Japan Restarts Two of Its 50 Nuclear Reactors

Darth_brooks writes "Japanese Prime Minister Yoshihiko Noda ordered the restart of two idle nuclear reactors Saturday, amid split public response. The Japanese government is trying to fill a summer power shortfall. According to the article, the two reactors supply power to the Kansai region near Osaka, where local officials were predicting a 15% shortfall in power capacity during July and August."

Re:That's good news

[SuperTechnoNerd]

It's not that simple because Japan has the additional problem that some of the country uses 60Hz like here in the us and some places use 50Hz like in europe.

not actually that unpopular locally

[Trepidity]

While restarting any nuclear reactors is currently quite unpopular in Japan nationally, the decision to restart this particular plant's two reactors was actually made with local input and approval. Local councils aren't normally required to approve such matters, but due to the current controversy, Japan's government de-facto made restart contingent on approval from the local government. After several months of safety studies and deliberation, the municipal council voted 11-1 in favor of restarting the reactors [japantimes.co.jp] in mid-May, which gave the national government some cover to go ahead with it.

Re:That's good news

[gstrickler]

Actually, that's not a problem, they use an HVDC line between the two grids.

Re:That's good news

[Anonymous Coward]

You know, do at least *some* research before stating bullshit.

It is a HUGE PROBLEM. Any interconnect is very limited in size. If a significant portion of one grid is impacted, you can't easily move power from one grid to another. This is exactly the situation in Japan.

Re:That's good news

[nojayuk]

The HVDC links between the two grids have a limited capacity, about 2GW as I recall. They've not needed anything bigger since both parts of the country have adequate generating capacity for each region, or at least they did until the nuclear stations in the Kansai area and points south shut down for inspection and refuelling and didn't restart. The Kanto area (Tokyo and environs) has a lot of older coal-burning and oil-burning power stations that were demothballed after they lost the Fukushima Daiichi and Daini reactors and the other stations shut down due to the quake and tsunami (Onagawa, Tokai and Hamaoka) were refused permission to restart. Kansai (Osaka, Kobe, Hiroshima etc.) has fewer fossil-burners available to bring back to use hence the predicted electricity supply shortages in the region this summer.

Re:Shortages are a solved problem.

[GreatBunzinni]

There's another way to fix the shortfall: simply raise the price of peak hour electricity until

...until industrial production is affected by the skyrocketing costs and the whole economy of Japan faces a recession caused by the increased production costs and lack of ability to compete in the economic field.

In alternative, they can simply turn on a couple of the 50 power generators they have just sitting there, that never exhibit a single problem in their entire existence.

I wonder what's the best option.

Re:That's good news

[petermgreen]

Some older electronics with PSUs that use mains frequency transformers and whose design was close to the edge may have problems as may some stuff that uses mains as a time reference but mostly electronics should be fine.

Clocks (whether electronic or mechanical) that derive their timebase from the mains would be a nuisance but ultimately if it was the main issue I think they would have forced a transition through by now.

Afaict the real problem is the big stuff, big motors and generators are usually at least somewhat locked to grid frequency and a 10% change in operating speed is probablly not acceptable. Transformers can also be problematic as a lower frequency can cause core saturation leading to overheating. Replacing that stuff would be seriously expensive.

Re:Nuclear disaster nearly shut down Tokyo

[solferino]

The 400-page report, due to be released later this week, also describes a darkening mood at the prime minister's residence as a series of hydrogen explosions rocked the plant on March 14 and 15. It says Mr. Kan and other officials began discussing a worst-case outcome if workers at the Fukushima Daiichi plant were evacuated. This would have allowed the plant to spiral out of control, releasing even larger amounts of radioactive material into the atmosphere that would in turn force the evacuation of other nearby nuclear plants, causing further meltdowns.

The report quotes the chief cabinet secretary at the time, Yukio Edano, as having warned that such a 'demonic chain reaction' of plant meltdowns could result in the evacuation of Tokyo, 150 miles to the south.

"We would lose Fukushima Daini, then we would lose Tokai," Mr. Edano is quoted as saying, naming two other nuclear plants. "If that happened, it was only logical to conclude that we would also lose Tokyo itself."

Source: NY Times article [nytimes.com] on top-level report reviewing the disaster.

Re:Yep...

[OeLeWaPpErKe]

Supplying coal is one problem, dumping the toxic remains is another. Coal power plants are a disaster as bad as fukushima even when nothing goes wrong.

Re:That's good news

[MacGyver2210]

after they lost the Fukushima Daiichi and Daini reactors

The Fukushima Daini reactor was not lost, and didn't even sustain damage. It shut down automatically during the earthquake, and was not restarted due to the unfounded fear/danger/hype that began about nuclear power.