6 Aug (NucNet): Concentrations of radioactivity in measurements taken from groundwater monitoring posts at the Fukushima-Daiichi nuclear plant today have fallen slightly from the same measurements taken yesterday, Tokyo Electric Power Company (Tepco) has said.
Tepco said measured total beta-radiation activity (all-β) was 47,000 becquerels per litre (Bq/ℓ), down from 56,000 Bq/ℓ yesterday. The plant operator said the chemical element antimony was also detected today.
Tepco said it is “working intensely” to speed up contamination prevention measures in an effort to stop radioactive isotopes leaking into the sea near the plant, which was hit by an earthquake and tsunami in March 2011.
The company said analysis of seawater near the south discharge channel at the plant has shown that concentrations of radioactive material are below the legal limit.
Readings taken on 5 August near units 1-4 showed that concentrations of iodine-131, caesium-134, caesium-137 and antimony-125 were all below the limit. The company said all-β was also below the limit.
Tepco said the measured all-β at one groundwater monitoring post to the east of the units 1 to 4 turbine buildings had increased to 56,000 becquerels per litre (Bq/ℓ), up from 1,200 Bq/ℓ at the same monitoring post on 31 July 2013. A sample from another drill hole nearby had shown 150,000 Bq/ℓ on 23 July.
On 4 August, sampling was performed at 14 locations in underground reservoir drain holes and showed “no significant change” compared to results from 3 August.
Readings for concentrations of radioactivity leaking into the groundwater around Fukushima-Daiichi have fluctuated in recent weeks.
One of Tepco’s priorities is to prevent the release of cesium-137 and strontium-90 into the ocean via the intake and the outlet canals next to the plant’s sea port.
According to Reuters, Shinji Kinjo. head of a Nuclear Regulatory Authority (NRA) task force, said Tepco is struggling to solve the problem of contaminated water leaks and that radioactive water seeping into the ocean from the plant would create an “emergency”.
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To contact the editor responsible for this story: David Dalton at david.dalton@nucnet.org
