2. 0 Zinc Injection from Hot Functional Test in Tomari Unit 3 Nov. 2008 MITSUBISHI HEAVY INDUSTRIES, LTD. HOKKAIDO ELECTRIC POWER CO., INC

3. 1 Tomari Unit 1 Tomari Unit 2 Tomari Unit 3 Summary of Tomari PS

4. 2 Location of Tomari PS  Northern Part of Japan : Hokkaido Island

5. Summary of Tomari PS- ３ Rated Electrical Output ： 912MWe Reactor Type ： PWR （ 3Loop Plant ） Hot Function Test: It is from September to November 2008. Core loadings : Scheduled in February, 2009 Commercial Operation: Scheduled in December, 2009

6. HFT （ Hot Function Test ） ・ HFT is performed from Sep. 2008 to Nov.2008. ・ Before core loading, RCS temperature is raised to about 300 o C that is near operational temperature. And operational status of every equipment is confirmed. ・ Because RCS temperature is raised, corrosion occurs on SG tube etc.. Therefore water chemistry control is needed.

7. Trend of annual radiation exposure of advance nations. (per unit) ● JAPAN ■ USA ▲ Germany × French

8. 6 Reduction of dose rate of workers 1) Reduction of dose rate (Use of Improved material, water chemistry control ） 2) Longer distance from radiation source, or use of shield 3) Shorter time of work （ Automatic equipment or use of robot ）

9. 7 Radiation reduction (radiation source reduction) countermeasures Suppression of corrosion Promotion of removal Low Co content material for SG tubing and SS material Hydrogen and LiOH chemistry during HFT Extreme low hydrogen control (outer layer removal) chemistry Zircaloy grid 690TT for SG tubing File pore size pre-filter in CVCS line Increase of CVCS flow rate during shutdown operation pH control during power operation Zinc injection Suppression of transport Material Improvement Water chemistry improvement Purification system reinforcement Water chemistry Improvement

10. 8 Suppression of corrosion 1) Improvement of material Low Co content material for SG tubing and SS material 690TT for SG tube was used in Tomari unit 3 2) Improvement of water chemistry control Improvement of water chemistry control during hot function test (HFT) Zinc injection from HFT

11. 9 Improved HFT water chemistry control In usual HFT chemistry, deaerated water was used. In 1988, improved HFT chemistry (hydrogen + lithium addition) was at first adopted in Tomari unit 1. This is the first case in Japan.

12. 10 Improvement of water chemistry control during hot function test (HFT) Amount of corrosion reduced under H 2 + Li condition. (alloy 600TT) E. Yamada et al., 1991 JAIF Conference

13. 11 Improvement of water chemistry control during hot function test Reduction of dose rate (ex. Tomari unit 1) E. Yamada et al., 1991 JAIF Conference  The first annual inspection, dose rate was decreased about 10%.

14. 12 Zinc injection Zinc injection mechanism Zinc intake preferably occurs in inner oxide and replaces cobalt site.

15. 13 Status of zinc injection In 1994, zinc injection was started in Farley-2 (USA) Recently, in Tsurga unit 2 and other plant also start zinc injection. By adopting zinc injection, reduction of dose rate can be about 50%

16. 14 Zinc injection in test operation In 2000, Angra-2 (Brazil) Zinc injection was started after 2 days later of initial critical, and dose rate decreased remarkably.

17. 15 Zinc injection beginning of hot function test in Tomari unit 3 Amount of corrosion on SG tube (Ni base alloy) reduced by zinc injection at start of HFT  Reduction of Ni amount generated from SG  Reduction of Co-58 generated from Ni  Reduction of dose rate from Co-58  Reduction of dose rate is assumed to be about 10%.

18. 16  Adoption of improved HFT chemistry (hydrogen + lithium addition) was decided.  Adoption of zinc injection beginning of hot functional test was decided. Water chemistry control of Tomari unit 3 during HFT

19. Zinc injection plan Point of zinc injection (*) (*)

20. 18 Plan of zinc injection Equipment of zinc injection

21. 19 Zinc concentration control Zinc injection without oxide film is the first experience. Zinc injection rate was considered based on zinc amount (composition) of NUPEC’s out-of-pile test*. Zinc injection rate was decided after many discussions between Hokkaido Electric power and MHI. (*OGAWA et al. BNES 8, 2000) Plan of zinc injection

22. 20 Example of injection rate HFT period Plan of zinc injection Injection rate is gradually decreased. Temperature ( o C) Injection rate (g/h) Elapsed time

23. 21 Future plan ・ Comparison of corrosion product concentration and dose rate between Tomari unit 3 and reference plant (without zinc injection).