Probabilistic Analysis of Radiation Doses for Shore-Based Individuals in Operation Tomodachi

Abstract

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Radiation Dose Assessments for Shore-Based Individuals in Operation Tomodachi, Revision 1

“…Dose rates at non-MEXT locations, such as at stations of the System for Predictions of Environmental Emergency Dose Information (SPEEDI) near Yokota AB (D-8) and Yokosuka NB (D-11) were compared with dose rates obtained at the corresponding MEXT stations. External doses for the 60-day OTR period agreed within 10 percent (Chehata et al, 2013) DARWG considers this observation as sufficient support for assumptions used in deriving external dose rates, and air concentrations for times without reliable measurements using results of other, reasonably nearby locations.…”

“…Excel worksheets supported the conservative point estimates of dose using deterministic calculation methods as presented in this technical report. Mathcad worksheets supported the probabilistic dose results to be reported in the follow-on DARWG publication DTRA-TR-12-002, Probabilistic Analysis of Radiation Doses for Shore-Based Individuals in Operation Tomodachi (Chehata et al, 2013).…”

“…It is usually assumed that the whole body received a uniform radiation dose as determined from dosimeters, surveys, or calculations. additional analyses to estimate doses and associated uncertainties using probabilistic dose assessment methods to further assess the validity of the conservative dose estimates (Chehata et al, 2013). To estimate these radiation doses, the DARWG assumes that (1) the potentially exposed populations are exposed to the radiological conditions described by the environmental data presented in Section 2 of this report, (2) the human behavior or habit data are "upper percentile" values (EPA, 2011) including accounting for time spent indoors and different physical activity levels, and (3) the inhalation and ingestion DCs from ICRP databases released on compact disc read-only memory (CD-ROM) (ICRP, 2001) apply assuming 1 µm activity median aerodynamic diameter (AMAD) aerosols.…”

“…* Doses were calculated based on conservative assumptions resulting in PEP doses that were greater than the 95 th percentile values from the probabilistic dose analysis(Chehata et al, 2013).† These PEP doses were calculated assuming no time indoors and highest physical activity levels. ‡ Dose contributions from air inhalation at these sites were calculated using Yokota AB air concentration data.…”

Radiation Internal Monitoring by In Vivo Scanning in Operation Tomodachi

“…al., (2012) assumed that everyone drank from contaminated surface water supplies, which resulted in a high-sided value of 32 percent contribution to thyroid dose from water ingestion. Chehata et al (2013) showed that the doses in Cassata et. al.…”