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2010 ISOE Asia ALARA Symposium

2010 ISOE Asia ALARA Symposium. Development of Hi-F Coat for Carbon Steel Piping. Hitachi- ＧＥ Nuclear Energy, Ltd. H. Matsubara, N. Usui, M. Nagase. Energy & Environmental Research Laboratory, Hitachi, Ltd. T. Ito, H. Hosokawa. 5. NWC. HWC. 4. PLR （ A). Point 1.

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2010 ISOE Asia ALARA Symposium

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  1. 2010 ISOE Asia ALARA Symposium Development of Hi-F Coat for Carbon Steel Piping Hitachi-ＧＥ Nuclear Energy, Ltd. H. Matsubara, N. Usui, M. Nagase Energy & Environmental Research Laboratory, Hitachi, Ltd. T. Ito, H. Hosokawa

  2. 5 NWC HWC 4 PLR（A) Point 1 NWC preoxidation operation Point 2 PLR（B) 3 Pipe Dose rate of PLR inlet piping（mSv/h) replacement Chemical decon. Shroud replacement 2 Hi-F Coat Chemical decon. NWC preoxidation (90 days） 1 0 17 18 19 20 21 22 23 24 25 26 27 28 Number of outage（-） １．Application result of Hi-F Coat for SS Low recontamination by Hi-F Coat was confirmed for Stainless Steel. Hi-F Coat ; Hitachi Ferrite Coating NWC ; Normal water chemistry M. Nagase, et al.,2009 ISOE Asian ALARA Symposium HWC ; Hydrogen water chemistry

  3. 2．Enlargement of Hi-F Coat application area CUW piping is one of the biggest sources of radiation exposure. 【Countermeasure to reduce recontamination】 Recontamination No treatment 60Co in oxide film Operation Decon. Reduction Hi-F Coat Principal: Reduction of 60Co deposition by reducing base metal corrosion 【System and its countermeasure】 ※1 ; Reactor recirculation system ※2 ; Reactor water clean up ※3 ; Stainless steel ※4 ; Carbon steel

  4. 400 SUS CS SUS 200 Film amount （μｇ/cm2） Base metal corrosion -200 CS 3．Problem of Hi-F Coat for CS Hi-F Coat procedure for SS is not applicable for CS. 【Procedure of Hi-F Coat】 Heat-up 【Problem of film formation】 KMnO4 Oxidation C2H2O4 N2H4 ＨＯＰ method Reduction, clean-up Repeat Decomposition, clean-up Fe（HCOO）2 H2O2 N2H4 Hi-F Coat treatment Hi-F Coat method Decomposition Final clean-up

  5. BM 4．Idea for Hi-F Coat procedure for CS Higher pH is a key parameter to reduce CS corrosion. 【Procedure of film formation for SS】 【Idea for film formation】 0.4 Pure water H2O2 & N2H4 Countermeasure 0.3 Fe(HCOO)2 7 ・Low corrosion at higher pH 6 Film formation CS corrosion rate（g/m2/h） 0.2 Solution pH (-) 5 4 Apply to CS 0.1 ・Surface corrosion ・No film BM 0 8 3 4 5 6 7 Time Solution pH (-) BM ; Base Metal

  6. 5．Conditions of film formation 【Experimental apparatus】 【Injection order and pH】 Pure water１ℓ N2 gas pH N2bubbling Heat up（90℃） Test piece Chemicals TP Reaction Start 3 hours 90℃ Mixed chemicals 8 Film formation Fｅ(HCOO)2 New method 7 Analysis pH （-） 6 Analysis method ・Crystal structure・・・・X ray deflection ・Binding status・・・・XPS ・Film structure・・・・SEM ・Film composition・・・・Raman spectrum 　　　　　　 ・・・・Auger spectrum 5 Ni金属皮膜形成 Former 4 N2H4, H2O2

  7. 6．Film amount Thenew method enables to make a enough film amount on CS. 300 Ｈｉ-Ｆ Coat film Target film amount (90μg/cm2) 200 2μm CS 100 0 Weight change （μｇ/cm2） -100 -200 -300 New method Former

  8. 7．Detail analysis of formed film Fine mono layer of polycrystalline Fe3O4 was identified. 【Cross section】 【Film composition】 Identified as Fe3O4 Formed film Protect film for work Fe3O4 Fe(OH)3 Formed film Relative strength Fe2O3 CS 2μm 200 600 800 400 Raman shift (cm-1) 【Crystal structure】 【Binding status】 Existing ratio agrees with Fe3O4 Polycrystalline Fe3O4 Fe2+ Fe3+ Relative strength Relative strength 700 710 730 10 20 30 40 720 50 70 80 90 100 60

  9. 8．Co deposition test conditions Test was performed under simulated NWC conditions. Test conditions（NWC） Pressure Control Valve Cooler Demi. Test section E. C. DO P Hx. P

  10. 9Weight change Weight gain of CS was reduced to about 1/4 under simulated NWC. 9

  11. 10Co-60 deposition Co-60 deposition on CS was reduced to about 40% under simulated NWC.

  12. 10Summary Film formation method on CS was studied in order to reduce corrosion and Co-60 deposition and its effect was confirmed. 【Results】 　　・Film formation was realized by reducing CS corrosion. 　　・Target film amount of 90 μg/cm2 was realized. 　　・Weight gain was reduced to about 1/4 by Hi-F coat film under simulated NWC. 　　・Deposition amount of Co-60 was reduced to about 40% by Hi-F coat film under simulated NWC. 11

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