Radionuclide Release to Stagnant Water in Fukushima-1 Nuclear Power Plant

Abstract

After the severe accident in the Fukushima 1 nuclear power plant, a large amount of contaminated stagnant water has been produced in turbine buildings and surrounding areas. This rapid communication reports the calculation of the radionuclide inventory in the core, the collection of the measured inventory in the stagnant water, and the estimation of the radionuclide release ratios from the core to the stagnant water. The present evaluation is based on data obtained before June 3, 2011. It was revealed that the release ratios of tritium, iodine and cesium were several tens of percent, while those of strontium and barium were smaller by one or two orders of magnitude. These release ratios of the Fukushima accident were equivalent to those of the TMI 2 accident.

Quantities of I-131 and Cs-137 in accumulated water in the basements of reactor buildings in process of core cooling at Fukushima Daiichi nuclear power plants accident and its influence on late phase source terms

“…Similar study has been already published [11] and showed almost the same tendencies in radioactive quantities in the accumulated water as the present study. However, small differences in the ratios of I-131 and Cs-137 quantities in the accumulated water to each core inventory were found between the previous and present Table 6.…”

Direct tritium emissions to the ocean from the Fukushima Dai-ichi nuclear accident

“…This is far below the Maximum Contaminant Level (MCL) of 3 H for drinking water, a limit of 740 Bq/L issued by the U.S. Environmental Protection Agency (2000). The 137 Cs concentrations are much higher than those of 3 H at almost all stations, because of the substantially higher amounts of 137 Cs produced in the damaged reactors of the F1-NPP compared to 3 H (Nishihara et al, 2015). High 3 H concentrations were found close to the shore.…”

Fukushima Daiichi–Derived Radionuclides in the Ocean: Transport, Fate, and Impacts

“…An initial 137 Cs/ 90 Sr ratio of 39 ± 1 in seawater was measured 30-600 km seaward of the FDNPPs in June 2011, which is significantly higher than the global atmospheric fallout ratio of 1.6 but closer to the 137 Cs/ 90 Sr ratio of 12.5 measured in stagnant water at the FDNPP site (average core release ratio from Nishihara et al 2012). 137 Cs/ 90 Sr ratios decreased with time, averaging 3.8 in 2013 in waters within 100 km of the FDNPP site (Castrillejo et al 2015).…”