Publication Date:
2013-12-15
Description:
Publication date: Available online 14 December 2013 Source: Radiation Measurements Author(s): Jun Saegusa , Ryo Yasuda , Hiroshi Kurikami After the accident at the Fukushima Daiichi nuclear power plant (NPP), outdoor school swimming pools at Fukushima were decontaminated to curb the redistribution of radioactivity into downstream farmlands. In the process, the radioactivity concentrations of the pool water and sediment substances (residue) were measured to estimate the deposition density of the fallout. At a pool situated 50 km away from the NPP, the average concentrations of radiocesium ( 134+137 Cs) for the water and residue were quantified as 170 Bq L -1 and 3.6×10 5 Bq kg -1 , respectively. Taking account of the radioactivity concentrations and of the water balance in and around the pool, the deposition density of radiocesium, as of August 2011, was precisely estimated to be 0.32±0.03 MBq m -2 ( k =1). The density corroborated the previous results obtained by other methods, i.e., airborne surveys, in-situ Ge surveys and soil samplings at neighboring locations. Other than radiocesium, the only gamma-emitting nuclide detected was 110m Ag, with a concentration of 560 Bq kg -1 in the residue. The radioactivity concentrations of 89 Sr, 90 Sr, 238 Pu and 239+240 Pu in the water were all less than the minimum detectable activities — 2, 0.1, 0.002 and 0.002 Bq L -1 , respectively.
Print ISSN:
1350-4487
Electronic ISSN:
1879-0925
Topics:
Electrical Engineering, Measurement and Control Technology
,
Physics
