T. Aoyamaa,b, T. Ishikawab, C. Itob, Y. Iwatab, Y. Morohashic

and T. Takedaa a Research Institute of Nuclear Engineering, University of Fukui

b Experimental Fast Reactor Department , Japan Atomic Energy Agency c Engineering Department, Fast Breeder Reactor Research and

Development Center, Japan Atomic Energy Agency

Study on High Sensitive FFDL Technique for Monju and next generation SFR Using RIMS

FR13 conference

Paris, March, 2013

FFDL: Failed Fuel Detection and Location

RIMS: Laser Resonance Ionization Mass Spectrometry

1

Present study includes the result of “Core R&D program for commercialization of the

fast breeder reactor by utilizing Monju” entrusted to University of Fukui by the Ministry

of Education, Culture, Sports, Science and Technology of Japan (MEXT).

Conventional technique FFDL: Tagging, Selector valve, Sipping (wet, dry)

Sodium leak detection: Sodium Ionization Detector (SID),

Radiation Ionization Detector(RID), Contact Leak Detector (CLD)

Ultra high sensitive (~ppt), Highly reliable (prevent from false signal)

- FFDL by measuring Xe, Kr gas

-Sodium leak detection by measuring sodium aerosol

Applied to

Introduction

Failed Fuel Detection and Location (FFDL) and

sodium leak detection are essential for SFR safety.

more sensitive, simple, robust, reliable,

RIMS: Laser Resonance Ionization Mass Spectrometry Ultra high sensitive (~ppt), Highly reliable (prevent from false signal)

2

…

What is RIMS ?

System Digital signal processor

Time-of-flight mass spectrometer (TOFMS)

Sample

gas

Tunable OPO laser system

Laser resonance ionization

Mass spectrometry

MC

P o

utp

ut

[mV

] 200

180

160

140

120

100

80 109 110 111

Flight time [μs]

1ppb

0.1ppb

128Xe

129Xe

130Xe

131Xe

132Xe

134Xe 136Xe 124Xe

126Xe

112

Ionization

potential

Exited

level

Ground level

λ=256.02nm

λ=256.02nm Xenon

(Natural Xe in Ar gas)

λ=256.02nm

3

What is RIMS ?

High sensitivity

< ppb, ~ ppt

High S/N

by selective ionization

Isotopic ratio measurement

by mass spectrometry

(Time-of-flight)

Characteristics System Digital signal processor

Time-of-flight mass spectrometer (TOFMS)

Sample

gas

Tunable OPO laser system

4

Resonance Ionization + Time Of Flight Mass Spectrometer (TOFMS)

Optical Parametric Oscillation (OPO) Adjustable Laser Beam Length

Kr (217 nm): OPO(557 nm)& YAG(355 nm) Sum Frequency Generator(SFG)

Xe (256 nm): OPO(512 nm) Second Harmonic Generator(SHG)

Ground

State

Ionization

Potential

Excited

State

2γ+1γ

λ

λ

λ

Isotopic analysis of Kr and Xe by Resonance

Ionization Mass Spectrometry (RIMS)

TOFMS

5

YAG (355 nm)

OPO (557 nm)

SFG Sum

Frequency

Generator

(217 nm)

OPA: Optical Parametric Amplifier 557 nm 557 nm

355 nm 355 nm

Laser for Krypton Ionization (JAEA Oarai R&D Center)

6

Laser beam

Pulsed Supersonic Molecular Beam Valve (PSV)

Reflectron type TOFMS (JAEA Oarai R&D Center)

Ｏリング

ノズル

Gas

Gas

Current

Ｏリング

ノズル

Gas

Gas

Cur

rent

O-ring Nozzle

Gas Gas

Electric

Current

7

Procedure

1. Detect tag gas release

- Activated tag gas nuclides by OLGM 2. Identify ruptured capsule

- Isotopic ratios of tag gas by RIMS On-Line Gamma-ray

Monitor (Ge detector)

Core

Cover gas Volume :6.5m3

Gas sampling

Reactor vessel

φ 6.9 mm

42 m

m

Tag gas capsule

Capsule: Cylindrical tube

Xe: ~5cc, Kr: ~5cc

with no fuel

Temp. : 750 ˚C (max.)

Inner pressure (helium) :

< 22 MPa

Tag gas isotopic ratio

(6 kinds):

126Xe / 129Xe,

131Xe / 129Xe,

132Xe / 129Xe

Tag gas release experiments *1

(Joyo)

RIMS

(Off-line)

8

*1 C. Ito et al., “Experimental method of in-pile creep rupture behavior of ODS cladding materials

in the experimental fast reactor Joyo,” Journal of Power and Energy Systems (2008)

~100 %

released from the capsule Core

Gas sampling

Reactor vessel

Tag gas release experiments

(Joyo)

RIMS

(Off-line)

Radio

activity (

Bq/c

c)

Tag gas radioactivity in primary cover gas

101

102

103

Jun.12 Jun.13 Jun.14 Jun.15'06

127Xe

135Xe

OLGM signal increased

at ‘06 Jun. 12 22:08

Cover gas sampling

at ‘06 Jun. 13 9:36

9

Cover gas Volume :6.5m3

0

50

100

150

200

108 109 110 111 112

Natural

xenon

Mass spectrum by RIMS

MC

P o

utp

ut (m

V)

124Xe

126Xe

128Xe

129Xe

130Xe

131Xe

132Xe

134Xe 136Xe

Flight time (µs)

Measured

gas

Xenon isotopic ratios

Result of RIMS measurement

(Joyo)

Tag gas was successfully identified by measuring

xenon isotopic ratios.

Tag gas No. 126Xe

/129Xe

131Xe

/129Xe

132Xe

/129Xe

１ 0.632 0.896 0.891

２ 0.069 0.101 0.298

３ 0.209 0.890 0.101

４ 0.630 0.301 0.101

５ 0.629 0.102 0.892

６ 0.071 0.888 0.889

by RIMS 0.065 0.099 0.295

Tag gas No. 126Xe

/129Xe

131Xe

/129Xe

132Xe

/129Xe

1 0.632 0.896 0.891

2 0.069 0.101 0.298

3 0.209 0.890 0.101

4 0.630 0.301 0.101

5 0.629 0.102 0.892

6 0.071 0.888 0.889

by RIMS 0.065 0.099 0.295

10

Ar供給系

ベーパトラップ

ポンプ

流量計

γ線検出器

ベーパトラップ

Ar Gas

γ-ray Detector

Flow Meter

Pump

Sodium sipping

Procedure

Sipping

Port

S/A

Na

Ar

Gas ＋Na

Loop B

DN Detector (A)

Core

FP

Coolant (Sodium)

DN Detector (B)

Failed Fuel

Loop A

Coolant Flow

Coolant Flow

FP

Cesium Trap

(0.1mm x 1mm)

Spacer wire

Gas plenum

Axial reflector

Fuel pellet

Cladding

Slit(pre-defected)

Test Pin

Ar+FP

Bubbling

FP +Na

Fuel failure simulation test in Joyo *2

(test fuel pin with a slit at gas plenum region)

11

*2 K. Ishida et al., “Fuel failure simulation test in the experimental fast

reactor Joyo,” Proc. of GLOBAL 2005, Tsukuba, Japan (2005)

MC

P o

utp

ut

(mV

)

0

10

20

30

40

50

108 109 110 111 112

124Xe 126Xe

128Xe

129Xe 131Xe

136Xe 130Xe

-------

Natural Xenon

gas

Flight Time (µs)

------

Measured

cover gas

132Xe

134Xe

133Xe

Radioactive nuclide:

“133Xe” was detected

(~10ppt)

RIMS was able to assume the burn-up of the

failed fuel subassembly; even it can be

applicable to selector valve (for JSFR). 12

Reactor vessel Coolant sodium

Defect hole

Fuel pin

RIMS can measure tag gas isotopic ratios

directly with no concentration process

Tag gas capsule

(Xe: 1cc, Kr: 1cc)

Procedure

using magnetic sector

mass spectrometer

Gas release

Cover gas volume:

70 m3

5 % released from failed fuel

> 7 ppt

1. Concentration

~ ppm

2. Measurement

FFDL using tag gas (Monju)

Fission-product gas

Tag gas

13

Mass spectrum of Kr and Xe by RIMS

(natural abundance)

14

57000 53000 54000 55000 56000

80

60

40

20

0

Time of flight (ns)

Xe-124

(8ppt)

Xe-130

(319ppt)

Xe-129

(2053ppt)

Xe-134

(809ppt)

Xe-136

(692ppt)

Xe-132

(2092ppt)

Xe-126

(7ppt)

Xe-128

(149ppt)

Xe-131

(1656ppt)

Io

n sig

na

l in

te

nsity (m

V)

Xe: 7ppb (total)

Laser wavelength : 256nm

Laser power : 9.5mJ

Measurement time : 2000s

Amplification : X10

Kr-78

(7ppt)

Concentration

(Red marked nuclide

is used as tag gas

for Monju FFDL)

Kr-80

(45ppt)

Kr-82

(229ppt)

Kr-83

(227ppt)

Kr-84

(1124ppt)

Kr-86

(341ppt)

Time of flight (ns)

42000 43000 44000 45000

Io

n sig

na

l in

te

nsity (m

V)

120

90

60

30

0

Kr: 2ppb (total)

Laser wavelength : 217nm

Laser power : 3.0mJ

Measurement time : 2000s

Amplification : X100

2

1

0

42000 43000

126Xe/

129Xe was measured within 7.1% error (1 σ)

Less than 25 % 15

Identification of neighboring Xe tag gas

0.020

0.025

0.030

0.035

0.040 Is

oto

pe rat

io（

126Xe/

129Xe）

Fuel Burn-up (MWd/t)0 98,000

Tag No.1

Tag No. 2

Spaci

ng

fact

or（

1.2

5）

Manufacturing

error: 2 % Design value

Tag No.1 upper l imit

Tag No.2 lower l imit

78Kr/

80Kr was measured within 4.7% error (1 σ)

Less than 25 % 16

Identification of neighboring Kr tag gas

0.3

0.4

0.5

0.6 Is

oto

pe rat

io（7

8Kr/

80Kr）

0 98,000

Tag No.1

Tag No. 2S

paci

ng

fact

or（

1.2

5）

Manufacturing

error: 2 %

Tag No.2 lower l imit

Tag No.1 upper l imit

Design value

Fuel Burn-up (MWd/t)

0

20

40

60

80

100

54 54.5 55 55.5 56

2012

2006

Measured Tag Gas Sampled in Joyo

Measured in 2012 (1/893) Same concentration in Monju primary cover gas

Measured in 2006 (1) 126Xe : about 10 ppt

Time of Flight(μs)

Ion s

ignal in

tensity(

mV

)

<Tag Gas Nuclide Ratio>

17

128Xe

129Xe

130Xe

131Xe

132Xe

134Xe 136Xe

126Xe

Ratio of Measured Nuclide 126Xe 128Xe 129Xe 131Xe 132Xe

2012 / 2006 0.97 0.94 1 1.09 1.02

124Xe

0

20

40

60

80

100

54 54.5 55 55.5 56

2012

2006

Measured Tag Gas Sampled in Joyo

Measured in 2012 (1/893) Same concentration in Monju primary cover gas

Measured in 2006 (1) 126Xe : about 10 ppt

Ion s

ignal in

tensity(

mV

)

<Tag Gas Nuclide Ratio>

18

Ratio of Measured Nuclide 126Xe 128Xe 129Xe 131Xe 132Xe

2012 / 2006 0.97 0.94 1 1.09 1.02

124Xe

128Xe

129Xe

130Xe

131Xe

132Xe

134Xe 136Xe

126Xe

Time of Flight(μs)

Outlook of RIMS system

19

Laser for Xenon

Laser for Krypton

Ionization

Chamber

Shielding Tube for Laser Beam

Air conditioner

TOFMS

Air conditioning

booth

Cooler for

Laser

Aux. Laser

(for Kr, Xe)

Expanded View

Mirror

20

Primary cover gas supply line

The sampling tank is installed

in front of Ionization chamber

in order to supply the cover gas

above atmospheric pressure.

Ar cover gas

Primary Ar cover gas line

Coolant

Sodium

TOFMS

Cover gas

sampling tank

Waste gas line

or

Ar cover gas

V1

Ionization

chamber

PSV

Ｏリング

ノズル

Gas

Gas

Current

Ｏリング

ノズル

Gas

Gas

Curr

ent

O-ring Nozzle

Gas Gas

Electric

Current

Valve

FFDL system (present)

V2

V3

FFDL (RIMS)

Reactor Vessel

Charcoal

filter bed

Min. : +31kPa(gage)

0

2

4

6

8

10

12

-10 10 30 50 70A

mount of ion signal (V・ns)

Gage pressure（kPa）

Measured while changing the pressure of

sampling tank.(Total 1300 seconds mesured）

129Xe：2ppb

20

Sampling tank

(placed inside Pb shield )

The high sensitive Failed Fuel Detection

and Location technique for fast reactors

has been developed using RIMS.

Major Achievements

- Tag gas (krypton and Xenon) was successfully identified

with no concentration process in Joyo.

- Burn-up of the failed fuel subassembly can be assumed.

- Prototype FFDL system for Monju was proposed.

Summary

Further enhancement of fast reactor safety

21

JSFR

ASTRID

Monju

The RIMS FFDL system is expected to be a promising innovative instrumentation system for future SFRs.

RIMS Research Members

University of Fukui, RINE

Japan Atomic Energy Agency

Oarai, Joyo

Tsuruga, Monju

23

Thank you for your kind attention

Merci Beaucoup !