eci & npc

ECI & NPC

ECI

� Purpose� To protect the fuel� To provide cooling to the fuel after loss of

coolant accidents� Provide back-up to normal HTS cooling

during some none LOCA events

Simplified ECI

Water Accumulator

GasAccumulator

ORWaterStorage

HighPressurePumps

ECI HeatExchanger

Recovery Pump

Recovery Sump

LOCA

� Large� HTS voids rapidly� Fuel heats until ECI refills HTS� Ultimately recovery will cool fuel

� Small� Fuel cooled mostly by normal HTS path� Crash cool-down cools HTS� Recovery may be used

Recovery Sump

Grade Level Storage Tank

Accumulator Water Tanks

Accumulator Gas Tanks

Storage Tank

ECI Header

Unit 5 Unit 6 Unit 8Unit 7

To Reactor Headers

Bruce

� High pressure� Low pressure� Recovery

OH #5OVH-28184-00006 R000

Three phases of injection

Containment

� Purpose� Protective envelope that contains radioactive

material released from the heat transport system

� Minimize size and duration of an overpressure in containment following a LOCA

� Maintain containment sub-atmospheric following a LOCA

Pressure Suppression Containment

VacuumBuilding

Tank 1

Tank 3

V4To Spent Fuel Bay Exhaust

V5 V2MV15

MV16AO

AO AO AO

AO

Upper Chamber

Main Chamber

MV1 MV2 MV3Main ChamberPumps

UpperChamberPumps

Vacuum Building Operation

Vacuum Building

Relief Manifold

Pressure Relief DuctsFuelling Machine

Room

Reactor Vaults

5 6 7 8

Containment Envelope

Air Locks and Transfer Chambers

� Allow access and egress from containment� 2 doors one of which must be properly

closed at all times� Correct procedure must be followed when

operating the doors

8'

Vent Duct

APRV CV500

Isolation Valve MV501

Pressure Relief Valve #2

Pressure Relief Valve Manifold Floor

Vacuum Duct

Flap Valve

36" Diameter Pressure Relief Valve Bypass Pipe

PRV and APRV

Pressure Relief Valves

KPa(g)+7

+4

0-1

-2

-3

-5

Containment Pressure

Time

Vault Cooling

� Normally used to maintain the vault temperature less than 40°C

� Sufficient capacity to condense steam from small LOCAs

EFADS & PARMS

� Post accident mitigation systems� Emergency Filter Air Discharge System

� De-misters� HEPA filters� Charcoal filters� Fans

� Post Accident Radiation Monitoring System� Measures what we release after and accident

Emergency water system EWS

� Not the same as emergency water storage system� EWST is the tank in the top of the vacuum building

� EWS� Purpose: a redundant source of cooling water for

decay heat removal in the event of a loss of the normal systems

� 3 pumps in Emergency Water & Power Supply Building

� Suction from the CCW discharge channel