Dose reduction actions in Tsuruga-2 NPP

1. 2008 ISOE International ALARA Symposium Dose reduction actions in Tsuruga-2 NPP The Japan Atomic Power Company Hiroshi WADA, Yuuichi HAMANAKA, Masayuki FUKUDA Tomomi YOSHINAGA, Eiji SANEHIRA,Masahiro YANO, Yasuo UNI, Kazushige HAYASHI Fumitoshi NAKAO NUCLEAR PLANT SERVICE ENGINEERING Co.,Ltd. The following materials may contain JAPC’s proprietary and confidential information; and all or any part of these materials or information contained herein may NOT be used for any purposes other than originally intended or may NOT be reproduced, disclosed, transferred, distributed or in any manner transmitted in any tangible, electronic or any other form to any third party without prior written consent thereto by JAPC.

2. 2008 ISOE International ALARA Symposium Contents • Outline of JAPC • Transition of dose in Tsuruga-2 NPP • Dose reduction actions so far • Action to large-scale work • Situation of countermeasure for reducing radiation exposure • Electric personnel dosimeter • Conclusion The following materials may contain JAPC’s proprietary and confidential information; and all or any part of these materials or information contained herein may NOT be used for any purposes other than originally intended or may NOT be reproduced, disclosed, transferred, distributed or in any manner transmitted in any tangible, electronic or any other form to any third party without prior written consent thereto by JAPC.

3. 2008 ISOE International ALARA Symposium Outline of JAPC’s NPP Tsuruga-1 (BWR) 357 MW Tsuruga-2 (PWR) 1160 MW Tokai (GCR) (Decomi. phase) Tsuruga-3 and 4 (PWR) (Currently planed) Tokai II (BWR) 1,100 MWe JAPC Total 2,617 MWe The following materials may contain JAPC’s proprietary and confidential information; and all or any part of these materials or information contained herein may NOT be used for any purposes other than originally intended or may NOT be reproduced, disclosed, transferred, distributed or in any manner transmitted in any tangible, electronic or any other form to any third party without prior written consent thereto by JAPC.

4. 2008 ISOE International ALARA Symposium Reactor containment Steam generator (SG) △ △ △ △ △ To turbine ▲ pressurizer △ From condensor Cold leg MCP Nuclear reactor Ｒ △ Outline of Tsuruga-2 NPP • Entering into the reactor containment is limited in operation condition. • Many equipments containing radioactivity are opened every periodical outage for inspection or maintenance. The following materials may contain JAPC’s proprietary and confidential information; and all or any part of these materials or information contained herein may NOT be used for any purposes other than originally intended or may NOT be reproduced, disclosed, transferred, distributed or in any manner transmitted in any tangible, electronic or any other form to any third party without prior written consent thereto by JAPC.

5. 2008 ISOE International ALARA Symposium Transition of dose in Tsuruga-2 The following materials may contain JAPC’s proprietary and confidential information; and all or any part of these materials or information contained herein may NOT be used for any purposes other than originally intended or may NOT be reproduced, disclosed, transferred, distributed or in any manner transmitted in any tangible, electronic or any other form to any third party without prior written consent thereto by JAPC.

6. 2008 ISOE International ALARA Symposium Dose reduction action so far (1/4) • Design and Construction phase • Commercial operation phase • Action to hardware and software • Recent action The following materials may contain JAPC’s proprietary and confidential information; and all or any part of these materials or information contained herein may NOT be used for any purposes other than originally intended or may NOT be reproduced, disclosed, transferred, distributed or in any manner transmitted in any tangible, electronic or any other form to any third party without prior written consent thereto by JAPC.

7. 2008 ISOE International ALARA Symposium Dose reduction action so far (2/4) • Action in design and Construction phase The following materials may contain JAPC’s proprietary and confidential information; and all or any part of these materials or information contained herein may NOT be used for any purposes other than originally intended or may NOT be reproduced, disclosed, transferred, distributed or in any manner transmitted in any tangible, electronic or any other form to any third party without prior written consent thereto by JAPC.

8. 2008 ISOE International ALARA Symposium Dose reduction action so far (3/4) • Action in operation phase(1/2) The following materials may contain JAPC’s proprietary and confidential information; and all or any part of these materials or information contained herein may NOT be used for any purposes other than originally intended or may NOT be reproduced, disclosed, transferred, distributed or in any manner transmitted in any tangible, electronic or any other form to any third party without prior written consent thereto by JAPC.

9. 2008 ISOE International ALARA Symposium Dose reduction action so far (4/4) • Action in operation phase(2/2) The following materials may contain JAPC’s proprietary and confidential information; and all or any part of these materials or information contained herein may NOT be used for any purposes other than originally intended or may NOT be reproduced, disclosed, transferred, distributed or in any manner transmitted in any tangible, electronic or any other form to any third party without prior written consent thereto by JAPC.

10. 2008 ISOE International ALARA Symposium Recent action to hardware The following materials may contain JAPC’s proprietary and confidential information; and all or any part of these materials or information contained herein may NOT be used for any purposes other than originally intended or may NOT be reproduced, disclosed, transferred, distributed or in any manner transmitted in any tangible, electronic or any other form to any third party without prior written consent thereto by JAPC.

11. 2008 ISOE International ALARA Symposium Recent action to software Contractor JAPC RP Maintenance Maintenance RP Review of work contents and radiation dose Disapproval Work plan Design Work Plan Annual dose Shielding, Decon. Prediction, Assessment Cost plan Validity check /review Check, Review Rad. work plan Work Start Approval Work control Radiation control Possibility of planned dose significant exceedance The following materials may contain JAPC’s proprietary and confidential information; and all or any part of these materials or information contained herein may NOT be used for any purposes other than originally intended or may NOT be reproduced, disclosed, transferred, distributed or in any manner transmitted in any tangible, electronic or any other form to any third party without prior written consent thereto by JAPC.

12. 2008 ISOE International ALARA Symposium Action to large-scale work (1/5)(SG nozzle stub weld mending) Steam (to turbine) SG From condenser SG lower shell (High dose rate) SCC at nozzle welds From reactor to reactor MCP* (High dose rate) * MCP: Main Coolant Pipe The following materials may contain JAPC’s proprietary and confidential information; and all or any part of these materials or information contained herein may NOT be used for any purposes other than originally intended or may NOT be reproduced, disclosed, transferred, distributed or in any manner transmitted in any tangible, electronic or any other form to any third party without prior written consent thereto by JAPC.

13. 2008 ISOE International ALARA Symposium Action to large-scale work (2/5)(Work plan) SG coolant inlet nozzle SG lower shell (High dose rate) Nozzle stub MCP* (High dose rate) Contaminated Contaminated Cutting Contaminated Elbow replacement Cutting * MCP: Main Coolant Pipe The following materials may contain JAPC’s proprietary and confidential information; and all or any part of these materials or information contained herein may NOT be used for any purposes other than originally intended or may NOT be reproduced, disclosed, transferred, distributed or in any manner transmitted in any tangible, electronic or any other form to any third party without prior written consent thereto by JAPC.

14. 2008 ISOE International ALARA Symposium Action to large-scale work (3/5)(Planned dose) Shielding Decontamination Automatic and remote equipment Mock-up training 1600 man-mSv (planned) The following materials may contain JAPC’s proprietary and confidential information; and all or any part of these materials or information contained herein may NOT be used for any purposes other than originally intended or may NOT be reproduced, disclosed, transferred, distributed or in any manner transmitted in any tangible, electronic or any other form to any third party without prior written consent thereto by JAPC.

15. 2008 ISOE International ALARA Symposium Action to large-scale work (4/5)(action plan based on 1100 man-mSv) 24 mSv/h Shielding (additional) MCP 4.7 mSv/h 6 mSv/h Cutting off elbow Decontamination (additional) Shielding (additional) 3.7 mSv/h 1.5 mSv/h 2.8 mSv/h The following materials may contain JAPC’s proprietary and confidential information; and all or any part of these materials or information contained herein may NOT be used for any purposes other than originally intended or may NOT be reproduced, disclosed, transferred, distributed or in any manner transmitted in any tangible, electronic or any other form to any third party without prior written consent thereto by JAPC.

16. 2008 ISOE International ALARA Symposium Action to large-scale work (5/5)(Reexamined plan ) Shielding Decontamination Automatic and remote equipment Mock-up training 1600 man-mSv (planned) Additional shielding Additional decontamination 1100 man-mSv (approved) Dose for additional dose reduction ～ 20 man-mSv The following materials may contain JAPC’s proprietary and confidential information; and all or any part of these materials or information contained herein may NOT be used for any purposes other than originally intended or may NOT be reproduced, disclosed, transferred, distributed or in any manner transmitted in any tangible, electronic or any other form to any third party without prior written consent thereto by JAPC.

17. 2008 ISOE International ALARA Symposium Situation of countermeasure for reducing radiation exposure • Situation of installation of shield The following materials may contain JAPC’s proprietary and confidential information; and all or any part of these materials or information contained herein may NOT be used for any purposes other than originally intended or may NOT be reproduced, disclosed, transferred, distributed or in any manner transmitted in any tangible, electronic or any other form to any third party without prior written consent thereto by JAPC.

18. screen-type shield Screen-type shield for watchmen 2008 ISOE International ALARA Symposium Situation of installation of shield （1/3） Decontamination of MCP and SG nozzle inner surface Screen-type shield Shield The following materials may contain JAPC’s proprietary and confidential information; and all or any part of these materials or information contained herein may NOT be used for any purposes other than originally intended or may NOT be reproduced, disclosed, transferred, distributed or in any manner transmitted in any tangible, electronic or any other form to any third party without prior written consent thereto by JAPC.

19. Shielding for MCP Nozzle inside Shielding for SG nozzle inside 2008 ISOE International ALARA Symposium Situation of installation of shield （2/3） ・Shield for MCP nozzle inside Shield for SG nozzle inside The following materials may contain JAPC’s proprietary and confidential information; and all or any part of these materials or information contained herein may NOT be used for any purposes other than originally intended or may NOT be reproduced, disclosed, transferred, distributed or in any manner transmitted in any tangible, electronic or any other form to any third party without prior written consent thereto by JAPC.

20. ・Shield for RHR/SIS piping 2008 ISOE International ALARA Symposium Situation of installation of shield （3/3） Cold-leg, Charge, Boric acid injection, Accumulator injection piping RHR piping The following materials may contain JAPC’s proprietary and confidential information; and all or any part of these materials or information contained herein may NOT be used for any purposes other than originally intended or may NOT be reproduced, disclosed, transferred, distributed or in any manner transmitted in any tangible, electronic or any other form to any third party without prior written consent thereto by JAPC.

21. 2008 ISOE International ALARA Symposium Result of dose rate reduction 24 mSv/h MCP Cutting off elbow 6 → - mSv/h 4.7 → 9.0 mSv/h Shielding (additional) Shielding (additional) 1.5 → 0.9 mSv/h 3.7 → 6.0 mSv/h 2.8 → 1.6 mSv/h The following materials may contain JAPC’s proprietary and confidential information; and all or any part of these materials or information contained herein may NOT be used for any purposes other than originally intended or may NOT be reproduced, disclosed, transferred, distributed or in any manner transmitted in any tangible, electronic or any other form to any third party without prior written consent thereto by JAPC.

22. 2008 ISOE International ALARA Symposium Situation of training by using mock-up Installation of beveling machine Installation of cutting machine The following materials may contain JAPC’s proprietary and confidential information; and all or any part of these materials or information contained herein may NOT be used for any purposes other than originally intended or may NOT be reproduced, disclosed, transferred, distributed or in any manner transmitted in any tangible, electronic or any other form to any third party without prior written consent thereto by JAPC.

23. 2008 ISOE International ALARA Symposium Wireless monitoring unit of the E.P.D • Enable working without relying on the alarm Detail will be shown in another presentation of JAPC. The following materials may contain JAPC’s proprietary and confidential information; and all or any part of these materials or information contained herein may NOT be used for any purposes other than originally intended or may NOT be reproduced, disclosed, transferred, distributed or in any manner transmitted in any tangible, electronic or any other form to any third party without prior written consent thereto by JAPC.

24. 2008 ISOE International ALARA Symposium Result ～1100 ～990 The following materials may contain JAPC’s proprietary and confidential information; and all or any part of these materials or information contained herein may NOT be used for any purposes other than originally intended or may NOT be reproduced, disclosed, transferred, distributed or in any manner transmitted in any tangible, electronic or any other form to any third party without prior written consent thereto by JAPC.

25. 2008 ISOE International ALARA Symposium Conclusion (1/2) • Effective shielding and decontamination based on technical evaluation • Strictly mock-up training in works • Maintenance section is very cooperative for the matter which radiologicalprotection section recommends in JAPC and MHI. The following materials may contain JAPC’s proprietary and confidential information; and all or any part of these materials or information contained herein may NOT be used for any purposes other than originally intended or may NOT be reproduced, disclosed, transferred, distributed or in any manner transmitted in any tangible, electronic or any other form to any third party without prior written consent thereto by JAPC.

26. 2008 ISOE International ALARA Symposium Conclusion (2/2) • Positive inflection of the machinery automation and remoteness • Carrying out the radiation survey finely and limit an entrance to work area strictly • System which cooperated from a plan stage of the construction has begun to be seen. The following materials may contain JAPC’s proprietary and confidential information; and all or any part of these materials or information contained herein may NOT be used for any purposes other than originally intended or may NOT be reproduced, disclosed, transferred, distributed or in any manner transmitted in any tangible, electronic or any other form to any third party without prior written consent thereto by JAPC.