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

Korean Radioactive Waste Society (한국방사성폐기물학회)
권호 표지
DOI QR코드

DOI QR Code

Method for Evaluating Radionuclide Transport in Biosphere by Calculating Elapsed Transport Time

이동 경과 시간 계산을 이용한 생물권에서의 방사성 핵종 이동 평가 방법

  • Received : 2020.03.31
  • Accepted : 2020.08.06
  • Published : 2020.08.30
Download PDF
⟨ Previous Next ⟩

Abstract

For geological disposal of radioactive wastes, a method was proposed to evaluate the radionuclide transport in the biosphere by calculating the elapsed time of nuclide migration. The radionuclides were supposed to be introduced from a natural barrier and reached a large surface water body following a groundwater flow in a shallow subsurface. The biosphere was defined as a shallow subsurface environment that included aquifers on a host rock. Using the proposed method, a calculation algorithm was established, and a computer code that implemented the algorithm was developed. The developed code was verified by comparing the simulation results of the simple cases with the results of the analytical solution and a public program, which has been widely used to evaluate the radiation dose using the radionuclide transport near the surface. A case study was constructed using the previous research for radionuclide transport from the hypothetical geological disposal repository. In the case study, the code calculated the mass discharge rate of radionuclide to a stream in the biosphere. Because the previous research only demonstrated the transport of radionuclides from the hypothetical repository to the host rock, the developed code in the present study could help identify the total transport of radionuclide along the complete pathway.

방사성폐기물의 심층처분에서 생물권에서의 방사성 핵종 이동을 핵종의 이동 경과 시간을 계산하여 평가하는 방법이 제안되었다. 방사성 핵종은 자연 방벽에서 유출되어 지하 천부의 지하수 흐름을 따라 대규모 지표수체에 도달한다고 가정하였다. 생물권은 기반암 위에 있는 대수층을 포함하는 천부 지하 환경으로 정의하였다. 제안된 방법을 이용하여, 계산 알고리즘을 수립하였고, 알고리즘을 수행하는 컴퓨터 코드를 작성하였다. 작성된 코드는 간단한 사례에서 계산된 모의 결과를 해석해 계산 결과 및 지표 부근에서의 방사성 핵종 이동에 의한 방사선량 평가에 널리 이용되는 공공 프로그램의 계산 결과와 비교하여 검증하였다. 사례 연구 조건을 가상의 심층처분장에서의 방사성 핵종 이동에 대한 이전 연구를 통해 작성하였다. 작성된 코드는 사례 연구에서 생물권의 하천으로 유출되는 핵종의 이동량을 계산하였다. 이전 연구에서는 가상의 처분장에서 모암까지의 방사성핵종의 이동만을 보여주었기 때문에, 이 코드는 모든 경로를 지나가는 방사성 핵종의 전체적인 이동을 파악하는데 도움이 될 수 있었다.

Keywords

References

  1. H.J. Choi, J.Y. Lee, and J. Choi, "Development of Geological Disposal Systems for Spent Fuels and High-level Radioactive Wastes in Korea", Nucl. Eng. Technol., 45(1), 29-40 (2013). https://doi.org/10.5516/NET.06.2012.006
  2. Posiva, Safety case for the disposal of spent nuclear fuel at Olkiluoto - Synthesis 2012, Posiva Report, POSIVA 2012-12 (2012).
  3. Posiva, Annual report 2018, Posiva Oy (2019).
  4. Svensk Karnbranslehantering AB, Long-term safety for the final repository for spent nuclear fuel at Forsmark - Main report of the SR-Site project, SKB Technical Report, SKB TR-11-01 (2011).
  5. Radioactive Waste Management, Geological disposal - Overview of the generic disposal system safety case, Nuclear Decommissioning Authority (NDA) Report, NDA Report No. DSSC/101/01 (2016).
  6. Posiva, Safety Case for the Disposal of Spent Nuclear Fuel at Olkiluoto - Terrain and Ecosystems Development Modelling in the Biosphere Assessment BSA- 2012, Posiva Report, POSIVA 2012-29 (2013).
  7. Svensk Karnbranslehantering AB, Climate and climaterelated issues for the safety assessment SR-Site, SKB Technical Report, SKB TR-10-49 (2010).
  8. Korea Atomic Energy Research Institute, Geological disposal of pyroprocessed waste from PWR spent nuclear fuel in Korea, KAERI Technical Report, KAERI/ TR-4525/2011 (2011).
  9. Korea Atomic Energy Research Institute, A safety case of the conceptual disposal system for pyro-processing high-level waste based on the KURT Site (AKRS-16): Safety case synthesis report, KAERI Technical Report, KAERI/TR-6726/2016 (2016).
  10. C. Zheng and G.D. Bennett, Applied Contaminant Transport Modeling, 2nd ed., 621, John Wiley and Sons, Inc., New York (2002).
  11. O. Banton, F. Delay, and G. Pore, "A New Time Domain Random Walk Method for Solute Transport in 1-D Heterogeneous Media", Ground Water, 35(6), 1008-1013 (1997). https://doi.org/10.1111/j.1745-6584.1997.tb00173.x
  12. Y. Hwang, N.Y. Ko, J.W. Choi, and S.S. Jo, "Radionuclides transport from the hypothetical disposal facility in the KURT field condition on the time domain", J. Korean Radioact. Waste Soc., 10(4), 295-303 (2012). https://doi.org/10.7733/jkrws.2012.10.4.295
  13. N.Y. Ko, J. Jeong, K.S. Kim, and Y. Hwang, "Travel times of radionuclides released from hypothetical multiple source positions in the KURT site", J. Nucl. Fuel Cycle Waste Technol., 11(4), 281-291 (2013). https://doi.org/10.7733/JNFCWT-K.2013.11.4.281
  14. R.A. Freeze and J.A. Cherry, Groundwater, Prentice- Hall, Inc., New Jersey (1979).
  15. S. Painter, V. Cvetkovic, J. Mancillas, and O. Pensado, "Time-Domain Particle Tracking Methods for Simulating Transport with Retention and First-Order Transformation", Water Resour. Res., 44(1), W01406, doi:10.1029/2007WR005944 (2008).
  16. A. Kreft and A. Zuber, "On the Physical Meaning of the Dispersion Equation and Its Solution for Different Initial and Boundary Conditions", Chem. Eng. Sci., 33(11), 1471-1480 (1978). https://doi.org/10.1016/0009-2509(78)85196-3
  17. J.P. Sauty, "An analysis of hydrodispersive transfer in aquifers", Water Resour. Res., 16(1), 145-158 (1980). https://doi.org/10.1029/WR016i001p00145
  18. S.L. Painter, V. Cvetkovic, and O. Pensado, "Time-Domain Random Walk Algorithm for Simulating Radionuclide Transport in Fractured Porous Rock", Nucl. Technol., 163(1), 129-136 (2008). https://doi.org/10.13182/NT08-A3976
  19. R. Yamashita and H. Kimura, "Particle Tracking Technique for Nuclide Decay Chain Transport in Fractured Porous Media", J. Nucl. Sci. Technol., 27(11), 1041-1049 (1990). https://doi.org/10.1080/18811248.1990.9731289
  20. E.K. Gnanapragasam and C. Yu, User's Guide for RESRAD-OFFSITE, United States Nuclear Regulatory Commission (U.S. NRC), NUREG/CR-7189 (2014).
  21. M.L. Rockhold, C.M.R. Yonkofski, J.L. Downs, V.L. Freedman, S.R. Waichler, and M.J. Truex, Draft Technical Impracticability Evaluation for Iodine-129 in Groundwater at Hanford: 200-UP-1 Operable Unit, Pacific Northwest National Laboratory, PNNL-28057 (2018).