1 Dose reduction actions in Tsuruga-2 NPP Hiroshi WADA, Yuuichi HAMANAKA, Masayuki FUKUDA Tomomi YOSHINAGA, Eiji SANEHIRA,Masahiro YANO, Yasuo UNI, Kazushige HAYASHI Fumitoshi NAKAO The Japan Atomic Power Company NUCLEAR PLANT SERVICE ENGINEERING Co.,Ltd ISOE International ALARA Symposium 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 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 2008 ISOE International ALARA Symposium 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 Outline of JAPC ’ s NPP Tsuruga-1 (BWR) 357 MW Tokai II (BWR) 1,100 MWe Tsuruga-3 and 4 (PWR) (Currently planed) JAPC Total 2,617 MWe Tsuruga-2 (PWR) 1160 MW Tokai (GCR) (Decomi. phase) 2008 ISOE International ALARA Symposium 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 Outline of Tsuruga-2 NPP 2008 ISOE International ALARA Symposium 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. Entering into the reactor containment is limited in operation condition. Many equipments containing radioactivity are opened every periodical outage for inspection or maintenance.

5 Transition of dose in Tsuruga ISOE International ALARA Symposium 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 Dose reduction action so far (1/4) Design and Construction phase Commercial operation phase Action to hardware and software Recent action 2008 ISOE International ALARA Symposium 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 Dose reduction action so far (2/4) Action in design and Construction phase 2008 ISOE International ALARA Symposium 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 Dose reduction action so far (3/4) Action in operation phase(1/2) 2008 ISOE International ALARA Symposium 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 Dose reduction action so far (4/4) Action in operation phase(2/2) 2008 ISOE International ALARA Symposium 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 Recent action to hardware 2008 ISOE International ALARA Symposium 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 Recent action to software 2008 ISOE International ALARA Symposium JAPC Contractor RPMaintenance RP Work plan Desig n Prediction, Assessmen t Rad. work plan Shielding, Decon. Check, Revie w Cost plan Review of work contents and radiation dose Validity check /review Work Plan Annual dose Disapproval Work control Radiation control Approval Work Start 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 Steam (to turbine) From condenser From reactor to reactor SCC at nozzle welds SGSG 2008 ISOE International ALARA Symposium Action to large-scale work (1/5) (SG nozzle stub weld mending) MCP* (High dose rate) SG lower shell (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 SG lower shell (High dose rate) MCP* (High dose rate) Elbow replacemen t SG coolant inlet nozzle Nozzle stub Cutting Contaminate d * MCP: Main Coolant Pipe Contaminated 2008 ISOE International ALARA Symposium Action to large-scale work (2/5) (Work plan) 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.

ISOE International ALARA Symposium Action to large-scale work (3/5) (Planned dose) 1600 man- mSv (planned) Shielding Decontamination Automatic and remote equipment Mock-up training 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.

ISOE International ALARA Symposium Action to large-scale work (4/5) (action plan based on 1100 man-mSv) Cutting off elbow MCP Shielding (additional) Decontamination (additional) Shielding (additional) 24 mSv/h 6 mSv/h 4.7 mSv/h 3.7 mSv/h 2.8 mSv/h 1.5 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.

ISOE International ALARA Symposium Action to large-scale work (5/5) (Reexamined plan ) 1600 man- mSv (planned) 1100 man- mSv (approved) Additional shielding Additional decontamination Shielding Decontamination Automatic and remote equipment Mock-up training 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 Situation of countermeasure for reducing radiation exposure 2008 ISOE International ALARA Symposium 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 Situation of installation of shield （ 1/3 ） screen-type shield Screen-type shield for watchmen Decontamination of MCP and SG nozzle inner surface Screen-type shield Shiel d 2008 ISOE International ALARA Symposium 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 Situation of installation of shield （ 2/3 ） Shielding for MCP Nozzle inside Shielding for SG nozzle inside ・ Shield for MCP nozzle inside Shield for SG nozzle inside 2008 ISOE International ALARA Symposium 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 Situation of installation of shield （ 3/3 ） ・ Shield for RHR/SIS piping Cold-leg, Charge, Boric acid injection, Accumulator injection piping RHR piping 2008 ISOE International ALARA Symposium 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.

ISOE International ALARA Symposium Result of dose rate reduction Cutting off elbow MCP 24 mSv/h 6 → - mSv/h 4.7 → 9.0 mSv/h 3.7 → 6.0 mSv/h 2.8 → 1.6 mSv/h 1.5 → 0.9 mSv/h Shielding (additional) Shielding (additional) 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 Situation of training by using mock-up Installation of cutting machine Installation of beveling machine 2008 ISOE International ALARA Symposium 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 Wireless monitoring unit of the E.P.D Enable working without relying on the alarm 2008 ISOE International ALARA Symposium 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 Result 2008 ISOE International ALARA Symposium ～ 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 Conclusion (1/2) 2008 ISOE International ALARA Symposium Effective shielding and decontamination based on technical evaluation Strictly mock-up training in works Maintenance section is very cooperative for the matter which radiological protection 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 Conclusion (2/2) 2008 ISOE International ALARA Symposium 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.