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© Hitachi-GE Nuclear Energy, Ltd. 2010. All rights reserved.コピーライトの表示については、作成元で責任を持って適宜変更してください。 ⇒
2010 ISOE Asia ALARA Symposium
Hitachi- GE Nuclear Energy, Ltd.
Development of Hi-F Coat for Carbon Steel Piping
H. Matsubara, N. Usui, M. Nagase
Energy & Environmental Research Laboratory, Hitachi, Ltd.
T. Ito, H. Hosokawa
© Hitachi-GE Nuclear Energy, Ltd. 2010. All rights reserved. 2
M. Nagase, et al.,2009 ISOE Asian ALARA Symposium
Low recontamination by Hi-F Coat was confirmed for Stainless Steel.
1. Application result of Hi-F Coat for SS
Hi-F Coat ; Hitachi Ferrite Coating
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 pip
ing
(m
Sv/h
)
PLR ( A)PLR ( B)
NWC HWC
Pipereplacement
NWC preoxidation operation
Shroud replacementChemical decon.
Chemical decon.Hi-F Coat
NWC preoxidation(90 days )
Point 1Point 2
NWC ; Normal water chemistryHWC ; Hydrogen water chemistry
© Hitachi-GE Nuclear Energy, Ltd. 2010. All rights reserved. 3
CUW piping is one of the biggest sources of radiation exposure.
2 . Enlargement of Hi-F Coat application area
System Material ProblemCountermeas
ure
RRS※1 SS※3 ・ RI deposition
Hi - F
RWCU※2SS
CS※4
・ RI deposition・ Corrosion
No method after chemical
decon.
【 System and its countermeasure 】
60Co in oxide film
No treatment
Hi-F Coat
Decon.
Recontamination
Operation Reductio
n
Principal: Reduction of 60Co deposition by reducing base metal corrosion
【 Countermeasure to reduce recontamination 】
※1 ; Reactor recirculation system※2 ; Reactor water clean up※3 ; Stainless steel 4 ; Carbon steel※
© Hitachi-GE Nuclear Energy, Ltd. 2010. All rights reserved. 4
Hi-F Coat procedure for SS is not applicable for CS.
3 . Problem of Hi-F Coat for CS
Oxidation
Decomposition, clean-up
KMnO4
RepeatRepeat
C2H2O4
N2H4
Heat-up
Reduction, clean-up
Final clean-up
Hi-F Coat treatmentHi-F Coat treatment
Decomposition
Fe ( HCOO ) 2
H2O2
N2H4
【 Problem of film formation 】
-200
200
400SUS
CS
Base metal corrosion
SUS CS
Film
am
ou
nt
(μ
g/c
m2
)
HO
P
met
ho
dH
i-F
Co
at m
eth
od
【 Procedure of Hi-F Coat 】
© Hitachi-GE Nuclear Energy, Ltd. 2010. All rights reserved. 5
Higher pH is a key parameter to reduce CS corrosion.
4 . Idea for Hi-F Coat procedure for CS
Solution pH (-)
0
0.1
0.2
0.3
0.4
3 4 5 6 87
Solu
tion
pH
(-
)
7
4
6
5
Fe(HCOO)2
H2O2 & N2H4
Film formati
on
【 Procedure of film formation for SS 】
CS
corr
osi
on
rate
(g
/m2/h
)
Time
Apply to CS
・ Surface corrosion・ No film
Countermeasure・ Low corrosion at higher pH
【 Idea for film formation 】
Pure water
BM
BM
BM ; Base Metal
© Hitachi-GE Nuclear Energy, Ltd. 2010. All rights reserved. 6
5 . Conditions of film formation
Pure water1ℓ N2bubbli
ngHeat up ( 90℃ )
Reaction Start
Film formation
3 hours
Test pieceChemica
ls
Chemical conc. (ppm)1 2 3
FormerFe
(HCOO)2
(300)
H2O2
(15)N2H4
(600)
New method
Mixing all chemicals in advance
AnalysisAnalysis method・ Crystal structure ・・・・ X ray
deflection・ Binding status ・・・・ XPS・ Film structure ・・・・ SEM・ Film composition ・・・・
Raman spectrum ・・・・ Auger
spectrum
【 Experimental apparatus 】
Ni 金属皮膜形成
【 Injection order and pH 】
7
4
Mixed chemicals
F e(HCOO)2
5
6
8
Former
New method
pH
(-)
N2 gas
pH
TP
90℃
N2H4, H2O2
© Hitachi-GE Nuclear Energy, Ltd. 2010. All rights reserved. 7
The new method enables to make a enough film amount on CS.
6 . Film amount
300
200
100
0
-100
-200
-300
Former New method
2μmCS
Hi - F Coat film
Weig
ht
change (
μg
/cm
2)
Target film amount(90μg/cm2)
© Hitachi-GE Nuclear Energy, Ltd. 2010. All rights reserved. 8
Fine mono layer of polycrystalline Fe3O4 was identified.
7 . Detail analysis of formed film
2μmCS
Formed film
Protect film for work
102030405060708090100
Fe3O4
BM
Polycrystalline Fe3O4
Raman shift (cm-1)200 400 600 800
Formed film
Fe(OH)3
Fe2O3
Fe3O4
Identified as Fe3O4
700 710 720 730
Fe2
+Fe3
+
Existing ratio agrees with Fe3O4
【 Cross section 】
【 Crystal structure 】
【 Film composition 】
【 Binding status 】
Rela
tive
stre
ngth
Rela
tive
stre
ngth
Rela
tive
stre
ngth
© Hitachi-GE Nuclear Energy, Ltd. 2010. All rights reserved. 9
Test was performed under simulated NWC conditions.
8 . Co deposition test conditions
DO
Demi.
Cooler
E. C.
Hx.
Pressure Control Valve
Test section
Temperature 280 ℃
Time 500 h
Pressure 7.8 MPa
Concentration (ppb)
DO 100
DH 10
H2O2 200
Cr 5
Co-60 30
Test conditions ( NWC )
P
P
© Hitachi-GE Nuclear Energy, Ltd. 2010. All rights reserved. 1010
9 Weight change
Weight gain of CS was reduced to about 1/4 under simulated NWC.
0
20
40
60
80
100
120
140
160
Polished Hi- F
Wei
ght g
ain
(μ
g/cm
2 )
Simulated NWCDO:100 ppbDHP:200 ppbCr:5 ppbCo- 60:30ppbTime:500h
© Hitachi-GE Nuclear Energy, Ltd. 2010. All rights reserved. 11
10 Co-60 deposition
Co-60 deposition on CS was reduced to about 40% under simulated NWC.
0
0.2
0.4
0.6
0.8
1
1.2
Polished Hi- F
Dep
ositi
on a
mou
nt o
f Co
-60
(Rel
ativ
e)
Simulated NWCDO:100 ppbDHP:200 ppbCr:5 ppbCo- 60:30ppbTime:500h
© Hitachi-GE Nuclear Energy, Ltd. 2010. All rights reserved. 1212
10 Summary
Film formation method on CS was studied in order to reduce corrosion and Co-60 deposition and its effect was confirmed.
【 Results 】
・ Film formation was realized by reducing CS corrosion.
・ Target film amount of 90 μg/cm2 was realized.
・ Weight gain was reduced to about 1/4 by Hi-F coat film under simulated NWC.
・ Deposition amount of Co-60 was reduced to about 40% by Hi-F coat film under simulated NWC.