Authors:K. Kondo, S. Ueda, Y. Chikuchi, H. Kawabata, N. Akata, H. Hasegawa, O. Mitamura, Y. Seike and J. Inaba
Lake Obuchi is on the Shimokita Peninsula, Aomori Prefecture, Japan, near several nuclear fuel-related facilities. The lake
contains from oligohaline to polyhaline regions, and the salinity fluctuates greatly both spatially and temporally. This study
examined the possible effect of salinity on biological concentrations of 137Cs in phytoplankton on the basis of a culture experiment using stable Cs and phytoplankton species isolated from the lake.
In both Cyclotellaand Skeletonema, the biological concentrations of Cs varied with salinity conditions, and a positive linear relation was found between maximum
proliferation and biological concentrations of Cs.
Authors:T. Iyogi, S. Ueda, S. Hisamatsu, K. Kondo, H. Haruta, H. Katagiri, M. Kurabayashi, Y. Nakamura and N. Tsuji
To obtain an average dose from 222Rn to the people in Aomori Prefecture where the first Japan"s nuclear fuel cycling facilities are now under construction, we surveyed 222Rn concentrations in 109 dwellings in the Prefecture from 1992 to 1996. The outdoor 222Rn concentrations were also measured in gardens of 15 dwellings. The 222Rn concentrations were measured with passive 222Rn detectors which used a polycarbonate film for counting a-ray and could separate concentrations of 222Rn from 220Rn. Counting efficiencies of the detectors were calibrated with a standard 222Rn chamber in the Environmental Measurement Laboratory in USA and in the National Radiological Protection Board in UK. Geometric means of 222Rn concentration were 13 and 4.4 Bq.m-3 in the dwellings and outdoor, respectively. These values were consistent to nationwide survey results in Japan. The 222Rn concentrations in the dwellings depended on their age. The concentrations were higher in recent dwellings than in older ones. The radiation dose from 222Rn was estimated, taking into account the occupancy factor for inside and outside of dwellings. The annual dose was 0.32 mSv.y-1, and 99% of the dose came from the exposure to 222Rn inside the dwelling.
Authors:V. Shantarovich, T. Suzuki, Y. Ito, K. Kondo, V. Gustov, A. Pastukhov, L. Sokolova, A. Polyakova, E. Belousova and Yu. Yampolskii
Elastic and glassy polymers are normally considered as homogeneous disordered materials with unimodal (statistical) distribution
of elementary free volumes. In this work, we discuss the results of our positron annihilation lifetime (PAL) measurements
for a number of elastic and glassy polymers, where observations of the two long-lived ortho-positronium components in the
PAL spectra and irregular (nonlinear) variations of annihilation characteristics in the vicinity of glass transition temperature
reveal structural heterogeneity of these systems. The conclusion is confirmed by measurements of thermo-stimulated luminescence,
thermo-mechanics and mobility of penetrants.