1 OCCUPATIONAL EXPOSURE at JAPANESE NUCLEAR POWER PLANTS in 2005 October 12, 2006 Shigeyuki Wada Safety Information Division Japan Nuclear Energy Safety Organization (JNES) 2006 Asian ISOE ALARA Symposium

2 1.General Status of NPPs in Japan 2.Analysis of Exposure in FY Improvement on Inspection Way Contents

3 Nuclear Power Plants in Japan BWRPWRTotal In Operation No. of Units Output (MWe) 30,21419,36649,580 Under Construction No. of Units 112 Output (MWe) 1, ,285 On Planning No. of Units 9211 Output (MWe) 11,8693,07614,945 as of March 31, 2006

4 55 Units in Operation (PWR 23, BWR 32) as of March 31, 2006 Nuclear Power Plants in Japan

5 Trend of Capacity Factor in Japanese plants

6 Occupational Exposure in 2005 Fiscal Year (April 2005 – March 2006) PlantsUnitsPerson-Sv /Unit BWR ３２４４．５１１．３９ PWR ２３２２．３００．９７ GCR １０．１０ Total ５６６６．９１１．２１ (LWR)

7 Individual Dose in 200 ５ Fiscal Year (April 2005 – March 2006) PlantsUnitsPersons mSv /Person BWR ３２４４，２９７１．０ PWR ２３２１，８００１．０ GCR １１，３５１０．１ Total ５６６６，３２２１．０

8 Trend of BWR Exposure per Unit in Japanese plants

9 Trend of PWR Exposure per Unit in Japanese plants

10 Trend of Maintenance Exposure at Japanese BWRs

11 Trend of Maintenance Exposure at Japanese PWRs

12 BWR Average Exposure per Unit by Country

13 PWR Average Exposure per Unit by Country

14 BWR Three Year Rolling Average by Plant in USA and Japan Fukushimamaiic h

15 PWR Three Year Rolling Average by Plant in USA and Japan

16 ５ -year Dose Reduction Goals in USA Exposure (BWR)1.20 person-Sv (1.65) 1.20 person-Sv Exposure (PWR)0.65 person-Sv (0.76) 0.60 person-Sv Capability Factor9192 Forced Loss Rate Automatic Scram<1.0<0.5 Safety System % Unavailability 2 or 2.5 Fuel Defects00 Chemical Index Industrial Safety Accident Rate ( )2005 Quarter 3 Performance

17 Dose Rate at PLR Piping in both Japanese BWR and US BWR

18 Dose Rate at PLR Piping in both Japanese BWR and US BWR mSv/h at PLR Piping Number Median:1.55 mSv/h Median:0.89 mSv/h Japan: USA :2005.1

19 Operation Period and Maintenance Period by Country from 1994 to 2004 Operation Period (days) ◆ USA ■ Finland ▲ Korea × Japan ж Switzerland ● Belgium Maintenance Period (days) Capacity Factor 90% Capacity Factor 80%

20 Mandatory Inspection Items in Japanese BWRs System Disassembled Inspection ISI No Equipment or Components ○ 1 Category One & Three Mechanism Reactor ○ 2Main Steam Safety Valve Cooling ○ 3Main Steam Relief Safety Valve System ○ 4High Pressure Injection System Pumps & Valves ○ 5 Residual Heat Removal （ RHR) Pumps & Vaves ○ 6 Core Spray Pumps & Valves ○ 7 Low Pressure Core Spray Pumps & Valves ○ 8 High Pressure Core Spray Pumps & Valves Instrument & ○ 1 CRD Mechanism Control System ○ 2 Scram Valves of Hydraulic Control Unit Pressure ○ 1 PCV Isolation Valves Containment ○ 2 PCV Spray Pumps & Valves Vessel (PCV) ○ 3 Flammability Control System Valves Diesel Power ○ 1 Emergency Diesel Power Generator Generator ○ 2 High Pressure Core Spray DG Turbine ○ 1 * * Shall be inspected within 13months after former inspection

21 Mandatory Inspection Items in Japanese PWRs System Disassembled Inspection ISINo Equipments or Components ○ 1 Category One & Three Mechanism Reactor ○ 2 Category Three Piping in Reactor Containment Vessel Cooling ○ 3Pressurize Safety Valves System ○ 4Pressurize Relief Valves ○ 5High Pressure Injection System Pumps & Valves ○ 6Low Pressure Injection System Pumps & Valves ○ 7 Accumulator Injection System Valves ○ 8Component Cooling System Pumps ○ 9Main Steam Safety Valves ○ 10Main Steam Relief Valves ○ 11Main Steam Isolation Valves Instrument & ○ 1 Boric Acid Pumps Control System ○ ○ 1 PCV Isolation Valves PCV ○ 2 PCV Spray Pumps & Valves Diesel Power Generator ○ 1 Emergency Diesel Power Generator Turbine ○ 1

22 Improvement on Inspection Way NISA submitted the draft report “ Improvement on Inspection Way for Nuclear Facilities ” September (Utilities) Maintenance program ・ Condition-directive maintenance ・ Time-based maintenance ・ Online maintenance NISA Approval (Applied in 2008)

23 Summary Japanese plants had 1.21 person-Sv/unit in 2005 which is lower than 2004 by 0.23 person-Sv. However it is still the highest level in the world. Japanese plants do not have much source term and perform relatively more maintenance work which may increase the exposure. NISA submitted the draft report for the improvement on inspection way including maintenance program with condition-directive maintenance and online maintenance etc. It is expected that the maintenance improvement will promote to decrease the exposure in Japanese plants.

24 Thank you for your attention !!

25 Source Term Reduction Measures in Japanese BWRs Measures Applied plants Crud Reduction O 2 InjectionAll Plants Condensate Filters29/31 Improved Material (Weatherability Steel) for Condensate System 21/31 Improved Material (Low Alloy Steel) for Feed Water Heater Shells All Plants Co Reduction Improved Material （ Low Cobalt ) for Reactor Core Structures All Plants Improved Material (Low Cobalt) for Feed Water Heating System 25/31

26 Source Term Reduction Measures in Japanese PWRs Measures Applied plants Crud Reduction pH ControlAll Plants Oxidation Operation in Shutdown Stage All Plants Clean-up Feed Water Operation in Shutdown Stage All Plants Co Reduction Improved Material （ Low Cobalt ) for Reactor Core Structures 18/23 Improved Material (Low Cobalt) of Steam Generators 21/23