– The highest reading of all β nuclides detected in seaside of reactor2 / 1,100,000,000 Bq/m3 (Fukushima Diary, Nov 30, 2013):
Even after Tepco built the impervious wall on the coastal line, the radiation level of the groundwater is still high in the seaside of reactor2.
The highest reading of all β nuclides (Including Strontium-90) was detected on 11/28/2013. The reading was 1,100,000,000 Bq/m3.
On 11/25/2013, 910,000,000 Bq/m3 of all β nuclides was detected at the same boring, which was the former highest reading.
It rose up by 120 % within 3 days.
About the possible cause, Tepco hasn’t made any announcement.