Applied Laser Technology Institute

Japan Atomic Energy Agency

65-20 Kizaki Tsuruga-shi，Fukui-ken 914-8585，Japan P h o n e ： +81-（0）770-21-5050 Facsimile： +81-（0）770-25-5782

Summary

Organization of Applied Laser Technology Institute

We are pursuing to develop useful laser based techniques in the field of nuclear engineering. At the same time we are also pursuing to develop the safe and robust techniques as advance industrial technology. We are happy to advertise our own efforts to the variety of industrial and academic societies all over the world to extend the applicability of laser and light technology originated from the nuclear applications. On the other hand, we are also very happy to make fruitful collaborations with people in Fukui prefecture such as Wakasa wan Energy Research Center, the University of Fukui and local industries.

H.Daido ，Director

Subjects of the Applied Laser Technology Institute

・Organization of symposiums, research meetings

○Various meetings of academic societies and so on

○Seminars

・Responding to business needs

○Implementation of laboratory tours from the industry

○Technology transfer to the industry

Laser Technology Promotion Office General Manager : Noboru Tsuchida

Applied Laser Technology Development Office General Manager : Toshiharu Muramatsu

Principal Researcher (Group Leader): Akihiko Nishimura

1 Summer intern ship Laboratory tours Result debrief session

Advertisement and consultation of development of laser technology for Industrial applications.

Research and development of laser techniques for nuclear engineering and nuclear facilities as well as industrial applications originated from nuclear engineering.

・The laser engineering for nuclear engineering and relevant techniques

・Outreach activities

○Summer Science Camp （for High school students）

○Organization of laboratory tours

○Summer internship （ for Graduate students and university students ）

Applied Laser Technology Institute Director : Hiroyuki Daido

Noboru Tsuchida

Toshiharu Muramatsu Akihiko Nishimura

Hiroyuki Daido

Research content

・Development of fiber laser cutting and crushing techniques applied to removal of fuel debris for decommissioning of the Fukushima Daiichi NPPs.

・Monitoring techniques with laser and light technology for decommissioning of nuclear plants.

・Standardization of laser welding / cutting technologies supported by high quality experiments and computer science simulations.

・Maintenance and repair techniques of heat exchanger tubes in the nuclear facilities

・Medical applications of laser technology originated by nuclear engineering.

・Fundamental study on transparent sodium in the vacuum ultraviolet spectral range.

・Research on improving surface properties by laser irradiation

・Research and development of structural health monitoring with an optical fiber technique for a coolant pipeline of nuclear power plants

・Composition analysis for Laser Induced Breakdown Spectroscopy

Laser cutting experiment

2

Laser micromachining experiments

using a microscope objective

Laser irradiation experiments of

simulated blood vessel using a

composite optical fiber

Laser crushing experiment Laser cutting -crushing experiment

Heat exchanger tube repair experiment

Development of laser cutting and crushing control system and classification of irradiation conditions fit to an object . Experiments are being conducted by 6kW+4kW fiber lasers.

Reactor construction of nuclear power plant

Underwater laser cutting and crushing system

According to the decommissioning of the Three Mile Island Nuclear Power Station Unit 2, fuel debris were characterized by indefinite shapes, porous bodies, multi-compositions, higher-hardness.

Laser crushing by pulse irradiation

Laser cutting by a continuous irradiation

Development of fiber laser cutting and crushing techniques applied to removal of fuel debris for decommissioning of the Fukushima Daiichi NPPs.

Laser light

Laser light

20mm

10mm

Alumina pellet attachment

SUS304 austenitic stainless steel

１．A surface of a test piece is characterized as a complicated geometry.

２．An indefinite shape is measured by a 3D underwater laser scanner.

３．Form an optical path of a laser by an assist gas.

４． A continuous irradiation and pulsed irradiation makes it possible to cut the stainless steel and to crush the ceramic pellet underwater.

Shape scanning by 3D laser scanner

Laser power：6 kW

Pulse irradiation time：100 ms

Assist gas：compressed air

Assist gas flow rate：

350 ℓ/min.

Sweep velocity：30 mm/min.

Stand-off：5 mm

Water depth：130 mm

3

Laser Head

Assist gas Laser light

water

Indefinite shapes Higher hardness (Ceramics) Porous bodies (18±11%) Multi-compositions

Moving direction

Continuous wave irradiation

Pulsed irradiation

Continuous irradiation

water

Laser working head

Drag Lines

Dross

5mm

Inlet of coolant

Inlet of coolant

Upper grid damage

Solidifiedmaterial

Hole in the baffle plate

Ablated in-core instrument guide

Cavity

Core debris

Crust

Solidifiedmaterial

Lower plenum debris

Debris

12 m

Pore

Metallic ingots

Ceramic two-phase region (U, Zr)O2

200μm

Fuel debris microstructure

Laser cutting

The work is performed under the collaboration with the Wakasa Wan Energy Research Center, Fugen Decommissioning Research Center , etc. The objective of this collaboration is development of a nuclear reactor dismantling technique using a 6kW+4kW high-power fiber lasers.

Melting a target by laser irradiation.

Remove a molten metal by an assist gas.

Cutting

Mechanism of laser cutting

Underwater cutting example of stainless steel

Supplementary building for Reactor

Core of Reactor such as calandria tanks

Reactor building

Helium cleaning room, poison resolution room

Helium circulation system (3rd Floor)

Room for Cleaning heavy water

Kerf width : 1.5～2mm 1

0 c

m

15 cm

Laser illuminates from the audience.

Cross-section

5 c

m

Dross (Solidified molten metal)

Bird view of Transfer reactor “Fugen” under a decommissioning process.

Cutting direction

Laser light

Assist gas (compressed air)

Molten metal

Dragline

Nozzle

Test underwater laser of the cutting for decommissioning of a nuclear reactor.

4

Heat exchange pump for heavy water

Total Height：

66m

Monitoring techniques with laser and light technology for decommissioning of nuclear plants.

K

【Laser welding】 Toward the understanding of the welding phenomena and controlling the residual stresses, we have been developed a real-time X-ray imaging technique using an intense monochromatic X-ray beam and simulation code.

Standardization of laser welding / cutting technologies supported by high quality experiments and numerical simulation.

【Laser cutting】 Optimization of laser cutting conditions for decommissioning of aging nuclear power plants with help of the numerical simulation code.

【Multi-physics phenomena in a laser cutting process】

Real-time observation of interior of a molten pool during laser welding using an intense monochromatic X-ray beam at SPring-8.

The result of the SPLICE code which simulates interior of a molten pool during laser welding.

【Multi-physics phenomena in a laser welding process】

Real-time observation of laser cutting process using video camera The laser cutting simulation using SPLICE code

Laser working head

Steel plate

30 mm

Molten metal

Laser light

Tracer particle (Tantalum carbide)

Convection flow Solid phase

Molten pool Solid-liquid interface

1mm

Molten pool

Solid phase Solid-liquid interface

1mm

Steel plate

30 mm

Molten metal

Laser working head 1600

1400

1200

1000

800

600

400

200

0

Tem

pe

ratu

re [

oC

]

0

10

20

30

40

50

60

70

y [m

m]

0 10 20 30 40 50 60 x [mm]

25 m/s

Assist gas

5

Based on thermofluid dynamics Thermofluid dynamics, Fluid-solid interaction,

Surface transfer (gas-liquid-solid), Phase change

溶融金属対流領域

q..

き裂補修前処理部

半溶融帯q..

q..Heating Cooling

半溶融帯 半溶融帯凝固

熱伝導領域

レーザー光 レーザー光

加熱 冷却

溶融金属対流領域

q..

き裂補修前処理部

半溶融帯q..

q..Heating Cooling

半溶融帯 半溶融帯凝固

熱伝導領域

レーザー光 レーザー光

加熱 冷却

Laser cladding device to repair wall thinning in 1-inch tube

We have developed maintenance and repair techniques of heat exchanger tubes in nuclear facilities and industrial plants by composite-type optical fiberscope system. This was composed of a central fiber for beam delivery surrounded by fibers for visible image delivery including illumination.

We could irradiate the work with the best accuracy of laser beam and with a filler wire in laser cladding. This device was designed to work in a 1-inch tube.

Demonstration of laser cladding by a welding expert

Example of a clad on a flat plate.

A welding expert successfully made a line clad on a flat plate by manual handling of a laser torch and a wire.

Simulated thinning

SS400 test piece

The guide tube

Welding wire

Laser light

Molten droplet

X-ray shadowgraph of a laser cladding process

A molten droplet of a wire tip was formed and grew up. It is important that the wire is contact with a base metal to make a clad.

6

Laser light

Wire

Laser spot

1 mm

Heat exchange tube

Adjust the position of the wire and laser heats guides by an observation image

Wall thinning of petrochemical plant

23 mm

Thinning point （A shadowed area）

10 mm

900 mm

150 mm

Cross section

Maintenance and repair techniques of heat exchanger tubes in the nuclear facilities

Heat exchanger tube

Laser torch

Visible and near-infrared heat-resistant mirror

Condenser lens

Argon gas Wire feeder

Circumferential position adjustment

Z-axis position adjustment

Composite-type optical fiber

Coupling device

Heat source (QCW fiber laser)

Laser spot

We should pay careful attention to the strength degradation at every aging welded joints when massive earthquakes may attack nuclear power plants. Advanced monitoring system is now getting more important against coming catastrophic earthquakes along the Nankai Trough.

Heat resistant strain sensor fabricated by ultra-short laser processing

We are now fabricating heat resistant strain sensors using an ultra-short pulsed laser in our laboratory. The installation of the stain sensors on the sodium coolant pipeline of Fast Breeder Reactor is under development.

Core

Grating structure in a fiber core

Reflection of the grating structure shows peak shift due to strain and heat.

Ultra-short laser pulses can generate a grating structure along a fiber core (Fiber Bragg Grating :FBG). The FBG can hold the designed reflection peak even over 600 ℃. Such a superior heat resistance can make it possible that laser cladding strongly embedded it on a SUS plate.

Weld bead sealing a FBG sensor in a SUS plate

Heating laser pulses

Seismic-vibration-strain measurement under laser heating by heat resistant FBG sensor

7

1545 1550 1555 1560

Wavelength (nm)

1545 1550 1555 1560

Processing stage and microscope Ultra-short pulse laser system

Femtosecond laser pulse

Oscillator Pulse stretcher

Regenerative amplifier

Multi-pass amplifier

Pulse compressor

Objective lens

1m 100mm stage

1mm

10mm

50μm

Irradiating a laser at equal intervals

Research and development of structural health monitoring with an optical fiber technique for a coolant pipeline of nuclear power plants

Detection light

Minimally invasive laser treatment device

We have developed a laser treatment system that keeps minimum damage to patients and treat precisely by irradiating a laser while watching the affected part. Started to commercialize at OK Fiber Technology Co., Ltd. that is the venture company certified by JAEA.

Optical fibers for image transmission (~f4 mm ,~10,000 pixels)

A fiber for laser irradiation (f100～200μm, 1 unit)

f1～2mm

Optical fibers for illumination

Applications of Minimally invasive laser treatment device

Laser source

CCD camera

Dichroic mirror Coupling device

Source for illumination

Monitor

Illumination light Laser

Image

Composite-type optical fiber scope

Composite-type optical fiber Constitution of device

Laser hyperthermia for cancer of the uterine body

Photodynamic therapy (PDT) for peripheral lung cancer

Non‐occlusive bypass surgery

Hemostasis of bloody issue Diagnostic equipment

for Bile duct and Pancreatic duct Small-bowel endoscope

for the ileus patient

Development of laser treatment system for early cancer of the uterine body that can be uterus-sparing.

Peripheral lung cancer

（The onset in the peripheral part）

Endoscope

Development of laser treatment system for peripheral lung cancer that can observe and treat.

Building a tool that allows to bypass surgery without cutting off the blood flow.

Development of non-contact hemostatic tool using a laser.

Aneurysm

Recipient vessel

Donor vessel

Incision and suturing of the vessel wall

Endoscope

cerebral hemorrhage

Development of diagnostic equipment without having to incise the duodenum papilla.

Gallbladder

Liver

Bile duct

Pancreas

Duodenum papilla

Endoscope

Pancreatic duct Small bowel disease

Development of a new small bowel endoscope that combines optical fiber scope and ileus tube.

8

Medical applications of laser technology originated by nuclear engineering.

Uterine cancer (The onset in the uterine body)

Layout drawing of sodium transparent

Optical property of alkali metals including sodium was intensively investigated in the 20th century. Wood and Sutherland et al. Obtained the plasma wavelength of 218 nm. In the wavelength range of 218 nm, the sodium can be partially transparent down to the threshold of the core electron excitation wavelength of 40.5 nm. On the basis of the previous works, we should extend the characterization into much thicker sodium region to clarify the value of the coefficient. We have made the direct measurement of actual transmittance of a sodium samples in a spectral range longer than 115 nm, resulting in several tens of % transmittance of a 3 mm-thick solid sodium sample including windows at the wavelength of ~120 nm

Experimental setup of an imaging experiment

Image of the metal mesh. A blackened area corresponds to that covered with a pyrex glass plate which is opaque in the vacuum ultraviolet spectral range.

The extinction coefficient ~5 orders of magnitude lower than the previous result. We also find very weak temperature dependency of the transmittance up to 150 degrees centigrade where the solid sample is melted at 97 degrees. In order to confirm measured transmittance, we also make a simple imaging experiment with a 8-mm-thick sodium sample. The photo of the sample and the mesh with the optical system is shown. We successfully obtain a clear image The result opens a way to construct an optical imaging device for objects inside or through a solid or a liquid sodium medium. The result also encourages us to find out the physical origin of the high transparency.

9

10 mm

Heater

Sodium sample (Thickness=8mm) Phosphor

+ CCD

MgF2 Lens

MgF2 Lens VUV light

Deuterium lamp

MgF2 Windows

Mesh

Pyrex glass

Fundamental study on transparent sodium in the vacuum ultraviolet spectral range.

Sodium dedicated glove box

Material irradiation technique by laser pulses

We are trying to improve surface properties of materials by laser irradiation. Nanosecond or femtosecond laser pulses are available for industrial demands. A compact vacuum chamber, X-Y linear translation stage, focusing optics are prepared. Highly trained technical staff will support you to proceed your study. Surface modification for advanced materials is under development by laser irradiation.

Example was continuously irradiated over a wide range of materials

A sample was held on a material position control stage in an irradiation chamber. Laser light timing is controlled by a mechanical shutter. It is possible to perform the sample in various irradiation environments such as an inert gas atmosphere or under reduced pressure depending on the characteristics of the material.

10

Laser irradiation range

Irradiation target sample range

About 1.1cm

Irradiation interval ＝150μm

Users can try surface modifications for a test sample with femtosecond laser pulses.

Examples of materials irradiation test environment

State of the material irradiation test

Laser light

Material position control stage

Irradiation chamber

100mm

Test system

Control system

Monitoring system

1mm

Research on improving surface properties by laser irradiation.

When laser pulses are focused on a target, one can see a tiny flash by laser induced plasma on the target. This can be used for a real time composition analysis of the target material. A nanosecond laser pulse can generate plasma effectively. By combining a laser system, a multichannel spectrometer and fiber optics, you can get the information of breakdown plasma emission spectra.

11

Spectral comparison of the welded parts and piping material by LIBS

This technique is named laser-induced breakdown spectroscopy.（”Laser-Induced Breakdown Spectroscopy”=LIBS）. The following is an example to apply LIBS to the mold made by laser cladding. It can also be applied to verify the distribution of specific elements on the sample. You can see that the chromium containment is higher at the cladding mold (yellow) than that of piping material (red).

300 400 500 600 700 800 900 1000

配管材料

溶接部分

鉄

クロム

Stre

ngt

h[a

.u.]

Wavelength[nm]

Peak of chromium-specific

Coupling device

CCD camera

Spectroscope

Plasma emission on the sample surface

Video observation monitor

Acquisition of spectrum

Composite-type optical fiber

Laser Pulse

Laser pulse Visible Image

10mm 100mm

0.8mm

0.2mm

Example of the combination of the monitoring system and laser equipment

Piping material

Cladding mold

Iron

Chromium

Composition analysis for Laser Induced Breakdown Spectroscopy.

12

6kW+4kW Fiber laser：

Laboratory equipment

Chiller

Laser oscillator

4kW

6kW

Water depth 3m

≪ Applications ≫ Development of laser processing technology aimed at using in general industrial facilities and nuclear facilities. ≪ Specifications ≫ ・4kW Fiber Laser，Chiller Emission Wavelength：1070 ～1080nm Nominal Output Power：4 kW ・6kW Fiber Laser，Chiller Emission Wavelength：1070 ～1080nm Nominal Output Power：6 kW

Particle Image Velocimetry (PIV) system

≪ Applications ≫ Development on the quantitative evaluation method of an assist gas flow related to laser cutting. ≪ Specifications ≫ ・ Double-pulsed Nd: YAG laser Wavelength ：532nm， Power ：50mJ/pulse， Repetition rate ：20Hz Pulse width：6～8ns ・High-speed camera

Test flow channel

Nozzle

High-speed camera

Laser sheet

Equipment for High-Power Laser Welding

Equipment for High-Power Laser Cutting in Air / Under Water

≪ Applications ≫ Development of technology for laser welding of same kind or different kinds of materials intended for thick plates. ≪ Specifications ≫ ・x-y-z Stage，Welding jig

≪ Applications ≫ Development of laser cutting in air / under water. ≪ Specifications ≫ ・X-Y-Z Triaxial Robot System Speed Range : 5 mm/min～5000 mm/min ・Laser Scanner Wavelength ：520 nm， Power ：30 mW, Waterproof Performance ： Maximum Water Depth 100 m ・ Water Tank Maximum Water Depth：3 m

Laser Welding head

Welding jig

x-y-z Stage

Laser scanner head

Test pieces

X-Y-Z Triaxial

450mm

Laser Cutting Head

Robotic arm

Joint research with The Wakasa Wan Energy Research Center, Fugen, Lasax.

Inner wall laser welding repair device for a heat exchanger tube

Femtosecond laser system

≪ Applications ≫ Fiber Bragg Grating(FBG) processing into the optical fiber. Development of ultra-short pulsed laser processing. ≪ Specifications ≫ ・Laser unit Center wavelength ：790nm Pulse width ：～150fs Pulse energy：～10mJ Repetition rate ：～1kHz ・ Processing stage and microscope

≪ Applications ≫ Technical development of weld repair of metal piping and other. ≪ Specifications ≫ ・Fiber laser 1)YLR-300-AC：Wavelength:1,070nm，CW，Power:300W 2)YLR-150/1500/QCW：Wavelength:1,070nm，Pulse/CW， Pulse width:0.2-50ms，Power:150W/250W(CW) ・ Coupling device ： Light guide up to 1kW ， The observation by the CCD camera ・Composite optical fiber：(Core fiber)Φ0.2mm (Image transmission fiber)About 20,000 ・ Laser torch ：Φ15mm，Length:120mm， Jet of gas can be ・ Wire feeder ：Φ0.4mm use wire，Feed rate:0.5-20mm/s

13

Q-switched Nd:YAG laser

≪ Applications ≫ Development of pulsed laser processing. ≪ Specifications ≫ ・ Laser unit Wavelength：1064nm or 532nm（SHG） Pulse width ：5-7ns Pulse energy ： ～ 270mJ@1,064nm,

～130mJ@532nm Repetition rate ：10Hz ・ Processing stage

150cm

77cm

Soft X-ray and ultraviolet spectroscopy, microscopy test equipment

14

≪ Applications ≫ Fundamental and applied studies on ultraviolet light and soft x-ray such as measurement of sodium transmission , microscopy , and surface cleaning. ≪ Specifications ≫ ・Soft X-ray microscope Wavelength：20nm，4nm Optics：Schwarzschild Resolution in the XY direction ：100nm Observed area ：1mm×1mm Resolution in the Z direction ：30nm Imaging range ：40×40μm～200×200μm ・ Soft X-ray, ultraviolet spectrometer Main vacuum vessel ： Inner diameter 560mm Vacuum ultraviolet spectrometer ： Wavelength 100nm～300nm Soft X-ray spectrometer ： Wavelength 0.5nm～5nm，5nm～30nm

Minimally invasive laser treatment equipment 1

≪ Applications ≫ Development of techniques of irradiating a laser to the affected area while watching an image using the composite optical fiber. ≪ Specifications ≫ ・Fiber laser YLR-50-SMLP：Wavelength 1,070nm，CW，Power 50W ・Blood flow meter ・Coupling device ・Control of certain irradiation output ・Monitor ・Composite optical fiber

Minimally invasive laser treatment equipment 2

≪ Applications ≫ Development of techniques to observe the affected area by placing minimally invasively optical fiber inside pancreas. ≪ Specifications ≫ ・Uninterruptible power system ・Image observation device ・Monitor ・Optical fiber：outer diameter 0.8mm

45cm

Applied Laser Technology Institute at Quantum Beam Science Center, Sector of Nuclear Science Research Japan Atomic Energy Agency (JAEA)

and at Tsuruga Head Office

65-20 Kizaki Tsuruga-shi,Fukui-ken 914-8585 Japan Phone☎：+81-（0)770-21-5050 Facsimile：+81-（0)770-25-5782

Home page：http://www.jaea.go.jp/04/turuga/laser/index.html

Revised：July 7th 2014

Tsuruga Head Office／ Applied Laser technology Institute

Fugen Decommissioning Engineering Center

Fast Breeder Reactor Research and Development

Center

FBR Safety Technology Center／ International Nuclear Information

and Training Center

【Photo】 The Tsuruga Peninsula from a airplane on the Japan sea.

Tsuruga Station

The Wakasa Wan Energy Research Center