Korean Standard Nuclear Power Plant

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Reduction Method of Spent Resin Generated from
SG BD  Ion Exchangers of PWR NPPS
SEP. 12, 2007
Sung, Ki-Bang kbsung_at_khnp.co.kr
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Contents
1. Introduction 2. Review of the early SGBD IX
Replace Criteria 3. Experiment of IX Resin
Capacity 4. Review of Experimental Results 5.
Conclusions
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KHNPs RD Institute (1)

4
KHNPs RD Institute (2)

5
KHNPs RD Institute (3)

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1. Introduction (1)

• ? 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 23 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 and solved the
  sophisticated problems

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1. Introduction (2)
SG BD system functions
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1. Introduction (3)
Spent IX Resin Source
SFP IX 2.0ton (9.4)
CVCS IX 3.3ton (18.9)
LRW System IX1.7ton (7.1)
0
22.4 ton/Yr
2.12 t
3.71 t
7.95 t
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1. Introduction (4)
Ion Exchange Resin ?
Model of Ix Resin
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2. Review of the early SGBD IX Replace Criteria
(1)
In Domestic Plants,

•  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)

•  IX Resin Replacing Procedures of SGBD IX
• - 22 of 73 PWR plant didnt consider the Na
  ion as IX replacement Criteria

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2. Review of the early SGBD IX Replace Criteria
(2)
Table IX Exchanger Replacement Criteria of
Domestic Plants
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3. Experiment of IX Resin Capacity (1)
Scheme and Shots
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3. Experiment of IX Resin Capacity (2)
Ion selectivity experiment with H-type IX resin
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3. Experiment of IX Resin Capacity (3)
ETA, NH4, Na Ion selectivity experiment with
Cs-type IX resin
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4. Review of Experimental Results (1)
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4. Review of Experimental Results (2)
Ion Absorbing Capacity on Resin

• 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  lt  NH4   ETA lt  Na  lt Cs  

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4. Review of Experimental Results (3)
Ion Breakthrough Curve Characteristics

•   ETA
•       0.5 Output conc./Input conc. Breakthrough
  time(T) -gt     
• 
  (ETANH3) 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
•      Nas sensitivity was stronger than NH3 or
  ETA. So, Na was eluted after NH3 or ETA.
•   High Peak position of Na Conc. was
  overrode on Css 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.

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4. Review of Experimental Results (4)
The resin replacement criteria of cation resin
  - 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
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4. Review of Experimental Results (5)
The resin replacement criteria of IX resin

• 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?/?

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4. Review of Experimental Results (6)
The SGBD Ion Exchangers cation/anion mixing ratio
Table Ion load for water quality of flow water
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4. Review of Experimental Results (7)
The SGBD Ion Exchangers cation/anion mixing ratio
Table.  Calculated Resin Volume with system ion
loads
? SG BD demineralizers 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
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5. Conclusions (1)
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5. Conclusions (2)
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5. Conclusions (3)
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Thank you for your attentions !