Thursday, June 28, 2012

Problem after Problem after Problem at Ooi Nuke Plant, Still Set to Restart on July 1


(UPDATE) "... after Problem" Alarms sounded off in the central control room for the Reactor 3's pump in the afternoon of June 29, according to Jiji Tsushin (6/29/2012). The pump circulates the primary coolant that goes into the Reactor 3 Pressure Vessel.

Today's protest in front of the PM's Official Residence is shaping up to be big, people are tweeting.

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I have a feeling that KEPCO may be worse than TEPCO when it comes to cost cutting and deferred maintenance. After all, Kansai merchants are historically known for shrewd, economizing ways to make more profit.

In a matter of few days, Ooi Nuclear Power Plant has managed to have three separate minor problems, and two of them triggered alarms. First it was poor maintenance, then it was a human error, then probably another case of poor maintenance.

First, about aging rubber seal that caused the short circuit, from Sankei Shinbun local Fukui version(6/29/2012):

大飯原発3号機一時漏電 雨水浸入が原因

Temporary short circuit at Reactor 3 at Ooi Nuclear Power Plant, caused by rainwater leaking in

大飯原子力発電所3号機(おおい町)の開閉所で一時漏電した問題で、関西電力は28日、開閉所の電源系統を制御する設備に雨水などが浸入したことが原因だったと発表した。

KEPCO announced on June 28 that a temporary short circuit at the switching station for Reactor 3 at Ooi Nuclear Power Plant (in Ooi-cho) was caused by the rainwater leaking into the equipment that control the power supply system at the station.

関電によると、制御設備108個を確認したところ、設備1個に水が溜まっていたという。関電はゴムパッキンが老朽化し、雨水が浸入したとみており、ゴムパッキンを取り換えるなど対策を講じるとしている。

According to KEPCO, after checking the 108 parts that control the system, the company found one of the parts filled with water. KEPCO thinks the rubber seal had deteriorated, allowing the rainwater to leak in. The company says it will take countermeasures such as replacing the rubber seal.


Then, an alarm went off in the central control room at the power panel for Reactor 3, as KEPCO reported on June 28.

From KEPCO's press release on June 28, 2012:

大飯発電所3号機「C直流電源盤故障注意」警報の発信について(お知らせ)

About the alarm "Attention C DC power panel failure" sounding off at Reactor 3 at Ooi Nuclear Power Plant(announcement)

大飯発電所3号機(加圧水型軽水炉 定格電気出力118万キロワット、定格熱出力342万3千キロワット)は、再稼動に向けた作業中の平成24年6月28日15時58分に、中央制御室の3号機所内盤において、「C直流電源盤故障注意」警報が発信しました。

Reactor 3 at Ooi Nuclear Power Plant is currently prepared for the restart. At 3:58PM on June 28, 2012, an alarm "Attention C DC power panel failure" sounded off at the panel for Reactor 3 in the central control room.

16時05分に警報はリセットしました。

The alarm was reset at 4:05PM.

警報が発生した原因については、当社運転員が、モニタ画面が消灯していたため、画面を点灯させようと誤って、電源スイッチを切ったために警報が発生したものです。

The alarm was set off when our operator accidentally turned off the power switch when he tried to turn on the monitor screen.

設備の故障はありません。

There is no failure of the equipment.

なお、本件は、保安規定上の運転上の制限を満足しており、法令に基づくトラブルには該当せず、現在行っている再稼動に向けた作業とも関連がなく、今後の同作業への影響はありません。

This incident is within the safety regulations and it is not a trouble as defined by laws and regulations. It has nothing to do with the work currently undertaken for the restart of the reactor, and there will be no effect on the work.

また、本事象による環境への放射能の影響はありません。

Also, there is no radiation leak in the environment.


That's what the government regulations do. As long as it is within the government-mandated laws and regulations, it is not a problem as far as the laws and regulations are concerned. No one will be at fault.

"Pro forma" was mentioned by the reader Atomfritz on another post about Ooi Nuke Plant mishap. Right on the money.

But wait, there's more. Another alarm was set off on June 29, this time at Reactor 4.

From Jiji Tsushin (6/29/2012):

大飯4号機で警報=冷却水採取ポンプに異常か-保安院

NISA: An alarm at Reactor 4 at Ooi Nuke Plant, possible failure at the pump that samples coolant

経済産業省原子力安全・保安院は29日、政府が再稼働を決めた関西電力大飯原発4号機(福井県おおい町)で、タービンを動かすため発生させた蒸気を冷やす復水器に、海水が混じっていないか調べる採取用ポンプで、異常を示す警報が鳴ったと発表した。保安院と関電はポンプを分解し、原因を調べる。

Nuclear and Industrial Safety Agency under the Ministry of Economy, Trade and Industry announced on June 29 that an alarm was set off at the pump at the steam condenser. The pump is used to sample coolant to make sure no seawater is mixed in. NISA and KEPCO will disassemble the pump and investigate.

保安院によると、警報は29日午前10時前に鳴った。ポンプに大きな圧力が掛かっていることを示す警報で、採取した水が流れにくくなったり詰まったりした可能性があるという。

According to NISA, the alarm was sounded before 10AM on June 29. The alarm is set off when there is a large excess pressure in the pump. There is a possibility that the sampled water didn't flow smoothly or was blocked.


3 comments:

gary minesmall said...

People can hardly drive let alone...

Janick in Tokyo said...

frightening....... Thanks for the detailed info.

Atomfritz said...

Indeed, frightening.
Kepco guys seem to be of the reLAXed sort.

Rainwater leak k.o.-ing the reactor power supply due to relaxed maintenance. Amazing.

Amazing too, how the guy managed to turn off one of the DC buses.
Placing and protective-capping of important switches, an old practice in the industry (at least outside of Japan) should prevent such potentially catastrophic human errors.
Or the operator was under influence or otherwise mentally absent?

Maybe Kepco's company motto is:
Oops! Don't be angry, nobody is perfect!

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