An exploration of the relationship between nuclear decommissioning projects characteristics and cost performance
Introduction
Until now, the nuclear sector and its stakeholders (industry, academia, policy-makers etc.) have mostly focused on the design and construction of new nuclear infrastructure while, in comparison, the body of knowledge on decommissioning is more limited. Indeed, more than 500 Nuclear Power Plants (NPPs) have been built in the world, but only 16 NPPs have been fully decommissioned (OECD/NEA, 2016). However, due to safety, security, economic, environmental, social and ethical reasons, in the near future, more and more nuclear facilities will need to be decommissioned, and a number of new challenges will arise.
Decommissioning encompasses all the “administrative and technical actions taken to allow the removal of some or all the regulatory controls from a facility, except a repository which is closed and not decommissioned” (IAEA, 2017). Nuclear Decommissioning Projects and Programmes (NDPs) are therefore here intended as site-level projects and programmes undertaken to restore the site to new use.
NDPs are characterized by extremely diverse inventories of radiological material, whose handling increases the project complexity and uncertainties. NDPs range from smaller projects like the decommissioning of Vandellós-1 NDP (in Spain), whose final costs of the work to reach dormancy in 2003 was €94.6million (IAEA, 2011, p.55), to major national multibillion projects, like Sellafield NDP (in the UK). Indeed, Sellafield alone reaches almost £120bn (€136bn), i.e. more than 70% of the decommissioning cost estimates of the whole UK nuclear legacy, which is estimated at £163bn (€185bn) (NDA, 2017b). Additionally, year after year, the estimates at completion for some of these NDPs keep increasing (see Table 2 in section 2.2), and there is only a limited understanding of why this happens. Consequently, there is a need to systematically investigate which are the NDP characteristics that mostly impact on the NDP cost performance.
NDP characteristics encompass country-specific characteristics (such as the governance, the funding and the regulatory environment, etc.), site-specific characteristics (such as the age and the operational history of the nuclear facility, etc.) and management-related characteristics (such as scope definition and planning of the NDPs). For illustrative reasons, the NDP performance are assessed in this paper in terms of the NDP cost performance, however this approach can be applied to other project performance (such as time, safety, etc.). The NDP characteristics and the NDP performance are described in more detail in section 2.
Until now, only limited research has investigated NDPs from the project management perspective, and the literature still lacks a systematic analysis to assess the association between NDP characteristics and NDP performance.1 Therefore, this paper describes a methodology based on benchmarking to analyse NDPs, focusing on the selection and application of suitable statistical tests to address this knowledge gap.
Indeed, benchmarking is ideal to compare actual or planned practices in order to identify best practices and generate ideas for improvement (PMBOK, 2013), as it is a flexible approach that can address the alleged uniqueness of NDPs. Indeed, every project can be argued to be “unique” (PMBOK, 2013). NDPs can be seen as “more unique” than other projects due to their complexity and variety of their design, the legal requirements to decommission them, the stakeholders involved, etc. However, lessons from benchmarking NDPs can still be learned, but benchmarking needs to firstly be adapted to the context of NDPs (Invernizzi et al., 2018a).
Indeed, in parallel with the growth of the decommissioning industry, the information available on decommissioning will also increase in the next decades. This information will be both qualitative and quantitative in nature, so there is a need to develop a robust methodology to guarantee a systematic analysis, in which both qualitative and quantitative data are used, and that lessons can be learned and re-applied to seemingly unique projects.
This aim of this paper is to present a systematic approach to test the association between the NDP characteristics and the NDP performance through statistics. Therefore, two statistical tests that are suitable for investigating NDPs (which consists of a small sample size) are selected and applied on 24 European NDPs with an illustrative purpose.
The remaining part of the paper proceeds as follows: section 2 reports the methodology based on benchmarking developed to investigate NDPs, detailing the process of selection of the statistical tests suitable for small sample sizes. Then, these statistical tests are applied on European NDPs; results are presented in section 3 and discussed in section 4; section 5 highlights the limitations of this analysis, while section 6 concludes the paper, paving the way for future research.
Section snippets
Adapting benchmarking to nuclear decommissioning
Invernizzi et al. (2018a; 2017a) presented a selection of benchmarking studies both in the nuclear and non-nuclear sector, highlighting that the meaning of the term “benchmarking” has been widely discussed in the last decades, and that a number of different benchmarking processes are presented in the literature (e.g. see (Anand and Kodali, 2008)). Invernizzi et al. (2018a; 2017a) also proposed a methodology based on benchmarking and tailored for NDPs, based on 5 steps:
- 1.
Research initiation, which
Results of the statistical analysis
Table 3 lists the p-values that result from the implementation of the Fisher's exact test and the Barnard's test, and that are lower than 10%. Several considerations can be drawn from these results.
The first consideration is that of the ∼80 independent variables (i.e. the NDP characteristics) that have been collected, operationalized, clustered, summarised and tested against the dependent variable “NDP cost overruns” using four different thresholds, only 17 NDP characteristics show a p-value
Discussion
This paper investigates the association between project characteristics and project performance in the nuclear decommissioning industry through statistical analysis. The originality of this research lays on both the methodological approach developed to investigate NDPs (and described in this paper) and on its application on NDPs (which has an illustrative purpose).
In terms of methodological development, compared to previous research, this paper implements the Barnard's test alongside the
Limitations and scope for future developments
Despite marking a major step towards the rigorous investigation of decommissioning projects, this paper has some limitations. The first one that affects this study is the quality of the cost data. Indeed, cost data have been collected from publicly available sources and often only a limited explanation regarding the assumptions underlying the calculation of these cost data is available: for example, the NDP estimates at completion refer to different stages of the NDP development (an information
Conclusions
NDPs are a novel class of projects that has emerged in recent years, issuing new challenges to a number of different stakeholders, including policy-makers, project managers, employees on site, and the local community surrounding the NDP. Moreover, the NDP estimates at completion for many of these projects keep increasing, and there is a limited research embracing this area. Benchmarking is a way to tackle these challenges and understand which NDP characteristics mostly impact on the NDP
Acknowledgements
This research has been supported by the grant NNL/UA/002. The authors are extremely grateful to all the NDA and NNL experts for all the support received. The opinions in this paper represent only the point of view of the authors, and only the authors are responsible for any omission or mistake. This paper should not be taken to represent in any way the point of view of NDA, NNL or any other organization involved in the decommissioning process of nuclear facilities either in the UK or abroad.
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