start-up (a),(b),(c)

Reactor Ready (3a)




Shutdown (2)

Full shutdown (2a)

Insert RSS

Standby (3)

ReactorStartup

(a),(b),(c)

56

Reactor start-up (a),(b),(c)Stepwise procedure

• Confirm that the protection bypass that allows SBS/CCSoperations at low Reactor Outlet Temperature (ROT) is activated• Withdraw the control rods and keep the shutdown rods and theRSS inserted;• Empty the Small Absorber Spheres (SAS) channels one at atime• When the neutron count rate takes more than 60 seconds tostabilise, withdraw the control rods slowly to make the reactorcritical and switch to the ROT reactivity controller• The next SAS channel is emptied and the control rods areinserted while keeping the reactor critical (1)

• Repeat (1) until the control rods approach a pre-determinedlower limit;

57

Reactor start-up (a),(b),(c)Stepwise procedure

• Increase the ROT with nuclear heating using the control rods.The ROT must remain below 550 �C;• Repeat (1) until all SAS channels have been emptied;• Remove the shutdown rods while inserting the control rodswithout exceeding a pre-determined lower limit on the controlrods• Increase the ROT with nuclear heating using the control rodsuntil the shutdown rods are fully withdrawn;• The protection interlock, which allows SBS/CCS operation for alow ROT temperature is automatically activated when the ROTreaches 755 �C.

58

Insert …transitions

Reactor Ready (3a)


ReactorStartup (a)

Insertshutdown

rods

MPS Ready (3b)



Shutdown (2)

InsertControl rods

Full shutdown (2a)

ReactorStartup (b)

ReactorStartup (c)

Insert RSS

Standby (3)

59

Insert …transitionsStepwise procedure

� Insert the rods/SAS in a controlled manner

60

Conditioning

Reactor Ready (3a)


MPS Ready (3b)

Standby (3)

61

ConditioningStepwise procedure

Get the MPS to specified temperature levels (to reducetemperature differentials when the Brayton cycle is started)Conditioning Controller is activated

Actuator Regulated variableSBS Mass flow rate through reactorControl rods Reactor outlet temperature

Recuperator bypass valves

Recuperator LP outlet temperatureReactor inlet temperature

HP coolant valveRecuperator LP inlet temperature

Compressor bypass Power turbine powerResistor banks Power turbine speed

62

Synchronisation


PCU Trip

PowerOperation

(5)

MPS Ready (3b)


PCU Operational (4)

Close-down

Loss of load

4

PCUdisengage

Standby (3)

PCU Startupand

Synchronisation

PCU start-up and synchronisation

63

Stepwise procedure• The ROT reactivity controller will control the reactor outlettemperature• The SBS operates at maximum possible delivery• The generator excitation is already switched on at a Power TurbineGenerator (PTG) shaft speed of 600rpm. The helium pressure andthe shaft speed limit the voltage to which the generator is excited.• A power request of 1 MW for the generator is set together with aspeed request of 30 Hz. The LPB and HPB together with the resistorbank will ensure that the generator is stable in this state;• INITIAL START-UP CONDITION


64


Stepwise procedure• The spin-up sequence: The PTG will pass through the criticalfrequencies rapidly enough not to exceed undesirable vibration orforce limits at the critical frequencies;

Release resistor bankControl for 1 MW

• The control system will adjust the PTG speed to a value just belowthe grid frequency;• The synchronisation sequence is entered

65

KEY TO THE GRAPHS THAT FOLLOW

Conditioned MPS and :Maintain Power Turbine at 1 MW with bypass valves (Power Controller)Maintain Power Turbine at 30 Hz with Resistor Bank (Speed Controller)

Start-up Process:A: Reduce power dissipated by Resistor Bank and allow Power Turbine

to speed-up, maintaining Power Turbine fluidic power between 1MWand 1.6 MW with bypass valves (Power Controller)

B: Activate Resistor Bank when Power Turbine reaches 50 Hz(Speed Controller) and commence synchronization

C: Synchronized to Grid and switch over to high cycle efficiency byclosing bypass valves

A-C: Brayton cycle self-sustaining - switch off SBS Blowers.


66

Brayton Cycle Start-Up Graphs (1)

67


68


69


70


71


72

Transients

73

Loss of load transient

Synchronisation


PCU Startupand

Synchronisation

PCU Trip

PowerOperation

(5)

MPS Ready (3b)

PCU Operational (4)

Close-down

Loss ofload

4

PCUdisengage

Standby (3)

74


Stepwise procedure• A loss of load condition is detected• The Gas Cycle Bypass valve (GBP) will open within 0.3 secondswith no feedback control. Opening the valves will ensure the PTGdoes not over-speed• The GBP valves will close as soon as the rotational acceleration isnegative. This will ensure that the Brayton cycle remains functioning;• Simultaneously the HPB, LPB and HCV are opened and the resistorbank load is set to maximum.• The low- and high-pressure bypass valves and resistor bank areused to control the PTG rotational frequency to 50 Hz.• The HCV will ensure that the recuperator low pressure inlettemperature does not exceed 600 �C;

75


Stepwise procedure• The electrical protection may operate to trip the generator circuitbreaker or the HV breaker, depending on the nature of the initiatingevent.• The ROT reactivity controller (control rods) will control the averagereactor outlet temperature (ROT).

76


[PTG_accel>2.5]

[PTG_accel<0]

[PTG_speed<50.2]

Detection

LOEL_transition

Open_valvesentry: open_valves = 1;exit: open_valves = 0;

Stabiliseentry:run_stabilise = 1;exit:run_stabilise = 0;

PCU_operationalentry: run_speedcontrol = 1;

A

B

C

77

Loss of load transient Graphs (1)

100 101 102

0

20

40

60

80

100

120

140Power turbine power [MW]

Time [s]

Pow

er [M

W]

4e29 Grid power : Power Turbine -33e29 Fluidic power : Power Turbine

A B

C

78


100 101 10248

49

50

51

52

53

54

55Power turbine speed

Time [s]

Spe

ed [H

z]

5e29 Speed : Power TurbineA B

C

79


100 101 1023000

4000

5000

6000

7000

8000

9000System pressure

Time [s]

Pre

ssur

e [k

Pa]

2n78 Pressure : Manifold 2n50 Pressure : LPC Inlet NodeA B

C

80


100 101 10250

60

70

80

90

100

110

120

130

140

150Reactor mass flow

Time [s]

Mas

s flo

w [k

g/s]

1e7 Mass flow rate : Core Outlet PipeA B C

81


100 101 10250

100

150

200

250

300

Reactor power

Time [s]

Pow

er [M

W]

7e1 Neutronic heat : Reactor Core33e1 Fluidic heat : Reactor Core

A B

C

82


100 101 102860

865

870

875

880

885

890

895

900

905

910

915Reactor outlet temperature

Time [s]

Tem

pera

ture

[°C

]

4n4 Temperature : Inlet to Core Outlet PipeA B

C

83


0 20 40 60 80 100 120 1400.8

1

1.2

1.4

1.6

1.8

2

2.2

1.086 1.448 1.810 2.172 2.895 3.619 4.343 5.067 5.791 6.515 7.239 7.963 8.687 9.41010.13410.85811.58212.30613.030

lpcompver51__orig__V600.cmp

Pre

ssur

e ra

tio

Corrected mass flow rate

84

PCU trip transient

Synchronisation


PCU Startupand

Synchronisation

PCU Trip

PowerOperation

(5)

MPS Ready (3b)

PCU Operational (4)

Close-down

Loss of load

4

PCUdisengage

Standby (3)

85

PCU trip transient

This transient occurs when there is a fault within the PCUStepwise procedure• The generator breaker should trip on reverse power conditions;

• The gas cycle bypass valve (GBP) opens and remains open untilthe Brayton cycle has shut down completely;

• The resistor bank will decelerate the PTG;

• The SBS will be activated to keep flow through the reactor.

86

Control rod SCRAM / Reverse


ReactorStartup (a)


PowerOperation

(5)

ReactorSCRAM



Shutdown (2)

PCU Operational (4)4

4

3

Insert Controlrods

2(c)

3

Full shutdown (2a)

C

ReactorStartup (b)

ReactorStartup (c)

Insert RSS

Standby (3)

Critical

87

Control rod SCRAM / Reverse

Stepwise procedure• The SBS/CCS inhibit for low ROT temperatures is activated

• A Control rod SCRAM / Reverse transient is accomplished bygravitationally fully inserting the control rods into the reactor (SCRAM)or fully inserting them in a controlled manner using the motor drives(Reverse);

• A controlled shutdown of the PCU will take place with the operationof the LPB and HPB valves.

• The generator breaker will trip on reverse power conditions

• The resistor bank will decelerate the PTG

• The SBS will be started and the ROT control will be passed fromthe ROT reactivity controller to the ROT decay heat controller.

88

Reactor SCRAM


ReactorStartup (a)


PowerOperation

(5)

ReactorSCRAM



Shutdown (2)

PCU Operational (4)4 4

3

Insert Controlrods

2(c)

3

Full shutdown (2a)

C

ReactorStartup (b)

ReactorStartup (c)

Insert RSS

Standby (3)

Critical

89

Reactor SCRAM

Stepwise procedure• The SBS/CCS inhibit for low ROT temperatures is activated

• The shutdown and control rods are gravitationally fully inserted intothe reactor;

• The gas cycle bypass valve (GBP) will be opened and will remainopen until the Brayton cycle has shut down completely.

• The GBP causes the speeds and the power of the turbo units to bereduced.

• The generator breaker will trip on reverse power conditions;

• The resistor bank will decelerate the PTG

• The SBS will be started and the ROT control will be passed fromthe ROT reactivity controller to the ROT decay heat controller.

90

Conclusion

The objective of the presentation was to inform andeducate the NRC regarding the operation of the PBMRas well as demonstrate the application of analyticalcodes used to evaluate plant operation.

91End of Presentation

Conclusion

Quick overview of the PBMR Main PowerSystem components and control functions

HPT LPT

PT

Recuperator

Pre-coolerIntercooler

Generator

HPC LPC

Core

HCV LCV

RBP

SBSVSBS

SIV

SBP

SBPC

GBP

HPBHPBC

LPBLPBC

HPHelium injection and removal

LPHelium injection

ContinuousResistor Bank

(CRB)

PeakBrakingSystem(PRB)

HICS HICS

Description of Codes used by PBMR to evaluateplant operations

PBMR Definitions used to describe plant operations

Description of the Modes, States, Transitionsand Transients

Examples of analyses used to evaluate plantoperation

1Rea ctor_ Core (R)

3

Re a ctor_O utle t_Conne ction_ to_ Core_ Outle t_ Pi

pe (FP)

7 Core _Outlet_ Pipe (FP)

9CM

1 1

HPT_Diffuse r (FP)

1 3

HPT_ Outle t_Pipe (FP)

1 7

Low _Pre ss ur e_ Turbine (T)

CM1 9

LPT_ Diffus er (FP)

21LPT_ Outlet_ Pipe (FP)

27PT_ Inta ke (FP)

29

Powe r_ Turbine (T)

3 1PT_Diffuse r (FP)

3 5

PT_ Outle t_Contrac tion (FP)

3 9

Rec upe ra tor_ LP (H)RX

41

Pre -cooler_ oute r_ bundle (H)CX

4 3

Pre-c oole r_inne r_ bundle (H)CX

4 7

PC_ Outle t_C ontra ction (FP)

5 1

LPC_ Inta k e (FP)

5 3CM

5 5

LPC_ Diffus er (FP)

57

LPC_ Outlet_ Pipe (FP)

6 1

Interc oole r_outer _bundle (H)CX63

Inter coole r_ inner_ bundle (H)CX

67

IC_ Outlet_ duc ting(FP)

7 1

HPC_ Inta k e (FP)

7 3CM

75

HPC_ Diffus e r (FP)

77HPCe _Holes _to_ Ma nifold (FP)

7 9

M aintane nc e_ Valv e (V)RD

83 RX(HP)_ Inle t_Pipes (FP)

85RX

87 RX(HP)_Outlet_ Pipe s(a ) (FP)

8 9

C ore _Inlet_ Pipe s(e ) (FP)

91

Re ac tor_Annula r_Pipes (FP)

93

Re ac tor_ Ga s_ Inle t_Plenum_ Hole s (FP)

9 5Control_Rod_Cooling_flow_ conne ction (FP)

10 2CX

1 04CX

1 0 9CX

11 1CX

78P

1 13

Ma nifold_ to_HPTe_ Le a ka ge (L)R D7 8

P1 1 6

RD

1 19HPC_By pas s_ Valv e_ (HPB) (V)

12 0

LPC _By pa s s_ Valv e_ 1_ (LPB1 ) (V)

1 2 1

G as _Cy c le _By pas s_ Valv e_ 1_ (GBP1) (V)

78P

13 3

Ma nifold_to_HPTi_Le ak age (L)RD

7 8P

13 5

RX_by pa s s_ va lve _(1 TO 4 )_(R BP1 ) (V)

1 3 6R ea ctor_ Ple num _Re duc tion_ Area (FP)

1 37 Rea ctor_ Outle t_Slots (FP)

1 3 8

Contr ol_ Rod_ Bypa ss (filled) (FP)

1 40

Control_R od_ Bypas s (em pty ) (FP)

1 42

Le ak flow_ from_ Control_R od_ to_ Outle t_M a nifold (FP)

RD

14 4

Inside _Ca vity _Slots_ to_ Core (FP)RD

14 6Re ac tor_Outs ide _

Cav ity (FP)

14 8 Rea ctor_ Le a k_ into_M anifold (FP)

R L

15 0HPT_ Inta ke (FP) 1 52

LPT_Intak e (FP)

1 5 8

RX(LP)_to_ PC_c onnec tion (FP)

1 6 0

Annular_ flow _path_ to_ IC (FP)

1 62

Annula r_ flow_ pa th_. . ._ to_IC_ core (FP)

1 63

Rec upe ra tor _Outlet_ Pipe (FP)

1 65

Core _Inle t_Pipes (a) (FP)

1 67Core _Inle t_Pipes (b) (FP)

1 69

Cor e_ Inle t_ Pipe s(c ) (FP)

17 1

Core _Inlet_ Pipe s(d) (FP)

1 74

17 5

LPC_ Bypa ss _Va lv e _Pipe2 (FP)

17 8

LPC_ Bypa ss _Va lv e _Pipe 1 (FP)

18 0By pas s_ Valv e_ Pipe (FP)

1 81 HPCe _to_HPCi_ Le ak a ge (L)R D

7 8P

1 82

M a nifold_ to_ LPTi_ Le a ka ge (L)

R D

1 8 3

LPCe _to_LPCi_Le ak age (L)RD

18 4 Cas ing_ cooling_flow (L)RD

561 85

LPCe_ to_PT_c as ing_ flow (FP)

1 86

PTi_ to_Ba sk et_ lea k (L)RD

1 8 8

1 88 25 %_c a sing_ cooling_flow (L)

RD19 0

19 0 7 5% _c as ing_ cooling_flow (L)

RD

19 2

Ba sk e t_ to_PTe_ lea k (L)RD

1 94

PT_interna l_fp2 (FP)

RD

1 96

19 6 Buffer _to_ga spath_ le a k (L)

19 7

1 97 ECLS_ uppe r (L)

19 8

ECLS_ low er (L)

30 0

ECLS_to_ PToutlet (L)RD

30 1

dum my

3 0 3

HPS_s upply _line (FP)RD

3 05

PTG_ Sha ft_La by rinth_ Sea l(a) (L)

3 07

30 7 PTG_Sha ft_Laby rinth_ Se a l(b) (L)

3 09

PT_top_volum e

_ to_ PTe(FP)

78P

31 0

Shaft_ va lve (V)RD

1 533 12

Pipe _ RXe _ to_ SBSi_ 2 (FP)

31 4

SBS_Isolation_v alv e_ 2(SBSV2 ) (V)

3 16

SBS_ Blow er2 (CM)

M

CM32 7 31 8

Pipe _ SBSe 2_ to_RX_ ma nifold (FP)

1 533 19

Pipe_ RXe_ to_ SBSi_1 (FP)

32 1

SBS_ Isolation_v alv e_ 1(SBSV1 ) (V)

3 23

SBS_Blowe r1 (CM )

M

CM32 7 32 5

Pipe _SBSe 1_ to_RX_ ma nifold (FP)

32 6

SBS_ Inline_ va lve _1 _ (SIV1) (V)

7 8P

3 29

HP_c oola nt_ v alv e_ 1_ (HCV1) (V)78

P33 0

LP_c oola nt_v alv e_ 1_ (LCV1) (V)

33 2SBS_ La byrinth_Se al2 (L)

33 4SBS_ Labyr inth_Se al1 (L)

3 36

RX(HP)_Outlet_ Pipes

(b) (FP)

3 38 RX_ inle t_ hea der_ pipe (FP)

34 0PC_Im pingem ent_ pla te

(FP)

3 41HPC_ Bypa ss _Control_ Valv e_ (HPBC) (V)

34 2

LPC_By pas s_ Contr ol_ Valv e[LPBC] (V)

34 3

SBS_ Bypas s _v alv e_ (SBP) (V)

34 4

SBS_By pas s_ Control_Va lve _(SBPC) (V)

34 5


34 6


3 4 7

3 4 8

3 4 9

3 5 0

3 5 1

3 5 2

3 5 3 Gas _C yc le _ Bypas s _Va lv e _8 _(GBP8 )(V)

7 8P

3 54

HP_ coola nt_v alv e_ 2_ (HCV2) (V)

78P

35 5

LP_ coolant_v a lv e_ 2 _(LCV2) (V)

35 6

SBS_Inline_ v alv e_ 2_ (SIV2) (V)

35 7

SBS_ Inline_ va lve _3 _ (SIV3 ) (V)

7 8P

36 1

7 8P

36 2

7 8P

36 3

3 64HPC_ By pa ss _ Control_Va lv e _Pipe (FP)

3 6 5LPC_By pas s_ Contr ol_ Valve_Pipe 2 (FP)

36 6

LPC _By pa s s_ Control_Va lve _Pipe1 (FP)

3 68

PT_1 s t_s tg_ sta tor (FP)

37 0

37 0 PT_1 st_ stg_ rotor_ inle t (FP)

3 7 1

3 71 Inlet_ 1 st_ stg_throat (FP)

3 73

37 3 2 5% _rim_ c ooling_ flow (L)

RD

37 5

3 7 5 75 %_ rim_ cooling_flow (L)

RD

37 6

Rim_ cooling_flow (L)RD

3 77

OD_u_ ECLS_ ba ck up_ lab (L)

3 80

3 80 ID_u_ECLS_ ba ck up_ lab (L)5 6 3 81

PT_ inte rnals _cooling flow

(FP)

38 3

PT_ inte rnal_ fp1 (FP)

RD

3 8 7

Inle t_to_SBS_ Blowe r1 (FP)

38 8

SBS_ Blowe r1 _Outlet_ Diffus er (FP)

3 90O utle t_From_ SBS_Blower1 (FP)

3 9 3

Inle t_to_ SBS_ Blow er2 (FP)

39 4

SBS_Blowe r2_ Outle t_ Diffuse r (FP)

3 96

Outlet_ Fr om _SBS_ Blowe r2 (FP)

78P

1 70 2

Ba sk e t_v entilation_ flow (L)RD

1 7 03 Rea ctor_ Outle t_Pipe_ to_ CCS (FP)

1 70 5

CCS_ Splitting_ Res trictor (FP)RD

17 07

CCS_ Outle t_Pipe_ to_ Re ac tor (FP)

2Rea ctor_ Core_ Outle t

H

4

6

Rea c tor_ Outlet_ Ma nifold

8 10 1 2

HPT_Diffuse r_Volume

16 1 8 20

LPT_ Diffus er_ Volum e

26

PT_Inle t_Volume

2 8 3 0

3 4

PT_Diffuse r_ Volume

3 8 RX(LP)_Inne r_ Ves se l_Volum e40

PC_ Inlet_ Volum e

42

4 6

PC_ Outle t_Volum e

505 2545 65 8

IC_Inlet_ Volume

6 2

66

IC_O utle t_Volum e

7 0727 4

76HPC_Diffuse r_ Volume

78

Ma nifold

P82 RX(HP)_ Inlet_ Ple num

84RX(HP)_Core _Inle t

86

88 RX(HP)_O utle t_Plenum

9 0

Rea c tor_ Inle t_M anifold

9 2

Rea ctor_ Gas _ Inlet_ Ple num _ Volume 1

9 4Re ac tor_Ga s _Inle t_Ple num _Volum e2

9 6

9 8Void_a bov e _the_ Re a

c tor _CoreH

99IC_ Wa ters ide_ Inlet

PT

10 3

1 05

IC_ Wa ters ide_ Outle tM

10 6

PC_ Wa ters ide _ Inlet

PT1 10 11 2

PC_Wate rs ide _Outlet

M

1 3 914 1

14 3

Rea c tor_ Ins ide _ Cav ity

T

14 5

Re ac tor_Upper_ Volume

T

14 7

Re a ctor_Lowe r_Volum e

T

14 9HPT_ Inta ke _Volum e

15 1

LPT_Intak e_ Volume

15 3

RX_Oute r_Volum e

1 5916 1

1 64

1 66

1 68

1 701 72

1 73

17 6 17 7

17 9

18 7

18 7 Turbine _c as ing_ te m p

T

18 9PT_c a sing_ v olume

19 1

PT_ bas ke t_v olum e

19 5

PT_Inne r_ Volume

19 9

3 02

HPS_outlet_ purified

M T30 4

G enera tor_Volume

3 06

3 08

3 08 Volume _on_top_of_PT

31 1

HPS Extra ction

M

31 331 5

Inle t_ Volume _To_SBS_ Blowe r2

3 17

32 032 2

Inle t_Volume _To_SBS_ Blowe r1

3 24

3 2 7RX_ Oute r_ Annulus _Volume

3 28

3 33SBS_ Motor _Ca sing_Volum e2

3 35

SBS_ Motor_Ca s ing_Volum e 1

3 37Inle t to RX(HP)_O utle t_Pipe s (b)

33 9

3 67

36 9

3 7 2 37 4

37 4 Turbine _rim_ te mp

T

3 78

3 78 u_ ECLS_ OD_ volume

3 79

37 9 u_ECLS_ ID_ v olume3 82 3 8 4

3 8638 9

SBS_ Blow er1 _Dum p_ Volume

3 91

SBS_Blowe r1_ Dump_Volum e

3 9239 5

SBS_Blower 2_ Dum p_Volum e

3 97

SBS_ Blow er2 _Dum p_ Volum e

3 98

17 00 1 70 1

1 70 4CC S_ Volum e1

17 0 6

SYMBOLOGY

Reactor Ready (3a)

Synchronisation


MPS Startupand

Synchronisation

PCU Trip



ReactorStartup (a)


PowerOperation (5)

ReactorSCRAM

MPS Ready (3b)


Normalpower

operation (5b)



Shutdown (2)

PCU Operational (4)



(1b)

4

3(b)

De-fuel


4

3(b)

3(a)

Close-down

Insert Controlrods

De-pressurise PPB


2(c)

3(a)

Loss of load

Increasecapabil ity

Reducecapability

FuelledMaintenance

(1)

4

Full shutdown (2a)

Pressurise PPBFuel

C

C

ReactorStartup (b)

ReactorStartup (c)

S

MPSShutdown

Insert RSS

Standby (3)

Synchronised

Critical

[PTG_accel>2.5]

[PTG_accel<0]

[PTG_speed<50.2]

Detection

LOEL_transition

Open_valvesentry: open_valves = 1;exit: open_valves = 0;

Stabiliseentry:run_stabilise = 1;exit:run_stabilise = 0;

PCU_operationalentry: run_speedcontrol = 1;

100 101 10250

100

150

200

250

300

Reactor power

Time [s]

Pow

er [M

W]

7e1 Neutronic heat : Reactor Core33e1 Fluidic heat : Reactor Core

A B

A B

C

Documents

PBMR OPERATIONAL MODES AND STATES