Journal of Nuclear Fuel Cycle and Waste Technology(JNFCWT) (방사성폐기물학회지)

Korean Radioactive Waste Society (한국방사성폐기물학회)
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Evaluation of Separation Distance from the Temporary Storage Facility for Decontamination Waste to Ensure Public Radiological Safety after Fukushima Nuclear Power Plant Accident

후쿠시마 원전 사고 이후 일반인의 방사선학적 안전성 확보를 위한 제염폐기물 임시저장시설 이격거리 평가

  • Received : 2016.04.12
  • Accepted : 2016.06.20
  • Published : 2016.09.30
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Abstract

The object of this study was to evaluate the separation distance from a temporary storage facility satisfying the dose criteria. The calculation of ambient dose rates took into account cover soil thickness, facility size, and facility type by using MCNPX code. Shielding effects of cover soil were 68.9%, 96.9% and 99.7% at 10 cm, 30 cm and 50 cm respectively. The on-ground type of storage facility had the highest ambient dose rate, followed by the semi-ground type and the underground type. The ambient dose rate did not vary with facility size (except $5{\times}5{\times}2m\;size$) due to the self-shielding of decontamination waste in temporary storage. The separation distances without cover soil for a $50{\times}50{\times}2m\;size$ facility were evaluated as 14 m (minimum radioactivity concentration), 33 m (most probably radioactivity concentration), and 57 m (maximum radioactivity concentration) for on-ground storage type, 9 m, 24 m, and 45 m for semi-underground storage type, and 6 m, 16 m, and 31 m for underground storage type.

후쿠시마 원전사고 이후 광역의 방사성 오염부지가 발생되었으며, 이에 대한 제염작업으로 인하여 다량의 제염폐기물이 발생하였다. 일본에서는 이를 보관하기 위하여 각 지역에 임시저장시설이 운영되고 있으며, 이들 시설들은 피난지시해제가 이루어진 지역의 일반인에 대하여 방사선학적 영향을 미칠 것으로 판단된다. 본 연구에서는 임시저장시설 인근에 거주하는 일반인의 방사선학적 안전성 확보를 위하여 임시저장시설 특성에 따른 거리별 공간 방사선량률 및 선량제한치를 만족하는 임시저장시설로부터의 이격거리를 평가하였다. 이를 위해 임시저장시설의 형태 및 크기, 복토 두께 등을 고려하였으며, MCNPX를 이용하여 방사선량률을 평가하였다. 복토에 의한 차폐효과는 두께가 10 cm일 때 68.9%, 30 cm일 때 96.9%, 50 cm 일 때 99.7%로 나타났다. 임시저장시설 형태에 따른 공간 방사선량률은 지상 보관형일 때 가장 높게 나타났으며, 이어서 반지하 보관형, 지하 보관형일 순으로 나타났다. 임시저장시설 크기에 따른 공간 방사선량률은 $5{\times}5{\times}2m$ 시설을 제외한 시설에 대하여 유사하게 나타났다. 이는 임시저장시설 내 적재된 제염폐기물에 의하여 자기차폐가 이루어지기 때문이다. 최종적으로 크기가 $50{\times}50{\times}2m$이고, 복토가 없는 임시저장시설의 경우, 지상 보관형의 평가된 이격거리는 14 m(최소농도), 33 m(최빈농도), 57 m(최대농도)이며, 반지하 보관형의 이격거리는 9 m(최소농도), 24 m(최빈농도), 45 m(최대농도), 지하보관형의 이격거리는 6 m(최소농도), 16 m(최빈농도), 31 m(최대농도)로 나타났다.

Keywords

References

  1. Y. Morino, T. Ohara, and M. Nishizawa, "Atmospheric Behavior, Deposition, and Budget of Radioactive Materials from the Fukushima Daiichi Nuclear Power Plant in March 2011", Geophys Res Lett., 38(7) (2011).
  2. Ministry of Environment, Aug. 2011. "Goal of Decontamination Work in Special Decontamination Area and Intensive Contamination Survey Area", MOE, Accessed Mar. 12. 2016. Available from: http://josen.env.go.jp/about/method_necessity/goal.html.
  3. International Atomic Energy Agency, The Fukushima Daiichi Accident; Post-accident Recovery, IAEA Technical Volume 5/5, 16-24, STD/PUB/1710 (2015).
  4. Ministry of Environment, Feb. 15. 2016. "Progress of Decontamination Work in the Special Decontamination Area", MOE, Accessed Mar. 12. 2016. Available from: http://josen.env.go.jp/material/pdf/josen_gareki_progress_201603.pdf.
  5. Ministry of Environment, Sep. 2015. "Progress of Decontamination Work in the Intensive Contamination Survey Area", MOE, Accessed Mar. 12. 2016. Available from: http://www.env.go.jp/press/files/jp/28496.pdf.
  6. Ministry of Environment, July. 21. 2015. "Current State of Intermediate Storage Facility", MOE, Accessed Mar. 12. 2016. Available from: http://josen.env.go.jp/chukanchozou/facility/effort/investigative_commission/pdf/proceedings_150721_03.pdf.
  7. Ministry of Environment, Sep. 2011. "Outline of Road map for the Special Decontamination Areas", MOE, Accessed Mar. 12. 2016. Available from: http://josen.env.go.jp/en/roadmap/pdf/chart1_5.pdf.
  8. Ministry of Environment, Mar. 4. 2016. "Amount of Waste in Temporary Storage Facility in Fukushima Prefecture", MOE, Accessed Mar. 12. 2016. Available from: http://josen.env.go.jp/area/provisional_yard/number.html.
  9. Ministry of Environment, Sep. 2015. "Number of Waste in Temporary Storage Facility in Outside Fukushima Prefecture", MOE, Accessed Mar. 12. 2016. Available from: http://josen.env.go.jp/zone/pdf /removing_soil_storage_amount_h27_09.pdf.
  10. Ministry of Environment, Planning of Decontamination Waste Transportation to Interim Storage Facilities in H26-H27, Ministry of Environment Report, 2-17 (2015)
  11. Ministry of Environment, Basic Plan for the Transportation of Contaminated Soil to Interim Storage Facility, Ministry of Environment Report, 3-5 (2014)
  12. Ministry of Environment, Decontamination Guidelines, 2nd ed, Tentative Translation, Ministry of Environment Report, 4-8 (2013).
  13. Fukushima Prefecture, Temporary Storage Technical Guideline, 3rd ed, Fukushima Prefecture Report, 14-16 (2015).
  14. Ministry of Environment, July. 31. 2015. "Amount of Design Waste in Temporary Storage Facilities in Fukushima Prefecture", MOE, Accessed Mar. 12. 2016. Available from: http://shiteihaiki.env.go.jp/initiatives_fukushima/pdf/specified_waste_status_150731.pdf?var02.
  15. International Commission on Radiation Units and Measurements, Gamma-ray spectrometry in the environment, ICRU Report 53, Bethesda. ICRU (1994).
  16. United Scientific Committee on the Effects of Atomic Radiation, "Report of the United Scientific Committee on the effects of atomic radiation to the general assembly", UNSCEAR 2013 Report, Vol 1, New York (2014).
  17. International Commission on Radiological Protection, "Conversion Coefficients for Use in Radiological Protection against External Radiation", ICRP Publication 74, Pergamon Press, Oxford (1997).
  18. Ministry of Environment, Aug. 2011. "Calculation of Ambient Dose Rate Under Dose Criteria", MOE, Accessed Mar. 3. 2016. Available from: http://josen.env.go.jp/#map_on.
  19. International Atomic Energy Agency, The Follow-up IAEA International Mission on Remediation of Large Contaminated Areas Off-site the Fukushima Daiichi Nuclear Power Plant, International Atomic Energy Agency Report, 26-28, NE/NEFW/2013 (2014).
  20. Nuclear Emergency Response Headquarters, Aug. 26. 2011. "Decontamination Guideline by Municipalities of Japan", NERHQ, Accessed Mar. 3. 2016. Available from: http://www.city.sakura.lg.jp/cmsfiles/contents/0000008/8474/20110826001-6.pdf.
  21. Ministry of Environment, Aug. 29. 2014. "Results of Decontamination work in Naraha", Accessed Mar. 11. 2016. Available from: http://josen.env.go.jp/area/data/naraha.html#.