Decommissioning Plan of Fukushima Daiichi Nuclear Power > Plan & Action > Major Initiatives for Water Management > Seawater Piping Trench
Since the accident, highly contaminated water has been accumulating inside the seawater piping trench; a underground tunnel originally designed to store pipes and cables, connected to the seaside of Unit 2 to Unit 4 turbine buildings. TEPCO has been trying to reduce the risks of soil/ocean contamination by removing this accumulated water and filling the inside of trench. Considering the conditions or the quality/quantity of water contained in the tunnels or vertical shafts of the trench, the contaminated water is carefully transferred to the turbine buildings. The inside of trench is also filled with materials selected considering the individual structure or length, combining several materials where needed.
Please refer to the following materials for more details since the structure of seawater piping trench differs among each unit.
Progress of Contaminated Water Removal: 100%
| Unit 2 | Unit 3 | Unit 4 | |
|---|---|---|---|
| Situation | ・Tunnel completed to be filled on Dec. 18, 2014. ・Vertical shafts completed to be filled on Jul. 10, 2015 (until O.P. +4.0m*). ・Transfer of retained water completed on Jun. 30, 2015. |
・Tunnel completed to be filled on Apr. 8, 2015. ・Vertical shafts completed to be filled on Aug. 27, 2015. ・Transfer of retained water competed on Jul. 30, 2015. |
・Tunnel completed to be filled on Mar. 21, 2015. ・Vertical shafts (I to III) completed to be filled on Apr. 28, 2015. ・Transfer of retained water completed on Dec. 11, 2015. ・Tunnel above water discharge channels completed to be filled on Dec. 21, 2015. |
| Amount of retained water remained | 0 m³ | 0 m³ | 0 m³ |
| Amount being filled | approx. 4,660 m³ | approx. 5,980 m³ | approx. 780 m³ |
*The filling was completed until O.P.+4.0m on July 10 and the entire filling was completed on July 28 except for the observation hole for Vertical Shaft C and the frozen drilling duct on the building side.
July 30, 2015
Fukushima Daiichi Nuclear Power Plant Filling Unit 2 Seawater pipe trench
February 9, 2015
Unit 3 Trench-Filling operation
November 25, 2014
Operational Start to Fill in Unit 2 Seawater Piping Trench(Japanese only)
Archive
October 16, 2014
Gap-filling Starts: Progress of Water cutoff operation on the connection between the seawater piping trench and Unit 2 and 3 buildings
December 15, 2014
Confirmation Test of the Material to Fill in Seawater Piping Trench (Japanese only)
August 19, 2014
Construction Progress to Stop Water Movement between Unit 2 and 3 Seawater Piping Trenches and the Turbine Buildings (Japanese only)
July 24, 2014
Operational Test to Insert Ice into Unit 2 Trench for Water Cutoff (Japanese only)
July 7, 2014
Construction Progress to Stop Water Movement between Unit 2 and 3 Seawater Piping Trenches and the Turbine Buildings (Japanese only)
March 28, 2014
Construction to Inject Coolant Pipes to Freeze and Stop Water inside Unit 2 Seawater Piping Treanch (Japanese only)
January 20, 2014
Camera Observation for the Inside of Unit 2 Seawater Piping Trench (Japanese only)
November 28, 2013
Mockup Test to Freeze and Cut off Water inside Trench (Japanese only)
August 13,2013
Investigation of Unit 3, 4 Seaside Trench
2015.01.28
Approaches to Contaminated Water - Removing Contamination Sources - “Removal of Highly Contaminated Water Retained Inside the Trench”
2014.08.05
Measures to stop water - Differences between freezing the trench water and the "Ice Wall"
February 18, 2014
Measures for Contaminated Water in the Seaside Trenches of Turbine Buildings
© Tokyo Electric Power Company Holdings, Inc.
