1 SEP. 12, 2007 Sung, Ki-Bang 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

2 1. Introduction 2. Review of the early SGBD IX Replace Criteria 3. Experiment of IX Resin Capacity 4. Review of Experimental Results 5. Conclusions ContentsContents

3 KHNP’s R&D Institute (1)

4 KHNP’s R&D Institute (2)

5 KHNP’s R&D Institute (3)

6 ○ Background  In Project of Kori #3,4 NPP PSR, Main system of LLW Resin : SG BD Demineralizer Cause : Secondary Side water pH control agent : NH 3 ⇒ 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 and solved the sophisticated problems 1. Introduction (1)

7 Block the leaked Activities Recovery Heat Recovery BD Bleed water Capacity : 5000ℓ×2ea Design flow : 45ℓ/sec Normal flow : 45ℓ/sec SG BD system ’ functions 1. Introduction (2)

8 SFP IX 2.0ton (9.4%) LRW System IX 1.7ton (7.1%) CVCS IX 3.3ton (18.9%) SG BD Demin 15.4ton/Yr (65%) Spent IX Resin Source ton/Yr 2.12 t3.71 t7.95 t 1. Introduction (3)

9 IX Mechanism Ion Exchange Resin ? Model of Ix Resin Bead of amorphous and sphere type high polymers 100billions IX sites / bead 1. Introduction (4)

10 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

11 Criteria Plnat IX Replacing Criteria note Operation Demin.After Demin. A PlantNa + ≥ 5ppb C.C ≥0.5 μS/ ㎝ Na, Cl -, SO 4 -2 ≥ 2 ppb B PlantNa +. DF ≤1Na +. Cl -, C.C DF ≤1 DF = Inlet Conc. Outlet Conc. C PlantSO 4 -2 DF ≤1 D PlantC.C increase or Na + ≥2ppb C.C≥0.2 μS/ ㎝ Na +, Cl -, SO 4 -2 ≥ 2ppb E Plant C.C≥0.5μS/ ㎝ Na +, Cl -, SO 4 -2 ≥ 2 ppb NA 1 Operation, 1 Stand-by F Plant C.C≥0.1μS/ ㎝ NA“ G Plant C.C≥0.1μS/ ㎝ Na + ≥3 ppb Cl -, SO 4 -2 ≥5ppb NA“ Table : IX Exchanger Replacement Criteria of Domestic Plants 2. Review of the early SGBD IX Replace Criteria (2)

12 Scheme and Shots 3. Experiment of IX Resin Capacity (1)

13 Ion selectivity experiment with H-type IX resin Volume Flow NH 4 NaCsETA 3. Experiment of IX Resin Capacity (2)

14 ETA, NH4, Na Ion selectivity experiment with Cs-type IX resin NaCsETANH 4 3. Experiment of IX Resin Capacity (3)

15 ETANH 4 NaCs NH 4 Na ETA Cs Saturated IX Resin Same characteristics of new IX Resin 4. Review of Experimental Results (1)

16 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 + Ion molecular weight ion concentration system concentration (ppm) ratio with system ion concentration (ppm) (meq/l) ETA NH Na Cs ∞ total Ion Absorbing Capacity on Resin 4. Review of Experimental Results (2)

17 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

18 - 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 OperationOperation mode Na criteria (ppb) Cl criteria (ppb) Startup operation reload→ cold standby (mode 6-5)≤ 100 hot shutdown (mode 4)≤ 100 hot standby (mode 3)≤ 100 startup operation (mode 2)≤ 100 Reactor power operation reactor power (5~30%)≤ 100 reactor power ( 30%)≤ Review of Experimental Results (4) The resin replacement criteria of cation resin

19 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, SO 4 -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 : [SO 4 -2 ≥ 5 ppb, C.C ≥ 0.3 ㎲ / ㎝ ] 4. Review of Experimental Results (5) The resin replacement criteria of IX resin

20 Table : Ion load for water quality of flow water Item Ion Max.conc (ppb)M.W (g./mol) Ion load ( x eq/ℓ) Considered ETA, NH4not considered ETA, NH4 ETA5, NA NH NA N2H4N2H Na total AnionMax organic acid x 1Max organic acid x 5 Cl SO SiO Acetic acid Glycolic acid Formic acid total Review of Experimental Results (6) The SGBD Ion Exchanger’s cation/anion mixing ratio

21 Table. Calculated Resin Volume with system ion loads Item Resin Ion Load of System (x10 -9 eq/ℓ) Removal Capacity of Resin * (eq /ℓ resin) Calculated Resin Volume capacity (x ℓ resin) ETA considering ETA not considering ETA considering ETA not considering Cation Anion Max organic acid x Max organic acid x ◆ 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

22 Satisfaction of PWR FSAR ’ s Requirements Saturated IX with ETA Capture the Na and Cs ion Cs + > Na + > ETA + ≥ NH 4 + > H + Confirm the cation IX Resin Selectivity in ETA solution No load IX Resin for ETA or NH 4 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)

23 Establish Spent Resin change Criteria 1 Standardization Spent Resin Criteria and Mixing IX Resin 2 Examined Na ’ s behavior in system 4 Obtain ion Selectivity f or H- type ion 3 Technical Effects 5. Conclusions (2)

24 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 ExposureWater quality treatment tech. Co-works 5. Conclusions (3)

25 Thank you for your attentions !