Comparison of different dismantling cutting tools in the same experimental conditions Guy PILOT IRSN (Institut de Radioprotection et de Sûreté Nucléaire)

Comparison of different dismantling cutting tools in the same experimental

conditions

Guy PILOT

IRSN(Institut de Radioprotection et de Sûreté Nucléaire)

G. PILOT, IRSN, chapter 6.4

• Assessment of resuspension coefficients due to the use of dismantling cutting tools

Comparison of different Comparison of different dismantling cutting tools in the dismantling cutting tools in the same experimental conditionssame experimental conditions

• General term :

Resuspension coefficient


• Resuspension factor

• Resuspension fraction


( )1MES Lionconcentratsurfacicionconcentratvolumic

=F

( )quantityinitial

suspensioninputquantity=KMES

• Resuspension rate

• Resuspension flux


( )1MES Tquantityinitialflowrateemission

=T

( )12MES TML

surfaceatedmincontaflowrateemission

=Flux

• Radioactive cutting


( )workpiececutthebymasslosttheofityradioactiv

nventilatioexhausttheindrawnityradioactiv=Aacav

( )workpiececuttheofzoneaffectedtheofityradioactiv

nventilatioexhausttheindrawnityradioactiv=Aacav

• Non radioactive cutting


( )workpiececuttheoflossmass

)me(nventilatioexhausttheinmassaerosol=A inv

( )workpiececuttheoflossmass

wallscelltheonmassdeposit+me=A int

( )1-MLlengthcutme

=A invl

• Innovative prefiltration devices Acoustic declogging of an

electrostatic filter

Cartridge filter with pleated metallic media


• Acoustic horn characteristics (Manufacturer’s specifications)


Frequency: 250 Hz

Sound pressure level (1 m): 145 dB

Air pressure during signal: 0.3 – 0.4 Mpa

Air consumption during signal: 20 – 30 l.s-1

Weight: 20 kg

• Levels of protection and expected consequences


Capture at source associated with secondary cleaning network

LEVEL

A

Protection techniques considered

Prefiltration upstreamof the general ventilationExhaust network

LEVEL

B

PrefiltrationImmediatelyUpstream of theHEPA filters

LEVEL

C

Expected consequences

. Increased visibility

. Reduced deposits on tool on the walls of cell

. Reduction of deposits in general ventilation exhaust network

. Increase lifetime of HEPA filters


Blowernetwork

CELL

Cuttingtool

1

2

34

Exhaust

network

HEPAFilter

• Electrostatic filter efficiency during comparative tests of cutting tools for dismantling (1/2)


Cutting cool Specimen materialCutting

Thickness(mm)

Electrostatic filterEfficiency

(%)

Disk grinderStainless steelStainless steel

Mild steel

103010

98.498.395.6

Reciprocating saw Stainless steel 10 > 81

Plasma torch

Stainless steelStainless steelStainless steel

Mild steelMild steelMild steel

103050103050

93.192.494.091.484.186.7

• Electrostatic filter efficiency during comparative tests of cutting tools for dismantling (2/2)


Cutting cool Specimen materialCutting

Thickness(mm)

Electrostatic filterEfficiency

(%)

Arc-air cutter

Stainless steelStainless steel

Mild steelMild steel

10301030

96.397.696.691.7

Arc sawStainless steel

Mild steel1010

97.097.2

LSI

Stainless steelStainless steelStainless steel

Mild steelMild steelMild steel

103050103050

85.989.891.989.395.692.2

• Filter cleaning test results


Cutting toolSpecimen material

Membrane material

Thickness (mm)

Recoverablemass*(g)

Cleaning(%)

PlasmaTorch

Stainless steelMild steel

PVCPVC

3050

13**30**

9283

Arc-air Mild steel PVC 10 51** 81

Arc sawMild steelMild steel

Stainless steel

PVCPVCPVC

101010

9.6**11.1**4.8**

879083

LSIMS/SSMS/SSMS/SS

PVCSSSS

1030

50/100

149.4**113.6***141.2***

49.164.868.8

* Efficiency for recoverable particle mass (i.e particles deposited on ionizer and collector only)** Calculated value*** Measured value

DECOMMISSIONING

DISMANTLING

WASTES CONTAINERS

DIMENSIONS

CUTTING

SECONDARY EMISSIONS

PROTECTION DEVICES ex. PREFILTRATION

CHARACTERIZATION


• Identical working conditions (same cell at scale 1)

• Same steel and thickness

• Same measuring devices

• Same cutting parameters (except

cutting speed and power)


• ToolsReciprocating saw (5 – 10 – 30 – 50 mm)Grinder (5 – 10 – 30 mm)Plasma torch 50 A (5 – 10 mm)Plasma torch 200 A (10 – 30 – 50 mm)Arc-air (5 – 10 – 30 – 50 mm)Arc saw (5 – 10 – 30 – 50 mm)Nd-YAG Laser ( 2 – 5 – 10 mm)LSI (10 – 30 – 50 – 100 – 150* - 200* mm)(LSI: Lichtbogen Sauerstoff Impulsschneiden – Lost wire pulsed oxycutting tool)


*mild steel

• The cutting performances of the tools : Maximal thickness to be cut Cutting speed Wear of the tool


• The secondary emissions Distribution:

Sedimented dross Attached slag Deposits on the cell walls Aerosols in the exhaust duct

Measurments: Mass concentration Size distribution


• Grinder- trademark: bosch- energy: electric- wheel trademark: barcut- wheel diameter: 300 mm- wheel thickness: 4 mm- rotation speed: 5000 r.p.m.- equivalent input: 2200 W- equivalent output: 1550 W- weight: 6 kg- cutting position: gravity position


• Plasma torch

- trademark: saf- type: nertajet 200- working voltage: 120 V- working intensity: 200 A- plasma gas: Argon- flow rate of gas: 60 l.min-1

- nozzle diameter: 2 mm- working standd-off: 7 mm- working position: gravity position


• Arc air

- working voltage: 40 V

- working intensity: 450 A

- electrode nature: carbon

- electrode diameter: 6.35 mm

- working standd-off: 1 mm

- working position: gravity position


• Alternating saw- trademark: fein

- blade length: 400 mm- teeth number per cm: 6- tooth height: 1 mm- blade nature: stainless steel- rate: 2.5 blows/s- working counterweight: 5 kg- working angle with the piece: 45°


• Arc saw- origin: prototype

- working voltage: 44 – 60 V- working intensity: 200 – 1200 A- wheel nature: fluginox 130- wheel diameter: 320 mm- wheel thickness: 5 mm- rotation speed: 250 – 300 r.p.m.


• Nd-YAG LASER- power on plate: 1 kw

- frequency: 10 Hz- pulse energy: 100 J- focal point position: on the plate- assistant gas: without- stand-off: 1 m- optical fiber: 1=50m

d=1mm


• LSI- electrode : steel

d=1.6 mm or 2.4 mm- working voltage: 28-35 V- working intensity: 250-500 A- stand-off: 5 to 40 mm- oxygen pressure: 10 bar- oxygen consumption: 70 m3/h- wire consumption: 4-17 m/min


• Three tools : Plasma torch

Consumable electrode

Contact arc metal cutting


• Non radioactive experiments:

PLASMA TORCH

STAINLESS STEEL CONSUMABLE

ELECTRODE

e=80 mm C A M C

• Radioactive experiments:

MILD STEEL PLASMA TORCH

e=16*2 mm C A M C


• Radioactive plates (e=16 mm)

60Co 61 +/- 13 Bq/g

137Cs 1.5 +/- 1 Bq/g


• Objectives Balance of solid emissions

sedimented dross

suspended particlesaerosols

Gaseous emissions:

NO, NOx, O3, CO2, H2


• CharacterizationSEDIMENTED DROSS

(size distribution)

SUSPENDED PARTICLES(size distribution, chemical analysis,

suspension/solution)

AEROSOLS(size distribution, chemical analysis)



• Plasma torch

- nozzle diameter: 6 mm- stand-off: 18 mm- pilot gas: argon, 60 l/min, 7 bar- cutting gas: argon, 150 l/min, 7 bar- voltage: 190 V- current: 950 – 1100 A


• Contact arc metal cutting

- electrode dimensions: L=150 – 170 mml=100 mme=8 mm

- voltage: 52 V average

- current: 1800 A average

- water pressure jet: 15 bar


• Consumable electrode

- wire diameter: 3 mm

- nozzle diameter: 3.2 mm

- voltage: 63 V average

- current: 2000 A average

- water pressure jet: 17.5 bar

• Main Features of the Experiments (1/2)


N° of experi-ment

Tool Place MaterialMaterial

thickness (mm)

Radio-activity

Water deph (m)

Cutting speed (mm/min)

1Consumable

electrodeUnderwater

Stainless steel

80 NO 0.6 – 0.85 110

2Consumable

electrodeUnderwater

Stainless steel

80 NO 1.65 – 1.90 110

3 CAMC UnderwaterStainless

steel80 NO 0.4 – 0.9 45

4 CAMC UnderwaterStainless

steel80 NO 1.4 – 1.8 45

5Plasma torch

UnderwaterStainless

steel80 NO 0.47 150

• Main Features of the Experiments (2/2)


N° of experi-ment

Tool Place MaterialMaterial

thickness (mm)

Radio-activity

Water deph (m)

Cutting speed (mm/min)

5 bisPlasma torch

UnderwaterStainless

steel80 NO 0.56 150

6Plasma torch

UnderwaerStainless

steel80 NO 1.93 150

7 CAMC Underwater Mild steel 32 YES 1.5 – 2.17 50-100

8 CAMC Underwater Mild steel 32 YES 1.03 - 1.93 50-100

9Plasma torch

Underwater Mild steel 32 YES 2.05 300

CONS.ELECT. CAMCPLASMA

Sedimenteddross 99.5% 93.4% 99%

Suspendedparticles 0.5% 6.6% 1%

Aerosols 0.0005% 0.04% 0.006%


• Aerosol size distribution


ExperimentN°

ToolMass mean aerodynamic

diameter(10-6 m)

Geometric standard deviation

1

2

Consumable

electrode 0.3 (Fe)

3

4CAMC

0.37 (Fe)

0.57 (Fe)

2.65

2.06

5 bis

5Plasma torch

0.12 (mass)0.12 (Fe)Bimodal

1.933.59

• Distribution of the 60Co and 137Cs in experiments n° 7, 8 and 9


Distribution at the activity (%)

Sedimented dross Suspended particles Aerosols

60Co 137Cs 60Co 137Cs 60Co 137Cs

Experiments n° 7 and 8 CAMC

96.8 < 21 3.2 > 79 1.4.10-3 > 0.1

Experiment n° 9PLASMA

99.83 < 33 0.17 > 67 2.6.10-4 > 0.5

Documents

Comparison of different dismantling cutting tools in the same experimental conditions Guy PILOT IRSN (Institut de Radioprotection et de Sûreté Nucléaire)