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Significant Incidents at Nuclear Power Plants
and Nuclear Fuel Facilities in 2002

Date Operator/ Owner Facility Name Type Short Description of Events
Jan. 30 KEPCO Takahama 4 PWR Damage to steam generator tube found during periodic inspection.
Mar. 4 TEPCO Kashiwazaki-Kariwa 1 BWR Reactor manually shut down due to coolant leak found caused by crack in shaft seal ring of recirculation pump motor
Mar. 7 Tohoku-EPCO Onagawa 2 BWR Coolant leak detected at condenser coolant flux measurement pipe during periodic inspection; 8cm crack found in welds of two measurement pipes.
Mar. 31 JAPCO Tokai II BWR Reactor automatically shut down due to transmission line stoppage caused by lightning; one of 185 control rods failed to insert into reactor core.
Apr. 2 Hokuriku-EPCO Shika 1 BWR Reactor manually shut down due to recirculation pump shaft oscillation during test operation.
Apr. 3 JAPCO Tokai II BWR Reactor manually shut down due to feedwater stopped during test operation; one control rod failed to insert into reactor core.
Apr. 18 Shikoku-EPCO Ikata 1 PWR Primary coolant pump shut down due to reactor containment sump water level increased alarm followed primary coolant pump shaft oscillation increased alarm during periodic inspection.
Apr. 21 JNC Fugen ATR Reactor manually shut down due to level of noble gasses storage equipment monitoring system and level of off-gasses chimney monitoring system during test operation; leak found at two special fuel assemblies.
Apr. 26 TEPCO Kashiwazaki-Kariwa 7 BWR Radioactive leak found at two fuel assemblies during periodic inspection.
May 5 TEPCO Kashiwazaki-Kariwa 3 BWR Reactor power manually reduced due to condenser vacuum rate lowered caused by turbine control equipment failed.
May 14 TEPCO Kashiwazaki-Kariwa 7 BWR Cracks found at reactor internal recirculation pump propeller during periodic inspection.
May 25 Chubu-EPCO Hamaoka 2 BWR Reactor manually shut down due to water leak from residual heat removal system low pressure injection pipe isolation valve drain piping weld during reactor start-up operation.
May 31 Shikoku-EPCO Ikata 3 PWR Leak found at heat exchange tube of feedwater heater during periodic inspection.
Jun. 4 JNC Tokai site PFFF Workers exposed to plutonium during glove exchange operation of glove box at plutonium fuel processing facility.
Jun. 20 Tohoku-EPCO Onagawa 2 BWR Reactor manually shut down due to increased water leak from recirculation pump mechanical seal.
Jun. 20 Shikoku-EPCO Ikata 2 PWR Containment vessel off-gasses monitoring system stopped due to filtration system being stuck.
Aug. 22 TEPCO Fukushima I-3 BWR Cracks found at control rod drive pressurized water system piping around contaiment vessel penetration area.
Aug. 23 TEPCO Kashiwazaki-Kariwa 3 BWR Cracks found at welds of core shroud on (made of SUS316L) lower region during periodic inspection; 360 degree crack found at outside surface of H6a position, and at inside surface of H7a position each.
Sep. 2 TEPCO Fukushima II-2 BWR Reactor manually shut down due to level of off-gasses radiation monitoring system increased.
Sep. 13 JNFL Rokkasho Repro. Repro. Mistake found at connection of piping in ventilation system.
Sep. 19 Chubu-EPCO Hamaoka 4 BWR Cracks found at welds of core shroud (made of SUS316L) lower region during periodic inspection; 360 degree crack found at outside surface of H6a position, and at inside surface of H7a position each.
Sep. 20 Tohoku-EPCO Onagawa 1 BWR Cracks found at welds of primary loop recirculation system piping(made of SUS316L) during periodic inspection.
Sep. 20 Chubu-EPCO Hamaoka 1/3 BWR Incident not available until Sep. 20, 2003; cracks found at welds of primary loop recirculation system piping (made of SUS316L) during former periodic inspection at Unit 1 and at Unit 3.
Sep. 20 TEPCO Kashiwazaki-Kariwa 1 BWR Cracks found at welds of primary loop recirculation system piping (made of SUS316L) during inspection outage.
Sep. 23 Tohoku-EPCO Onagawa 1 BWR Cracks found at welds of core shroud (made of SUS304L) middle and lower region during periodic inspection; cracks found at outside surface of H2 position and at outside surface of H6a position.
Sep. 30 Hokkaido-EPCO Tomari 1/2 PWR Significant wastage found at maintenance boiler tubes.
Sep. 30 Tohoku-EPCO Onagawa 1 BWR Wastage found at residual heat removal system welds during periodic inspection.
Oct. 3 TEPCO Fukushima II-2 BWR Cracks found at welds of core shroud (made of SUS316L) middle region during planned inspection; cracks found at inside surface of H3 position and at inside and outside surface of H4 position.
Oct. 5 TEPCO Kashiwazaki-Kariwa 1 BWR Cracks found at welds of core shroud (made of SUS316L) middle region during periodic inspection; cracks found at inside and outside surface of H3 position and at inside surface of H4 position.
Oct. 11 TEPCO Fukushima I-4 BWR Cracks found at control rod drive pressurized water system piping around contaiment vessel penetration area.
Oct. 13 TEPCO Fukushima I-4 BWR Cracks found at welds of core shroud (made of SUS316L) middle region during inspection outage; cracks found at inside surface of H4 position.
Oct. 21 Tohoku-EPCO Onagawa 1 BWR Cracks found at core spray nozzles during periodic inspection.
Oct. 23 TEPCO Fukushima II-3 BWR Cracks found at welds of core shroud (made of SUS316L) middle region during inspection outage; cracks found at inside surface of H3 position and at inside surface of H4 position.
Oct. 23 JAPCO Tokai II BWR recirculation flux control valve component lapsed and missed.
Oct. 24 JNFL Rokkasho Repro. Repro. Leaks and cracks found at spent fuel storage pool welds.
Oct. 30 Chubu-EPCO Hamaoka 4 BWR Cracks found at welds of primary loop recirculation system piping (made of SUS316L) during periodic inspection.
Oct. 31 TEPCO Fukushima II-4 BWR Cracks found at welds of core shroud (made of SUS316L) middle region during inspection outage; cracks found at inside surface of H3 position and at inside and outside surface of H4 position.
Nov. 15 KEPCO Mihama 1 PWR Reactor manually shut down due to primary coolant valve leak rate increased; cracks found at sea water drain pipes.
Nov. 25 JNFL Rokkasho Uranium Enrichment Plant Enrich. Homogenizing operation automatically stopped due to anti-overheat interlock system triggered by uranium hexafluoride cylinder temparature increased at RE-1 line homogeneous vessel.
Nov. 26 TEPCO Fukushima II-4 BWR Cracks found at welds of primary loop recirculation system piping (made of SUS316L) during inspection outage.
Dec. 3 TEPCO Kashiwazaki-Kariwa 2 BWR Cracks found at welds of primary loop recirculation system piping (made of SUS316L) during inspection outage.
Dec. 5 TEPCO Kashiwazaki-Kariwa 2 BWR Cracks found at welds of core shroud (made of SUS316L) top, middle and lower region during planned outage; cracks found at outside surface of H1 position and 360 degree crack found at outside surface of H6a position and at inside surface of H7a position.
Dec. 12 JAPCO Turuga 2 PWR Rector manually shut down due to fire at turbine building; pipe insulation substace fired.
Dec. 14 Tohoku-EPCO Onagawa 1 BWR Leak found at insturmentaion nozzle during periodic inspection.
Dec. 18 TEPCO Fukushima II-3 BWR Cracks found at welds of primary loop recirculation system piping (made of SUS316L) during inspection outage.
Dec. 26 TEPCO Fukushima II-2 BWR Cracks found at welds of primary loop recirculation system piping (made of SUS316L) during inspection outage.

TEPCO: Tokyo Electric Power Co.
JNC: Japan Nuclear Cycle Developent Institute 
KEPCO: Kansai Electric Power Co.
Tohoku-EPCO: Tohoku Electric Power Co.
JAPCO: Japan Atomic Power Co.
Hokuriku-EPCO: Hokuriku Electric Power Co.
JNFL: Japan Nuclear Fuel Limited
Shikoku-EPCO: Shikoku Electric Power Co.
Chubu-EPCO: Chubu Electric Power Co.
Hokkaido-EPCO: Hokkaido Electric Power Co.

ATR: Advanced Thermal Reactor
BWR: Boiling Water Reactor
PWR: Pressurized Water Reactor
PFFF: Plutonium Fuel Fabrication Facility
Repro.: Spent Fuel Reprocessing Plant
Enrich.: Uranium Enrichment Plant

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