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Application of Hi-F Coat for Recontamination Reduction at Shimane Unit 1

Application of Hi-F Coat for Recontamination Reduction at Shimane Unit 1. Hitachi- ＧＥ Nuclear Energy, Ltd. M. Nagase, N. Usui, S. Oouchi Energy & Environmental Research Laboratory, Hitachi, Ltd. H. Hosokawa Chugoku Electric Power Company, Ltd. H. Kajitani, A. Yamashita, T. Minami.

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Application of Hi-F Coat for Recontamination Reduction at Shimane Unit 1

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  1. Application of Hi-F Coatfor Recontamination Reduction at Shimane Unit 1 Hitachi-ＧＥ Nuclear Energy, Ltd. M. Nagase, N. Usui, S. Oouchi Energy & Environmental Research Laboratory, Hitachi, Ltd. H. Hosokawa Chugoku Electric Power Company, Ltd. H. Kajitani, A. Yamashita, T. Minami

  2. Background • Dose rate reduction effects don’t last long after operation. • Recontamination reduction is needed to keep low dose rate.

  3. What is Hi-F Coat Principal of recontamination reduction Formation of fine outer magnetite film before power operation 　⇒Reduction of inner oxide film formation to pick upＣｏ Hi-F Coat : Hitachi Ferrite Coating

  4. Section photograph of film Formation of fine magnetite film（thickness：～0.3μm） Outer (magnetite particle） Coating layer (magnetite） Inner (chromite） Vapor deposited carbon Vapor deposited carbon Base metal（type 304 SS） Base metal（type 304 SS） Film of Hi-F Caot Film formed under NWC 200ｈ (DO: 300 ppb)

  5. Reduction effect of activity deposition（laboratory data) ・Remarkable reduction of 60Ｃｏ deposition under HWC ・Continuous effect after ６ times of heat and cool（Stable) DO:<10ppb, DH:50ppb, DH2O2:5ppb Polished (no film) Amount of 60Co deposition (Bq/cm2) ～1/5 NWC treatment Hi-F Coat treatment Time (h)

  6. Outline of treatment procedure Heat-up Fe2O3，MFe2O4 (M : Fe, Ni, Co) KMnO4 Base metal Cr2O3 Oxidation C2H2O4 N2H4 ＨＯＰ method Dissolution of chromium oxides Reduction, clean-up Repeat Base metal Decomposition, clean-up Dissolution of iron oxides Base metal Fe（HCOO）2 H2O2 N2H4 Hi-F Coat treatment Base metal Hi-F Coat method Decomposition Formation of fine ferrite (Fe3O4) film Base metal Final clean-up

  7. Surge tank （with heater） Catalyst column Additional chemical injection system Pump Cooler Ion exchange column Target （PLR piping etc.） Filter Pump Outline of Hi-F Coat treatment equipments Only a little equipments are needed to decontamination equipments.

  8. Outline of Hi-F Coat treatment chemicals Only iron formate is added to HOP method chemicals. *：LOMI is one of chemical decontamination method.

  9. Target of HOP decontamination & Hi-F Coat PLR piping・PLR pump inlet & outlet・Ring header ・Riser piping (A & B loops)

  10. Hi-F Coat treatment conditions

  11. Hi-F Coat treatment results Test piece unit Surge tank P Temporary piping P

  12. Hi-F Coat treatment results More than target value of 0.1μm（60μg/cm2) was achieved.

  13. Surface observation (SEM)

  14. Dose rate of PLR piping (1/2)

  15. Dose rate of PLR piping (2/2)

  16. Effect of dose rate reduction (1/4) Point 1: inlet piping

  17. Effect of dose rate reduction (2/4) Point 2: inlet piping

  18. Effect of dose rate reduction (3/4) Point 3: outlet piping

  19. Effect of dose rate reduction (4/4) Point 4: outlet piping

  20. Effect on chemical decontamination Hi-F Coat film was easy to be removed by chemical decontamination.

  21. 100 Polished 80 Hi-F Coat 60 60Co deposition amount (Bq/cm2) 40 20 0 0 2 4 6 Zn conc. (ppb) Effect of Zn injection on Hi-F Coat Farther Co deposition reduction can be expected with Zn injection. Time：500h Temp.：280℃ ECP：-0.5V Hitachi laboratory data

  22. Summary • Hi-F Coat was first applied to Shimane Unit 1 after chemical decontamination. • Hi-F Coat treatment was successfully applied to the decontaminated surface. Deposited amount of film was about 270 μg/cm2 which was more than target value of 60 μg/cm2. • Recontamination was suppressed about 1/2 to 1/3 after one operation cycle. • Coated film was easy to be removed by chemical decontamination. • Farther dose rate reduction can be expected with Zn injection.

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