steam gen tube rupture in S Korea nuke

[Norman Cohen <ncohen12@comcast.net>]

comments folks?

norm



Mika Ohbayashi wrote:



> Hi,

>

> FYI, the following message is from my friend in S. Korea.

>

> ===========

> Steam Generator Tube Rupture Accident in Uljin 4 in Korea.

>

> Dear friends,

>

> The 12th "Steam Generator Tube Rupture (SGTR)" accident in the world

> occurred in Uljin nuclear power plant(unit 4) located in north-eastern part

> of South Korea. Due to this rupture accident 45 ton of the primary coolant

> was poured into the second coolant system. For the accident happened around

> 18 hours after the shut down for the regular inspection and fuel exchange,

> ECCS didn't work and operators had to manually input the emergency coolant

> to the reactor.

>

> Even though the accident happened in 5th of April, the Korean Hydro &

> Nuclear Power(KHNP) and the regulator(Ministry of Science & Technology)

> hided the accident for the past two months by deliberately using the

> concept of "coolant leakage incident" in their press release. We Korean

> nuclear activists didn't recognize this press release seriously at first

> due to their distorted information. The Korean Nuclear Safety Committee

> announced in last 25th of May that the scale of the "incident" is 1

> according to the International Nuclear Event Scale, insisting that there

> was not any radiation release to outside and no one affected by radiation

> from this event.

>

> Uljin 4 which started operating in Dec. of 1999, was inspected by

> licensee(KHNP) three times before this accident. The inspection methods

> called Bobbin and MRPC(Motorized Rotating Pancake Coil) were not so helpful

> to probe the cracks and predict this accident. According to the final

> investigation report of Korean Nuclear Safety Committee on this

> accident (though they insist as incident), the main causes of the accident

> were the several cracks around the Expansion Transition - just above the

> tube sheet. However, the report deliberately avoids commenting on the

> problematic material of the tube - so called Alloy 600 (HTMA), and even

> slightly denies the probability that the material may have caused the

> developing of the cracks. Nevertheless, according to the Korean Atomic

> Energy Research Institute, the exact cause of the accident has not been

> confirmed yet.

>

> There have been 11 SGTR accidents in the world so far, once in Belgium and

> Japan respectively and 9 times in the US. All the reactors experienced SGTR

> accidents had installed steam generators made of Alloy 600(or Inconel 600),

> and the material has been accused as a main cause of rapid deterioration of

> the tubes. Unfortunately, so called the Korean Standard Nuclear Plants from

> YoungKwang 3,4,5,6 to Uljin 3,4 have installed the same type of steam

> generators so far. The KHNP affirms that it can probe or predict this kind

> of crack on steam generators' tubes since it once experienced, and it will

> prevent same kind of "incident" from other nuclear reactors. However, it

> didn't explain clearly why it had failed to probe the cracks appropriately

> and how it will not repeat the same problem.

>

> We Korean anti-nuclear organizations are planning to have a public meeting

> collaborated with some congressmen in the late of this month. But we need

> more specialized recommendation and help, and need to collaborate with

> international actions. I hope that we can relate this issue to the recent

> issues such as Davis-Besse nuclear reactor's event or Indian Point 2's SGTR

> event since the events are also related with the problematic Alloy 600

> material. If you have any idea or recommendation regarding this issue,

> would you please share your experience and wisdom with us?

>

> Yours,

>

> Kwanghoon

>

> Kwanghoon Seok

> Energy and Nuclear Safety issues, Green Korea United

> Tel : 82 2 747 8500

> Fax : 82 2 766 4180

> Mail : nonuke@greenkorea.org, nonuke@hanmail.net



--

Coalition for Peace and Justice and the UNPLUG Salem Campaign; 321 Barr Ave.,

Linwood, NJ 08221; 609-601-8583 or 609-601-8537;  ncohen12@comcast.net  UNPLUG

SALEM WEBSITE:  http://www.unplugsalem.org/  COALITION FOR PEACE AND JUSTICE

WEBSITE:  http://www.coalitionforpeaceandjustice.org   The Coalition for Peace

and Justice is a chapter of Peace Action.

"First they ignore you; Then they laugh at you; Then they fight you; Then you

win. (Gandhi) "Why walk when you can fly?"  (Mary Chapin Carpenter)





************************************************************************

You are currently subscribed to the Radsafe mailing list. To unsubscribe,

send an e-mail to Majordomo@list.vanderbilt.edu  Put the text "unsubscribe

radsafe" (no quote marks) in the body of the e-mail, with no subject line.

You can view the Radsafe archives at http://www.vanderbilt.edu/radsafe/