all rights reserved. copyright © 2008, hitachi-ge nuclear energy, ltd. 1-0 ※...

1All Rights Reserved. Copyright © 2008, Hitachi-GE Nuclear Energy, Ltd. 1-1※ この資料の複写、第 3 者への公開を固く禁じます。 All Rights Reserved. Copyright © 2009, Hitachi-GE Nuclear Energy, Ltd.

Application of Hi-F Coatfor Recontamination Reduction

at Shimane Unit 1Hitachi- ＧＥ Nuclear Energy, Ltd.M. Nagase, N. Usui, S. Oouchi

Energy & Environmental Research Laboratory, Hitachi, Ltd.H. Hosokawa

Chugoku Electric Power Company, Ltd.H. Kajitani, A. Yamashita, T. Minami

2All Rights Reserved. Copyright © 2008, Hitachi-GE Nuclear Energy, Ltd. 1-2※ この資料の複写、第 3 者への公開を固く禁じます。 All Rights Reserved. Copyright © 2009, Hitachi-GE Nuclear Energy, Ltd. 2

　 Background

• Dose rate reduction effects don’t last long after operation.

• Recontamination reduction is needed to keep low dose rate.

0

1

2

3

4

5

17 18 19 20 21 22 23 24 25 26 27 28Number of outage -（）

Dos

e ra

te o

f PLR

out

let

pipe

Svh

)（ｍ

Point 3Point 4

NWC HWC

Chemical decon.NWC preoxidation operation

Pipereplacemen

t

Shroud replacementChemical decon.

Abnormal crud deposition


　 What is Hi-F Coat

Formation of fine outer magnetite film before power operation　⇒ Reduction of inner oxide film formation to pick up Ｃｏ Hi-F Coat : Hitachi Ferrite Coating

Film of Hi-F Coat Oxide film in plants

Chemical form

Outer Fe3O4Fe3O4 、 Fe2O3 、Ni （ Co)Fe2O4

Inner － CoCr2O4 、 Cr2O3

Size of particle ＜ 0.2μ ｍ 1 ～ 10μ ｍThickness of film ＜ 0.5μ ｍ 3 ～ 10μ ｍTemperature 90℃ 280℃

Principal of recontamination reduction


　 Section photograph of film

Formation of fine magnetite film （ thickness ：～ 0.3μm ）

Vapor deposited carbon

Base metal （ type 304 SS ）

Film formed under NWC 200 ｈ(DO: 300 ppb)

Film of Hi-F Caot

Outer (magnetite particle ）Inner (chromite ）

Coating layer (magnetite ）

Vapor deposited carbon

Base metal （ type 304 SS ）


　 Reduction effect of activity deposition

（ laboratory data)

・ Remarkable reduction of 60 Ｃｏ deposition under HWC・ Continuous effect after ６ times of heat and cool （ Stable)

0

50

100

150

200

250

0 500 1000 1500 2000 2500 3000 3500

(h)浸漬時間

Co-

60(B

q/cm

2)付

着量

Hi-F Coat treatment

NWC treatment

Polished (no film)

～ 1/5

Am

ou

nt

of 6

0C

o d

ep

osi

tion

(B

q/c

m2)

Time (h)

DO:<10ppb, DH:50ppb, DH2O2:5ppb


Outline of treatment procedure

Oxidation

Decomposition, clean-up

Final clean-up

KMnO4

Dissolution of chromium oxides

Fe2O3 ， MFe2

O4

(M : Fe, Ni, Co)Cr2O3Base metal

RepeatRepeat

C2H2O4

N2H4

Dissolution of iron oxides

Heat-up

Reduction, clean-up

Hi-F Coat treatmentHi-F Coat treatment

Decomposition

Fe （ HCOO ） 2

H2O2

N2H4

Formation of fine ferrite (Fe3O4) film

ＨＯ

Ｐ

met

ho

dH

i-F

Co

at m

eth

od

Base metal

Base metal

Base metal

Base metal


　 Outline of Hi-F Coat treatment equipments

Only a little equipments are needed to decontamination equipments.

Pump

CoolerIon exchange column

Catalyst column

Additional chemical injection system

Filter

Surge tank（ with

heater ）

Pump

Target（ PLR piping etc. ）


　 Outline of Hi-F Coat treatment chemicals

Only iron formate is added to HOP method chemicals.

Chemical Conc. (ppm)

Remarks

HOP decon.process

KMnO4 200 ～ 300 For oxidation

(COOH)2 2000 For reduction

N2H4 ～ 600 For ｐ H control

H2O2 － For decomposition of chemicals

Hi-F Coat treatmentprocess

Fe(HCOO)2

Fe ：～ 250Formic ion ：～

500

Raw material for film formationFormic acid is used for LOMI* process.

H2O2 － For ion value control

N2H4 200 ～ 500 For ｐ H control* ： LOMI is one of chemical decontamination method.


Target of HOP decontamination & Hi-F Coat

PLR piping・ PLR pump inlet & outlet・ Ring header・ Riser piping(A & B loops)

HOP Hi-F Coat

1st time 1st time

1st &2nd time 2nd time

2nd time 2nd time

10

All Rights Reserved. Copyright © 2008, Hitachi-GE Nuclear Energy, Ltd. 1-10※ この資料の複写、第 3 者への公開を固く禁じます。 All Rights Reserved. Copyright © 2009, Hitachi-GE Nuclear Energy, Ltd. 10

Hi-F Coat treatment conditions

Parameter Planned value Measured value

Fe conc. 250±50 ppm 263 ～ 296 ppm

N2H4 conc. 200 ～ 600 ppm 160 ～ 560 ppm

11


Hi-F Coat treatment results

P

P

Surge tank

Test piece unit

Temporary piping

12


Hi-F Coat treatment results

More than target value of 0.1μm （ 60μg/cm2) was achieved.

Sample item Application Sample No.Deposited

amount （ μg/cm2)

Test piece

1st time1 2302 270

2nd time3 3024 192

3rd time5 1256 132

4th time7 4028 498

Temporary piping

2nd time A 1504th time B 359

13


Surface observation (SEM)

Before Hi-F Coat(After decon.)

After Hi-F Coat

×1000

×10000

14


　 Dose rate of PLR piping (1/2)

0

1

2

3

4

5

17 18 19 20 21 22 23 24 25 26 27 28Number of outage -（）

Dos

e ra

te o

f PLR

inle

t pi

ping

Svh

)（ｍ

PLR A)（PLR B)（

NWC HWC

Pipereplacement

NWC preoxidation operation


Chemical decon.Hi-F Coat

NWC preoxidation(90 days）

Point 1Point 2

15


　 Dose rate of PLR piping (2/2)

0

1

2

3

4

5

17 18 19 20 21 22 23 24 25 26 27 28Number of outage -（）

Dos

e ra

te o

f PLR

out

let

pipi

ngSvh

)（ｍ

PLR A)（PLR B)（

NWC HWC

Chemical decon.NWC preoxidation operation

Pipereplacemen

t


Abnormal crud deposition

Chemical decon.Hi-F Coat

NWC preoxidation(90 days）

Point 3Point 4

16


0

0.5

1

1.5

2

23 28

Dos

e ra

te o

f PLR

(m

Sv/

h)

After decon.After operationIncrease

No countermeasure

90 days NWCpreoxidation operation

Hi-F Coat＋-54%

　 Effect of dose rate reduction (1/4)

Point 1: inlet piping

17


0

0.5

1

1.5

2

23 28

Dos

e ra

te o

f PLR

(m

Sv/

h)


-81%


Hi-F Coat＋

No countermeasure


Point 2: inlet piping

18


0

0.5

1

1.5

2

23 26 28

Dos

e ra

te o

f PLR

(m

Sv/

h)


-60% 90 days NWCpreoxidation operation

Hi-F Coat＋


Contribution of Hi-F Coat-60%

No countermeasure


Point 3: outlet piping

19


0

0.5

1

1.5

2

23 26 28

Dos

e ra

te o

f PLR

(m

Sv/

h)


-74%


Hi-F Coat＋

No countermeasure

Contribution of NWC preoxidation-35%

Contribution of Hi-F Coat-39%



Point 4: outlet piping

20


0

0.2

0.4

0.6

0.8

1

1.2

0 50 100 150

Time after start of chemical decontamination (h)

Rel

ativ

e do

se r

ate

(-) 27th outage

28th outage

1st cycle 2nd cycle

　 Effect on chemical decontamination

Hi-F Coat film was easy to be removed by chemical decontamination.

21


Effect of Zn injection on Hi-F Coat

Farther Co deposition reduction can be expected with Zn injection.

Hitachi laboratory data

Time ： 500hTemp. ： 280℃ECP ： -0.5V

0 2 4

Zn conc. (ppb)

0

20

40

60

80

100

PolishedHi-F Coat

60C

o d

ep

osi

tion

am

ou

nt

(Bq

/cm

2)

6

22


Summary

1. Hi-F Coat was first applied to Shimane Unit 1 after

chemical decontamination.

2. Hi-F Coat treatment was successfully applied to the

decontaminated surface. Deposited amount of film

was about 270 μg/cm2 which was more than target

value of 60 μg/cm2.

3. Recontamination was suppressed about 1/2 to 1/3

after one operation cycle.

4. Coated film was easy to be removed by chemical

decontamination.

5. Farther dose rate reduction can be expected with Zn

injection.

all rights reserved. copyright © 2008, hitachi-ge nuclear energy, ltd. 1-0 ※...

Documents