atw - International Journal for Nuclear Power | 08/09.2019

atw Vol. 64 (2019) | Issue 8/9 ı August/September
400
DECOMMISSIONING AND WASTE MANAGEMENT
Review of the Analytical Methods Used
in Nuclear Decommissioning
Application vs. aspiration – an EU-wide survey of methods
in radioanalytical chemistry
Alexandra K. Nothstein, Ursula Hoeppener-Kramar, Laura Aldave de las Heras and Benjamin C. Russell
The wave of decommissioning of nuclear facilities that Europe is facing now and in the near future requires a solid
basis of efficient chemical and radiochemical analytical methods and capabilities. This study presents the results of a
survey among European laboratories to summarize current practices, covering radionuclides, activity levels, sample
types, and analytical instrumentation to create a clearer picture of the present status and future challenges. The results
reflect the particularity of decommissioning, which requires analysis of a wide range of sample matrices. As a result, a
wide variety of radioanalytical methods are deployed. However, gamma spectrometry, liquid scintillation counting and
alpha spectrometry remain by far the dominant analytical methods. Despite the need for novel methods for specific
nuclides, laboratories did not consider specialization or miniaturization of instruments as a focus for future developments.
Rather, two types of challenges emerged most prominently: firstly, process optimization, such as improved and
more integrated communication with customers and regulatory bodies and secondly, methodical improvements, such
as the more widespread application of new technologies and enhanced availability of reference materials.
Introduction
Decommissioning of the first nuclear
reactors is progressing and Europe is
currently facing a decommissioning
wave, which will continue into the
future due to the planned shutdown
of the first and second generation
nuclear power plants (NPPs) and
facilities in the next 5 to 50 years
[ European Commission, 2016]. With
about a third of the EU’s 186 reactors
requiring decommissioning at an
estimated cost of 4 to 5 billon € each,
this adds up to a total of 200 to
300 billion € for near future decommissioning
projects within the EU
[OECD, 2016]. Thus, processes that
improve the efficiency of decommissioning,
analytical methods for radionuclide
determination, and availability
of Europe-wide standards are
all becoming increasingly relevant
[Judge & Regan, 2017].
Decommissioning is a strongly
regulated process [McIntyre, 2012],
in which a range of radionuclides
must be analyzed using approved
methods that reach specified limits of
detection and accuracy. Decommissioning
also requires a spectrum of
analytical methods because of the
multitude of radionuclides, matrices
and sample preparation procedures,
all of which span a vast range of
activity levels [Hou, 2007]. The choice
of methods for each radionuclide
depends on the sample, i.e. sample
matrix, activity level and amount,
which, in turn, is dependent on legal
requirements and regulatory statutes
for sampling at nuclear facilities and
power plants during decommissioning.
Detection limits for specific nuclides
are then determined by
declaration criteria. Analysis of radionuclides
is therefore strongly dependent
on a number of parameters
and requires a variety of analytical
methods [Hou et al. 2016], which, to
some extent is contradictory to the
need for a highly efficient, routinebased
approach to radioanalytics with
high-output capacity required to meet
the challenge of the current wave of
decommissioning.
Moreover, an overview of the
analytical methods and the scope with
which they are employed throughout
Europe, is currently lacking. Meanwhile,
standardized measurement
procedures that rely on suitable
reference materials are absent or still
being developed [Larijani et al. 2017].
Therefore, it is difficult to determine
whether the available analytical
methods are sufficient and valid when
compared with requirements.
To improve the understanding of
current capabilities and future needs
and challenges, a survey was conducted
for end users of European
laboratories, as part of the Horizon
2020 INSIDER project. The survey
covered radionuclides measured,
their activity levels, analytical instrumentation
and sample matrices.
Materials and Methods
The survey was composed of open and
closed style questions. A total of 18
questions were posed to the participants.
Ten questions indicated the use
of several options (i.e. multiple
nuclides with multiple analytical options)
and a free text option to cover
all possibilities. The aim was to collect
information on the type of laboratories
working on decommissioning, the
sample types analyzed, the activity
levels measured, the sample preparation
techniques utilized, the radionuclides
determined, and the analytical
methods used. The final two open
style questions asked the participants
to provide their view of the future and
in particular the analytical challenges
for both their laboratory and decommissioning
in general.
The survey was created using
the online tool SurveyMonkey (ref:
https://www.surveymonkey.com/).
Laboratory managers from the
INSIDER consortium, as well as others
contacted through personal networks,
were initially contacted and asked to
collect European-wide data with the
intention to reach a representative
sample of laboratories working in
the field. A total of approximately
140 persons were contacted, of which
80 agreed to participate. Out of
75 personalized survey links that were
sent out, 34 surveys were completed
from 16 countries (10 from Germany,
5 from France, 2 from Belgium,
Hungary, Romania, Sweden and
Switzerland. Austria, Croatia, Denmark,
Finland, Italy, and one from
each of the Netherlands, Slovakia,
Spain and the United Kingdom). Five
additional surveys were begun, but
not completed. Only completed
surveys were analyzed. The survey
Decommissioning and Waste Management
Review of the Analytical Methods Used in Nuclear Decommissioning ı Alexandra K. Nothstein, Ursula Hoeppener-Kramar, Laura Aldave de las Heras and Benjamin C. Russell