On 27 December 2013, the Nuclear Regulation Authority (NRA) of Japan provided the IAEA its latest F1 Issues brief.
The issues brief noted that water leaked from a dike in the H5 tank area on 21 and 22 December 2013. In this case, "water" means that rainwater in the dikes surrounding storage tanks has been contaminated by radioactive material found within the dikes. Water levels inside the dikes in the H4 and H4 East tank areas decreased substantially on 24 December 2013, compared with the levels on 20 December 2013.The cause of the decreased water levels has been under investigation by TEPCO.
The NRA provided a report on the daily monitoring by TEPCO of seawater at the sampling pointsT1, T-2 and T-2-1are shown in the tables. The concentrations of all radionuclides (i.e. Cs-134, Cs-137, total Beta and H-3) did not vary remarkably in the time period from 16 to 24 December 2013 at these sampling points. See details of monitoring results here.
In addition, the IAEA has been informed that the Nuclear Emergency Response Headquarters has decided on 20 December 2013 Preventive and Multi-Layered Measures for Decommissioning and Contaminated Water Management, which are summarized here.
As a part of the cooperation between the IAEA and the NRA on marine monitoring, two IAEA experts in marine monitoring observed the seawater sampling near Fukushima Daiichi Nuclear Power Station (NPS) on board an NRA vessel at sea on 7 November 2013, and subsequently visited TEPCO's Analysis Facility at the Fukushima Daiichi NPS on 8 November 2013. This NRA video provides highlights of the observation mission by IAEA experts.
The NRA informed the IAEA that the next report on F1 Issues will be published in the second week of January 2014.