WorldÂ’s largest nuclear plant awaits restart approval

NIIGATA, JAPAN - The Tokyo Electric Power Company Incorporated (TEPCO) is awaiting approval from the governor of the Niigata prefecture, Hirohikio Izumida, to restart Unit 7 of the Kashiwazaki-Kariwa nuclear power plant, which was shut down following damages inflicted by the Chuetsu offshore earthquake in July 2007.

Late last month, Izumida indicated that he would discuss restarting the nuclear reactor with the prefectural assembly. The local governments of Kariwa and Kashiwazaki have already given their approval to restart the 1,356-megawatt (MW) advanced boiling water reactor.

In anticipation of a green light from Izumida, TEPCO has scheduled a test startup to be conducted over a period of 50 days later this month. Following a successful test run, the firm intends to resume commercial operations as early as July, just in time to address the rise in demand for electricity during the summer.

In February this year, TEPCO received approval from the Nuclear Safety Commission of the Cabinet Office, as well as the Nuclear and Industrial Safety Agency of Japan's Ministry of Economy, Trade and Industry to conduct a test startup of the reactor. On April 7, a technology commission of Niigata prefecture submitted a report confirming that the reactor is safe for restart.

Subsequently, all the members of the prefecture assembly were to convene to discuss resumption of reactor operations.

However, following a fire outbreak in a warehouse located on the premises of the nuclear power plant, the ninth such incident at the facility since it was shut down two years ago, the government of the prefecture asked TEPCO to submit a report of measures that would be undertaken by the firm to prevent the recurrence of such mishaps at the facility. Izumida is scheduled to address the prefectural assembly on May 7 to discuss the safety of Unit 7 against earthquakes. However, it remains unclear whether the governor would concede his approval on the same day or a few days after the meeting.

The Kashiwazaki-Kariwa nuclear power plant consists of seven reactors, the first of which commenced operations in 1985. With a total power generating capacity of 8,212 MW, the plant was the world's largest single-location nuclear power generating facility. The power plant accounted for 20% of TEPCO's total power generation output before the reactors were shut down following the Chuetsu offshore earthquake. An electric transformer on the premises caught fire, causing more than 400 barrels containing contaminated waste to topple, resulting in spillage of contents from at least 40 of these barrels. Further, water from a spent fuel-rod pool leaked through drainage pipes into the East Sea, leading to authorities immediately freezing operations at the plant.

Unit 7 was the newest and least-damaged of the seven reactors at the facility. Recommencement of operations of Unit 7 is estimated to reduce Japan's fuel purchase by $716 million every year, cut carbon-dioxide emissions by 5 million tons per year and reduce fuel consumption by 32,000 barrels of crude oil equivalent per day. Restoration of the other six reactors is also under way. Although TEPCO has not proposed a timeframe for resuming operations of the remaining units, Unit 6 with a power generation capacity of 1,356 MW is expected to come on stream after Unit 7.

Meanwhile, local residents and geology experts have expressed concern about the safety of Unit 7 and other reactors at the nuclear power plant.

According to a process approved by a panel of 70 scientists appointed by the government, TEPCO has upgraded the facility to withstand an earthquake with a magnitude of 7.0 on the Richter scale. The Chuetsu offshore earthquake had a magnitude of 6.8.

A few experts argue that the facility should be upgraded to withstand an earthquake of a magnitude of 7.5 because of the presence of a major seafloor fault line in the vicinity of the power plant. Although three of Japan's 15 leading tectonic experts agree on the existence of the fault line, the government denies its existence and acknowledges only the presence of a 36-kilometer-long crack in the seabed, much to the consternation of the local residents and geological experts.


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