Drawing No. EH–NR–014 // Nuclear Engineering & Radiation

Advanced PWR Reactor Simulator

Reviewed August 2026

Operate a detailed educational model of a two-loop pressurized water reactor using the AP1000 as the public reference design. Control rods and soluble boron, run four reactor coolant pumps, manage pressurizer pressure, steam-generator level and turbine/feedwater systems, and test AP1000-style passive safety during startup and abnormal transients.

3,415 MWt reference thermal power 1,110 MWe nominal net output 157 fuel assemblies 2 loops · 4 RCPs primary circuit 15.51 MPa(a) RCS pressure Passive PXS & PCS safety systems Public-data checked educational physics model

Public AP1000 design basis

Reference characteristics used by the model

ReactorTwo-loop PWR

Primary flowForced, subcooled

RCS pressure15.51 MPa(a)

Full-load T_avg≈300.9 °C

Hot leg321.1 °C

SG outlet≈5.76 MPa

Core157 fuel assemblies

Coolant pumps4 RCPs / 2 loops

ReactivityRods + boron

Pressure controlHeaters + spray

Passive injectionCMT / ACC / IRWST

Decay heatPRHR / ADS / PCS

Public AP1000 values anchor nominal conditions and system topology. This is an independent educational model: controller gains, transient coefficients, protection thresholds and setpoints are simplified approximations, not plant values, and no proprietary vendor analysis, core-loading data or licensing methodology is reproduced. The model uses point kinetics with the standard six delayed-neutron groups, multi-timescale decay heat, and lumped mass and energy balances for the primary circuit, pressurizer and steam generators. It does not calculate DNBR, local cladding temperature, three-dimensional power distribution, detailed two-phase break flow or any licensing margin.

Reactor controls

reactivity

Reactor modeAUTO

Power demand100%

Control-bank withdrawal84.0%

Higher withdrawal adds positive reactivity. In AUTO, the plant controller moves the bank to follow the power/Tavg program.

Soluble boron1200 ppm

Dilution adds positive reactivity; boration adds negative reactivity. This is a slow chemistry control, not a rapid shutdown system.

Primary / reactor coolant pumps

heat transport

RCP status4 / 4 ON

Loop 1 flow100%

Loop 2 flow100%

Hot leg321°C

Cold leg281°C

The RCPs establish forced primary circulation. Pump loss changes coolant flow; reactor power then responds through protection and temperature feedback.

Pressurizer controls

RCS pressure

Pressure modeAUTO

Pressure setpoint15.51 MPa

Manual heater0%

Manual spray0%

Steam-generator controls

secondary inventory

Feedwater modeAUTO

SG level setpoint50%

Manual feedwater100%

Two SGs are calculated separately. Feedwater changes secondary inventory; primary temperature responds through heat transfer.

Turbine / electrical load

secondary heat sink

Electrical load demand100%

Turbine control valves100%

Steam dump0%

Condenser8.0 kPa(a)

Failure scenarios

click ? for description

Plant process mimic

primary · secondary · passive safety

Plant trends

last 15 simulated minutes

Live instrumentation

control-room overview

Passive safety / PXS

AP1000-style

CMT A100% · 0 kg/s

CMT B100% · 0 kg/s

Accumulator A100% · 0 kg/s

Accumulator B100% · 0 kg/s

IRWST injection0 kg/s

PRHROFF · 0 MW

ADSStage 0

PCS / containmentOFF · 0 kPa(g)

CMT alignment does not automatically mean tank draindown. Net injection depends on RCS inventory/pressure conditions. ADS staging is a simplified educational sequence.

Active alarms

0 active

Operator event console

newest first

Startup procedure trainer

educational workflow · horizontal

This is a simplified teaching sequence, not an AP1000 operating procedure.

Diagnostics & engineering views

See PWR control and heat-transfer behavior

The diagnostic views connect reactivity, primary temperature, RCS pressure, steam-generator heat removal and passive safety response. They are schematic educational displays rather than plant protection-system replicas.

Conceptual 157-assembly core map

Schematic radial power distribution. Global intensity follows reactor power and control-bank insertion; it is not a pin-power or DNBR calculation.

Power / Tavg operating program

PWR load-following keeps average reactor-coolant temperature on a programmed band while control banks and secondary heat removal balance reactivity and load.

Theoretical background

How a pressurized water reactor actually works

Everything below explains the systems this simulator models, the physics behind the numbers on the panels, and every abbreviation used in the interface. Values quoted as "reference" are the nominal AP1000-class design points the model is anchored to.

1 · The primary side — the reactor coolant system

A closed, high-pressure water loop that carries fission heat out of the core and gives it to the steam generator. It never leaves containment.

Reactor vessel & core RPV

A forged steel pressure vessel holding 157 fuel assemblies of enriched uranium dioxide. Fission heats the fuel; the fuel heats the water flowing past it. The steel is thick because the whole loop runs at about 15.5 MPa — roughly 155 times atmospheric pressure.

That pressure is the entire point. Water at 15.5 MPa boils at about 345 °C, and the hottest coolant leaving the core is around 321 °C. The margin between those two numbers is called subcooling, and keeping it positive means the coolant stays liquid, keeps touching the fuel, and keeps carrying heat away.

3415 MWth157 assemblies15.51 MPa

Hot leg & cold leg loop piping

Heated coolant leaves the vessel through the hot leg (≈321 °C), gives up its heat in the steam generator, and returns through the cold leg (≈281 °C). The ~40 K difference across the core, multiplied by the mass flow, is the thermal power.

This simulator models two loops so you can fail one and watch the other carry the plant. The mimic draws a single steam generator for clarity, but both loops are calculated separately — the LOOP 1 and LOOP 2 readouts on the diagram are independent.

T_hot 321.1 °CT_cold 280.7 °CΔT ≈ 40 K

Reactor coolant pumps RCP

Four canned-motor pumps force roughly 100% design flow around the loops. They are what makes the difference between removing 3415 MW and removing a few tens of MW.

Lose one pump at power and the protection system trips the reactor, because reduced flow with unchanged power erodes the margin to boiling at the fuel surface. Lose all four and the plant falls back on natural circulation — hot water rises, cold water sinks, and the loop keeps turning over on density difference alone at roughly 4–8% of forced flow. That is enough for decay heat, which is the point.

4 pumpscanned motornat. circ. ≈ 6 %

Pressurizer PZR

The only place in the primary loop where water and steam coexist on purpose. A partly-filled vessel connected to a hot leg by the surge line, with electric heaters at the bottom and a cold-water spray at the top.

Pressure too low → heaters boil more water into the steam space → pressure rises. Pressure too high → spray condenses steam → pressure falls. Because the whole primary loop is liquid and nearly incompressible, this one steam bubble sets the pressure everywhere, and pressurizer level is the plant's most direct indication of primary coolant inventory.

level 45 %heatersspray

Steam generator SG

A vertical U-tube heat exchanger and the boundary between the radioactive primary loop and the clean secondary loop. Primary water flows inside the tubes; secondary water boils outside them. The two never mix — unless a tube ruptures, which is the SGTR scenario.

Above the tube bundle sit moisture separators and dryers, which spin liquid droplets out of the steam so the turbine receives nearly dry steam. Below it, the channel head is split by a divider plate into inlet and outlet halves. Secondary pressure (≈5.76 MPa) is set by how fast heat arrives versus how fast steam leaves.

5.76 MPalevel 50 %U-tube

Boron & control rods reactivity control

Two ways to control the chain reaction. Control rods are fast — neutron-absorbing rods that drop into the core in seconds on a trip signal. Soluble boron dissolved in the coolant is slow and uniform, used to compensate fuel burnup and xenon over hours and days.

Rods handle transients; boron handles chemistry. Neither is instantaneous in the way people expect — which is exactly what the ATWS scenario demonstrates.

1200 ppm Bbank 84 %

2 · The secondary side — turning heat into electricity

A separate, non-radioactive steam cycle. This is an ordinary Rankine cycle; the reactor is just the boiler.

Main steam & turbine bypass MSL / TCV

Steam leaves the generator at ≈5.76 MPa and travels to the turbine through the turbine control valves (TCV), which set how much steam the turbine swallows and therefore how much power the plant makes.

The turbine bypass (steam dump) is a separate valve that routes steam straight to the condenser, around the turbine. It exists for exactly one reason: when the turbine trips, the reactor cannot stop instantly, so the steam has to go somewhere. Without a bypass, secondary pressure would spike and the safety valves would blow to atmosphere. Watch both valves on the mimic during a turbine trip — TCV shuts red, bypass opens green.

1880 kg/sbypass ≈ 42 % cap.

Turbine, MSR & generator HP / LP / MSR

Steam expands first through the high-pressure (HP) turbine, then passes through the moisture separator reheater (MSR) — which dries and reheats it — before expanding again through the low-pressure (LP) turbine. The MSR exists because wet steam erodes turbine blades.

Both turbines sit on one shaft driving the generator, producing about 1110 MWe from 3415 MWth — a thermal efficiency near 33%, typical for a saturated-steam nuclear cycle and lower than a fossil plant because the steam is much cooler.

1110 MWeη ≈ 33 %

Condenser & circulating water hotwell / CW

A shell-and-tube heat exchanger held under vacuum (≈8 kPa absolute). Exhaust steam condenses on tubes carrying cold circulating water from a river, sea or cooling tower, and collects in the hotwell below.

The vacuum matters more than it looks: it lets steam expand further through the LP turbine, which is where a large share of the output comes from. Lose vacuum and you lose the turbine, the bypass path, and pump suction for the condensate system — which is why the "loss of condenser vacuum" scenario shuts down the whole secondary side at once.

8.0 kPa(a)2 tube banks

Condensate & feedwater MFW

Pumps take condensate from the hotwell and return it to the steam generator, closing the cycle. The feedwater controller matches feed flow to steam flow while trimming for SG level — the classic three-element control problem.

Feedwater is a heat-removal path, not just a plumbing detail. Losing it means the steam generator boils dry, the primary loop loses its heat sink, and the plant has to fall back on passive residual heat removal.

level setpoint 50 %auto / manual

3 · Passive safety systems — the AP1000 idea

Conventional plants keep the core covered with pumps that need AC power. The passive approach uses gravity, compressed gas, natural circulation and evaporation instead — things that keep working when the electricity does not.

Core makeup tanks CMT

Two tanks of borated water connected to the reactor at full RCS pressure — top connected to a cold leg, bottom to the vessel. Because both ends see the same pressure, nothing needs to overcome it: water simply drains down under its own weight as steam or hot water displaces it from above.

They provide makeup early in an accident, while pressure is still high and no pump could inject anyway.

high pressuregravity drainborated

Accumulators ACC

Two spheres of borated water pressurised with nitrogen to about 4.9 MPa, isolated by check valves. They are entirely passive — no signal, no power, no operator. When RCS pressure falls below the nitrogen pressure the check valves simply open and the gas pushes the water in.

They deliver a large volume very quickly, which is what a large-break LOCA needs.

N₂ ≈ 4.9 MPacheck valve

In-containment refuelling water storage tank IRWST

A very large tank of borated water high inside containment. It is the long-term water source: once the RCS has been depressurised to near containment pressure, the IRWST drains into the vessel by gravity alone and keeps the core covered indefinitely.

It also serves as the heat sink for the PRHR heat exchanger and as the discharge point for the ADS spargers — three jobs from one tank, which is why it appears in so many flow paths on the mimic.

gravity injectionPRHR heat sink

Passive residual heat removal PRHR HX

A C-shaped tube bundle submerged in the IRWST, connected to the reactor coolant system. Hot coolant enters the top, is cooled by the tank water, and — being denser — sinks back to the reactor. It runs on natural circulation, with no pump anywhere in the path.

This is the replacement heat sink when the steam generators are unavailable: loss of feedwater, station blackout, or any event that removes the secondary side.

≈68 MWnatural circulation

Automatic depressurisation system ADS

Four stages of valves that deliberately vent the primary system, in sequence, to bring it down from 15.5 MPa to near atmospheric. Stages 1–3 discharge from the pressurizer through spargers that condense the steam under the IRWST water; stage 4 vents the hot legs directly into containment.

Deliberately depressurising a reactor sounds wrong, but it is what makes low-pressure gravity injection possible. ADS trades pressure for the ability to keep water going in forever.

4 stagesADS-4 → containment

Passive containment cooling PCS

The containment vessel is steel, not just concrete, so it can transfer heat outwards. Above it sits a gravity tank; when containment pressure rises, water is released to run down the outside of the steel shell as a film.

Evaporation of that film carries decay heat to the atmosphere, driven by air rising in the annulus between the steel shell and the outer concrete shield. No pump, no fan, no operator, no AC power.

steel shellevaporative film

4 · The physics behind the numbers

Point kinetics & delayed neutrons

Reactor power is solved with six-group point kinetics. The critical quantity is β, the delayed-neutron fraction — about 0.0065 for uranium fuel. A small share of fission neutrons appears seconds to minutes late, and that delay is what makes a reactor controllable at human timescales.

dn/dt = ((ρ − β)/Λ)·n + Σ λᵢ CᵢReactivity ρ is measured against β. Below ρ = β the power change is paced by delayed neutrons — seconds. At ρ ≥ β the reactor is prompt critical and paced by Λ ≈ 5×10⁻⁵ s instead. That is the boundary the design never crosses.

Temperature feedback

A PWR is stable because heating it up shuts it down. Two effects do the work, both negative:

Doppler — hot fuel broadens the U-238 absorption resonances, capturing more neutrons. It acts within milliseconds, in the fuel itself, and is the reason power excursions self-limit.

Moderator temperature coefficient (MTC) — hotter, less dense water moderates neutrons less effectively, so reactivity falls. It acts over seconds as coolant heats up.

ρ_total = ρ_rods + ρ_boron + ρ_Doppler + ρ_MTC + ρ_XeTogether these make the reactor self-regulating: raise steam demand, coolant cools, reactivity rises, power rises to match — with no operator action.

Decay heat

Shutting down a reactor stops fission, not heat. Fission products keep decaying, releasing roughly 6–7% of rated power immediately after trip, around 1% after an hour, and still roughly half to one percent after a day for a long-operated core.

For this plant that is over 200 MW in the first minute — comparable to a small power station — and it cannot be switched off. Every safety system on the passive side exists to remove this heat, which is why "the reactor is shut down" is never the end of an accident.

P_decay(t) ≈ 6.5 · (1 + t)^−0.2 %A smooth Way–Wigner-style educational approximation: about 6.5% at shutdown, 1.3% after one hour and 0.7% after one day. It is not a licensing decay-heat model.

The Tavg programme

PWRs are usually run so that average coolant temperature follows a programmed ramp with power, rather than being held constant. This is a compromise: constant Tavg would swing secondary pressure badly, while constant steam pressure would swing primary temperature and stress the vessel.

The operating map in the diagnostics section plots the live operating point against that programmed band. In AUTO the controller moves the control bank to keep you on it.

Xenon-135

The strongest neutron absorber in the core, produced partly directly and partly by iodine-135 decay. After a power reduction, xenon keeps building for hours before decaying away — the classic xenon transient.

It is why a reactor tripped from full power can become impossible to restart for a day or so, and why boron is adjusted continuously in normal operation.

Subcooling & natural circulation

Two quantities operators watch constantly in an accident. Subcooling margin is how far the hottest coolant is below saturation — lose it and voids form, heat transfer degrades, and instrument readings stop meaning what they normally mean.

Natural circulation is the fallback flow path: the core sits low, the steam generators sit high, and the density difference between hot and cold legs drives flow with no pump. It is weak — a few per cent of forced flow — but decay heat is also only a few per cent of rated power.

5 · What the initiating events actually do

Each scenario in the failure panel is a real class of event from PWR safety analysis. This is what to watch for in each.

Event	Physical cause	What the plant does
Turbine trip	Stop valves shut; generator disconnects	Reactor trips at power; bypass opens to dump steam to the condenser and hold secondary pressure
100% load rejection	Grid connection lost; turbine runs at house load	Coordinated runback plus steam dump instead of an immediate trip
Loss of main feedwater	Feed pumps or valves lost	SG inventory falls, low-level trip, PRHR takes over decay-heat removal
Loss of off-site power	All four RCPs, turbine and feedwater lost	Trip, coastdown to natural circulation; passive systems remain available
Station blackout	No AC power at all	Passive systems only — PRHR and natural circulation carry decay heat
One / all RCP trip	Forced flow reduced or lost	Low-flow trip protects margin to boiling; flow coasts down to natural circulation
Loss of condenser vacuum	Air in-leakage or CW loss	Backpressure rises; turbine, bypass and condensate suction all lost; steam relieves to atmosphere
Main steam-line break	Pipe failure downstream of an SG	Rapid SG blowdown, strong primary overcooling, safeguards signal
Feedwater-line break	Pipe failure in a feed line	Affected SG drains and its feed is isolated; heat sink degrades
SG tube rupture	Tube fails inside an SG	Primary-to-secondary leak: RCS inventory falls while that SG's level rises
Small-break LOCA	Small breach of the pressure boundary	Slow depressurisation; CMTs first, then staged ADS, accumulators, IRWST gravity injection
Large-break LOCA	Major breach	Rapid blowdown; accumulators discharge quickly, IRWST provides long-term cooling
Rod withdrawal	Control bank driven out uncontrolled	Power rises until Doppler feedback and the high-flux trip stop it
ATWS	Trip signal present, rods fail to insert	Temperature feedback and delayed boration limit power — a demonstration of why feedback matters
PRHR / CMT unavailable	Latent single-train failure	No effect at power; consequence appears only when the system is demanded
Pressurizer spray stuck open	Spray valve fails open	Continuous condensation drives RCS pressure down

6 · Abbreviations

Every abbreviation that appears in the mimic diagram, control panels or instrument list.

ACC: Accumulator — nitrogen-pressurised borated water tank that injects automatically when RCS pressure drops below its gas pressure.

ADS: Automatic Depressurisation System — staged valves that vent the primary system so low-pressure gravity injection can start.

ATWS: Anticipated Transient Without Scram — a transient during which the control rods fail to insert.

CMT: Core Makeup Tank — full-pressure borated water tank that drains into the vessel by gravity.

CW: Circulating Water — the cooling water passing through the condenser tubes from the ultimate heat sink.

DNBR: Departure from Nucleate Boiling Ratio — margin to the heat flux at which the fuel surface would become vapour-blanketed. Not calculated here.

DVI: Direct Vessel Injection — the nozzle where passive injection enters the reactor vessel directly rather than via a cold leg.

HP / LP: High- / Low-Pressure turbine — the two expansion stages of the steam turbine.

IRWST: In-containment Refuelling Water Storage Tank — large borated water tank used for gravity injection, as the PRHR heat sink, and as the ADS discharge point.

LOCA: Loss-of-Coolant Accident — a breach of the reactor coolant pressure boundary.

LOOP: Loss of Off-site Power — loss of the external grid supply to plant auxiliaries.

MFW: Main Feedwater — the normal feedwater supply from the condensate system to the steam generators.

MSL: Main Steam Line — piping carrying steam from the SG to the turbine.

MSLB: Main Steam-Line Break — rupture of a main steam line, producing rapid SG blowdown and primary overcooling.

MSR: Moisture Separator Reheater — dries and reheats steam between the HP and LP turbines.

MTC: Moderator Temperature Coefficient — reactivity change per degree of coolant temperature; negative in a PWR at power.

PCS: Passive Containment Cooling System — evaporative water film on the outside of the steel containment shell.

PCT: Peak Cladding Temperature — the licensing figure of merit for fuel damage. Not calculated here.

PRHR: Passive Residual Heat Removal — heat exchanger submerged in the IRWST that removes decay heat by natural circulation.

PWR: Pressurized Water Reactor — reactor type in which the primary coolant is kept liquid by high pressure and boiling occurs only in a separate secondary loop.

PXS: Passive Core Cooling System — the collective name for CMT, accumulators, IRWST injection, PRHR and ADS.

PZR: Pressurizer — steam-space vessel that controls reactor coolant system pressure.

RCP: Reactor Coolant Pump — pump providing forced circulation around a primary loop.

RCS: Reactor Coolant System — the primary loop: vessel, hot and cold legs, pumps, steam-generator tubes and pressurizer.

RPV: Reactor Pressure Vessel — the steel vessel containing the core.

SG: Steam Generator — U-tube heat exchanger transferring heat from the primary to the secondary side.

SGTR: Steam-Generator Tube Rupture — failure of an SG tube, creating a primary-to-secondary leak.

SI: Safety Injection / safeguards — the actuation signal that aligns the passive injection systems.

TCV: Turbine Control Valve — modulates steam flow to the turbine and therefore electrical output.

Tavg: Average coolant temperature — the mean of hot- and cold-leg temperature; the controlled variable in normal operation.

Xe-135: Xenon-135 — strongly neutron-absorbing fission product that builds up after a power reduction.

7 · Scope and limits

Why a PWR behaves differently

The primary coolant is maintained at high pressure so bulk boiling does not normally occur in the core. Heat is transferred to separate secondary water in the steam generators. Reactor power, primary temperature, primary pressure and SG inventory are therefore distinct control problems.

AP1000 passive-safety logic

The model separates high-pressure core makeup tanks, nitrogen accumulators, IRWST gravity injection, passive residual heat removal, staged automatic depressurization and passive containment cooling. The paths animate only when the model calculates actual flow or heat removal.

Model boundaries

This is a lumped educational model. It does not calculate DNBR, PCT, local peaking, detailed multi-node two-phase hydraulics, boron precipitation, 3-D neutronics, containment CFD, licensing setpoints or operator procedures.

Public reference basis: Westinghouse AP1000 overview and U.S. NRC AP1000 design-certification / NUREG-1793 material. Nominal topology and major design values follow public sources; dynamic coefficients are transparent educational approximations chosen for qualitative behavior and numerical stability.

Model equations and assumptions

The reactor uses six-group point kinetics with control-bank, soluble-boron, moderator-temperature, Doppler and xenon reactivity terms. Primary energy balance compares total core heat with two steam-generator heat-transfer terms. The pressurizer model controls RCS pressure with heater/spray action plus inventory and break/depressurization effects. Each SG has an independent mass/pressure balance. Passive injection flows depend on pressure and inventory rather than being scripted animations. The IRWST gravity-flow criterion is referenced to containment pressure: the educational model opens the gravity path only after safeguards alignment and when RCS pressure falls to approximately 0.1 MPa above containment pressure. PRHR is demanded by safeguards or loss of the normal secondary heat sink rather than by every ordinary reactor trip. For the educational SBLOCA sequence, ADS stages 1–3 depressurize only to an intermediate-pressure floor while CMT drain continues; ADS-4 is then required before IRWST gravity flow. The secondary-pressure program rises from the full-power 5.76 MPa(a) reference toward approximately 7.62 MPa(a) at hot standby, preventing the steam dump from artificially overcooling the RCS after a routine turbine trip.

FAQ — is this suitable for safety analysis?

No. It is intended for education and qualitative system understanding. Safety analysis requires validated codes, plant-specific inputs, uncertainty treatment, safety limits and regulatory methods.

Model item	Value / implementation	Status and basis
Rated reactor thermal power	3,415 MWt	PUBLICAP1000 Design Control Document and NRC design-certification material.
Reference electrical output	~1,110 MWe net	PUBLICWestinghouse and NRC public AP1000 plant description.
Core	157 fuel assemblies, 17×17 array	PUBLICAP1000 reactor core description.
Primary circuit	Two loops, four reactor coolant pumps	PUBLICAP1000 reactor coolant system description — two hot legs, four cold legs, two canned-motor pumps per steam generator.
RCS operating pressure	15.51 MPa(a)	PUBLICAP1000 nominal reactor coolant system pressure.
Full-load average coolant temperature	≈300.9 °C	PUBLICAP1000 nominal T_avg at full power.
Hot-leg temperature	321.1 °C at rated conditions	PUBLICAP1000 reactor coolant system design conditions.
Steam generator outlet pressure	≈5.76 MPa(a)	PUBLICAP1000 secondary-side steam conditions at full load.
Passive safety architecture	Two core makeup tanks, two accumulators, IRWST gravity injection, passive residual heat removal heat exchanger, four-stage automatic depressurisation, passive containment cooling	PUBLICAP1000 passive core cooling system (PXS) and passive containment cooling system (PCS) descriptions.
Reactivity control	Control rods plus soluble boron	PUBLICArchitecture is public; individual rod worths, boron worth and letdown rates in this model are educational approximations.
Point kinetics	Six delayed-neutron groups	EDUCATIONALStandard six-group formulation with representative thermal-fission parameters. Not a core-specific kinetics dataset.
Reactivity feedback coefficients	Lumped Doppler, moderator temperature and boron coefficients	EDUCATIONALSigns and orders of magnitude are representative of a PWR at power; values are not burnup-dependent and do not reflect any specific core loading.
Protection setpoints and time delays	Trip thresholds, actuation delays and controller gains	EDUCATIONALChosen to give coherent transient behaviour. These are not plant setpoints and must not be read as such.
Passive system flows and timing	CMT, accumulator, IRWST and PRHR delivery	EDUCATIONALArchitecture and actuation logic follow the public description; delivered flows and timing are simplified.
Mimic geometry and colour zones	Schematic plant diagram	SCHEMATICLayout is illustrative. Indicated bands are not operator limits or trip setpoints.