In-water Transmission System

The 6th International Symposium on Material Test Reactors (ISMTR-7) 20-23 Oct. 2014, Otwock-Swierk, Poland

Development of Radiation Resistant Development of Radiation Resistant

In-water Transmission System

T. Takeuchi

¹

, H. Shibata

¹

, S. Ueno

¹

, T. Shibagaki

²

, H Komanome

²

Y Matsui

¹

and K Tsuchiya

¹

H. Komanome

²

, Y.Matsui

¹

and K. Tsuchiya

¹

1: Japan Atomic Energy Agency, 4002 Narita, Oarai, Higashiibaraki, Ibaraki 311-1393, Japan 2: Ikegami Tsushinki Co., Ltd, 3-6-16 Ikegami, Ohta-ku, Tokyo, 146-8567, Japan

Background

○ Selection of important information about the nuclear facility.

○ Development of transmission system which available under severe accident.

○ Selection of important elements for observation system in the nuclear facility and

○ Selection of important elements for observation system in the nuclear facility, and demonstration of it.

Spent fuel storage pool

Measuring instrument Receiver

Transmitter

Wireless transmission technology (underwater)

Development of transmission system which available with small electrical voltage in severe condition.

1

Introduction

We started from 2012 a research and development so as We started from 2012 a research and development so as to monitor the NPPs situations during severe accidents.

Considering that reactor buildings could be filled with water Considering that reactor buildings could be filled with water under the severe accidents, a development of an in-water wireless transmission system was started. y

Our group completed the basic design of the system and the radiation-resistant tests of the candidate transmittingg and receiving devices by the end of FY2013. In this presentation, the results of the gamma irradiation tests of the devices, and preliminary of a developed transmission test system will be reported.

2

Comparison of Transmitting Method under Water

Method

Item

Radio wave Visible light Sonic wave

Transmitting

△ ○ ○

Status g △ ○ ○

Range Several meters Unknown Several hundred

meters

Advantages

・Existence of many general purpose components

F t T i i

・Resistant to EM- noise

・Small Attenuation in

th t

・Long Range

・Fast Transmission the water

・Fast transmission

・Large electricity consumption

・Influence of the other light noise

・Slow transmission Large transmitter Disadvantages consumption

・Available only low frequency

other light noise

・Large scattering ・Large transmitter

E l f U d t U d t

Examples of use

In water Underwater

Transceivers Communication device Underwater Transceivers

Visible light has low attenuation coefficient in water and enough transmission rate.

Thus, we use visible light against underwater wireless transmitting system. 3

Considering Suitable Light Wavelength

Influence of Cherenkov light Optical absorption coefficient of distilled water

of distilled water

ent 1.2

1.4

/nm)

Thermal output of KUR : 1MW Depth of water : 6m

Rapid increase slightly more than 600nm

n coefficie -3 cm-1 )

1.0 0.8

nW/cm2 / Rapid decrease slightly

less than 600nm

bsorption (×10-

0.6 0.4

diance (n 0 20.2 Ab

Irrad 0.0

Th lt t th t it bl li ht l th i b t f 550 650

Wave length (nm) Wave length (nm)

The results suggest that suitable light wavelength is about from 550-650 nm.

4

Samples of LED and PD

Sample

Item LED-A LED-B LED-C

【 Light Emitting Diode (LED)】

Lens

Bonding wire

S face of eflection

Externals

Material Epoxy resin

Surface of reflection

Semiconductor Die

Cathode Leadframe Anode

Leadframe Material Epoxy resin

Wave length 575nm 609nm 635nm

Emitting

P 0.31mW 2.48mW 4.64mW

Notch

Power

Sample

Item PD-A PD-C

【 Photo Diode (PD)】

Case Cover

Item

Externals

Semiconductor Die

Short wave Long

wave Positive

Material Quartz

glass Borosilicate glass Silicone resin

P layer N layer

Insulator film Depletion wave

wave

Receiving

area 33mm² 7.26mm²

N layer

Negative layer

5

Outline of Gamma-rays Irradiation Tests

Characteristic tests of

i di d l

Characteristic Tests

Spectro-scope Adjustable light

Experiment Flow

un-irradiated samples

G i di ti

Integral sphere

Adjustable light

beam generator LED

・Total luminous flux

・Current-voltage curve

Gamma-rays irradiation (1)

Laptop PC

PD

・Light sensitivity

Gamma Irradiation Field

Characteristic test of irradiated samples

60Co Total dose

(kGy) 10,20,50, 100,1000

Gamma-rays irradiation

(2) source (kGy) 100,1000

Dose rate

(kGy/h) 10

Temp. 20

( )

・・・・

p

(˚C) ~20

6

Characteristic tests of irradiated samples

Irradiation Effect on LEDs (1/2)

Current-voltage curves of LEDs

100 LED A（ l th 575 ） LED C（ l th 635 ）

10

A ）

LED-A（wave length：575nm） LED-C（wave length：635nm）

1

ent （m A

V

current voltmeter

Curr e

0.1

：0kGy

：10kGy

：20kGy

：50kGy 100kGy

：0kGy

：10kGy

：20kGy

：50kGy

：100kGy current

source

0.01

1.4 1.6 1.8 2.0 1.4 1.6 1.8 2.0

Voltage （V） Voltage （V）

：100kGy

：1000kGy

：100kGy

：1000kGy

Properties between current and voltage are almost stable up to 1000kGy.

Voltage （V） Voltage （V）

No significant difference about electrical properties for total dose

7

Irradiation Effect on LEDs (2/2)

Appearance

Dose 0kGy 50kGy 1000kGy

Degradation of total

luminous flux with total dose

1

Sample 0kGy 50kGy 1000kGy

LED-A

(575nm) 0.8

ux[lm] at 0 kGy) (575nm)

LED-B

(609nm) 0.4

0.6

umiousflu ized to 1 a

635nm

LED-C

(635nm) Total lu (normali 0.2

609nm

575nm

(635nm) 0

10 100 1000

Dose [kGy]

Epoxy resin of LED changed brown.

The total luminous flux reduced with increasing of dose.

Colored epoxy resin of LED lenses absorb light.

⇒ Total luminous fluxes decrease.

8

Irradiation Effect on PDs (1/2)

Sample

PD-A PD-B

Appearance of PDs after 1000kGy irradiation

Item

PD-A PD-B

Window material Quartz glass Borosilicate glass Silicone resin

Appearance

Quartz glass

（transparence） S

Borosilicate glass

（transparence ）

Cross section inspection

（transparence） Space

Case

（transparence ）

Silicone resin (brown) Case

Space

Result

Quartz glass did not

change even at 1000kGy. Silicone resin was colored to brown.

Case Case

change even at 1000kGy. to brown.

9

Irradiation Effect on PDs (2/2)

Degradation of light sensitivity with total dose

0.8 1

[A/W] at 0 kGy)

Quartz glass

650nm

0 4 0.6

nsitivity zed

to 1 a

550nm

0.2 0.4

Light se normali

z Silicone & Borosilicate glass

450nm

0

10 100 1000

(n

Dose [kGy]

Browning of the silicone resin makes the light sensitivity decrease.

[ y]

Quartz glass is desirable for window material of PD.

10

Underwater Transmitting Testing System

Testing System Waveform of Transmit and Receive

Experimental Condition

Range 6m

Frequency 100Hz

Duty 50%

1m Remove reflected

light caused

at inner surface Sending signal

Duty 50%

Connectable 6 units (max 6m)

PD output signal

( )

LED sender circuit PD receiver circuit

Digital output signal

This testing system reduces light reflection at the inner surface.

⇒ This system simulates infinity water space. ₁₁

Summary and Future Plan

Transmission with red light have advantage in point of radiation

Summary

(1) Transmission with red light have advantage in point of radiation- resistant while the attenuation coefficient is low.

Gamma irradiation does not significantly cause the degradation (1)

(2) Gamma irradiation does not significantly cause the degradation of the semiconductor parts of LEDs and PDs up to 1000 kGy.

Glass is more suitable than resin for light window materials of ( )

(3)

LEDs and PDs under radiation environment.

Design and fabrication of higher-integrity transmission system

Future Plan

(1) Design and fabrication of higher integrity transmission system Transmission confirmation tests using in-water environment simulator which simulates under severe accident environment ( )

(2)

simulator which simulates under severe accident environment

12