| DATE |
Operator |
Facility Name |
Type |
Short Description of Incidents |
| Feb. 7 |
JNFL (Japan Nuclear Fuel Limited) |
Rokkasho Reprocessing Plant |
Reprocessing Plant |
Leak detected at fuel assembly transfer pit |
| Feb. 12 |
Kansai-EPCO |
Takahama-1 |
Pressurized Water Reactor (PWR) |
During periodic inpection crack found at neutron flux monitor nozzle (made of Inconel 600) mounted to reactor vessel bottom |
| Feb. 18 |
Shikoku-EPCO |
Ikata-1 |
PWR |
Leak detected at chemical volume control tank outlet piping |
| Feb. 27 |
JAPC (Japan Atomic Power Company) |
Tsuruga-1 |
Boiling Water Reactor (BWR) |
Reactor manually shut down due to leak detected at mechanical seals of recirculation pumps (B and C) |
| Feb. 27 |
Tokyo-EPCO |
Kashiwazaki-Kariwa-3 |
BWR |
Cracks found at welds of primary loop recirculation system piping (made of SUS316L) during planned stoppage |
| Feb. 28 |
Tokyo-EPCO |
Fukushima I-3 |
BWR |
Control rod interlock cancelation found at ‘one control rod draw check’ during periodic inspection |
| March 4 |
Tokyo-EPCO |
Fukushima I-3 |
BWR |
A control rod insertion delayed at ‘control rod insertion/draw examination’ during periodic inspection |
| March 5 |
Tokyo-EPCO |
Fukushima II-1 |
BWR |
Foreign metal material found at the top of a nuclear fuel assembly during periodic inspection |
| March 10 |
Chubu-EPCO |
Hamaoka-3 |
BWR |
Cracks found at welds of core shroud (made of SUS316L) middle and lower region during periodic inspection; cracks found at inside surface of H4 position, at outside surface of H6a position, at inside surface of H7 position, etc. |
| March 27 |
Tokyo-EPCO |
Kashiwazaki-Kariwa-4 |
BWR |
Cracks found at 6 welds of primary loop recirculation system piping (made of SUS316L) during periodic inspection |
| April 16 |
Tokyo-EPCO |
Fukushima II-1 |
BWR |
Cracks found at a weld between reactor pressure vessel nozzle safe-end pipe (made of SUS316L) and primary loop recirculation system piping (made of SUS304L) during periodic inspection |
| April 17 |
Chubu-EPCO |
Hamaoka-3 |
BWR |
Cracks found at welds of primary loop recirculation system piping (made of SUS316L) during periodic inspection |
| April 17 |
Chubu-EPCO |
Hamaoka-4 |
BWR |
Cracks found at welds of primary loop recirculation system piping (made of SUS316L) during periodic inspection |
| April 29 |
Chugoku-EPCO |
Shimane-2 |
BWR |
Cracks found at welds of core shroud (made of SUS316L) middle region during periodic inspection; cracks found at inside surface of H4 position |
| May 8 |
Kansai-EPCO |
Mihama-2 |
PWR |
Generator power reduced due to leak at 5th high pressure feed water heater |
| May 12 |
Tokyo-EPCO |
Kashiwazaki-Kariwa-5 |
BWR |
Cracks found at welds of primary loop recirculation system piping (made of SUS316L) during periodic inspection |
| May 15 |
Kyushu-EPCO |
Sendai-1 |
PWR |
Damage to 15 steam generator tubes during periodic inspection |
| May 20 |
Tokyo-EPCO |
Kashiwazaki-Kariwa-5 |
BWR |
Cracks found at welds of core shroud (made of SUS316L) middle region during periodic inspection; cracks found at inside surface of H4 position and of V14 position |
| May 21 |
Kansai-EPCO |
Mihama-3 |
PWR |
Cracks found at reactor vessel bottom mounted conduit tube during periodic inspection |
| May 22 |
Kansai-EPCO |
Takahama-4 |
PWR |
Damage to 2 steam generator tubes during periodic inspection |
| May 26 |
Tohoku-EPCO |
Onagawa-3 |
BWR |
Reactor automatically shutdown due to ‘large ground acceleration’ signal set off by an earthquake (magnitude 7.0) |
| May 28 |
Tokyo-EPCO |
Fukushima II-3 |
BWR |
Cracks found at guide roller installed area of a control rod handle during periodic inspection |
| June 9 |
Tohoku-EPCO |
Onagawa-2 |
BWR |
Cracks found at welds of core shroud (made of SUS316L) middle region and lower region during periodic inspection; cracks found at outside surface of H3 position and at inside surface of H7a position |
| June 10 |
Chubu-EPCO |
Hamaoka-1 |
BWR |
Cracks found at a weld of core shroud (made of SUS304) lower region during periodic inspection; cracks found at inside surface of H7b position |
| June 14 |
Tokyo-EPCO |
Fukushima II-3 |
BWR |
Fuel assemblies installation operation stopped due to lack of a control rod at a fuel cell during periodic inspection |
| June 16 |
Chubu-EPCO |
Hamaoka-1 |
BWR |
Cracks found at upper region of a weld of the core shroud (made of SUS304) during periodic inspection; crack found near upper lattice plate base |
| June 23 |
Tohoku-EPCO |
Onagawa-2 |
BWR |
Cracks found at a weld of primary loop recirculation system piping (made of SUS316L) during periodic inspection |
| June 24 |
JAPC |
Tsuruga-1 |
BWR |
Cracks found at surface of control rod blades during periodic inspection |
| July 4 |
JNC (Japan Nuclear Cycle Development Institute) |
Fugen |
Advanced Thermal Reactor |
Fire alarm set off at waste treatment building; window of low-level radioactive waste incinerator broken due to explosion and 460 million bequerels of radioactive ash leaked |
| July 8 |
JNC |
Joyo |
Experimental Fast Reactor |
Reactor automatically shut down due to ‘neutron flux high’ signal |
| July 15 |
Tokyo-EPCO |
Fukushima II-2 |
BWR |
Cracks found at welds of primary loop recirculation system piping (made of SUS316L) during periodic inspection |
| July 24 |
Tokyo-EPCO |
Fukushima I-2 |
BWR |
Leak found at instrumentation outlet of residue heat removal system during periodic inspection |
| July 29 |
Hokuriku-EPCO |
Shika-1 |
BWR |
Cracks found at welds of primary loop recirculation system piping (made of SUS316L)during periodic inspection (also on Aug. 26 and on Sep. 3) |
| July 31 |
Tokyo-EPCO |
Fukushima II-2 |
BWR |
Cracks found at welds of core shroud (made of SUS316L) middle region during periodic inspaction; cracks found at outside surface of H4 position |
| Aug. 1 |
Tohoku-EPCO |
Onagawa-2 |
BWR |
Cracks found at welds of primary loop recirculation system piping (made of SUS316L)during periodic inspection |
| Sep. 7 |
Hokkaido-EPCO |
Tomari-2 |
PWR |
Leak found at regenerated heat exchanger; reactor manually shut down for inspection on Sep. 11 |
| Sep. 10 |
JAPC |
Tsuruga-2 |
PWR |
Build up of boric acid powder and cracks found at welds of pressurizer relief valve nozzle and of pressurizer safety valve nozzle during periodic inspection |
| Oct. 6 |
Tohoku-EPCO |
Onagawa-2 |
BWR |
Leak detected at containment vessel sump; damage found at mechanical seals of recirculation inlet pump and of recirculation outlet pump during periodic inspection |
| Oct. 6 |
Tokyo-EPCO |
Fukushima II-4 |
BWR |
Cracks found at guide roller installed area of control rod handles and at surface of control rod blades during periodic inspection |
| Oct. 7 |
Tokyo-EPCO |
Kashiwazaki-Kariwa-7 |
BWR |
Cracks found at impellers of reactor internal pumps during periodic inspection |
| Oct. 9 – Nov. 7 |
Tokyo-EPCO |
Fukushima I-1,2,3,4,6 |
BWR |
Various foreign materials (scaffolding members, clamps, vinyl sheet chips, vinyl tape chips, ropes, spanner, pen, etc.) found in suppression chambers during periodic inspection |
| Oct. 14 |
Chugoku-EPCO |
Shimane-1 |
BWR |
Spacers slippage found at fuel assemblies during periodic inspection |
| Oct. 14 – Nov. 7 |
Tokyo-EPCO |
Kashiwazaki-Kariwa-1,2,3,5,7 |
BWR |
Various foreign materials (vinyl sheet chips, ropes, electromoved grinder, pliers, dust mask, video tape, boot, heat insulating materials, etc.) found in suppression chambers during periodic inspection |
| Oct. 16 – Nov. 7 |
Tokyo-EPCO |
Fukushima II-1,2,3,4 |
BWR |
Various foreign materials (vinyl sheet chips, vinyl tape chips, ropes, spanner, pen, etc.) found in suppression chambers during periodic inspection |
| Oct. 17 |
Shikoku-EPCO |
Ikata-3 |
PWR |
Emergency diesel generator activation failed at start-up operation |
| Oct. 22 |
Kansai-EPCO |
Takahama-2 |
PWR |
Reactor manually shut down due to steam leak from 3rd low-pressure turbine inlet flange during conditioning operation |
| Oct. 22 |
Tokyo-EPCO |
Fukushima II-4 |
BWR |
Crack found at weld of primary loop recirculation system piping (made of SUS316L) during periodic inspection |
| Nov. 5 |
Tokyo-EPCO |
Kashiwazaki-Kariwa-2 |
BWR |
One part of cleaning device fell into reactor vessel during core shroud cleaning test operation during periodic inspection |
| Nov. 6 |
Tohoku-EPCO |
Onagawa-2 |
BWR |
Various foreign materials (wire, vinyl sheet chips, vinyl tape chips, ropes, miniature lamp, etc.) found in suppression chambers during periodic inspection |
| Nov. 9 |
Kansai-EPCO |
Mihama-2 |
PWR |
Reactor manually shut down due to primary coolant leak found at cap of bent line attached to pressurizer spray piping |
| Nov. 18 |
Tokyo-EPCO |
Fukushima I-6 |
BWR |
One part of cleaning device fell into reactor vessel during control rod drive mechanism housing tub tube cleaning operation during periodic inspection |
| Nov. 19 |
Chubu-EPCO |
Hamaoka-2 |
BWR |
SCRAM signal set off accidentally due to ocsillation in value indicated by average power range monitor |
| Nov. 22 |
Chubu-EPCO |
Hamaoka-1 |
BWR |
One part of cleaning device fell into reactor vessel during core shroud support cylinder cleaning operation during periodic inspection |
| Nov. 25 |
Chubu-EPCO |
Hamaoka-1 |
BWR |
Cracks found at welds of core shroud support cylinder and of core shroud support legs during periodic inspection |
| Dec. 2 |
Chugoku-EPCO |
Shimane-1 |
BWR |
A worker exposed due to inhalation of 917 bequerels of cobalt-60 during containment vessel head installation operation |
| Dec. 5 |
Kansai-EPCO |
Ohi-1 |
PWR |
Reactor manually shut down due to leak from mechanical seal of primary coolant pump |
| Dec. 5 |
Tokyo-EPCO |
Fukushima I-6 |
BWR |
Leak found at water level gauge tube opening during periodic inspection |
| Dec. 18 |
Chubu-EPCO |
Hamaoka-1 |
BWR |
Cracks found at welds of jet pumps during periodic inspection |
| Dec. 19 |
JAPC |
Tsuruga-1 |
BWR |
Reactor automatically shut down due to lightning |
| Dec. 20 |
Tokyo-EPCO |
Fukushima I-6 |
BWR |
Stress reduction device stopped during operation to reduce stress on control rod drive mechanism housing stub tubes during periodic inspection |
| Dec. 26 |
JAPC |
Tsuruga-1 |
BWR |
Leak detected at mechanical seal of recirculation pump; reactor manually shut down on Dec. 28 |
