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2006 Asian ISOE ALARA Symposium. OCCUPATIONAL EXPOSURE at JAPANESE NUCLEAR POWER PLANTS in 2005. October 12, 2006 Shigeyuki Wada Safety Information D i vision Japan Nuclear Energy Safety Organization (JNES). Contents. General Status of NPPs in Japan Analysis of Exposure in FY 2005
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2006AsianISOEALARASymposium OCCUPATIONALEXPOSUREatJAPANESENUCLEARPOWERPLANTSin2005 October12, 2006 ShigeyukiWada Safety Information Division Japan Nuclear Energy Safety Organization(JNES)
Contents • General Status of NPPs in Japan • Analysis of Exposure in FY 2005 • Improvement on Inspection Way
Nuclear Power Plants in Japan as of March 31, 2006
Shika 志賀 Oma Namie Kodaka Fugen ふげん Tomari (2003 ) (on a decommissioning stage since 2003) 年より廃止措置準備中 Kashiwazaki- kariwa Higashi Dori Monju 2 2 (FBR)) (FBR)) ( ( Higashi Dori TEPCO TEPCO Onagawa 女川 Tsuruga 敦賀 2 2 1 1 Fukushima Daiichi 福島第一 Mihama 8 8 7 7 Fukushima Daini Oi Tokai Takahama (On the decommissioning stage since 1998) Tokai No. 2 3 Shimane Kaminoseki Hamaoka 5 5 5 5 5 Ikata Genkai Sendai 出力規模 Output scale In operation Total 55 Units 49,580MWe Under Construction 合計 53 基 出力 47,122MWe (PWR 23 units, BWR 32 units ) Less than More than 50 kW 万 未満 Less than 100 kW 100 kW 万 未満 万 以上 On planning stage 500,000kW 1,000,000kW 1,000,000kW Nuclear Power Plants in Japan 55 Units in Operation (PWR 23, BWR 32) as of March 31, 2006
BWRThreeYearRollingAveragebyPlantinUSAandJapan Fukushimamaiich
5-year Dose Reduction GoalsinUSA ( )2005 Quarter 3 Performance
Dose Rate at PLR Piping in both Japanese BWR and US BWR Median:0.89 mSv/h Median:1.55 mSv/h Number Japan:2000.12-2003 USA :2005.1 mSv/h at PLR Piping
Operation Period and Maintenance Period by Countryfrom1994to2004 OperationPeriod(days) Capacity Factor 90% Capacity Factor 80% MaintenancePeriod(days) ◆USA ■Finland ▲Korea ×Japan жSwitzerland ●Belgium
MandatoryInspection Items in JapaneseBWRs * *Shall be inspected within 13months after former inspection
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)
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.