2010 ISOE Asia ALARA Symposium Development of HiF

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 コピーライトの表示については、作成元で責任を持って適宜変更してください。 ⇒ © Hitachi-GE Nuclear Energy, Ltd. 2010. All rights reserved.

１．Application result of Hi-F Coat for SS Low recontamination by Hi-F Coat was confirmed for Stainless Steel. Dose rate of PLR inlet piping（m. Sv/h) 5 NWC HWC 4 PLR（A) Point 1 Point 2 PLR（B) NWC preoxidation operation 3 Pipe replacement Chemical decon. Hi-F Coat NWC preoxidation (90 days） Shroud replacement Chemical decon. 2 1 0 17 18 19 20 Hi-F Coat ; Hitachi Ferrite Coating NWC ; Normal water chemistry HWC ; Hydrogen water chemistry 21 22 23 24 Number of outage（-） 25 26 27 28 M. Nagase, et al. , 2009 ISOE Asian ALARA Symposium © Hitachi-GE Nuclear Energy, Ltd. 2010. All rights reserved. 1

2．Enlargement of Hi-F Coat application area CUW piping is one of the biggest sources of radiation exposure. 【Countermeasure to reduce recontamination】 60 Co No treatment in oxide film Operation Decon. Recontamination Reduction Hi-F Coat Principal: Reduction of 60 Co deposition by reducing base metal corrosion 【System and its countermeasure】 System RRS※ 1 RWCU※ 2 Material SS※ 3 SS CS※ 4 Problem ・RI deposition ・Corrosion Countermeasure Ｈｉ-Ｆ No method after chemical decon. ※ 1 ; Reactor recirculation system ※ 2 ; Reactor water clean up ※ 3 ; Stainless steel ※ 4 ; Carbon steel © Hitachi-GE Nuclear Energy, Ltd. 2010. All rights reserved. 2

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 C 2 H 2 O 4 N 2 H 4 Reduction, clean-up Repeat Fe（HCOO）2 H 2 O 2 Hi-F Coat treatment N 2 H 4 Decomposition Final clean-up Hi-F Coat method Decomposition, clean-up 400 Film amount （μｇ/cm 2） Oxidation ＨＯＰ method KMn. O 4 【Problem of film formation】 SUS CS 200 -200 Base metal corrosion CS © Hitachi-GE Nuclear Energy, Ltd. 2010. All rights reserved. 3

4．Idea for Hi-F Coat procedure for CS Higher p. H is a key parameter to reduce CS corrosion. 【Procedure of film formation for SS】 【Idea for film formation】 Solution p. H (-) Pure water 7 H 2 O 2 & N 2 H 4 Fe(HCOO)2 6 Film formation 5 4 Apply to CS ・Surface corrosion BM ・No film Time CS corrosion rate（g/m 2/h） 0. 4 0. 3 Countermeasure ・Low corrosion BM at higher p. H 0. 2 0. 1 0 3 4 5 6 Solution p. H (-) 7 8 BM ; Base Metal © Hitachi-GE Nuclear Energy, Ltd. 2010. All rights reserved. 4

5．Conditions of film formation 【Experimental apparatus】 TP 90℃ p. H Pure water１ℓ N 2 bubbling Heat up（90℃） Test piece Chemicals Reaction Start 3 hours Film formation Analysis method ・Crystal structure・・・・X ray deflection ・Binding status・・・・XPS ・Film structure・・・・SEM ・Film composition・・・・Raman spectrum ・・・・Auger spectrum Former New method 8 Chemical conc. (ppm) 1 2 3 Ｆｅ(HCOO)2 N 2 H 4 H 2 O 2 (15) (300) (600) Mixing all chemicals in advance Mixed chemicals Fｅ(HCOO)2 p. H （-） N 2 gas 【Injection order and p. H】 7 New method 6 5 Ni金属皮膜形成 Former 4 N 2 H 4 , H 2 O 2 © Hitachi-GE Nuclear Energy, Ltd. 2010. All rights reserved. 5

6．Film amount The new method enables to make a enough film amount on CS. Weight change （μｇ/cm 2） 300 200 Ｈｉ-Ｆ Coat film Target film amount (90μg/cm 2) CS 2μm 100 0 -100 -200 -300 Former New method © Hitachi-GE Nuclear Energy, Ltd. 2010. All rights reserved. 6

7．Detail analysis of formed film Fine mono layer of polycrystalline Fe 3 O 4 was identified. 【Film composition】 Identified as Fe 3 O 4 Formed film CS Relative strength 【Crystal structure】 2μm Polycrystalline Fe 3 O 4 BM 10 20 30 40 50 60 70 80 90 100 Formed film Fe 3 O 4 Fe(OH)3 Fe 2 O 3 200 600 800 400 -1 Raman shift (cm ) 【Binding status】 Existing ratio agrees with Fe 3 O 4 Relative strength Protect film for work Relative strength 【Cross section】 700 Fe 2+ Fe 3+ 710 720 730 © Hitachi-GE Nuclear Energy, Ltd. 2010. All rights reserved. 7

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 Hx. P P Temperature 280 ℃ Time 500 h Pressure 7. 8 MPa Concentration (ppb) DO 100 DH 10 H 2 O 2 200 Cr 5 Co-60 30 © Hitachi-GE Nuclear Energy, Ltd. 2010. All rights reserved. 8

9 Weight change Weight gain of CS was reduced to about 1/4 under simulated NWC. © Hitachi-GE Nuclear Energy, Ltd. 2010. All rights reserved. 9

10 Co-60 deposition on CS was reduced to about 40% under simulated NWC. © Hitachi-GE Nuclear Energy, Ltd. 2010. All rights reserved. 10

10 Summary 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/cm 2 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. © Hitachi-GE Nuclear Energy, Ltd. 2010. All rights reserved. 11

© Hitachi-GE Nuclear Energy, Ltd. 2010. All rights reserved. 12