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

Korean Radioactive Waste Society (한국방사성폐기물학회)
권호 표지
DOI QR코드

DOI QR Code

Scoping Calculations on Criticality and Shielding of the Improved KAERI Reference Disposal System for SNFs (KRS+)

  • Received : 2020.09.18
  • Accepted : 2020.11.16
  • Published : 2020.11.30
Download PDF
⟨ Previous Next ⟩

Abstract

In this paper, an overview of the scoping calculation results is provided with respect to criticality and radiation shielding of two KBS-3V type PWR SNF disposal systems and one NWMO-type CANDU SNF disposal system of the improved KAERI reference disposal system for SNFs (KRS+). The results confirmed that the calculated effective multiplication factors (keff) of each disposal system comply with the design criteria (< 0.95). Based on a sensitivity study, the bounding conditions for criticality assumed a flooded container, actinide-only fuel composition, and a decay time of tens of thousands of years. The necessity of mixed loading for some PWR SNFs with high enrichment and low discharge burnup was identified from the evaluated preliminary possible loading area. Furthermore, the absorbed dose rate in the bentonite region was confirmed to be considerably lower than the design criterion (< 1 Gy·hr-1). Entire PWR SNFs with various enrichment and discharge burnup can be deposited in the KRS+ system without any shielding issues. The container thickness applied to the current KRS+ design was clarified as sufficient considering the minimum thickness of the container to satisfy the shielding criterion. In conclusion, the current KRS+ design is suitable in terms of nuclear criticality and radiation shielding.

Keywords

References

  1. International Atomic Energy Agency Power Reactor Information System (IAEA PRIS). "Country Statistics: Korea Republic of", Accessed Jul. 1 2020, Available from: pris.iaea.org/PRIS/CountryStatistics/CountryDetails.aspx?current=KR.
  2. Korea Hydro & Nuclear Power Co. Ltd. "Public Information System of NPP Operation and Rad-waste Management: Status of SNF Storage", Accessed Jul. 1 2020, Available from: npp.khnp.co.kr/index.khnp.
  3. D.K. Cho, J.W. Kim, I.Y. Kim, and J.Y. Lee, "Investigation of PWR Spent Nuclear Fuels for the Design of Deep Geological Repository", J. Nucl. Fuel Cycle Waste Technol., 17(3), 339-346 (2019). https://doi.org/10.7733/jnfcwt.2019.17.3.339
  4. J. Lee, I.-Y. Kim, H. Ju, H.-J. Choi, and D.-K. Cho, "Proposal of an Improved Concept Design for the Deep Geological Disposal System of Spent Nuclear Fuel in Korea", J. Nucl. Fuel Cycle Waste Technol., 18(S), 1-19 (2020).
  5. International Atomic Energy Agency. Criticality Safety in the Handling of Fissile Material, IAEA Specific Safety Guide No. SSG-27 (2014).
  6. American Nuclear Society. Nuclear Criticality Safety in Operations with Fissionable Materials Outside Reactors, ANSI/ANS-8.1-1998 (1998).
  7. L.H. Johnson and F. King. Canister Options for the Direct Disposal of Spent Fuel Nagra, NAGRA Technical Report, NAGRA NTB 02-11 (2003).
  8. D.-H. Kook, D.-K. Cho, and H.-J. Choi, "Radiation Safety Assessment of CANDU Spent Fuel Disposal System", J. Radiat. Prot. Res., 35(4), 142-150 (2010).
  9. I.-Y. Kim, D.-K. Cho, and H.-J. Choi. Analysis on Characteristics of Reference SNF for KRS+ Design - I. PLUS7 SNF, Korea Atomic Energy Research Institute Report, KAERI/TR-7996/2019 (2019).
  10. I.-Y. Kim, D.-K. Cho, and H.-J. Choi. Analysis on Characteristics of Reference SNF for KRS+ Design - II. Westinghouse-type fuel (KOFA), Korea Atomic Energy Research Institute Report, KAERI/TR-8055/2020 (2020).
  11. J. Choi, K.-S. Chun, H.-J. Choi, D.-K. Cho, and P.S. Hahn. Study on the Preliminary Conceptual Design of a Waste Package for the Disposal of Spent Nuclear Fuel, Korea Atomic Energy Research Institute Report, KAERI/TR-2936/2005 (2005).
  12. D.-H. Kook, D.-K. Cho, J.-Y. Lee, M.-S. Lee, J.-T. Jeong, and H.-J. Choi. Dose Evaluation of CANDU Spent Fuel Disposal System, Korea Atomic Energy Research Institute Report, KAERI/TR-3855/2009 (2009).
  13. J.C. Wagner and C.E. Sanders. Assessment of Reactivity Margins and Loading Curves for PWR Burnup-Credit Cask Designs, U.S. Nuclear Regulatory Commission Report, NUREG-CR/6800 (ORNL/TM2002/6) (2012).
  14. Nuclear Data Center at KAERI. "Table of Nuclides", Accessed Aug. 8 2020, Available from: atom.kaeri.re.kr:81.
  15. H.-S. Dho, T.-M. Kim, and C.-H. Cho, "The Evaluation of Minimum Cooling Period for Loading of PWR Spent Nuclear Fuel of a Dual Purpose Metal Cask", J. Nucl. Fuel Cycle Waste Technol., 14(4), 411-422 (2016). https://doi.org/10.7733/JNFCWT.2016.14.4.411