Publication Laka-library:
Safety Benchmark of Borssele Nuclear Power Plant

AuthorBorssele Benchmark Commission
DateDecember 2018
Classification (BORSSELE I - GENERAL)
Remarks Available at government website, with Dutch summary, here

From the publication:

Safety Benchmark of Borssele
     Nuclear Power Plant

Second report of the Borssele Benchmark Committee – 2018

 Summary and Conclusions

    The task of the Borssele Benchmark Committee                            To establish an expert opinion on the safety
    is to determine whether the Elektriciteits                              level of KCB, as compared with the other 236
    Produktiemaatschappij Zuid-Nederland (EPZ)                              water-cooled and water-moderated power
    ensures that ”Borssele nuclear power plant                              reactors in operation in the EU, USA and Canada,
    (Kerncentrale Borssele – KCB) continues to be                           the Committee had to develop its own methodo-
    among the twenty-five percent safest water-                             logy. There are no internationally harmonised
    cooled and water-moderated power reactors                               evaluations available for all safety aspects of a
    in the European Union, the United States of                             nuclear power reactor that expresses the safety
    America and Canada. As far as possible, safety                          in one well-defined number. Requirements for
    shall be assessed on the basis of quantified                            nuclear safety are established in most countries
    performance indicators. If quantitative                                 in line with international safety standards of
    comparison is not possible for the design,                              the International Atomic Energy Agency (IAEA)
    operation, maintenance, ageing and safety                               and (within the EU) with the guides set up by
    management, the comparison shall be made                                the Western European Nuclear Regulators
    on the basis of a qualitative assessment by                             Association (WENRA) and the European Nuclear
    the Committee.”                                                         Safety Regulators Group (ENSREG). However,
                                                                            the responsibility lies with the national regula-
    This condition is part of an agreement not to                           tory authorities and despite the efforts of the
    close the plant in 2013 – as was politically                            international organisations to harmonize these
    intended – but to allow it, in principle, to                            requirements, national differences remain, and
    continue operation until 31 December 2033,                              the importance attached to various safety
    if safety requirements are met as stated in                             aspects is not necessarily uniform.
    regulations and license.
                                                                            In principle, advanced Probabilistic Safety
    This agreement was formalised in a covenant,                            Analysis (PSA) would make it possible to combine
    which also included the installation of the                             all relevant safety aspects of design and opera-
    Borssele Benchmark Committee to evaluate                                tions into one model. However, PSA methodo-
    whether KCB meets this condition.                                       logies have not been standardized, and PSAs
                                                                            have not been conducted for all nuclear power
    This document represents the second report of                           plants. For those plants that do have PSAs, not
    the Committee.                                                          all of them are available to the Committee. To
                                                                            develop PSAs would require an enormous effort
    Since the publication of the first Committee                            and would be hindered by the unavailability of
    report, some reactors have been permanently                             standardised reactor specific information and
    shut down. Therefore, the list of reactors was                          data for all the 237 peer reactors.
    revised to include only the reactors still in
    operation by 31 December 2016 (the cut-off                              Furthermore, opinions about what is important
    date set by the Committee for its assessment).                          for nuclear safety evolve due to operating
    The final list of reactors involved in the bench-                       experience, including root cause analyses of
    mark contains a total of 237 reactors.                                  incidents.

Ranking reactor safety is, therefore, a compli-    Secondly, the wider use of the Safety Aspects
cated, if not impossible task with a time-         of Long Term Operation (SALTO) review mission
dependent outcome. Nevertheless, the               made it possible to conduct the evaluation of
Committee is convinced that it developed a         ageing using the recently refined and interna-
meaningful methodology based on all available      tionally consistent methodology developed
information in combination with expert assess-     by the IAEA for SALTO review. The use of the
ment, that could be used to compare the safety     findings in SALTO reports is now the basis of
of KCB with the other reactors the Committee       the ageing benchmark, in a way comparable to
had to assess.                                     Operational safety evaluations that uses the
                                                   IAEA OSART findings (chapter 5).
For the second report, the Committee retained
the overall structure of the methodology           Thirdly, the increased worldwide consciousness
previously developed, and improved it to reflect   about the importance of safety culture is
recent developments. In particular, three recent   reflected in a more consistent and standardized
developments led to refinements and additions:     approach (chapter 8).

Firstly, post-Fukushima studies and their follow   Schematically the Committee opted for the
up brought new insights about design safety,       approach as shown in Figure 1-1 (see page 8).
leading to refinement and extension of the
design benchmark methodology (chapter 4) and
a separate evaluation of siting (chapter 6).