isoe/atc alara symposium 2006 the japan atomic power company 1 progress of the zinc injection in...
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1ISOE/ATC ALARA ISOE/ATC ALARA Symposium Symposium 2006 2006
The Japan Atomic Power CompanyThe Japan Atomic Power Company
Progress of the Zinc Injection in Tsuruga NPP Unit 2
October 12, 2006October 12, 2006
THE JAPAN ATOMIC POWER COMPANYTHE JAPAN ATOMIC POWER COMPANYNobuaki NAGATA, Hideaki ICHIGE, Eiichi KADOINobuaki NAGATA, Hideaki ICHIGE, Eiichi KADOI
HOKKAIDO ELECTRIC POWER CO., INC.HOKKAIDO ELECTRIC POWER CO., INC.Yoshifumi WATANABEYoshifumi WATANABE
THE KANSAI ELECTRIC POWER CO., INC. THE KANSAI ELECTRIC POWER CO., INC. Hideya IKOMAHideya IKOMA
SHIKOKU ELECTRIC POWER CO., INC. SHIKOKU ELECTRIC POWER CO., INC. Tsuyoshi SEMBATsuyoshi SEMBA
SHIKOKU RESEARCH INSTITUTE INC. SHIKOKU RESEARCH INSTITUTE INC. Toshiaki HAMAGUCHIToshiaki HAMAGUCHI
2ISOE/ATC ALARA ISOE/ATC ALARA Symposium Symposium 2006 2006
The Japan Atomic Power CompanyThe Japan Atomic Power Company
Objectives
• Effect of water chemistry during zinc injection
• Effect of decreasing dose equivalent rate on primary equipment and pipes after zinc injection
• Evaluation of the fuel performance by observing the external appearance and thickness of oxide film on the fuel installed in core during zinc injection
To evaluate followings of the zinc injection for Japanese PWR plants by using Tsuruga-2
3ISOE/ATC ALARA ISOE/ATC ALARA Symposium Symposium 2006 2006
The Japan Atomic Power CompanyThe Japan Atomic Power Company
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1 2
Zn- 64Zn- 66,67,68,70 Isotope
Abundance(%)
RadioIsotope
RadioactiveHalf-life
Zn-64 48.6 Zn-65 244 D
Zn-66 27.9 - -Zn-67 4.1 - -
Zn-68 18.8Zn-69 56 M
Zn-69m 13.8 H
Zn-70 0.6 Zn-70m 4 HNatural Zn Depleted Zn
Isot
ope
Ab
un
dan
c e( %
)General idea for dose reduction by application of Zn injection
Suppression of the dissolution of corrosion products
Suppression of redeposition
Outer layer ( Ferrite ): NiFe2O4
Inner layer ( Chromite:CoCr2O4
) : Oxygen :Zinc
:Co, ( Ni ): Cr
Pip
e
Pip
ePrimary Water
FuelDeposition
Accumulation RadioactivationCo(Ni)
58Co, 60CoZnZn
ZnZn
Redeposition58Co, 60Co
Depleted Zn : Suppression of dose increase due to reducing the abundance of Zn-64 below 1%
Accumulation and radioactivation of the corrosion products
4ISOE/ATC ALARA ISOE/ATC ALARA Symposium Symposium 2006 2006
The Japan Atomic Power CompanyThe Japan Atomic Power Company
Zn Injection Equipment designing, manufacturing, setting
Fuel Performance
FY 2004 FY 2005 FY 200615/12~ 25/2 22/4~ 22/5
# 14
Planning and Pre-adjustment
Zn Injection
Evaluation Water Chemistry
Dose equivalent rate
# 15Outage (Tsuruga-2)
The Application Study Schedule of Zn Injection
Depleted Zn Purchase
Start of Zn Injection(10/8) ▼
5ISOE/ATC ALARA ISOE/ATC ALARA Symposium Symposium 2006 2006
The Japan Atomic Power CompanyThe Japan Atomic Power Company
Zinc Injection System in Tsuruga-2
Tsuruga-2 4 loops PWR Start Operation : Feb. 1987 Electric Power : 1160 MWe
Charging pump Reactor vessel
Steam generator(SG)
Zn injectionequipment
Demineralizer
Volume control tank(VCT)
Samplingrack
Sample Water Return Injection Pump
Zinc acetatetank
Chemical VolumeControl System
Sampling Roomfor Primary Water
Pressurizer
Primary Loop
※
※
6ISOE/ATC ALARA ISOE/ATC ALARA Symposium Symposium 2006 2006
The Japan Atomic Power CompanyThe Japan Atomic Power Company
Zn Injection Equipment
Equipment Configuration・ Chemical Tanks : 2 (10 little)・ Concentration of Zinc Acetate : about 5~ 12( g/little)Safety Precaution・ Chemical tank : low level detection・ injection pressure : high detection・ Leakage : detection・ check valve in sampling sink
Automatic stop
Connection Point
Sampling Sink
Zn Injection Equipment
Zn injection equipment was downsized with making consideration to safety precaution, and was connected to the sampling return line.
Chemical Tanks
Drain Line
Zn Injection Equipment
7ISOE/ATC ALARA ISOE/ATC ALARA Symposium Symposium 2006 2006
The Japan Atomic Power CompanyThe Japan Atomic Power Company
Zn Injection Plan
Zn injection had been performed in Tsuruga-2 for eight months within a range of 5-7 ppb based on the European experience. (Upper limit : 10 ppb)
Zi C
once
ntr
atio
n in
Pri
mar
y W
ater
(ppb
)
Nov., 2005 Jan., 2006 Mar., 2006 May, 2006Jul., 2005 Aug., 2005
21
0May, 2005
6543
10987
About 5 ppb
About 7 ppb
Detection Limit : 1ppb
Start of Zn Injection
Outage #15
Incubation Period ※
※ Because most of the Zinc is incorporated in the oxide layers on primary equipment and piping , zinc concentration of primary water is not detected in a early stage of Zn injection.
8ISOE/ATC ALARA ISOE/ATC ALARA Symposium Symposium 2006 2006
The Japan Atomic Power CompanyThe Japan Atomic Power Company
Primary Water Chemistry during the Zn Injection
Although concentration of the radioactive Co was increased by a factor of ten with Zn injection than before, the increase was expected based on the European experience. RCS purity, pH and conductivity, was not affected.
0
500
1000
1500
発電機出力
(MW
e)
0
2
4
6
8
10 炉水 亜鉛イオン
亜鉛イオン濃度
(ppb
)
0
10
20
30
40 pH炉水 炉水 導電率
pH(-
),(μ
S/cm
)導電率
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2003/ 10/ 29 2004/ 2/ 6 2004/ 5/ 16 2004/ 8/ 24 2004/ 12/ 2 2005/ 3/ 12 2005/ 6/ 20 2005/ 9/ 28 2006/ 1/ 6 2006/ 4/ 16
Co58炉水 イオン Co60炉水 イオン
放射性コバルトイオン
(Bq/
cm3)
Start of Zn Injection
#14 Operation cycle #15 Operation cycle
pH
Conductivity
Co-58 Ion
Zinc Ion
Co-60 Ion
Ele
ctri
c P
ower
(Mw
e)C
once
ntr
atio
n(p
pb
)p
H (
-)C
ond
. (μ
S/c
m2 )
Con
cen
trat
ion
(Bq
/ml)
9ISOE/ATC ALARA ISOE/ATC ALARA Symposium Symposium 2006 2006
The Japan Atomic Power CompanyThe Japan Atomic Power Company
Measurement of the Radioactive Zinc(Verification of the depleted Zinc)
The increase in Zn-65 was not found due to using depleted zinc.
14/1/04 13/4/04 12/7/04 10/10/04 8/1/05 8/4/05 7/7/05 5/10/05 3/1/06 3/4/06
0.001
0.01
0.1
1
10
100
Act
ivit
y C
once
ntr
atio
n (
Bq
/ml)
Zn-65 Crud Zn-69m Crud
Zn-65 Ion Zn-69m Ion
#14 Operation Cycle #15 Operation Cycle
Start of Zn Injection
10ISOE/ATC ALARA ISOE/ATC ALARA Symposium Symposium 2006 2006
The Japan Atomic Power CompanyThe Japan Atomic Power Company
Relative dose equivalent rate on the primary equipment and pipes
The zinc injection reduced the dose rate of primary equipment and pipes to 70-80 % than that of previous outage. This effect of dose reduction is higher than expectation based on the foregoing plants.However, low temperature nonregenerater had no effect due to zinc injection.
Charging pumpReactor Vessel
Steam generator (SG) Nonregenerative heat exchanger (1.1)
Zn injection equipment
Demineralizer
Volume control Tank(VCT)
Sampling Rack
Sample water return
*Injection Pump
Zinc Acetate Tank
*
Crossover leg(0.69)
SG channel head(0.64 - 0.78)
Cold leg(0.81)
Hot leg(0.73)
Regenerative heat exchanger (0.3)
RCS pump(0.86) : Dose rate measuring points
(Ratio from the previous outage )
11ISOE/ATC ALARA ISOE/ATC ALARA Symposium Symposium 2006 2006
The Japan Atomic Power CompanyThe Japan Atomic Power Company
Behavior of dose equivalent rate in SG Channel head
Dose equivalent rate in SG channel head had increased with age, but was reduced to its about 20-30% thanks to the application of zinc injection.
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1 2 3 4 5 6 7 8 9 10 11 12 13 14 15
Outage #
Dos
e eq
uiv
alen
t ra
te (
mS
v/h
)
SG channel head (Hot)
SG channel head (Cold)
Zn Injection
※
※ : Radiation source decay due to unscheduled plant shutdown when dose rate was measured
12ISOE/ATC ALARA ISOE/ATC ALARA Symposium Symposium 2006 2006
The Japan Atomic Power CompanyThe Japan Atomic Power Company
L K J H G F EN M D CP B AR
1
2
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8
9
10
11
15
14
13
12
#13 Operation CycleFuel Burn-up : 13202MWd/tSpecific Power ratio : 0.84
#14 Operation CycleFuel Burn-up : 31265MWd/tSpecific Power ratio : 1.15
#13 Operation Cycle (Zn Injection)Fuel Burn-up : 46365MWd/tSpecific Power ratio : 1.00
# R 08 (46365MWd/t)
# P 02 (46560MWd/t)
Evaluation of the Fuel Cladding- Visual Inspection of the fuel external appearance -
Fuel surface showed no significant differences with or without zinc injection. (The region looked white on the figure due to difference of growth of the oxide film (thickness, crystal structure) does not show an abnormality for the fuel performance.)
Fuel experienced Zn injection Fuel experienced no Zn injection
13ISOE/ATC ALARA ISOE/ATC ALARA Symposium Symposium 2006 2006
The Japan Atomic Power CompanyThe Japan Atomic Power Company
Evaluation of the Fuel Cladding- Measured thickness of oxide film -
In the result of the evaluation, it was not considered that zinc injection would affect corrosion on fuel cladding because the measured thickness of oxide film was included in past database.
※ Sendo et al. AESJ, 2003,Mitsubishi Heavy Industrial,LTD, NHI-NES-1012
Th
ick
nes
s of
oxi
de
film
(μ
m)
Past database ※
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従来スズジルカロイー 4
低スズジルカロイ -4 (先行照射 )
低スズジルカロイ -4 (Vandellos 2) *
低スズジルカロイ -4 (North Anna 1)
低スズジルカロイ -4 (高浜3号機 ) **
低スズジルカロイ -4 (敦賀2号機;亜鉛経験なし )
低スズジルカロイ -4 (敦賀2号機;亜鉛経験あり )
10 20 30 40 50 60 70 0
* (財)原子力発電技術機構、平成11年度 軽水炉改良技術確証試験 (高燃焼度等燃料に関するもの)に関する報告書、平成12年3月** (財)原子力発電技術機構、平成10年度 軽水炉改良技術確証試験 (高燃焼度等燃料に関するもの)に関する報告書、平成11年3月
: Slightly rough surface
Average of fuel burn-up(GWd/t)
Past Data ※
: Zircaloy-4 (No Zn injection): Zircaloy-4 (Zn injection)
14ISOE/ATC ALARA ISOE/ATC ALARA Symposium Symposium 2006 2006
The Japan Atomic Power CompanyThe Japan Atomic Power Company
SummaryWater Chemistry
・ Concentration of zinc in primary water was controlled well within the target value (5-7 ppb).
・ Although concentration of the radioactive Co was increased by a factor of 10 with Zn injection than before, the increase was included within the expectation based on the European experience.
・ The increase in Zn-65 was not found due to using depleted zinc.
Dose equivalent rate・ The zinc injection reduced the dose equivalent rate of primary equipment
and pipes to 70-80 % than that of previous outage.
Fuel Performance・ It was not considered that zinc injection (eight months) would affect
corrosion on fuel cladding by observing the fuel external appearance and thickness of oxide film on the fuel cladding.
Zinc injection in Tsuruga-2 will continue to be performed.Influence of long-term zinc injection on the plant and fuel performances will be estimated.