Japan restarts first nuclear reactor under new safety rules

On August 11, Kyushu Electric Power Company's 846 megawatt (MW) Sendai Nuclear Power Station Unit 1 became the first reactor to restart after nearly two years with no generation from nuclear power plants in Japan. Following the disaster at Fukushima in 2011, Japan began a temporary shutdown of all nuclear power plants as each reactor entered scheduled maintenance and refueling outages. By September 2013, all 54 reactors in Japan's nuclear fleet were shut down. Following its restart, Sendai Unit 1 will begin generating electricity within days and return to normal operation in early September.

The restart of Japan's nuclear power plants requires the approval of both Japan's Nuclear Regulation Authority (NRA) and the central government, as well as consent from governments of the local prefectures. In July 2013, the NRA issued more stringent safety regulations to address issues dealing with tsunamis and seismic events, complete loss of station power, and emergency preparedness. Currently, the NRA has approved the restart of five reactors: Sendai Units 1 and 2, Kansai Electric Power Company's (KEPCO) Takahama Units 3 and 4, and Shikoku Electric Power Company's Ikata Unit 3. Sendai Unit 2 will likely be the second reactor to restart, with an anticipated restart date in October. Although the Kagoshima Prefecture approved the restart of Sendai Units 1 and 2, the Fukui Prefecture continues to oppose the restart of Takahama Units 3 and 4. Ikata Unit 3 could restart in early 2016 if approval is received from Ehime Prefecture.

Beyond these 5 reactors, 19 of Japan's remaining 38 operable reactors have filed restart applications with the NRA that are in different stages of the review process. The total capacity of reactors under review is about 18,400 MW. There is still some uncertainty about whether some of these reactors can meet the new NRA regulations, particularly with respect to the ability to withstand severe earthquakes.

Before the 2011 earthquake and tsunami, Japan had 54 operating reactors. Following the disaster at Fukushima, all six Fukushima reactors, totaling about 4,500 MW, were permanently shut down. In April 2015, five additional relatively old, small reactors, totaling about 2,100 MW, were permanently shut down.

Japan was the world's third-largest producer of nuclear power (after the United States and France) before the disaster at Fukushima, and Japan's nuclear power plants historically accounted for about 30% of the country's total electricity generation. The gradual displacement of all of Japan's nuclear generation as the country's nuclear fleet was shut down resulted in increased dependence on liquefied natural gas, oil, and coal to make up the difference. The replacement of nuclear generation led to higher electricity prices for consumers, higher government debt levels, and revenue losses for electric utilities. As part of Japan's long-term energy policy, the central government has called for the nuclear share of total electricity generation to be 20–22% by 2030.

Japan restarts first nuclear reactor under new safety rules

From what I have read, it appears that it was their "safety rules" which caused the disaster.

My understanding is that the reactor melted down because it takes approximately 3-4 days to shut it down once the decision has been made to shut it down. During this time, the Reactor is still very "hot" in terms of both thermal output and radiation, and must be cooled continuously for these three or four days to prevent meltdown.

Trouble was, they had no electrical power to run the cooling system, and their backup diesel generators were rendered inoperable by the floodwaters of the Tsunami.

Had they only had electricity at the plant, they could have ran the cooling systems and safely shut down the reactors. Problem was, they *SHUT DOWN* the reactors, and could therefore no longer produce electricity from them. Had they kept the reactors producing electricity, they could have powered the cooling system themselves.

Why did they shut down the reactors? Because the "Safety Rules" in effect in Japan at the time, *REQUIRES* nuclear reactors to be shut down in the event of a big earthquake or Tsunami, even if such an event does not actually damage the reactors.

So basically it was their "safety rules" that caused the cascade failure of the whole disaster, and made things far worse than they would have been had they simply kept the reactors going.

That's my understanding of the situation. If it is in error, someone please set me straight.

Disclaimer: Opinions posted on Free Republic are those of the individual posters and do not necessarily represent the opinion of Free Republic or its management. All materials posted herein are protected by copyright law and the exemption for fair use of copyrighted works.