Hostname: page-component-586b7cd67f-vdxz6 Total loading time: 0 Render date: 2024-11-24T16:59:38.007Z Has data issue: false hasContentIssue false
  • English
  • Français

Consequence modelling of hypothetical post-closure criticality events for spent fuel disposal

Published online by Cambridge University Press:  02 January 2018

R. M. Mason ,
J. K. Martin ,
P. N. Smith  and
R. J. Winsley
R. M. Mason*
Affiliation:
Amec Foster Wheeler, Kings Point House, Queen Mother Square, Poundbury, Dorchester DT1 3BW, UK
J. K. Martin
Affiliation:
Amec Foster Wheeler, Kings Point House, Queen Mother Square, Poundbury, Dorchester DT1 3BW, UK
P. N. Smith
Affiliation:
Amec Foster Wheeler, Kings Point House, Queen Mother Square, Poundbury, Dorchester DT1 3BW, UK
R. J. Winsley
Affiliation:
Radioactive Waste Management, Curie Avenue, Building 587, Harwell, Oxford OX11 0RH, UK
*
*E-mail: [email protected]
Rights & Permissions [Opens in a new window]

Abstract

Core share and HTML view are not available for this content. However, as you have access to this content, a full PDF is available via the ‘Save PDF’ action button.

In support of the Radioactive Waste Management (RWM) safety case for a geological disposal facility (GDF) in the UK, there is a regulatory requirement to consider the likelihood and consequences of nuclear criticality. Waste packages are designed to ensure that criticality is not possible during the transport and operational phases of a GDF and for a significant period post-closure. However, over longer post-closure timescales, conditions in the GDF will evolve.

For waste packages containing spent fuel, it can be shown that, under certain conditions, package flooding could result in a type of criticality event referred to as 'quasi-steady-state' (QSS). Although unlikely, this defines a 'what-if' scenario for understanding the potential consequences of post-closure criticality. This paper provides an overview of a methodology to understand QSS criticality and its application to a spent fuel waste package.

The power of such a hypothetical criticality event is typically estimated to be a few kilowatts: comparable with international studies of similar systems and the decay heat for which waste packages are designed. This work has built confidence in the methodology and supports RWM's demonstration that post-closure criticality is not a significant concern.

Keywords

geological disposalpost-closurespent fuelcriticality
Type
Research Article
Information
Mineralogical Magazine , Volume 79 , Issue 6 , November 2015 , pp. 1505 - 1513
Creative Commons
Creative Common License - CCCreative Common License - BY
Copyright © The Mineralogical Society of Great Britain and Ireland 2015. This is an open access article, distributed under the terms of the Creative Commons Attribution (CC BY) license (http://creativecommons.org/licenses/by/4.0/), which permits unrestricted use, distribution, and reproduction in any medium, provided the original work is properly cited.
Copyright
Copyright © The Mineralogical Society of Great Britain and Ireland 2015

References

Environment Agency, Northern Ireland Environment Agency (2009) Geological Disposal Facilities on Land for Solid Radioactive Wastes: Guidance on Requirements for Authorisation. Environment Agency, Northern Ireland Environment Agency.Google Scholar
Hicks, T.W and Baldwin, T.D. (2014) Likelihood of Criticality: The Likelihood of Criticality Synthesis Report. AMEC Report to the Nuclear Decommissioning Authority, 17293-TR-022 Version 2.Google Scholar
Mason, R.M. and Smith, P.N. (2013) Modelling of consequences of hypothetical criticality: User guide for the rapid transient model and the bounding approach. AMEC Report to the Nuclear Decommissioning Authority, AMEC/SF2409/005 Issue 1.Google Scholar
Mason, R.M. and Smith, P.N. (2015a) Modelling of consequences of hypothetical criticality: Post-closure criticality consequence analysis for ILW, LLW and DNLEU disposal. AMEC Report to the Nuclear Decommissioning Authority, AMEC/SF2409/011 Issue 3.Google Scholar
Mason, R.M. and Smith, P.N. (20156) Modelling of consequences of hypothetical criticality: Post-closure criticality consequence analysis for HLW, spent fuel, plutonium and HEU disposal. AMEC Report to the Nuclear Decommissioning Authority, AMEC/ SF2409/012 Issue 3.Google Scholar
Mason, R.M., Cummings, R., Kudelin, Y, Martindill, J., Smith, PI and Smith, P.N. (2009) A suite of calculations using the QSS and RTM computer models. Serco Report to the Nuclear Decommissioning Authority, SA/ENV-0944 Issue 2.Google Scholar
Mason, R.M., Cummings, R., Kudelin, Y, Martindill, J., Smith, P.J. and Smith, EN. (2010) Further calculations using the QSS and RTM computer models. Serco Report to the Nuclear Decommissioning Authority, SERCO/TAS-1004 Issue 4.Google Scholar
Mason, R.M., Smith, P.N., Turland, B.D. and Jackson, C.P. (201 2a) The consequences of hypothetical criticality. MineralogicalMagazine, 76, 3155–3163.Google Scholar
Mason, R.M., Martin, IK., Smith, P.N. and Turland, B.D. (20126) Comparison of a post-closure transient criticality model with the Oklo natural reactors. Mineralogical Magazine, 76, 3145–3153.CrossRefGoogle Scholar
Mason, R.M., Smith, P.N. and Holton, D. (2014) Modelling of consequences of hypothetical criticality: Synthesis report for post-closure criticality consequence analysis. AMEC Report to the Nuclear Decommissioning Authority, AMEC/SF2409/013 Issue 2.Google Scholar
Newton, T, Hosking, G., Hutton, L., Powney, D., Turland, B. and Shuttleworth, T (2008) Developments within WIMS10. PHYSOR Meeting, Interlaken, Switzerland.Google Scholar
Nuclear Decommissioning Authority (2010a) Geological Disposal: An Introduction to the generic Disposal System Safety Case. NDA Report no. NDA/RWMD/061.Google Scholar
Nuclear Decommissioning Authority (20106) Geological Disposal: Generic Environmental Safety Case Main Report. NDA Report no. NDA/RWMD/030.Google Scholar
Nuclear Decommissioning Authority (2010c) Geological Disposal: Criticality Safety Status Report. NDA Report no. NDA/RWMD/038.Google Scholar
Richards, S.D., Baker, C.M.J., Bird, A.J., Cowan, P., Davies, N., Dobson, G.P, Fry, T.C., Kyrieleis, A. and Smith, PN. (2014) MONK and MCBEND: Current Status and Recent Developments. Annals of Nuclear Energy, 82, 63–73. http://dx.doi.Org/10.1016/j.anucene.2014.07.054 CrossRefGoogle Scholar
Smith, P.N. and Mason, R.M. (2015) Modelling of Consequences of Hypothetical Criticality: User Guide for the QSS Model. AMEC Report to the Nuclear Decommissioning Authority, AMEC/ SF2409/006 Issue 2.Google Scholar
Winsley, R.J., Baldwin, T.D., Hicks, T.W., Mason, R.M. and Smith, PN. (2015) Understanding the likelihood and consequences of post-closure criticality in a geological disposal facility. Mineralogical Magazine, 79, DOI: 10.1180/minmag.2015.079.6.30CrossRefGoogle Scholar