Hostname: page-component-cd9895bd7-jkksz Total loading time: 0 Render date: 2024-12-29T06:32:48.333Z Has data issue: false hasContentIssue false

Performance Indicators Quantifying the Contribution of Safety Functions to the Confinement of Radionuclides in a Geological Repository System

Published online by Cambridge University Press:  01 February 2011

Eef Weetjens
Affiliation:
eweetjen@sckcen.be, SCK-CEN, Performance Assessments Unit, Mol, Belgium
Jan Marivoet
Affiliation:
jmarivoe@sckcen.be, SCK-CEN, Performance Assessments Unit, Mol, Belgium
Suresh C. Seetharam
Affiliation:
sseethar@sckcen.be, SCK-CEN, Performance Assessments Unit, Mol, Belgium
Get access

Abstract

The main indicators for the evaluation of the safety of a geological repository are the dose or the risk that are estimated for a sufficiently representative set of possible evolution scenarios. In recent years complementary sets of safety and performance indicators have been developed within national geological disposal programmes and international projects. Whereas safety indicators aim at giving an indication on the level of safety provided by the repository system, performance indicators aim at illustrating how the repository system works. Most sets of performance indicators that have been introduced hitherto in safety cases of geological repositories are related to the multi-barrier concept; they quantify or illustrate the contribution of the main engineered and natural barriers to the confinement of the radionuclides within the repository system. However, the application of the defence-in-depth principle to geological disposal has led to the introduction of safety functions in safety cases. Because of the paramount role played by the multi-safety-functions concept in recent safety cases, we have derived performance indicators that quantify the contribution of the main safety functions to the confinement of radionuclides in the geological repository system. The considered safety functions are containment, limitation of release and retardation. The proposed performance indicators are based on time-integrated activity or radiotoxicity fluxes released from the main successive compartments of the repository system. The proposed indicators can be applied to individual radionuclides as well as to a weighted sum of all radionuclides.

Type
Research Article
Copyright
Copyright © Materials Research Society 2010

Access options

Get access to the full version of this content by using one of the access options below. (Log in options will check for institutional or personal access. Content may require purchase if you do not have access.)

References

1 IAEA, “Geological Disposal of Radioactive Waste: Safety Requirements”, IAEA, Vienna, Report No. WS–R–4 (2006).Google Scholar
2 IAEA, “Safety indicators for the safety assessment of radioactive waste disposal”, IAEA, Vienna, Report TECDOC–1372 (2003).Google Scholar
3 Becker, D.A., Buhmann, D., Storck, R., Alonso, J., Cormenzana, J.L., Hugi, M., Gemert, F. van, O'Sullivan, P., Laciok, A., Marivoet, J., Sillen, X., Nordman, H., Vieno, T. and Niemeyer, M., “Testing of safety and performance indicators (SPIN)”. EC, Luxembourg, Report EUR 19965 EN (2003).Google Scholar
4 Corcoran, W.R., Church, J.F., Cross, M.T., Guinn, W.M. and Porter, N.J., “The critical safety functions and plant operation”, Nuclear Technology 55(3), 690 (1981).Google Scholar
5 IAEA, “Defence in depth in nuclear safety. INSAG–10”, IAEA, Vienna (1996).Google Scholar
6 Preter, P. De, Bel, J., Gens, R., Lallieux, P. and Wickham, S., “The role of safety functions, scoping calculations and process models in supporting the choice of a reference design for Belgian high-level waste and spent fuel disposal“. Engineered Barrier Systems (EBS) in the Safety Case: the role of modelling. NEA workshop proceedings, La Coruña, Spain (2005).Google Scholar
7ONDRAF/NIRAS, “The long-term safety strategy for the geological disposal of radioactive waste”, ONDRAF/NIRAS, Brussels, report NIROND-TR 2009–12E (2009).Google Scholar
8 Becker, D.A., Cormenzana, J.L., Delos, A., Duro, L., Grupa, J., Hart, J., Landa, J., Marivoet, J., Orzechowski, J., Schröder, T.J., Vokal, A., Weber, J., Weetjens, E. and Wolf, J., “Safety and performance indicators”. Deliverable 3.4.2 of the PAMINA project (2009).Google Scholar
9 Marivoet, J., Weetjens, E., Raeymaekers, F. and Seetharam, S., “Testing Safety and Performance Indicators for a Geological Repository in Clay”, SCKCEN, Mol, Report ERNNN (2010).Google Scholar