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Japan Earthquake: nuclear plants

by gmax137
Tags: earthquake, japan, nuclear
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SteveElbows
#14113
Aug15-13, 03:02 PM
P: 630
Any chance of some info about this japanese document regarding installation of permanent monitoring equipment for reactor 2? Again computer translation is not great which is why I ask, but it does sound like the survey revealed problems so they have to think again about this plan?

http://www.tepco.co.jp/nu/fukushima-...30814_13-j.pdf
tsutsuji
#14114
Aug17-13, 03:41 AM
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Quote Quote by SteveElbows View Post
Any chance of some info about this japanese document regarding installation of permanent monitoring equipment for reactor 2? Again computer translation is not great which is why I ask, but it does sound like the survey revealed problems so they have to think again about this plan?

http://www.tepco.co.jp/nu/fukushima-...30814_13-j.pdf
01/03

02/03

03/03
Attached Thumbnails
01.jpg   02.jpg   03.jpg  
tsutsuji
#14115
Aug19-13, 07:14 AM
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http://www3.nhk.or.jp/news/genpatsu-...819/index.html

1) The radiation alarm rang from 09:30 to a little after 10:00 AM on 19 August in front of the seismic-isolated building. Two workers who were waiting for the bus there were found to have been contaminated up to 13 Bq/cm², which is 3 times Tepco's internal standard. However they have no internal contamination. Tepco checked that the alarm rang as a consequence of rising cesium concentration in the air. The mist generator, which was suspected for the contamination of the 10 workers on 12 August, was not being used on 19 August.

2) Water was found leaking outside the dam surrounding tanks on the mountain side of unit 4. The leakage came from a rainwater exhaust pipe and was stopped by closing a valve. The radiation near the surface of water puddles (approximately 90 litre) was 100 mSV/hour. Tepco is investing the cause, suspecting that a contaminated water tank must somehow be leaking.

http://www.tepco.co.jp/nu/fukushima-...30819_03-j.pdf Seismic Isolated Building Dust monitor alarm (Japanese)

http://www.tepco.co.jp/nu/fukushima-...30819_05-j.pdf Leakage in H4 tank area (Japanese)
tsutsuji
#14116
Aug20-13, 02:25 AM
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http://www3.nhk.or.jp/news/genpatsu-...515_kanri.html

Although the dam surrounding the tank area is designed to prevent contaminated water leakage, the valve equipping the rainwater exhaust pipe was left open, and leakage outside the dam could be stopped by closing the valve.

Tepco said "If we don't evacuate rainwater, we can't distinguish whether the water inside the dam is water leaked from the tanks or not. For that reason, the valve is usually open."

However, as it would be impossible to respond if a similar contaminated water leakage happened again, Tepco said it would study leakage detection and management methods.

The NRA said it is provisionally classifying the event as an International Nuclear Event Scale level 1 event.

http://www3.nhk.or.jp/news/genpatsu-...820/index.html One of the 26 tanks in the area, supposed to be filled with 1000 tons of water was found to contain only 700 tons. That means that 300 tons have leaked. This water is the output of the cesium removal process. Although it does not contain cesium, it contains strontium and the beta radiation is 80,000,000 Bq/l. Tepco will remove the earth contaminated by the water leak and closely monitor the consequences.

http://www.tepco.co.jp/nu/fukushima-...30820_01-j.pdf Leakage in H4 tank area (Japanese)
blab31
#14117
Aug20-13, 03:59 AM
P: 5
Quote Quote by tsutsuji View Post
NHK : "Although it does not contain cesium, it contains strontium and the beta radiation is 80,000,000 Bq/l."
If I read correctly, from your document - http://www.tepco.co.jp/nu/fukushima-...30820_01-j.pdf - Cs134 is still 46,000 Bq/l and Cs137 100,000 Bq/l, far higher than it should be after cesium removal systems.

I guess it's the usual TEPCO mistake, but japanese document shows 8x10E4 all beta, while english press release - http://www.tepco.co.jp/en/press/corp...9867_5130.html - is 8x10E-4 all beta. Same thing with cesium, 1x10E2 (japanese) versus 1x10E-2 (english).
tsutsuji
#14118
Aug20-13, 11:42 AM
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Quote Quote by blab31 View Post
If I read correctly, from your document - http://www.tepco.co.jp/nu/fukushima-...30820_01-j.pdf - Cs134 is still 46,000 Bq/l and Cs137 100,000 Bq/l, far higher than it should be after cesium removal systems.
You are right. I misinterpreted the NHK article which was merely saying that it is water "after cesium reduction process".

The Japanese press release at http://www.tepco.co.jp/cc/press/2013/1229852_5117.html is consistent with http://www.tepco.co.jp/nu/fukushima-...30820_01-j.pdf

I have no idea why Cs concentrations are so high (for example compared with http://www.tepco.co.jp/en/nu/fukushi...r_130809-e.pdf )

http://mainichi.jp/graph/2013/08/21/...0000c/001.html Helicopter picture showing workers on the top of the tanks at 05:14 PM on 20 August.
tsutsuji
#14119
Aug21-13, 06:57 AM
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http://www3.nhk.or.jp/news/genpatsu-...821/index.html Tank surveillance consisted of patrols twice a day. The tanks are not equipped with water level gauges. This is the fourth leakage event so far, among the 350 tanks.

http://www3.nhk.or.jp/news/genpatsu-...35_kiseii.html After a study group meeting held in the evening of 21 August, the NRA instructs Tepco to equip the tanks with water level gauges and to study alternative storage facilities. The study group will inspect the tanks at Fukushima Daiichi on 23 August.

http://www3.nhk.or.jp/news/genpatsu-...20_jouchu.html Tepco nuclear division top person, vice-president Aizawa will be permanently based in Fukushima. The existence of different people in charge at Fukushima Daiichi, at the Fukushima Daini-based Fukushima Daiichi stabilization center, at the main office and other places had been pointed out as a source of problems as regards information sharing and supervision.

http://www3.nhk.or.jp/news/genpatsu-...821/index.html 6 mSv/hour was measured on the side of the drain 50 m away from the leaking tank, so that one cannot rule out that contaminated water could have flowed into the sea. On 20 August, based on a measurement of the water in the drain finding low radioactive concentrations, Tepco had said there was little probablility that the sea had been contaminated.
zapperzero
#14120
Aug21-13, 03:19 PM
P: 1,044
Quote Quote by tsutsuji View Post
The tanks are not equipped with water level gauges.
Oh my.

By the way, we're not even one full year into the tanks' five-year warranty period and there's already problems. I wonder how it will all look another year on. Can we expect more leaks at least this big?
a.ua.
#14121
Aug21-13, 04:29 PM
P: 119
Quote Quote by tsutsuji View Post

I have no idea why Cs concentrations are so high (for example compared with http://www.tepco.co.jp/en/nu/fukushi...r_130809-e.pdf )

.
Perhaps because of this.

. It has been in use since October 2011.
http://ajw.asahi.com/article/0311dis...AJ201308210065
In those days it was still "hot".
a.ua.
#14122
Aug21-13, 04:33 PM
P: 119
Quote Quote by zapperzero View Post
Oh my.

By the way, we're not even one full year into the tanks' five-year warranty period and there's already problems. I wonder how it will all look another year on. Can we expect more leaks at least this big?
I wonder how radiation affects the rubber packing.?
tsutsuji
#14123
Aug22-13, 08:58 AM
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Quote Quote by a.ua. View Post
In those days it was still "hot".
The Kurion and Areva facilities were in service.

According to http://www.tepco.co.jp/en/nu/fukushi...10812_01-e.pdf , on 9 August 2011, Kurion and Areva achieved :

Cs 134 = ND (< 1.1 E0 Bq/cm³)
Cs 137 = ND (< 6.8 E-1 Bq/cm³)


See also http://www.tepco.co.jp/en/nu/fukushi...10818_01-e.pdf (17 August 2011)
tsutsuji
#14124
Aug22-13, 08:59 AM
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Quote Quote by zapperzero View Post
Oh my.

By the way, we're not even one full year into the tanks' five-year warranty period and there's already problems. I wonder how it will all look another year on. Can we expect more leaks at least this big?
Do you have a source for this five-year warranty period ?
tsutsuji
#14125
Aug22-13, 09:15 AM
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http://www3.nhk.or.jp/news/genpatsu-...000_genin.html The emptying operation of the leaking tank, by transferring the remaining 700 tons of contaminated water, was completed on 21 August after 09:00 PM. As the radiation is high, Tepco needs to carefully study the inspection method that will be used in order to determine the cause of the leakage. For that reason the inspection is not expected to start before next week.

http://www3.nhk.or.jp/news/genpatsu-...822/index.html Two other tanks were found with respectively 100 mSv/h and 70 mSv/h on their surfaces, but their water levels are normal. It could mean that they incurred leakage in the past.
nikkkom
#14126
Aug23-13, 05:06 AM
P: 610
Quote Quote by a.ua. View Post
I wonder how radiation affects the rubber packing.?
At these levels - probably insignificant.
zapperzero
#14127
Aug23-13, 06:31 AM
P: 1,044
Quote Quote by tsutsuji View Post
Do you have a source for this five-year warranty period ?
I remember reading it somewhere. Perhaps at ex-skf. In short, no.
blab31
#14128
Aug23-13, 08:42 AM
P: 5
Quote Quote by tsutsuji View Post
Do you have a source for this five-year warranty period ?
I can't find a tepco release with this information, but it has probably been given during a press conference, because it's all over the news sites, on NHK, or NYTimes here ( http://www.nytimes.com/2013/08/21/wo...lant.html?_r=0 ) "(...)Mr. Ono said that Tepco had assumed the tanks would last at least five years.(...) "

"assuming it will last 5 years" is not exactly a "five-year warranty period", oh well...
tsutsuji
#14129
Aug24-13, 12:03 PM
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Thanks, Blab31, for the source.

http://www3.nhk.or.jp/news/genpatsu-...824/index.html Checking past records, Tepco found that when it underwent the water filling test in another part of the plant premises, in July 2011, before being installed at its present location, the tank sunk by about 20 cm into the ground. This event might have caused deformations or damage. However after receiving a report from the contractor company that no problem had been found by an inspection, the tank was dismantled and mounted again at its present location. Two other tanks have a "sunk into ground" record, and although they were checked and found not to be leaking, Tepco has decided to empty them, starting on 25 August. Tepco doesn't know the reason why those 3 tanks sank into the ground during the water filling test.
a.ua.
#14130
Aug29-13, 04:23 AM
P: 119
with the help of a translator

Fukushima Daiichi nuclear power plant near
Geology and groundwater and analysis


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