Limits...
Reduction factors for wooden houses due to external γ-radiation based on in situ measurements after the Fukushima nuclear accident.

Yoshida-Ohuchi H, Hosoda M, Kanagami T, Uegaki M, Tashima H - Sci Rep (2014)

Bottom Line: The results indicated no statistically significant difference in the median reduction factor to the representative value of 0.4 given in the International Atomic Energy Agency (IAEA)-TECDOC-225 and 1162.However, with regard to the representative range of the reduction factor, we recommend the wider range of 0.2 to 0.7 or at least 0.2 to 0.6, which covered 87.7% and 80.7% of the data, respectively, rather than 0.2 to 0.5 given in the IAEA document, which covered only 66.5% of the data.We found that the location of the room within the house and area topography, and the use of cement roof tiles had the greatest influence on the reduction factor.

View Article: PubMed Central - PubMed

Affiliation: Graduate School of Pharmaceutical Sciences, Tohoku University, 6-3 Aramaki-Aoba, Aoba-ku, Sendai, Miyagi 980-8578, Japan.

ABSTRACT
For estimation of residents' exposure dose after a nuclear accident, the reduction factor, which is the ratio of the indoor dose to the outdoor dose is essential, as most individuals spend a large portion of their time indoors. After the Fukushima nuclear accident, we evaluated the median reduction factor with an interquartile range of 0.43 (0.34-0.53) based on 522 survey results for 69 detached wooden houses in two evacuation zones, Iitate village and Odaka district. The results indicated no statistically significant difference in the median reduction factor to the representative value of 0.4 given in the International Atomic Energy Agency (IAEA)-TECDOC-225 and 1162. However, with regard to the representative range of the reduction factor, we recommend the wider range of 0.2 to 0.7 or at least 0.2 to 0.6, which covered 87.7% and 80.7% of the data, respectively, rather than 0.2 to 0.5 given in the IAEA document, which covered only 66.5% of the data. We found that the location of the room within the house and area topography, and the use of cement roof tiles had the greatest influence on the reduction factor.

Show MeSH

Related in: MedlinePlus

Frequency distribution of the reduction factor.The median reduction factor with an interquartile range is 0.43 (0.34–0.53). The frequency reduction factor distribution measured experimentally for wooden frame houses, which is referred to as the CEX-59.1316, is also plotted as closed squares.
© Copyright Policy - open-access
Related In: Results  -  Collection

License
getmorefigures.php?uid=PMC4269877&req=5

f3: Frequency distribution of the reduction factor.The median reduction factor with an interquartile range is 0.43 (0.34–0.53). The frequency reduction factor distribution measured experimentally for wooden frame houses, which is referred to as the CEX-59.1316, is also plotted as closed squares.

Mentions: The frequency distribution of the reduction factor for 522 results calculated using Eq. (1) is shown as bars in Fig. 3. The median reduction factor with an interquartile range was 0.43 (0.34–0.53), which is close to the value of the slope obtained in Fig. 2. The interquartile range is expressed by Q1–Q3, which are the middle value in the first half and the second half of the rank-ordered data set, respectively.


Reduction factors for wooden houses due to external γ-radiation based on in situ measurements after the Fukushima nuclear accident.

Yoshida-Ohuchi H, Hosoda M, Kanagami T, Uegaki M, Tashima H - Sci Rep (2014)

Frequency distribution of the reduction factor.The median reduction factor with an interquartile range is 0.43 (0.34–0.53). The frequency reduction factor distribution measured experimentally for wooden frame houses, which is referred to as the CEX-59.1316, is also plotted as closed squares.
© Copyright Policy - open-access
Related In: Results  -  Collection

License
Show All Figures
getmorefigures.php?uid=PMC4269877&req=5

f3: Frequency distribution of the reduction factor.The median reduction factor with an interquartile range is 0.43 (0.34–0.53). The frequency reduction factor distribution measured experimentally for wooden frame houses, which is referred to as the CEX-59.1316, is also plotted as closed squares.
Mentions: The frequency distribution of the reduction factor for 522 results calculated using Eq. (1) is shown as bars in Fig. 3. The median reduction factor with an interquartile range was 0.43 (0.34–0.53), which is close to the value of the slope obtained in Fig. 2. The interquartile range is expressed by Q1–Q3, which are the middle value in the first half and the second half of the rank-ordered data set, respectively.

Bottom Line: The results indicated no statistically significant difference in the median reduction factor to the representative value of 0.4 given in the International Atomic Energy Agency (IAEA)-TECDOC-225 and 1162.However, with regard to the representative range of the reduction factor, we recommend the wider range of 0.2 to 0.7 or at least 0.2 to 0.6, which covered 87.7% and 80.7% of the data, respectively, rather than 0.2 to 0.5 given in the IAEA document, which covered only 66.5% of the data.We found that the location of the room within the house and area topography, and the use of cement roof tiles had the greatest influence on the reduction factor.

View Article: PubMed Central - PubMed

Affiliation: Graduate School of Pharmaceutical Sciences, Tohoku University, 6-3 Aramaki-Aoba, Aoba-ku, Sendai, Miyagi 980-8578, Japan.

ABSTRACT
For estimation of residents' exposure dose after a nuclear accident, the reduction factor, which is the ratio of the indoor dose to the outdoor dose is essential, as most individuals spend a large portion of their time indoors. After the Fukushima nuclear accident, we evaluated the median reduction factor with an interquartile range of 0.43 (0.34-0.53) based on 522 survey results for 69 detached wooden houses in two evacuation zones, Iitate village and Odaka district. The results indicated no statistically significant difference in the median reduction factor to the representative value of 0.4 given in the International Atomic Energy Agency (IAEA)-TECDOC-225 and 1162. However, with regard to the representative range of the reduction factor, we recommend the wider range of 0.2 to 0.7 or at least 0.2 to 0.6, which covered 87.7% and 80.7% of the data, respectively, rather than 0.2 to 0.5 given in the IAEA document, which covered only 66.5% of the data. We found that the location of the room within the house and area topography, and the use of cement roof tiles had the greatest influence on the reduction factor.

Show MeSH
Related in: MedlinePlus