Post by Ex_Nuke_Troop on Apr 19, 2014 18:11:02 GMT
The Japan Times : New steps worked out to deal with contaminated water
4:30 am, March 06, 2014
The Yomiuri Shimbun
Decommissioning operations at Tokyo Electric Power Co.’s Fukushima No. 1 nuclear power plant, which will take around 40 years to complete, are still in the earliest stages.
Over the past year, progress has been made in the decommissioning work, including removal of spent nuclear fuel from the storage pool at the No. 4 reactor.
However, the leakage of water contaminated with radioactive materials from storage tanks also developed into a serious problem. The government and TEPCO continue to work together to tackle such problems.
The issue regarding the contaminated water has two key facets. The first is that radioactive substances continue to flow into the sea. It appears that high-level radioactive contaminated water from tunnels extending from the No. 1 to No. 4 reactor building is flowing into the sea.
TEPCO is now proceeding with construction work to seal connections between the tunnels and buildings, in an effort to stop the water from leaking. After TEPCO stops the leakage, it will then start collecting the water beginning in June. The utility also will solidify sea floor soil in April to prevent radioactive substances in the soil from spreading.
The second facet is that groundwater continues to flow into the reactor buildings, and the volume of contaminated water keeps increasing.
Currently, TEPCO collects contaminated water from the building, treats it to remove radioactive cesium, then stores it in tanks. The amount of contaminated water in storage has reached about 350,000 tons.
There are now, all told, 1,000 storage tanks—far too many to manually inspect. Last summer, tanks in the H4 sector leaked large quantities of contaminated water, as did tanks in the H6 sector last month.
The government and TEPCO have jointly worked out measures to reduce the flow of groundwater into the reactor buildings.
These include groundwater bypass wells to pump up groundwater and discharge it to the sea before it flows into the buildings; installing subsurface frozen soil dams surrounding the buildings to block the flow of groundwater into the buildings; and paving the ground to prevent rainwater from sinking into the soil.
Construction of some groundwater bypass wells has already been completed.
The government and TEPCO are working together to explain the situation to local governments concerned in an effort to achieve understanding among local residents concerning discharges of water into the ocean.
Technical feasibility studies for the proposed underground frozen soil dams are scheduled to start soon.
Total capacity of the contaminated water tanks will be increased to about 800,000 tons by the end of fiscal 2015. TEPCO said that stronger, welded-construction tanks have been under construction, instead of the currently used hand-assembled tanks.
TEPCO is also speeding up purification of the contaminated water using a new technology called an Advanced Liquid Processing System (ALPS), seeking to minimize adverse effects in the event of any future leaks.
archive.today/3oqvL#selection-1371.1-1411.210
4:30 am, March 06, 2014
The Yomiuri Shimbun
Decommissioning operations at Tokyo Electric Power Co.’s Fukushima No. 1 nuclear power plant, which will take around 40 years to complete, are still in the earliest stages.
Over the past year, progress has been made in the decommissioning work, including removal of spent nuclear fuel from the storage pool at the No. 4 reactor.
However, the leakage of water contaminated with radioactive materials from storage tanks also developed into a serious problem. The government and TEPCO continue to work together to tackle such problems.
The issue regarding the contaminated water has two key facets. The first is that radioactive substances continue to flow into the sea. It appears that high-level radioactive contaminated water from tunnels extending from the No. 1 to No. 4 reactor building is flowing into the sea.
TEPCO is now proceeding with construction work to seal connections between the tunnels and buildings, in an effort to stop the water from leaking. After TEPCO stops the leakage, it will then start collecting the water beginning in June. The utility also will solidify sea floor soil in April to prevent radioactive substances in the soil from spreading.
The second facet is that groundwater continues to flow into the reactor buildings, and the volume of contaminated water keeps increasing.
Currently, TEPCO collects contaminated water from the building, treats it to remove radioactive cesium, then stores it in tanks. The amount of contaminated water in storage has reached about 350,000 tons.
There are now, all told, 1,000 storage tanks—far too many to manually inspect. Last summer, tanks in the H4 sector leaked large quantities of contaminated water, as did tanks in the H6 sector last month.
The government and TEPCO have jointly worked out measures to reduce the flow of groundwater into the reactor buildings.
These include groundwater bypass wells to pump up groundwater and discharge it to the sea before it flows into the buildings; installing subsurface frozen soil dams surrounding the buildings to block the flow of groundwater into the buildings; and paving the ground to prevent rainwater from sinking into the soil.
Construction of some groundwater bypass wells has already been completed.
The government and TEPCO are working together to explain the situation to local governments concerned in an effort to achieve understanding among local residents concerning discharges of water into the ocean.
Technical feasibility studies for the proposed underground frozen soil dams are scheduled to start soon.
Total capacity of the contaminated water tanks will be increased to about 800,000 tons by the end of fiscal 2015. TEPCO said that stronger, welded-construction tanks have been under construction, instead of the currently used hand-assembled tanks.
TEPCO is also speeding up purification of the contaminated water using a new technology called an Advanced Liquid Processing System (ALPS), seeking to minimize adverse effects in the event of any future leaks.
archive.today/3oqvL#selection-1371.1-1411.210