1 sep. 12, 2007 sung, ki-bang [email protected] reduction method of spent resin generated from sg bd...
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SEP. 12, 2007
Sung, [email protected]
Reduction Method of Spent Resin Generated from SG BD Ion Exchangers of PWR NPPS
Reduction Method of Spent Resin Generated from SG BD Ion Exchangers of PWR NPPS
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1. Introduction
2. Review of the early SGBD IX Replace Criteria
3. Experiment of IX Resin Capacity
4. Review of Experimental Results
5. Conclusions
ContentsContentsContentsContents
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KHNP’s R&D Institute (1)
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KHNP’s R&D Institute (2)
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KHNP’s R&D Institute (3)
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○ Background In Project of Kori #3,4 NPP PSR, Main system of LLW Resin : SG BD Demineralizer
Cause : Secondary Side water pH control agent : NH3 ETA-AVT ⇒ The SGBD cation loads was increased about 2~3 times Spent Resin Radwaste : Large volume and no Industrial waste…
Not easy to treat the ash, though spent resin is almost disposal object itself
PSR Team treated as safety issue item PSR Team(NETEC) and Kori 2 Chemistry Section agreed to the problems a
nd solved the sophisticated problems
1. Introduction (1)
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Block the leaked
ActivitiesRecovery Heat
Recovery BD Bleed
water
Capacity : 5000ℓ×2eaDesign flow : 45ℓ/secNormal flow : 45ℓ/sec
SG BD system’ functions
1. Introduction (2)
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SFP IX2.0ton (9.4%)
LRW System IX1.7ton (7.1%)
CVCS IX3.3ton (18.9%)
SG BD Demin15.4ton/Yr(65%)
Spent IX Resin Source
0 22.4 ton/Yr2.12 t
3.71 t
7.95 t
1. Introduction (3)
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IX Mechanism
Ion Exchange Resin ?
Model of Ix ResinBead of amorphous
and sphere type high polymers
100billions IX sites / bead
1. Introduction (4)
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2. Review of the early SGBD IX Replace Criteria (1)
• IX Resin Replacement Procedures of SGBD IX - No standard Criteria of SGBD IX
- Na was a typical ion to determine the IX removal capacity in many plants. - However, Na was not a typical ion to determine IX removal capacity other plants ( See the next page table )
In USA NPPs, (from EPRI report)
In Domestic Plants,
• IX Resin Replacing Procedures of SGBD IX - 22 of 73 PWR plant didn’t consider the Na ion as IX replacement Criteria
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CriteriaPlnat
IX Replacing Criteria
noteOperation Demin. After Demin.
A Plant Na+ ≥ 5ppbC.C ≥0.5 μS/ ㎝
Na, Cl-, SO4-2 ≥ 2 ppb
B Plant Na+. DF ≤1 Na+. Cl-, C.C DF ≤1 DF = Inlet Conc. Outlet Conc.
C Plant SO4-2 DF ≤1 SO4
-2 DF ≤1
D Plant C.C increase or Na+≥2ppb C.C≥0.2 μS/ ㎝
Na+, Cl-, SO4-2 ≥ 2ppb
E PlantC.C≥0.5μS/ ㎝
Na+, Cl-, SO4-2 ≥ 2 ppb NA
1 Operation, 1 Stand-by
F Plant C.C≥0.1μS/ ㎝ NA “
G PlantC.C≥0.1μS/ ㎝
Na+≥3 ppb Cl-, SO4-2≥5ppb NA “
Table : IX Exchanger Replacement Criteria of Domestic Plants
2. Review of the early SGBD IX Replace Criteria (2)
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Scheme and Shots3. Experiment of IX Resin Capacity (1)
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Ion selectivity experiment with H-type IX resin
Volume Flow
NH4 Na CsETA
3. Experiment of IX Resin Capacity (2)
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ETA, NH4, Na Ion selectivity experiment with Cs-type IX resin
Na
Cs
ETA
NH
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3. Experiment of IX Resin Capacity (3)
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ETA
NH4 Na
Cs
NH4
Na
ETA
Cs Saturated IX Resin
Same characteristics of new IX Resin
4. Review of Experimental Results (1)
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• Experiment : 1/80000 of 2.5 ㎥ which was equal to 30 ㎖ of resin capacity and experiment was achieved for resin which is 30 times of addicted chemical material • Experimental result (ion selectivity on resin) : H+ < NH4 + ≤ ETA+ < Na+ < Cs+
Ionmolecular
weight
ion concentrationsystem
concentration(ppm)
ratio withsystem ion
concentration(ppm) (meq/l)
ETA+ 61.08 122.16 2 3.5 35
NH3+ 17 34 2 0.2 170
Na+ 23 46 2 0.001 46000
Cs+ 133 266 2 0 ∞
total 101.08 202.16 8 3.701 -
Ion Absorbing Capacity on Resin
4. Review of Experimental Results (2)
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• ETA 0.5 [Output conc./Input conc.] Breakthrough time(T) -> (ETA+NH3) : Na : Cs = 2T : 3T : 4T This phenomenon came from ETA/NH3, Na and Cs ‘s different selectiveness.
• NH3 NH3 was eluted after ETA and exchange reaction was faster than ETA. ※ NH3 was produced from ETA or N2H4 which removes Oxygen. • Na Na’s sensitivity was stronger than NH3 or ETA. So, Na was eluted after NH3 or ETA. High Peak position of Na Conc. was overrode on Cs’s conc. 1.0 meq/ℓ(half input Conc.) ⇒ Cs extrude Na
• Cs Cs has S-shape breakthrough characteristics like single ion and it was absorbed on IX resin. Cs was not affected by other ions, and Its behavior look like single ion solution.
4. Review of Experimental Results (3)
Ion Breakthrough Curve Characteristics
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- ETA was not impurity in system, and should not be removed at deminerlizer (On the contrary it should be circulated) - The small Na leakage from new resins was not controlled and excluded at demineralizer exchange criteria. - Even impurities by outside influx was suddenly increased, the impurities concentration should be decreased in proportion to circulating volume as time passes. Impurities, concentration should be decreased.
Table. The SG blowdown water quality of PWR
Operation Operation modeNa criteria
(ppb)Cl criteria
(ppb)
Startupoperation
reload→ cold standby (mode 6-5) ≤ 100 ≤ 100
hot shutdown (mode 4) ≤ 100 ≤ 100
hot standby (mode 3) ≤ 100 ≤ 100
startup operation (mode 2) ≤ 100 ≤ 100
Reactor power
operation
reactor power (5~30%) ≤ 100 ≤ 100
reactor power ( 30%) ≤ 20 ≤ 20
4. Review of Experimental Results (4)
The resin replacement criteria of cation resin
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• Na concentration should be less than 100ppb at maximum or stop operation. If the limited concentration at the second step is less than Na 100ppb, the concentration at Na DF 10 should be 10ppb.• DF 10 of Na Spec value (20ppb) is 2ppb, and Max conc. of Na is 3ppb at operation over 30% generation. Therefore sum of them is less than 5ppb. • The water quality level is less than Na concentration(5ppb). Therefore, improvement of cation resin change criteria is that the Na outlet conc. is reasonable to be selected less than 5ppb.• Cl , SO4
-2 and Conductivity would be derived from system parameters as below.
◆ The resin exchange criteria of SG blowdown demineralizer
- exchange criteria of mixed bed : [Na, Cl ≥ 5 ppb ]
- reference exchange criteria : [SO4-2 ≥ 5 ppb, C.C ≥ 0.3 ㎲ / ㎝ ]
4. Review of Experimental Results (5)
The resin replacement criteria of IX resin
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Table : Ion load for water quality of flow water
ItemIon
Max.conc (ppb) M.W (g./mol)
Ion load( x 10-9 eq/ℓ)
Considered ETA, NH4 not considered ETA, NH4
ETA 5,000 61.08 81.86 NA
NH4+ 500 17.00 29.41 NA
N2H4 50 32.00 1.56 1.56
Na+ 20 23.00 0.87 0.87
total 115.05 3.78
Anion Max organic acid x 1 Max organic acid x 5
Cl- 20 35.50 0.56 0.56
SO4-2 20 96.06 0.42 0.42
SiO2- 100 60.08 1.66 1.66
Acetic acid 20 60.05 0.333 1.67
Glycolic acid 20 76.05 0.263 1.31
Formic acid 20 46.02 0.435 2.17
total 3.67 7.80
4. Review of Experimental Results (6)
The SGBD Ion Exchanger’s cation/anion mixing ratio
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Table. Calculated Resin Volume with system ion loads
ItemResin
Ion Load of System(x10-9 eq/ℓ) Removal Cap
acity of Resin *(eq /ℓ resin)
Calculated Resin Volume capacity
(x 10-9 ℓ resin)
ETA considering
ETA not considering
ETA considering
ETA not considering
Cation 115 3.78 1.8 63.9 6.5
Anion
Max organic acid x 1
3.67 3.67 1.2 3.1 3.1
Max organic acid x 5
7.80 7.80 1.2 2.1 2.1 ◆ SG BD demineralizer’s cation/anion resin mixing ratio
- the ratio of cation and anion resin was 10 : 1 considered ETA load - the ratio of cation and anion resin was 1 : 3 excluded ETA load - The Mixing ratio of Resin (margin : ETA elution effects) 3 : 1
4. Review of Experimental Results (7)
The SGBD Ion Exchanger’s cation/anion mixing ratio
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Satisfaction of PWR FSAR’s Requirements
Saturated IX with ETA Capture the Na and Cs ion
Cs+ > Na+ > ETA+ ≥ NH4+ > H+
Confirm the cation IX Resin Selectivity in ETA solution
No load IX Resin for ETA or NH4
Verify the Cs ion Selectivity of H-, ETA-saturated IX
Satisfaction of EPRI secondary water Guidelines
Confirm the Na ion Selectivity in ETA solution
5. Conclusions (1)
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Establish Spent Resin change Criteria
1Standardization Spent Resin Criteria and Mixing IX Resin
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Examined Na’s behavior in system
4Obtain ion Selectivity for H-type ion
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Technical Effects
5. Conclusions (2)
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Max. removal Capacity of Resin
Reduce works on Radiation area
Reduce Spent IX resin(370t/yr)
Save the Cost(3.3billionWon/total
Solving Problem example with another team
Other Effects
Min. Low Level Radioactive Wastes
Min. Radiation Exposure
Water quality treatment tech.
Co-works
5. Conclusions (3)
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Thank you for your attentions !