Commentary on the economic , geopolitical and simply fascinating things going on. Served occasionally with a side of snark.
Friday, July 11, 2014
Fukushima Nuclear Disaster Updates ( July 11 - 15 , 2014 ) Today's 6.8 quake near Fukushima is the second notable quake in less than a week for Japan ........... Plant status , updates regarding remediation attempts ......
[Breaking] M6.8 hit Fukushima offshore / No update on Fukushima plant status
Graph : Blue line shows the reactor temperature, Green line shows the SFP 5 temperature
Following up this article..
Tepco no clue to reboot coolant system of Pool of Reactor 5 / Gaining time by emergency measures – Photo [URL]
On 7/7/2014, Tepco announced they have no clue to reboot the coolant system of Reactor 5 Spent Fuel Pool.
Based on their estimate, there is 8 days left until the pool temperature reaches the safety limit of 65℃.
The pictures below show the leakage hole on the valve and their temporary repairs. The gray material is reported to be hardening agent but it is not explained if it’s merely cement or bond.
In order to slower the pool temperature going up, Tepco re-use the coolant system of the reactor itself as the emergency measures, but it causes the risk to let the reactor heated up again.
If the reactor temperature goes over 100℃, it is not the cold shutdown state. Tepco is commenting they still have time until it reaches 100℃ however the heating rate per hour is not announced.
From Tepco’s plant parameter, the temperature of Reactor 5 had rapidly increased since they directed the coolant system to SFP 5 (spent fuel pool in Reactor 5) on 7/8/2014.
Until they got the coolant system back to the normal stand on 7/10/2014, the reactor temperature jumped up from 29℃ to 42.5 ℃ (The graph above is the plotted plant parameters).
This means Reactor 5 is still aggressively heated even though Tepco declares it is in the cold shut down state.
In the meantime, SFP 5 was cooled down from 33℃ to 24 ℃.
Tepco still has no clue to reboot the coolant system of SFP 5. Until they finally restart the coolant system, Tepco will have to play a seesaw game to cool down both of the reactor and pool only by one coolant system.
Preceding frozen water wall hasn’t worked since April [URL]
Related to this article.. Fukushima worker “Frozen wall was originally designed to stand with clay wall but they removed to cut the cost.” [URL]
A preceding part of the frozen water wall hasn’t been frozen for over a month, according to Tepco.
Tepco has started installing the frozen water underground wall to isolate 4 reactor buildings in Fukushima plant. Preceding the wall, Tepco installed the same wall in underground trench of the seaside of Reactor2 and 3.
Approx. 11,000 t of highly contaminated water is assumed to be retained in this trench to leak to underground and the Pacific.
This was an attempt to stop additional contaminated water flowing from reactor2 turbine building to this trench by freezing water like a wall. However even though they have been trying to freeze the water since the end of April, the water hasn’t been frozen by now.
They assume it is because the inner structure prevents water from being frozen and also the contaminated water is still flowing.
On 7/7/2014, Tepco admitted the preceding “frozen” water wall hasn’t gotten frozen over 2 months after the operation.
They installed the coolant packers at 2 locations of underground trench of the seaside of Reactor2 in the end of April and June but neither of them have been frozen.
As the reason, Tepco comments the water flow is preventing it from frozen. Tepco plans to install additional packers and grout and announces they can still complete freezing the wall by the end of September.