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Hee cheon NO

Nuclear System/Hydrogen Lab.

KAIST

Chapter1: Nuclear Reactor Heat Transport System

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Contents

Chapter 1 Nuclear reactor heat transport sys-

tem

1.1 Nuclear fuel

1.2 Reactor vessel

1.3 Reactor core and fuel assembly

1.4 Rod cluster control assembly

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Fuel rod

1.1 Nuclear fuel

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Pellet hourglassing and Pellet-Cladding Mechanical In-teraction(PCMI)

1.1 Nuclear fuel

dish/cham-fer

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Fuel cracking

1.1 Nuclear fuel

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Example of fuel failure mechanisms

1.1 Nuclear fuel

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Intergranular SCC

1.1 Nuclear fuel: Intergranular SCC

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Transient cladding ballooning: LOCA

1.1 Nuclear fuel: Cladding Ballooning & rup-ture

stress

strain

ulti-mate tensile stress

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1.1 Nuclear fuel: Cladding rupture

Post-CHF operation: Non-LOCA

Reactivity-Ini-tiated Acci-dent(RIA)

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PCMI

1.1 Nuclear fuel

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APR1400

Typical 4 loop Rx ves-sel

1.2 Reactor vesselRCB: Rx Containment Building; TGB: Turbine/Generator Building; AB: Auxiliary Building; CB: Compound Building

NSSS

upper core plate

Lower plenum

Upper head

Upper plenum

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1.2 Reactor vessel

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1.2 Reactor vesselEstimation of core mass flow rate:

( ) ( ) ,

(1 )

( ) sec

( );

p p hot cold RCP primary losss feedwater steam feedwater p

p core bypss core p bypass

SG feedwater steam feedwater

Rx p p hot cold c

m c T T Q Q m h h m

m m m m m F

where

Q m h h ondary calorimetric

Q m c T T Q

( )

/

ore core p hot cold

bypass bypss p

m c T T

F bypass flow fraction m m

Flow paths APR1400 설계값

Vessel flow rate 20,991.2 kg/secGuide tube 154.9 kg/secCore shroud annulus 84.2 kg/secOutlet nozzle gap 288.9 kg/secAlignment key 101.9 kg/secAPR Bypass overall 629.9 kg/sec

3.0%UK EPR:

5.5%

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1.2 Reactor vessel

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1.2 Reactor vessel: irradiation specimen (Nil-ductility transition T)

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Typical 4-Loop core1.3 Reactor core and fuel assembly

APR

cladding volume(m^3)

3.72 Zr mass in fuel(Kg) Zr mass in struc(kg)

Zr total mass(kg) 29647 24197 5450

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core and fuel1.3 Reactor core and fuel assembly

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Assembly1.3 Reactor core and fuel assembly

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1.3 Reactor core and fuel assembly

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Assembly(PLUS7)

1.3 Reactor core and fuel assembly

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Assembly(PLUS7)

1.3 Reactor core and fuel assembly

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Assembly1.3 Reactor core and fuel assembly

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Spacer grid1.3 Reactor core and fuel assembly

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1.3 Reactor core and fuel assembly

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1.4 Rod cluster control assembly