2006 Asian ISOE ALARA Symposium OCCUPATIONAL EXPOSURE at

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

Contents 1. General Status of NPPs in Japan 2. Analysis of Exposure in FY 2005 3. Improvement on Inspection Way 2

Nuclear Power Plants in Japan as of March 31, 2006 In Operation Under Construction On Planning BWR PWR Total No. of Units 32 23 55 Output (MWe) 30, 214 19, 366 49, 580 No. of Units 1 1 2 Output (MWe) 1, 373 912 2, 285 No. of Units 9 2 11 Output (MWe) 11, 869 3, 076 14, 945 3

Nuclear Power Plants in Japan Shika 志賀 in Operation (PWR 23, BWR 32) as of March 31, 2006 55 Units Oma Fugen ふげん ( Namie Kodaka Tomari (2003 ) (on a decommissioning stage since 年より廃止措置準備中 2003) Kashiwazaki- kariwa Higashi Dori 2 Monju (FBR)) TEPCOHigashi Dori Tsuruga 敦賀 1 2 Mihama Onagawa 女川 Fukushima 福島第一 Daiichi 7 8 Fukushima Daini Oi Tokai Takahama ３ (On the decommissioning stage since 1998) Tokai No. 2 Shimane Kaminoseki Hamaoka Genkai Sendai 出力規模 Output scale 50 万k. Wthan 未満 Less 500, 000 k. W Less 100 万k. Wthan 未満 1, 000 k. W More than 100 万k. W 以上 1, 000 k. W In operation Under Construction On planning stage 5 Ikat a Total 55 Units 49, 580 MWe 合計 出力 47, 122 MWe (PWR 53基 23 units, BWR 32 units ) 4

Trend of Capacity Factor in Japanese plants 5

Occupational Exposure in 2005 Fiscal Year (April 2005 – March 2006) Plants Units Person-Sv /Unit BWR ３２ ４４．５１ １．３９ PWR ２３ ２２．３０ ０．９７ GCR １ ０．１０ Total ５６ ６６．９１ １．２１ (LWR) 6

Individual Dose in 200５ Fiscal Year (April 2005 – March 2006) Plants Units Persons BWR ３２ ４４，２９７ １．０ PWR ２３ ２１，８００ １．０ GCR １ １，３５１ ０．１ Total ５６ ６６，３２２ １．０ m. Sv /Person 7

Trend of BWR Exposure per in Japanese plants Unit 8

Trend of PWR Exposure per in Japanese plants Unit 9

Trend of Maintenance Exposure at Japanese BWRs 10

Trend of Maintenance Exposure at Japanese PWRs 11

BWR Average Exposure per Unit by Country 12

PWR Average Exposure per Unit by Country 13

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

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

５ -year Dose Reduction Goals in USA 2005 2010 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 Factor 91 92 Forced Loss Rate 2. 0 1. 0 Automatic Scram <1. 0 <0. 5 2 or 2. 5 0 0 Chemical Index 1. 10 1. 01 Industrial Safety Accident Rate 0. 30 0. 20 Safety System % Unavailability Fuel Defects ( )2005 Quarter 3 Performance 16

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

Dose Rate at PLR Piping in both Japanese BWR and US BWR Median: 0. 89 m. Sv/h Number Median: 1. 55 m. Sv/h Japan: 2000. 12 -2003 USA : 2005. 1 m. Sv/h at PLR Piping 18

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

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

Mandatory System Reactor Cooling System Inspection Items in Japanese PWRs Disassembled Inspection ISI No Equipments or Components ○ 1 Category One & Three Mechanism ○ 2 Category Three Piping in Reactor Containment Vessel ○ 3 Pressurize Safety Valves ○ 4 Pressurize Relief Valves ○ 5 High Pressure Injection System Pumps & Valves ○ 6 Low Pressure Injection System Pumps & Valves ○ 7 Accumulator Injection System Valves ○ 8 Component Cooling System Pumps ○ 9 Main Steam Safety Valves ○ ○ 10 Main Steam Relief Valves 11 Main Steam Isolation Valves ○ 1 Boric Acid Pumps ○ 1 ○ 2 PCV Isolation Valves PCV Spray Pumps & Valves Diesel Power Generator ○ 1 Emergency Diesel Power Generator Turbine ○ 1 Turbine Instrument & Control System PCV ○ 21

Improvement on Inspection Way NISA submitted the draft report “ Improvement on Inspection Way for Nuclear Facilities ” September 2006. (Utilities) Maintenance program ・Condition-directive maintenance ・Time-based maintenance ・Online maintenance Approval NISA (Applied in 2008) 22

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. 23

Thank you for your attention !! 24

Source Term Reduction Measures in Japanese BWRs Measures Crud Reduction Co Reduction Applied plants O 2 Injection All Plants Condensate Filters 29/31 Improved Material (Weatherability Steel) for Condensate System 21/31 Improved Material (Low Alloy Steel) for Feed Water Heater Shells All Improved Material（Low Cobalt ) for Reactor Core Structures All Plants Improved Material (Low Cobalt) for Feed Water Heating System 25/31 Plants 25

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