Wikipedia

Shika Nuclear Power Plant

The Shika Nuclear Power Plant (志賀原子力発電所, Shika genshiryoku hatsudensho, Shika NPP) is a nuclear power plant located in the town of Shika, Ishikawa, Japan. It is owned and operated by the Hokuriku Electric Power Company. It consists of two units with a total capacity of 1.746 GW on a site that is 1.6 km2 (395 acres).[1] Both units were put in a temporary shutdown in the wake of the 2011 Fukushima Daiichi nuclear disaster and received safety upgrades to comply with stricter regulatory requirements. As of 2023, Hokuriku aims to restart the plant in 2026.

Shika Nuclear Power Plant
Map
CountryJapan
Coordinates37°03′40″N 136°43′35″E / 37.06111°N 136.72639°E / 37.06111; 136.72639
StatusOut of service
Construction beganJuly 1, 1989 (1989-07-01)
Commission dateJuly 30, 1993 (1993-07-30)
Operator(s)Hokuriku Electric Power Company
Nuclear power station
Reactor type1 x BWR
1 x ABWR
Cooling sourceSea of Japan
Power generation
Units operational1 x 540 MW
1 x 1206 MW
Nameplate capacity1746 MW
Capacity factor0
Annual net output0 GW·h
External links
Websitewww.rikuden.co.jp/atomic/
CommonsRelated media on Commons
[edit on Wikidata]

The Hokuriku Technology Museum on nuclear power is located next to the plant site.

History

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Construction

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Construction of the first unit was started on July 1, 1989, and finished in three years. The reactor reached its first criticality on November 20, 1992, and went into commercial operation on July 30, 1993.[2] Construction of the second unit was started on August 20, 2001, and finished in three years. The reactor reached its first criticality on May 26, 2005, and went into commercial operation on March 15, 2006.[3] Both units use boiling water reactors from Hitachi.

Operation

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Unit 1 supplied an average of 3600 GWh of electricity to the grid yearly during the first ten years of operation with a peak production of 4432 GWh in 1997.[4]

The 1999 incident and cover-up

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On June 18, 1999, during an inspection, an emergency control rod insertion was to be performed on Unit 1. One rod was to be inserted into the reactor, however, three control rods fell by accident.[5] For the next 15 minutes, the reactor was in a critical state, an unintended self-sustaining nuclear fission chain reaction.[6] This incident was covered up by the operator, and was not revealed until March 15, 2007.[7]

Unit 1 was subsequently shut down from March 2007 to March 2009, during judicial and bureaucratic evaluation.[8] In April 2007 the event had been provisionally categorized as an INES level-2 incident.[9] A lower court had ordered the entire plant to be shut down, but that decision was later overturned by Nagoya's high court. The utility put in a request to the Ishikawa prefectural government and the town of Shika for the restart of unit 1.[10] The unit returned to power on May 11, 2009, and resumed commercial operation on May 13.[11]

Unit 2 reached a peak yearly electricity production of 9279 GWh in 2010.

Temporary shutdown

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Following the 2011 Fukushima nuclear accident, the plant was temporarily shut down in March 2011 to make changes in order to comply with new regulatory requirements.[12]

Construction of a reinforced concrete wall that should shield the reactors against a possible tsunami was started in October 2011. The wall was designed 4 meters high and 700 meters long, 11 meters above sea level. This was done to comply with extra governmental instructions ordered after the Fukushima accident. Next to this a new drainage gate was installed to minimize damage to plant facilities in case seawater would be able to climb over the wall and would submerge the plant. Other emergency safety measures included the installing of an extra pump to cool the reactors with seawater and an extra power source to operate a valve for venting steam out of reactors. Construction was expected to be completed by the end of March 2013.[13]

After finishing the safety upgrades, permission for the restart of unit 2 from the Nuclear Regulation Authority (NRA) was first sought in August 2014.[14] The NRA safety review was however delayed considerably over the determination of whether there are active geological faults underneath the site, which lasted until March 2023, when it was concluded that there are no such faults. Following these results, Hokuriku Electric submitted an application with a plan to restart unit 2 in early 2026. Unit 1 is to follow soon afterwards.[12][15] Earlier, the NRA had reached a unanimous decision not to seek further opinion from experts who raised concerns of the faults being active.[16]

The 2024 Noto Earthquake

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In January 2024 the plant was closest to a magnitude 7.6 earthquake in Ishikawa Prefecture, and survived the event with no major damage. Some water from a spent fuel pool spilled over during the earthquake.[17]

Following the Noto earthquake, the operator said the cooling pool water level "has not changed significantly" after the spillage of more than 400 litres at Units 1 and 2, and that it "did not impact radiation levels outside."[18]

The plant's transformers were also damaged by the quake, leaving it "unable to receive electricity from outside".[19]

On 10 January, a second oil leak "in several gutters surrounding the main transformer of the No.2 reactor" was reported, as well a second "oil slick measuring about 100 meters by 30 meters" on the sea in front of the power plant.[20] "In addition to the loss of the two external power sources [...] some 23,400 litres of oil leaked when transformers for both the No. 1 and 2 reactors were damaged," the Mainichi reported.[21] Following the incident, the plant's former construction site manager has claimed the plant should be decommissioned.[22]

On 17 April, NHK reported that a section of the No.1 reactor control system had been dislodged by the quake, and that the Nuclear Regulation Authority chairperson instructed the operator for constructural improvements.[23]

Evacuation plans have since been questioned, with the majority of the Ishikawa prefecture designated routes for resident to flee the 30-km radius were cut off, leaving communities isolated.[24]

Lawsuit

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On 13 May 2024, Kanazawa District Court held a hearing on a case, in which the plaintiffs are seeking the plant's decommission.[25][26]

Reactors on site

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Unit Type Commission date Electric Power Thermal Power Maker
Shika – 1 BWR-5 July 30, 1993[2] 540 MW 1,593 MW Hitachi
Shika – 2 ABWR March 15, 2006[3] 1,358 MW 3,926 MW Hitachi

See also

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References

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  1. ^ Hokuriku Power. Shika NPP information sheet.
  2. ^ a b "Shika 1, Japan". World Nuclear Association.
  3. ^ a b "Shika 2, Japan". World Nuclear Association.
  4. ^ "SHIKA-1". Power Reactor Information System.
  5. ^ "Japanese utility to shut reactor after admitting accident cover-up". The New York Times. 2007-03-15. ISSN 0362-4331. Retrieved 2024-06-24.
  6. ^ "Japan utility to keep nuclear units shut in '07/08". Reuters. 10 August 2007. Retrieved 25 June 2024.
  7. ^ Aldhous, Peter; Iovino, Zena (18 March 2011). "Japan's record of nuclear cover-ups and accidents". New Scientist. Retrieved 25 June 2024.
  8. ^ "Shika 1 restarted for tests". World Nuclear News. 2009-03-30.
  9. ^ "Shika 1 criticality rated at INES 2". world-nuclear-news.org. 2007-04-23. Retrieved 2017-03-06.
  10. ^ Reuters. Japan's Hokuriku seeks local OK for nuclear restart. March 18, 2009.
  11. ^ NucNet. Japan’s Shika-1 Returns To Service Archived 2011-10-04 at the Wayback Machine. May 22, 2009.
  12. ^ a b "Shika 2, Japan". www.world-nuclear.org. Retrieved 5 January 2024.
  13. ^ JAIF (5 October 2011)Earthquake-report 226: Construction of seawall begins at nuclear plant Archived 2011-10-28 at the Wayback Machine
  14. ^ "Safety review sought for Shika 2". World Nuclear News. 2014-08-12.
  15. ^ "Hokuriku Elec puts plan to restart Shika No.2 reactor in 2026 in price hike application". Reuters. 2023-10-24.
  16. ^ "Japan regulator bypasses experts in declaring faults under nuclear plant not active". Mainichi.jp. 16 March 2023. Retrieved 24 June 2024.
  17. ^ "'No abnormalities' reported at Japanese nuclear plants following earthquake". World Nuclear News. 2024-01-02.
  18. ^ "Shika Nuclear Power Staion after the 2024 Noto Peninsula Earthquake". www.rikuden.co.jp. Retrieved 2024-06-24.
  19. ^ Kobayashi, Yuki (12 March 2024). "The Problems of Nuclear Energy Use by Japan Raised Again by the Noto Peninsula Earthquake". The Sasakawa Peace Foundation. Retrieved 24 June 2024.
  20. ^ "Japan's Hokuriku Elec reports second oil leak from Shika nuclear plant". Reuters.com. 10 January 2024. Retrieved 24 June 2024.
  21. ^ "Generator fails in test at Japan's Shika nuclear power plant after Noto quake". Mainichi Daily News. 2024-01-18. Retrieved 2024-06-24.
  22. ^ "志賀原発、建設現場の元責任者が「廃炉にしたほうが…」 能登地震での変圧器トラブル「油漏れは大問題」". tokyo-np.co.jp (in Japanese). 14 May 2024. Retrieved 24 June 2024.
  23. ^ "志賀原発1号機 部品の一部 外れているのが見つかる 地震影響か". NHK - Japan Broadcasting Corporation. 17 April 2024. Retrieved 24 June 2024.
  24. ^ "Noto quake exposes flaws in planning for nuclear disasters". The Asahi Shimbun. 22 March 2024. Retrieved 25 June 2024.
  25. ^ "「避難計画は破たん」志賀原発運転差し止め求める 能登半島地震後初の口頭弁論・金沢地裁 | TBS NEWS DIG (1ページ)". TBS News (in Japanese). 13 May 2024. Retrieved 24 June 2024.
  26. ^ "「原発造ること自体間違い」 元規制委員 志賀訴訟原告団の総会". The Chunichi Shimbun (in Japanese). 26 May 2024. Retrieved 24 June 2024.
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