02.Reactivity

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Muhammad SubektiEmail: [email protected] SubektiMuhammad SubektiEmail:Email: [email protected]@batan.go.id

Reactivity Control

Course of Reactor Engineering I

Reactivity Control

Course of Reactor Engineering I

Centre for Reactor Technology and Nuclear Safety, BATAN

Puspiptek Complex, Building No.80, Serpong, Tangerang

Centre for Reactor Technology and Nuclear Safety, BATAN

Puspiptek Complex, Building No.80, Serpong, Tangerang


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Nuclear Engineering I

Course Content

I. FUNDAMENTAL

1. Current Status of NPP Program in Indonesia

2. Overview of Nuclear Physics3. Overview of Reactor Physics

I. FUNDAMENTAL



II. MAIN

1. NPP Technology

2. Characteristic of BWR

3. Characteristic of PWR

4. Fuel Engineering5. Core Inherent Characteristic

6. Reactivity Control

7. Reactor Structural Mechanics

8. Reactor Material Engineering

9. Decommissioning

II. MAIN

1. NPP Technology







9. Decommissioning

I. FUNDAMENTAL



I. FUNDAMENTAL



II. MAIN

1. NPP Technology







9. Decommissioning

II. MAIN

1. NPP Technology







9. Decommissioning

I. FUNDAMENTAL



I. FUNDAMENTAL



II. MAIN

1. NPP Technology







9. Decommissioning

II. MAIN

1. NPP Technology







9. Decommissioning


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Objectives

Mention the most important factor for reactorcontrol in view of inherent safety

PRESENTATION IN 20 MINUTES

Objectives

Mention the most important factorfor reactorcontrol in view of inherent safety

PRESENTATION IN 20 MINUTES

Objectives

Explain the definition of reactivity Mention the reactor control instruments

Explain the limitation of reactor control using control rod

and Boron in moderator Explain the reactivity design margin to compensate the

margin of shutdown, temperature defect, power defectand burnup

Explain the calculation flow approaching the couplingmodel of neutronics and thermalhydraulics

Objectives

Explain the definition of reactivity Mention the reactor control instruments

Explain the limitation of reactor control using control rod

and Boron in moderator Explain the reactivity design margin to compensate the

margin of shutdown, temperature defect, power defectand burnup

Explain the calculation flow approaching the couplingmodel of neutronics and thermalhydraulics

Today Content

AimStudy how to control the reactorreactivity

AimStudy how to control the reactorreactivity


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Inherent Reactivity

Nuclear Bomb vs. Nuclear Power PlantNuclear Bomb vs. Nuclear Power Plant

Burning in once time

Release all energy in a

second (less than 1 sec)

Burning in once time

Release all energy in a

second (less than 1 sec)

Burning a part by part

Release energy for a long

time (more than a year)

Burning a part by part

Release energy for a long

time (more than a year)

T [ ] = Reactivity [+]T [ ] = Reactivity [+] T [ ] = Reactivity [-]T [ ] = Reactivity [-]


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Reactivity Control

Briefly Reactivity

Reactor Control Design

The instruments

The capability limitation of reactor control

Reactor Kinetics Neutronics model

Thermalhydraulics model

Synchronization of neutronics andthermalhydraulics model

Reactivity Control

Briefly Reactivity


The instruments





Today Content


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Reactivity is a condition to describe the reactor core

criticality level, related with keff, where:

The neutron number is effected by keff,

Reactivity is a condition to describe the reactor core

criticality level, related with keff, where:

The neutron number is effected by keff,

Reactivity Control

Definition of Reactivity Definition of Reactivity

eff

eff

kk 1

=

neffn kNN )(0=

N = Jumlah neutron

n = Jumlah generasi neutrn ke- n = Reaktivitas

effK = Faktor multiplikasi neutron


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Reactivity Control

Definition of Reactivity Definition of Reactivity

Misalnya jumlah neutron dalam teras adalah 1000 dan keff=1,002. Jumlah neutron

setelah 50 generasi adalah:

50

50 )002,1(1000=N , dari persamaan (2)

110550 =N neutron

Reaktivitas dalam teras reaktor ketika keff=1.002 adalah

002,1

1002,1 = , dari persamaan (1)

001996.0= =

=

k

k

k

k01,0%1 1000 pcm

1 pcmkk= 00001,0


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Reactivity Control

Briefly Reactivity


The instruments





Reactivity Control

Briefly Reactivity


The instruments





Today Content


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Reactivity Control

Briefly Reactivity


The instruments

The instruments of reactor control isgrouped into reactor control system,

reactor control assembly, and

Boron as object of volume control

Reactivity Control

Briefly Reactivity


The instruments

The instruments of reactor control isgrouped into reactor control system,

reactor control assembly, and

Boron as object of volume control

Today Content


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The Instruments

The function of reactor control system

to control the fission reaction safely and optimally

The function of reactor control system

to control the fission reaction safely and optimally

Reactor Control System Reactor Control System

Reactor control system contains of control rod system and

volume control system (Boron)

Reactor control system contains of control rod system andvolume control system (Boron)

Gambar 3.1 Perbedaan posisi drivebatang kendali dalam reaktor

Th I


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The Instruments

System System

Gambar 3.2 Pengaturan bagian atas bejana tekan reaktor

Th I t t


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The Instruments

Fuel Assembly

Control Rod

Reactor Core

Fuel Assembly

Control Rod

Reactor Core

Control Rod Assembly Control Rod Assembly

Th I t tH t kH t k


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The Instruments

Fuel Assembly

Control Rod

Reactor Core

Fuel Assembly

Control Rod

Reactor Core

How to workHow to work


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Th I t t


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The Instruments

Control rod material

utilized Borosilicate

Glass (Pyrex)

The pattern of control

rod number in a fuel

assembly is 24, 9,and 12 rods.

Control rod material

utilized Borosilicate

Glass (Pyrex)

The pattern of control

rod number in a fuel

assembly is 24, 9,

and 12 rods.

Control Rod

Assembly

Control Rod

Assembly

(a). 24 batang kendali (b). 9 batang kendali

(c). 12 batang kendaliGambar 3.7 Pola posisi batang kendali pada perangkat bahan bakar

The Instruments


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The Instruments


Gambar 3.8 Pola posisi IFBA dalam perangkat bahan bakar

Westinghouse is utilizing burnable

absorber in the fuel rod called

Integrated Fuel Burnable

Absorber(IFBA), a pellet coatingfuel with Zirconium Dirboride

(ZrB2)

IFBA number in a fuel assembly hasnumber patters: 28, 44, 74, 88,

112

Westinghouse is utilizing burnable

absorber in the fuel rod called

Integrated Fuel Burnable

Absorber(IFBA), a pellet coatingfuel with Zirconium Dirboride

(ZrB2)

IFBA number in a fuel assembly hasnumber patters: 28, 44, 74, 88,

112

The Instruments


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The Instruments

Nuclear BombNuclear Bomb


Gambar 3.9 Pengaturan posisi batang kendali dan IFBA dalam teras PLTN

The Instruments


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The Instruments

Nuclear BombNuclear Bomb


Gambar 3.10 Pengaturan posisi batang kendali dalam teras PLTN

SD

SA

SC

SA

SE

SB

SB

D

SE

SBSC

SD

SA

SE

SB

SA

SB

SA

SD

SE

SB

SC

SA

SCSBSBSD

SASA

C A C

AA

C A C

B

C

B

B C B

B

C

B

BCB

D

D D

D

Model 1/8

AP1000

PWR1000

Today Content


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Reactivity Control

Briefly Reactivity


The instruments





Reactivity Control

Briefly Reactivity


The instruments





Today Content

The Capability Limitation of Reactor Control


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Tabel 3.1 Reaktivitas batang kendali beberapa PWR dalam pcm

Grup Batang Kendali PWR1000 AP600 AP1000

MA 540 625 299

MB 260 500 131

MC 110 300 204

MD 50 175 309

Negative reactivity in control rod Negative reactivity in control rod

The capability limitation is designed as agreement to

safety design margin

The capability limitation is designed as agreement to

safety design margin



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Suhu Bahan Bakar [ F]500 600 700 800 900 1000 1100 1200 1300

-1,2

-1,3

-1,4

-1,5

-1,6

-1,7

-1,8

-1,9

-2,0

-2,1

BOC

EOC

Gambar 3.12 Koefisien suhu akibat efek Doppler

Negative reactivity by

Doppler Effect for

EOC is less thanBOC due to atom

decrease of U-238

and P-240

Negative reactivity by

Doppler Effect for

EOC is less thanBOC due to atom

decrease of U-238

and P-240

reactivity

(%

)

Xe-135

Sm-149

sum Pu-241

Pu-239 & U-235

Pu-240

FP with large absorption XS

FP with small

absorption XSreactivity

(%

)

Xe-135

Sm-149

sum Pu-241

Pu-239 & U-235

Pu-240


FP with small


(%

)

Xe-135

Sm-149

sum Pu-241

Pu-239 & U-235

Pu-240


FP with small


(%

)

Xe-135

Sm-149

sum Pu-241

Pu-239 & U-235

Pu-240


FP with small

absorption XS

Doppler Effect Doppler Effect



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The number of Excess

Reactivity is

determined bydesigned operating

time of NPP or burnup

The number of Excess

Reactivity is

determined bydesigned operating

time of NPP or burnup

Gambar 3.15 Degradasi power defect

Defect due to burnup Defect due to burnup


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Today Content


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Reactivity Control

Briefly Reactivity


The instruments





Reactivity Control

Briefly Reactivity


The instruments





Today Content

Today Content


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Reactivity Control

Briefly Reactivity


The instruments





Reactivity Control

Briefly Reactivity


The instruments





Today Content

Neutronics Model


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Neut o cs ode

3D reactor core is divided by 27 zones as a nodal model; 9 zones at top,9 zone in the middle, and 9 zones at bottom

Every zone is approaching point kinetic method to calculate neutron flux

based on 6 groups delayed neutron

3D reactor core is divided by 27 zones as a nodal model; 9 zones at top,9 zone in the middle, and 9 zones at bottom

Every zone is approaching point kinetic method to calculate neutron flux

based on 6 groups delayed neutron

Gambar 4.1. Modeling teras dengan cara pembagian zona teras reaktor

Point kinetics method Point kinetics method


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Thermal Hydraulics Model


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y

T1

T2

R1

R2

C

Cladding

Gambar 4.2. Tampang lintang pelet bahan bakar

Heat transfer in fuel rod Heat transfer in fuel rod

1

2111

RTTQ

dtdTC n = & (4.9)

2

2

1

2122

R

TT

R

TT

dt

dTC C

= (4.10)



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nQ& = Panas yang dibangkitkan dari bahan bakar

1C = Kapasitas panas pelet bahan bakar = 112

1 ... pcr

2C = Kapasitas panas claddingbahan bakar = 222 .).(.2 pcrr

1R = Resistansi ruang UO2dan gap =ghrk ..2

1

.4

1

11 +

1T = Suhu rata-rata pelet bahan bakar

2T = Suhu rata-rata claddingbahan bakar

C

T = Suhu rata-rata pendingin reaktor

Heat transfer in fuel rod Heat transfer in fuel rod

y



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Heat transfer in primary system Heat transfer in primary system

Gambar 4.3. Jaringan perhitungan termohidrolik

y

Today Content


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Reactivity Control

Briefly Reactivity


The instruments





Reactivity Control

Briefly Reactivity


The instruments





Synchronization of Neutronics and TH Model


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Coupling Calculation Coupling Calculation

Gambar 4.4 Proses sinkronisasi perhitungan neutronik dan termohidrolik

Summarize


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Reactivity Control

1. Reactivity is a condition to describe the

reactor core reactivity level

2. Reactor Control Instrument is grouped

Reactor Control System

Control Rod Assembly

Boron

3. Reactor control has capability limitationwhich is designed for adequate safety

design margin

Reactivity Control

1. Reactivity is a condition to describe the

reactor core reactivity level

2. Reactor Control Instrument is grouped

Reactor Control System

Control Rod Assembly

Boron

3. Reactor control has capability limitationwhich is designed for adequate safety

design margin

Summarize


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Reactivity Control

4. Nuclear reactor calculation approaches

the coupling calculation of neutronics and

thermal hydraulics model

Reactivity Control

4. Nuclear reactor calculation approaches

the coupling calculation of neutronics and

thermal hydraulics model

Thank You


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TRINITY STONE formed by firstnuclear explosion in the world-radiation emitter - 1.5 mrem/hour

TRINITY STONE formed by firstnuclear explosion in the world-radiation emitter - 1.5 mrem/hour

@Muhammad Subekti 2005

02.Reactivity

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