A crane barge has begun lifting out rubble in the intake channel area on the seaward side of the Fukushima Daiichi nuclear site, in preparation for building work to permanently wall off units 1-4 from the sea.

To allow the crane barge access to the intake channel the protective fence that prevents silt from drifting out of the intake channel into the enclosed port area has had to be opened and closed again, but Tepco has monitored radionuclide levels there during the operation. However, it has not yet released any data. The sheet pile wall will be installed slightly beyond the existing seawall. Landfill will be poured in between the two. The sheet pile wall will extend below the seabed, below two permeable layers and one low-permeable layer of rock.

•Tepco has also announced that it has started up a unit 3 spent fuel pool water decontamination system, following treatment of unit 2, which was completed on 5 December. If it is set up in the same way as at unit 2, the system will take water that has been cooled by the alternate cooling system and run it through several truck-bed mounted units, including a valve unit and caesium adsorption tower, before returning the water to the cooling system. The unit 2 system reduced water radiation level by 1000 times.

•A Tepco inspection of the Fukushima Daiichi unit 4 main turbine has found what it describes only minor damage as a result of the Great Eastern Japanese earthquake. Traces of contact between moving and stationary surfaces were found in the high-pressure turbine, low-pressure turbine A, and in the oil thrower bearing in between them.

Regular updates may be found on the website of our sister journal, Nuclear Engineering International, reachable on <www.neimagazine.com> or by clicking on the link in the navigation bar to the left of this page.

The following sites are also posting continuing updates: