Evaluation of Gamma-Ray Dose Components in Criticality Accident Situations

Sono, Hiroki; Yanagisawa, Hiroshi; Ohno, Akio; Kojima, Takuji; Soramasu, Noboru

doi:10.3327/jnst.42.678

Cited by 2 publications

(14 citation statements)

References 12 publications

Supporting

Mentioning

Contrasting

Order By: Relevance

“…This neutron-induced dose component was evaluated to be 10-20% of the gross dose measured with the TLD in free air in criticality accident situations of solution systems. 10) The evaluation of the dose components of neutrons and gamma-rays requires a complicated computational anal-ysis after a thorough investigation of the accident. In this report, the gross dose measured with the TLD is used for a practical approach to emergency measures.…”

Section: Dosimetry Using Area Dosimetersmentioning

confidence: 99%

“…The uncertainty of 10-20% is allowable in radiation emergency medicine: its criterion is roughly 50% in 48 hrs and 25% in a week after the accident. 11) After the thorough investigation of the accident, the Monte Carlo simulation 10,12) under the condition at the time of the accident can remove the uncertainty from the first estimation.…”

Section: Dosimetry Using Area Dosimetersmentioning

confidence: 99%

“…As regards the dose range in criticality accidents, the previous criticality accident dosimetry at TRACY showed that the dose measured within a radius of $5 m from the radiation source was approximately in the range of 10 À15 -10 À17 Gy/fission. 9,10) The number of fissions was reported to be in the range of 10 15 -10 20 in the past sixty criticality accidents. 1) The possible dose range is thus estimated to be 1-10 À2 Gy for the smallest accident which was 10 15 fissions and 10 5 -10 3 Gy for the largest accident which was 10 20 fissions.…”

Section: Dosimetry Using Area Dosimetersmentioning

confidence: 99%

“…A spatial dose distribution is generally in inverse proportion to the square of the distance from a radiation source. Even in the area near the radiation source which is not regarded as a pointwise source, it is empirically found that the spatial dose distribution can be approximated by a simple power function: 10)…”

Section: Search For Center Of Radiation Sourcementioning

confidence: 99%

“…In other words, the combinations where observed in the TRACY radiation field (e.g., from À1:4 to À2:1), 10) we may consider that the dose at the point P i or P j has been locally attenuated. The values of a and b for the spatial dose distribution in the area are obtained where the dose seems not to be locally attenuated (hereinafter called 'unattenuated area'), using only the combinations of i and j yielding values of b in the above range.…”

Section: Estimation Of Spatial Dose Distributionmentioning

confidence: 99%

See 4 more Smart Citations

Retrospective Estimation of the Spatial Dose Distribution and the Number of Fissions in Criticality Accident Using Area Dosimeters

Sono

Ohno

Kojima

et al. 2007

J. Nucl. Sci. Technol.

Self Cite

View full text Add to dashboard Cite

A practical method is proposed for retrospective estimation of the spatial dose distribution and the number of fissions in a typical criticality accident where there is a single radiation source in an accessible room. In this method, two kinds of low-fading and tissue-equivalent dosimeters are used as area dosimeters: an alanine dosimeter and a thermoluminescence dosimeter made of enriched lithium tetra borate (7 Li 2 11 B 4 O 7). The procedure of the method consists of four parts: (1) dosimetry using area dosimeters (2) search for the center of the radiation source, (3) estimation of the spatial dose distribution in the room, and (4) estimation of the number of fissions in the accident. Dosimetry of criticality accident situations simulated at the TRACY facility demonstrates the practicability of the method. Although a post-hoc analysis in principle, this method gives useful information on the magnitude and hazard level of the accident to determine the strategy of radiation emergency medicine and other post-accident measures if the area dosimeters are retrieved immediately after the accident.

show abstract

Section: Dosimetry Using Area Dosimetersmentioning

confidence: 99%

Section: Dosimetry Using Area Dosimetersmentioning

confidence: 99%

Section: Dosimetry Using Area Dosimetersmentioning

confidence: 99%

Section: Search For Center Of Radiation Sourcementioning

confidence: 99%

Section: Estimation Of Spatial Dose Distributionmentioning

confidence: 99%

See 3 more Smart Citations

Retrospective Estimation of the Spatial Dose Distribution and the Number of Fissions in Criticality Accident Using Area Dosimeters

Sono

Ohno

Kojima

et al. 2007

J. Nucl. Sci. Technol.

Self Cite

View full text Add to dashboard Cite

show abstract

Assessment of Human Body Surface and Internal Dose Estimations in Criticality Accidents Based on Experimental and Computational Simulations

Sono

Ohno

Kojima

et al. 2006

J. Nucl. Sci. Technol.

Self Cite

View full text Add to dashboard Cite

For a study on the applicability of a personal dosimetry method to criticality accident dosimetry, an assessment of the human body surface and internal dose estimations was performed by experimental and computational simulations. The experimental simulation was carried out in a criticality accident situation created at the TRACY facility. The neutron and gamma-ray absorbed doses in muscle tissue were separately estimated by a dosimeter set of an alanine dosimeter and a thermoluminescence dosimeter made of enriched lithium tetra borate with a phantom. The computational simulation was conducted with a Monte Carlo code taking account of dose components of neutrons, prompt gammarays and delayed gamma-rays. Prior to the assessment of the body surface and internal dose estimations, the computational simulation was ascertained to be valid by comparison between the calculated dose distributions in the phantom and the measured ones. The assessment of the body surface and internal dose estimations based on the experimental and computational simulations confirmed that the personal dosimetry using the dosimeter set provided a first estimation of the body surface and internal doses with precision enough for emergency medical care.

show abstract

Evaluation of Gamma-Ray Dose Components in Criticality Accident Situations

Cited by 2 publications

References 12 publications

Retrospective Estimation of the Spatial Dose Distribution and the Number of Fissions in Criticality Accident Using Area Dosimeters

Retrospective Estimation of the Spatial Dose Distribution and the Number of Fissions in Criticality Accident Using Area Dosimeters

Assessment of Human Body Surface and Internal Dose Estimations in Criticality Accidents Based on Experimental and Computational Simulations

Contact Info

Product

Resources

About