Kashiwazaki Kariwa (Japan)

Map of Kashiwazaki Kariwa

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5 * 1100 MW BWR units; grid connection 1985-93
Units 6 and 7: 1300 MW ABWR; grid connection 1996

Facilities in Kashiwazaki Kariwa

plantreactor typconstruction startoperation startshut down
Kashiwazaki Kariwa 1BWR19801985
Kashiwazaki Kariwa 2BWR19851990
Kashiwazaki Kariwa 3BWR19871992
Kashiwazaki Kariwa 4BWR19901993
Kashiwazaki Kariwa 5BWR19851989
Kashiwazaki Kariwa 6ABWR19921996
Kashiwazaki Kariwa 7ABWR19921996

Restart of unit 7
After almost 22 months of checks and repairs, nuclear operations are about to restart at the earthquake-hit Kashiwazaki Kariwa site in Japan.

The nuclear power plant's seventh reactor is to start up again from 2pm on 9 May for a functional test of the entire power unit after approval from the mayors of Kawshiwazaki town, and Kariwa town as well as the governor of Niigata prefecture. Owner and operator Tokyo Electric Power Company (Tepco) made a promise to the leaders to make efforts to "disclose information" and "make safety the first priority."

The unit, a Advanced Boiling Water Reactor built by GE, Toshiba and Hitachi, is the newest at the site. It contributes 1315 MWe to the total of around 8000 MWe that makes Kashiwazaki Kariwa the biggest nuclear power plant in the world.

Tepco will be hopeful about bringing the all the reactors back into service after unit 7. The utility has suffered enormous bills for replacement power and fuel as well as geologic surveys, engineering, construction and repairs that prompted the first loss in it history. The company said it would "steadily address the confirmation of the soundness of the facilities, restoration works, seismic reinforcement works, etc without prejudice."

The plant was hit very hard by the 6.8 magnitude Niigata Chuetsu offshore earthquake of 16 July 2007. The earthquake exceeded the plant's design basis - the levels of ground acceleration it should essentially withstand and restart operation quickly after - but did not approach its safe shutdown basis, up to which environmental protection must be maintained in the most extreme circumstances.

At the time the earthquake struck three of the reactors were already shut down for maintenance, while the three in operation shutdown automatically as did one that was in the process of starting up. All of them remained in a safe state throughout the 6.8 magnitude earthquake, but there was widespread minor damage which necessitated absolutely exhaustive checks and many repairs. Some mildly radioactive cooling water was shaken from pools, many barrels of low-level waste were knocked over and an external transformer failed and caught fire. The site grounds also suffered, with widespread soil liquefaction and structural damage to office buildings.
(source: http://www.world-nuclear-news.org)

Concerning the restart of KK 7 there is a debate ongoing about serious problems that have not been resolved:
Some scientists believe that the design basis earthquake of M7.0 that NISA and NSC have approved was inadequate and that a DBA of M7.5 should be chosen instead. Also, some measurements of the ground level indicate that the plant was not built on firm ground. Some are also concerned that the casing of the coolant recirculation pump might not survive the next earthquake. A fire in unit 1 on March 5 increased the concerns of the local residents.
(source: nuclear monitor No. 688)


A fire occurred in the fifth underground floor RCIC pump room of the Number 1 reactor building a the Kashiwazaki-Kariwa nuclear power plant owned by Tokyo Electric Power Company (Tepco). The Japanese Nuclear and Industrial Safety Agency (Nisa) was informed of the fire and of one related injury; a slight burn to a worker extinguishing the fire. No release of radioactivity occurred.

The sequence of events was:

* At 8.57 am, Fire identified by detection system.
* At 8:59 am, TEPCO calls in fire fighters.
* At 10:36 am, Fire fighters confirm successful extinguishing of the fire.

Nisa implemented an on-the-spot inspection Kashiwazaki-Kariwa nuclear power plant on 6 March 2009. Nisa has issued a severe reprimand to Tepco and ordered an investigation and report on the cause and a preventive measures.
(source: world nuclear news)


" In KK-6 crosspins used at the drive axis universal joint of the overhead crane were damaged in three locations as a consequence of the Chuetsu-Oki Earthquake."
(source: http://cnic.jp/english)


" In KK-6 crosspins used at the drive axis universal joint of the overhead crane were damaged in three locations as a consequence of the Chuetsu-Oki Earthquake."
(source: http://cnic.jp/english)


A fire broke out in transformer 2B of KK-3 as a consequence of the Cuetsu-Oki Earthquake. From KK-6 water containing about 90,000 Bq of radioactive material, which leaked from the controlled area to the uncontrolled area, was discharged to sea.
(source: http://cnic.jp/english)
After this indicent "Officials from Tokyo Electric Power Co. and the Nuclear & Safety Agency said the seven reactors must be backfit to withstand seismic peak ground acceleration, or PGA, about four times greater than previously required. Moreover, a conclusion that several fault lines were involved in the 2007 quake, and not just one as had been assumed, could imply modification in the design basis of other Japanese nuclear power plants as well, some experts predicted.
The Cuetsu-Oki Earthquake registered 6.6 on the Richter scale and occured about 15 km (about 9.3 miles) from the K-K site.
(source: nucleonics week: volume 49)


"While preparing to shut down reactor 5 for periodic inspection, a deterioration of condensor vaccum caused the reactor to trip automatically. When switching operation of turbine gland sealing steam from the steam evaporator side to the auxiliary boiler side, the auxiliary boiler steam supply valve opened only 5%. The fault was not noticed and the operation was continued."
(source: http://cnic.jp/english/)


"Cracks found at KK-1 at welds of primary loop recirculation system piping (made of SUS316L) during inspection outage."
(source: http://cnic.jp/english/)


"Cracks found in KK-3 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."
(source: http://cnic.jp/english/)


"Cracks found at reactor KK-7 internal recirculation pump propeller during periodic inspection."
(source: http://cnic.jp/english/)


"Reactor KK-3 power manually reduced due to condenser vacuum rate lowered caused by turbine control equipment failed."
(source: http://cnic.jp/english/)


"Radioactive leak found at two fuel assemblies during periodic inspection at KK-7."
(source: http://cnic.jp/english/)


Reactor KK-1 manually shut down due to coolant leak found caused by crack in shaft seal ring of recirculation pump motor
(source: http://cnic.jp/english/)


Control rod manual operation system failed due to integrated circuit abnormality in KK-5.
(source: http://cnic.jp/english/)


Ruptures and cracks found on regenerated heat exchanger tubes during periodic inspection of KK-4.
(source: http://cnic.jp/english/)


Radioactivity leak found in fuel assembly of KK-7.
(source: http://cnic.jp/english/)


Control rod manual operation system failed due to integrated circuit abnormality at KK-5. Two weeks later the same problem occured in KK-6.
(source: http://cnic.jp/english/)


Reactor KK-6 manually shutdown due to coolant leak at reactor auxiliary cooling system valve.
(source: http://cnic.jp/english/)


"Control rod manual operation system of Kashiwazaki Kariwa 5 failed due to integrated circuit abnormality."
(source: http://cnic.jp/english/)


Kashiwazaki-Kariwa-7 by Tokyo Electric Power Co. (Tepco) and Onagawa-3 by Tohuku Electric Power Co. Kashiwazaki-Kariwa-7 was finished in 1996. Construction of Onagawa-3 got underway in 1996 and is expected to be finished in 2002. Tohuku also has approval for construction of Higashitori-1 but construction has not yet commenced.

Tepco officials said that Japan's biggest utility last year saw power demand increase by 3%. This year, given Japan's economic slump, demand growth is expected to be lower, unless a hoped-for increase in household consumption, led by more use of air conditioners, makes up for an anticipated lag in demand from Japanese industry.


Pin hole found in a fuel rod.


Troubles continue in the wolrd´s first ABWR

TEPCO´s Kashiwazaki-Kariwa 6, the world's first advanced boiling water reactor (ABWR, 1.356 MW) had to stop operation again during its trial run. The international pump trip which occurred in February was reported in NIT 52.
This time the cause of the trouble was a pin hole in the fuel rod. A rise in iodine concentration was detected in the primary coolant on August 19th, and on the 20th radioactivity level in the exhaust gas began to rise. Since the iodine concentration increased by a factor of 500 over the normal value on the 24th, showing a rising trend, the reactor's operation was manually suspended. It was the first time that this kind of trouble had occurred during a trial run.


failure of one internal pump -> manual shutdown


Kashiwazaki-Kariwa-6, the worlds first advanced boiling water reactor (ABWR), is "on target" to generate its first electricity at the end of the month, according to an industry source.
Tepco officials place the cost of the first 1,356-MW unit at 430-billion yen (About $4,3-billion, or some $3,170 per installed kilowatt).
The design and manufacture of the ABWR has been a joint effort of GE Nuclear Energy, Toshiba and Hitachi, under Tepco´s coordination. Components for the nuclear plant were manufactured in GE´s US plants in Wilmington, N.C. and Cleveland, Ohio, and in Japan by GE`s licensees, Toshiba and Hitachi. Design work on the ABWR has been underway for more than 15 years.
The ABWR design incorporated internal reactor pumps, which eliminated the external circulation system of large pipes and external pumps and valves.
Among state-of-the-art features contained in the ABWR are"fine-motion control rod drive systems"which "provide a diverse electrical and hydraulic method for scramming the reactor automatically."
A key feature of the reactor is the use of "digital solid state controls and a lot of man-machine interfaces". There are large touch-screen displays that allow operators to simply touch the screen to obtain readouts of temperature, pressure rating and other measures.
The plant makes extensive use of fiber optics for relaying data, instead of coaxial cable."Fiber optic requires laying a lot less cable."
The ABWR design contains improvements intended to reduce the chances of an accident. The"core damage frequency,"is 10 to 100 times better than that of any existing nuclear plant, says GE Nuclear Energy.
The US NRC granted final design approval for the ABWR in July 1994. GE "expects to obtain the final certification within a few month for use of the design in the US".


Turbine control oil leakage from piping near turbine by-pass valve.


SCRAM when transformer struck by lightning.


Drop of recirculation pump pressure due to entry of foreign substance into pump mechanical seal.