Friday, November 9, 2012

Further Trouble at South Korea's Yeonggwang Nuclear Power Plant: Cracks in Control Rod Tunnels

(UPDATE 11/10/2012 from Yomiuri) It was Reactor 3 that was found with cracks in control rod tunnels. If this reactor cannot come back online within this year, and with Reactors 5 and 6 stopped in order to replace parts with forged certificates, South Korea may have zero spare capacity in January.


Yeonggwang Nuclear Power Plant has 6 pressurized water reactors. It is the fourth largest nuclear power plant in the world in terms of capacity. Two of its reactors were shut down in just recently to replace parts, as over 5,000 parts used in the five reactors were found with improper (forged) certification.

Now, one of the reactors was found with cracks in 6 of the control rod tunnels. No indication on which reactor.

(The world number one is TEPCO's Kashiwazaki Kariwa Nuclear Power Plant, by the way.)

From CNBC quoting Reuters (11/9/2012; emphasis is mine):

South Korea finds cracks in control rod tunnels at nuclear plant

SEOUL (Reuters) - South Korean nuclear regulators have found microscopic cracks in tunnels that guide control rods at a nuclear plant under maintenance, government officials said on Friday, raising new concerns over the country's nuclear power sector.

The discovery of the cracks at the reactor comes just days after two reactors at the same plant in Yeonggwang county, in the southwest of the country, were shut down to replace parts that had been provided with forged certificates.

South Korea is investigating how thousands of parts for its nuclear reactors were supplied using forged safety documents, with regulators set to inspect all 23 of the country's facilities - a move that could test public support for the industry and threaten billions of dollars worth of exports.

"There are cracks in six tunnels. The reactor has been halted since October 18 for regular maintenance and now the process has been extended by a further 47 days for repair of the cracks," said a spokeswoman for the presidential Korea Nuclear Safety and Security Commission.

She said it was the first time cracks of this type had been found in South Korea's nuclear sector, but added the safety risk was not serious enough to require public disclosure.

The reactor affected by the cracks has a capacity of 1,000 megawatts, and a government official said the extended shutdown could complicate efforts to ensure steady supply of power through the peak winter season after the two other reactors had been stopped until the end of this year.

Asia's fourth-largest economy generates 30 percent of its electricity from 23 nuclear reactors at state-owned plants, and the government has warned of the potential for unprecedented power shortages due to the shutdowns as demand peaks in winter.

"This could affect power supplies, but we are preparing contingency plans," said a senior economy ministry official, who declined to be named as he is not authorized to speak to the media.

South Korea's state-run nuclear power utility said it was investigating the cause of the cracks, but said they had not caused any leaks.

"There are no penetrating cracks or leaks," Korea Hydro & Nuclear Power, a subsidiary of state utility Korea Electric Power Corp (KEPCO), said in a statement. It operates all of the country's nuclear power plants.

The country's power utility and nuclear regulators have come under heavy criticism this week after the disclosure that eight firms had used forged safety documents to supply parts to nuclear plants raising concern of broader potential problems in the large and growing nuclear programme.

A task force has been established with government and private sector experts to inspect all reactors to ensure their parts are properly certified. It will also inspect five reactors under construction to see if troubled parts with forged certificates have been provided.

(Additional reporting by Meeyoung Cho; Editing by Jack Kim, Ed Davies and Ian Geoghegan)

There are people in Japan ridiculing the Koreans for the forged certification issue and the shutdown of the reactors, no doubt partially fanned by the territorial row with South Korea over Takeshima Island.

I guess they've forgotten that Japan is downwind.


Anonymous said...

Makes you wonder what their threshold is for necessary "public disclosure", huh? It's not worth telling us until it's too late?

Those cracks may not be serious on their own, but I wonder if they've considered what might happen if those minor problems combined with unpredictable events (eg. earthquake).

Anonymous said...

Nuclear power requires perfection.

And this is another perfect example why PEOPLE should not build and operate nuclear power plants. There will always be contractors who use inferior (and cheaper) materials. There will always be suppliers who cut corners. There will be honest mistakes of judgement. People, as anyone who grows old enough will eventually understand, are not perfect.

Try as we might to get the science exactly right, or establish TEPCO-proof safety processes against all that modern warfare or mother nature can throw at us, the human factor will sometimes get it wrong.

And when we get it wrong, the consequences are severe. The lives of people near an accident are destroyed, people far from the accident are subjected to higher cancer rates and death rates, and the effects on the living include modifications to DNA that are passed on to future generations. This stuff not only kills in the now, but keeps on killing long into the future.

Humans have no business building or operating nuclear power plants. We are not perfect. We can never be perfect. When it comes to nuclear power, the cost of not being perfect is simply too high.

Anonymous said...

Why is there a threshold for public disclosure in the first place? Who decides whether an issue is more severe than the threshold?

What happens if the control rod tunnels are cracked? Could those cracks prevent the insertion of the control rods (maybe not now but if cracks go undetected a little longer)? Could the reactor start leaking from the cracked tunnels and run out of coolant? What happens if the reactor starts leaking AND at least some of the control rods get stuck and can't be inserted any more?

At Fukushima they could at least insert the control rods; what kind of accident do you get if you can not even insert the rods? Would the reactor and the "containment" blow open Chernobyl style?

Anonymous said...

Any unexpected degradation found in a nuclear anything is a problem it means that the "educated guesses" they used were wrong. This is pretty bad the 1000Mw reactors at Yeonggwang aren't that old according to this list.

South Korea have little to crow about when it comes to nuclear problems Kori NPP had some troubling problems in 2012 too.

You can be sure if they found cracks in a nuclear weapon they'd take it out of service until they knew exactly why it happened.

Atomfritz said...

It's Kori-3, a Westinghouse 895MWe reactor, commissioned in 1985.

Bribing and using counterfeit replacement parts for reactors is common in Korea no less than in Japan:

Anyway, from the Korean perspective, Kori is strategically well-placed, I have to admit.

Atomfritz said...

oops, I forgot that there are two nuke plants named "Kori" in Korea... thought it was the other one... so my last post is wrong.

Anonymous said...

Doesn't help that we keep finding out they found ways to cut costs or avoid safety measures. These devices are not something anyone should try to pull that kind of shit for.

People really... don't... get it.

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