No. 4 reactor at Oi plant resumes power generation

National Jul. 22, 2012 - 06:44AM JST ( 15 )

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15 Comments

2

mitoguitarmanJul. 22, 2012 - 09:15AM JST

Praying for no more big quakes/tsunami. Sad when we humans create such dangerous situations like this that all we can do is pray. To whom are we praying? That TEPCO will learn from its checkered past and change its ways? Fat chance.
0

nandakandamandaJul. 22, 2012 - 11:31AM JST

Quote, last paragraph: All but two of the country’s 50 nuclear reactors have been offline for checks amid concerns about safety, and the gap is being met by firing up costly fossil fuel units and through energy-saving steps.

All but two? No, all of them were off-line for checks and a moratorium until the government forced through two restarts.
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zichiJul. 22, 2012 - 11:38AM JST

The Oi reactors have a major corrosion problem. KEPCO replaced the parts on reactors 1-2 but not on 3-4. These reactors use baron for cooling and that is causing the corrosion.
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basroilJul. 22, 2012 - 11:55AM JST

zichiJul. 22, 2012 - 11:38AM JST

The Oi reactors have a major corrosion problem. KEPCO replaced the parts on reactors 1-2 but not on 3-4. These reactors use baron for cooling and that is causing the corrosion.

No, they use boron for moderation control and slow shutdown. Most of the time there is very low boron levels, since it is a powerful neutron poison. Main issue seems to be fuel rod caps, and boron killing the fuel reactions. Sure it's an issue, but a forced shutdown issue rather than safety one.
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basroilJul. 22, 2012 - 12:03PM JST

All but two of the country’s 50 nuclear reactors have been offline for checks amid concerns about safety, and the gap is being met by firing up costly fossil fuel units and through energy-saving steps.

What has this author been smoking? KEPCO has an in-house production limit of ~19.5GW including restarted coal plants, plus another 6.5GW from third parties if you don't include nuclear. With Oi 3 alone they get 1.2GW base load added plus 2.1 in pumped hydro attached to nuclear. 1GW or so is taken by the three other companies in the area. Last week they reached 98%+ of the pre-nuclear production capability, and this week they are expected to hit 100%+ of that level. The gap isn't being met in KEPCO region at all, hence the need for nuclear.

I know someone is going to mention the 8 turbines idled, so I can tell you in advance they are idled, not shut down, and they will be on should power be expected to reach over 26GW.
1

Thomas AndersonJul. 22, 2012 - 12:11PM JST

The last few days here in Osaka had been very hot (34C) and it has not went over 25GW. And people were told to conserve only 10%, not 15%. I'm not sure how seriously people are taking that since many stores and buildings here in Osaka are still running the air conditioners at full rate.

I mean come on, even with the two restarted reactors they only get 2.4 GW. The fact that we can't even save 2.4 GW, or they can't even supply 2.4 GW through buying electricity from other companies or using pumped-hydro storage, is strange.
0

basroilJul. 22, 2012 - 12:29PM JST

Thomas AndersonJul. 22, 2012 - 12:11PM JST

The last few days here in Osaka had been very hot (34C) and it has not went over 25GW. And people were told to conserve only 10%, not 15%. I'm not sure how seriously people are taking that since many stores and buildings here in Osaka are still running the air conditioners at full rate.

Not sure what you're talking about there, there were three times where they crossed 25GW (not three hours, three separate extended periods) last week .

I mean come on, even with the two restarted reactors they only get 2.4 GW. The fact that we can't even save 2.4 GW, or they can't even supply 2.4 GW through buying electricity from other companies or using pumped-hydro storage, is strange.

No, there is pumped storage that is directly connected to nuclear plant use. That provides at least 2.1GW on top of the stable load of 2.4GW (bit under actually) from the plant turbines themselves. Additionally, they are buying from other companies, but those companies are already maxed out and can't provide more (under 7GW using old plants that should not be used because they pollute a ton). Saving part is also difficult because last year they called for 15% and got just 4% savings.
-4

zichiJul. 22, 2012 - 12:56PM JST

Without the reactors the total is 25.42GW. With the reactors its 29.88GW.

Without the reactors. Figures are GW's. Nuclear(0). Pumped Hydro(2.39). Thermal (19.23). Hydro(2.54). Geothermal (0.05). From other utilities (1.21).

With the reactors. Figures are GW's. Nuclear (2.36). Pumped Hydro (4.49). Thermal (19.23). Hydro (2.54). Geothermal (0.05). From other utilities (1.21).
1

Thomas AndersonJul. 22, 2012 - 01:10PM JST

I meant to say it stayed at 25 GW and never went over 26 GW.

No, there is pumped storage that is directly connected to nuclear plant use. That provides at least 2.1GW on top of the stable load of 2.4GW (bit under actually) from the plant turbines themselves.

I believe they have 4.5GW of pumped-hydro storage and they can use fossil fuel plants to pump up the water.

Saving part is also difficult because last year they called for 15% and got just 4% savings.

Like I said people here are hardly saving anything. Last year I don't believe that people were told to save much electricity. Tokyo actually saved 15%.
-5

zichiJul. 22, 2012 - 01:31PM JST

The Oi reactors are Westinghouse design and suffer from a servere corrosion problem. There are about 30 of these reactor designs across the world which have a corrosion problem.

Reactor head corrosion and cracking issues. This is happening where the control rod drive mechanisms connect to the reactor head (cap). Borated water is used in these reactors and this has caused issues of corrosion in reactor caps. The caps at units 3 & 4 were not replaced even though cracks and leaking were found in the cap at unit 3. This known failure issue could easily cause a catastrophic problem at Oi units 3 or 4. The cracks and leaking boron were discovered in 2004.

The worse case to date was the Davis Besse reactor.

At the Davis Besse reactor the corrosion created a hole the size of a large football in the reactor head. The Davis-Besse Nuclear Power Station is in Oak Harbor, Ohio.

http://en.wikipedia.org/wiki/Davis-Besse_Nuclear_Power_Station

We need this reactors working like we need a hole in the head, or as in this case, a hole in the reactor cap.

http://www-pub.iaea.org/MTCD/Publications/PDF/P1522_web.pdf

There are a number of other serious safety issues with the Oi plant. No earthquake or radiation proof offsite emergency control center. The plant can only be reached by a single road and via a tunnel.
-1

basroilJul. 22, 2012 - 03:30PM JST

zichiJul. 22, 2012 - 01:31PM JST

The caps at units 3 & 4 were not replaced even though cracks and leaking were found in the cap at unit 3. This known failure issue could easily cause a catastrophic problem at Oi units 3 or 4. The cracks and leaking boron were discovered in 2004.

Page 26 says reactor 3's damaged caps were replaced in 2007. So this is a non-issue for reactor 3. Unless you can find evidence to counteract it, we can assume plant 4 was done at the same time.

Quite interesting read, mainly stating that while it is an issue it is far from catastrophic failure level issue. The main issue is requiring premature replacement , and thus lost income and added expense.

Solution is quite easy, changing metal type a small bit, and has already been implemented at Oi 3.
-1

basroilJul. 22, 2012 - 03:41PM JST

zichiJul. 22, 2012 - 01:31PM JST

At the Davis Besse reactor the corrosion created a hole the size of a large football in the reactor head. The Davis-Besse Nuclear Power Station is in Oak Harbor, Ohio.

Not a hole, a pit. The damage never reached the outside surface. In the case of Oi, it was an entirely different parts that are of concern. Not to mention that reactor is pretty much the Monju of USA.
-1

zichiJul. 22, 2012 - 04:00PM JST

basroil

Not a hole, a pit????

In March 2002, plant staff discovered that the borated water that serves as the reactor coolant had leaked from cracked control rod drive mechanisms directly above the reactor and eaten through more than six inches[12] (150 mm) of the carbon steel reactor pressure vessel head over an area roughly the size of a football (see photo). This significant reactor head wastage on the interior of the reactor vessel head left only 3⁄8 inches (9.5 mm) of stainless steel cladding holding back the high-pressure (~2500 psi, 17 MPa) reactor coolant.

The PWR's like the ones in Oi are suppose to be better or safer than the BWR's at Fukushima, but these too have some serious problems.
0

basroilJul. 24, 2012 - 12:51PM JST

Oi4 will be near 100% by friday. Just in time for 26.2GW expected need, a whole 5% above the average post rain capability before Oi 3-4 were restarted.
0

Thomas AndersonJul. 24, 2012 - 01:02PM JST

Prediction says 25.7 GW tomorrow. And yes that's just a prediction.

Right now we're using 22.8 GW... hurray.