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DATA: Significant incidents at Nuclear Facilities (2001)

Date Facility Brief Description of Event
Jan 15 Fukushima II-1 Reactor manually shutdown due to rupture of coolant flow measurement housing tube at jet pump.
Mar 4 Takahama-2 Power reduction due to steam leak into high pressure fead-water heater drain line.
Apr 5 Kashiwazaki-Kariwa-5 Control rod manual operation system failed due to integrated circuit abnormality.
Apr 19 Takahama-1 Reactor power manually lowered due to coolant leak caused by 2 heat exchange tube ruptures in high pressure feed water heater.
May 7 Fukushima II-2 Reactor manually shutdown due to failure of shutting check valve during residual heat removal system inpection.
May 23 Fugen Reactor manually shutdown due to tritium leak at helium circular system piping.
May 24 Fukushima I-6 Radioactivity leak found at fuel assembly during intermediate periodic inspection.
June 18 Kashiwazaki-Kariwa-6 Reactor manually shutdown due to coolant leak at reactor auxiliary cooling system valve.
July 6 Takahama-3 Damage to 17 steam generator tubes found during periodic inspection.
July 6 Fukushima II-3 Cracks found on core shroud lower ring during periodic inspection.
July 8 Kashiwazaki-Kariwa-5 Control rod manual operation system failed due to integrated circuit abnormality.
July 13 Kashiwazaki-Kariwa-5 Control rod manual operation system failed due to integrated circuit abnormality.
July 21 Kashiwazaki-Kariwa-7 Radioactivity leak found in fuel assembly.
July 27 Kashiwazaki-Kariwa-6 Control rod manual operation system failed due to integrated circuit abnormality.
Aug 10 Rokkasho repro. 1.6 tons of coolant leak from pool coolant system heat exchanger outlet valve at spent fuel storage pool.
Sep 8 Ikata-2 145 cracks found on reactor core monitor housing tubes due to chloride induced stress corrosion cracking during periodic inspection.
Sep 10 Kashiwazaki-Kariwa-4 Ruptures and cracks found on regenerated heat exchanger tubes during periodic inspection.
Sep 19 Kashiwazaki-Kariwa-5 Control rod manual operation system failed due to integrated circuit abnormality.
Sep 25 Onagawa-2 Reactor manually shutdown due to coolant leak from degraded recirculation pump mechanical sealing.
Oct 31 Joyo Fire at maintenance building during sodium cleaning operation.
Nov 1 Fukushima II-2 Reactor automatically shutdown due to high signal of reactor neutron flux during reactor start up operation.
Nov 7 Hamaoka-1 Reactor manually shutdown due to pipe rupture in residual heat removal system steam condense mode line caused by detonation of radiolysis gases during start-up test at high pressure core injection system pump.
Nov 9 Hamaoka-1 Reactor coolant leak due to crack of stub tube welding attached to control rod drive mechanism housing.
Dec 10 Tokai II Reactor power reduced to 65 % of full capacity due to lowered reactor water level caused by abnormality of water flow control integrated circuit during maintenance in feed water pump system.
Dec 28 Rokkasho repro. Coolant leak from PWR spent fuel storage pool.

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