The total number of samples for beta nuclide analyses from March 2011 to January 2014 is 20,866. It turns out that if the sample contains more than 200,000 Bq/Liter of beta nuclides, the instrument cannot accurately measure the radioactivity.
From Fukushima Minyu (2/15/2014):
Possibility of mistakes in measuring beta nuclides in 167 samples
TEPCO underestimated the densities of beta nuclides including strontium-90 in the analyses of contaminated water at Fukushima I Nuclear Power Plant. On February 14, TEPCO announced the result of the investigation that says TEPCO underestimated [the densities of beta nuclides] in 167 samples taken and analyzed between March 2011 and the end of January 2014. The actual densities are expected to be much higher.
According to TEPCO, these 167 samples were taken from the seawater, groundwater from the observation wells, and soil inside the plant compound.
The total number of samples for beta nuclide analyses from immediately after the start of the nuclear accident and the end of January this year is 20,866. The investigation so far has revealed that the instrument [used by TEPCO] cannot accurately measure the samples with beta nuclides exceeding 200,000 Bq/Liter, and there are 167 such samples. TEPCO says the company will analyze these samples again, and publish the accurate results.
Only now TEPCO is allowed to admit to the mistake. Now that the 2020 Olympics will be held in Tokyo, and now that the Tokyo gubernatorial election is safely over, with the win by a pro-nuclear candidate with whom TEPCO is very comfortable working.
TEPCO correctly measured the sample with 5 million Bq/L of strontium-90, but they did not disclose the number because their measurement of all-beta including strontium-90 in the same sample was 0.9 million Bq/L, which was an impossibility. They sat on it, and sat on it until February 7, 2014.
According to tweets by nuclear experts, TEPCO has the analysis lab at Fukushima I Nuclear Power Plant with 30 staff members. According to these experts, it is barely adequate for the amount of work they have to do.
And where is the promise of "the national government at the forefront" by the Abe administration?
Now that the 2020 Olympics is in the bag and the governor of Tokyo is the highly blackmailable Masuzoe, Abe has moved on to his pet project - Constitutional amendment, which will be determined solely by him as the "CEO" of the nation.