The radiation level in seawater doesn’t decrease. In order to investigate it, Tepco drilled 3 observation holes on the east side of the reactor1~4 turbine buildings.
As a result, significantly high level of radioactive water Tritium and Strontium-90 were detected. Tepco hasn’t published Sr-90 readings after 5/31/2013 as it is again “under analysis”.
Tepco states it is due to the contaminated water leakage out to the screen pump room of reactor2, which happened on 4/2/2013. In order to investigate the spread of the contaminated water, Tepco drilled 4 more observation holes. Tepco is planning to improve the ground by injecting chemical grout and fill the voids of crushed stone layer foundation.
It is assumed to be located on the east side of reactor2, where they have measured 500,000,000 Bq/m3 of Tritium since last December. The Tritium level is still significantly high.
The data of Strontium-90 is still under analysis as usual.
Strangely, they don’t analyze the samples for Tritium and Strontium-90 in the North side of reactor5 ~ 6 water outlet and the south water outlet of the plant. The reason is not announced.
On June 24, 2013 Tepco annonced us that “Tritium is travelling underground with groundwater”
Tepco found significantly high level of Tritium in groundwater and in seawater.
About 500,000,000 Bq/m3 of Tritium detected on the east side of reactor2, Tepco analyzed the cause and mechanism of how it is spreading as below.
When leakage from the reactor 2 water intake section occurred in April 2011, a part of leaked water permeated and spread into the north-side ground through the reactor 2 power cable conduit, and remains under the ground.
While cesium has been absorbed onto the soil, tritium has been moved by groundwater. http://www.tepco.co.jp/nu/fukushima-np/handouts/2013/images/handouts_130624_04-j.pdf http://www.tepco.co.jp/en/nu/fukushima-np/handouts/2013/images/handouts_130619_03-e.pdf
According to their press release on 6/24/2013, Tritium level increased to be over double within 2 weeks. It is assumed that Tritium is significantly leaking into the sea for some reason.
1) Sample : Seawater
Sampling location : North of water intake of reactor 1 ~ 4
6/21/2013 : 1,100,000 Bq/m3
6/10/2013 : 500,000 Bq/m3
2) Sample : Seawater
Sampling location : In front of the sea bank (cf, Fukushima plant tide embankment is still in the temporary state “EXIF of the picture is removed”
6/21/2013 : 910,000 Bq/m3
6/14/2013 : 600,000 Bq/m3
Tepco stating they are going to continue to analyze seawater, but it doesn’t stop the sea contamination anyway.
Finally on June 24, 2013 2013 via TEPCO Press Releases: “Tritium Density Result of Water Quality Survey inside the port of Fukushima Daiichi NPS”, where they admit Strontium presence...
”We have conducted water quality survey of the Tritium density in the seawater inside the port, of which sample taken on June 21, since a high concentration of Tritium and Strontium have been detected at the observation hole at the east side of the Unit 1-4 Turbine Buildings. According to the results shown as below, a rising trend of Tritium was observed.
<North side of the Unit 1-4 intakes>
-Sample as of June 21: 1,100 Bq/L
-Sample as of June 10: 500 Bq/L (previously announced)
<Front of Unit 1/2 bank protection>
-Sample as of June 21: 910 Bq/L
-Sample as of June 14: 600 Bq/L (previously announced)
We will take samples of the seawater and measure the concentration again.
There were no changes in the all beta concentration of the seawater. “
According to the results shown as above, a rising trend of Tritium was observed.
-Sample as of June