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‘reasonable’ only if the money, time, trouble or other costs involved in taking them would be
“grossly disproportionate” to the risk.
At this time, there is no authoritative guidance as to when cost is grossly disproportionate.
Hence, the judgment must be made on a case by case basis. Both Environment Agency
and HSE guidance on the topic of gross disproportion make clear that cost cannot form the
sole argument of a BAT, nor can it be used to undermine existing standards and good
practice. It is also important to note that, should a technique be adopted by an operator
even though it is clearly disproportionate, it would not determine BAT for other operators
(see Section 4).
2.3 Application of BAT in England and Wales
The Government
17
has stated that it will maintain, and continue to develop, a policy and
regulatory framework which ensures that radioactive wastes are not created unnecessarily.
Where such wastes are created, they are to be managed, treated and disposed of safely,
at appropriate times and in appropriate ways.
In 2009, DECC and the Welsh Assembly Government issued Statutory Guidance to the
Environment Agency for England and Wales
18
, laying down a requirement that regulators
set limits on radioactive discharges based on BAT. This includes the guidance that, “
where
the prospective dose to the most exposed group of members of the public is below
10 µSv/y from overall discharges … the Environment Agency should not seek to reduce
further the discharge limits in place, provided that the holder of the authorisation applies
and continues to apply BAT”.
*
Text Box 3. Threshold to Optimisation
The term ‘threshold to optimisation’ may be misunderstood. The key provision is that there is no
threshold in terms of dose to the public at which the techniques in place can be presumed to be
BAT simply because of their resulting impact
1
. The 10 μSv per year figure is not
a dose target, or a
dose limit, or a threshold, or a radiation standard. It merely represents an appropriate level of dose,
below which discharge limits need not be reduced further if the operator is continuing to apply BAT.
The onus remains with the operator under all
circumstances to demonstrate that BAT has been
applied. If any benefit or reduction in detriment, however small, can be achieved using little or no
additional resources then it should
be secured.
Guidance from the Environment Agency
9
states that BAT is the point when the detriments
from implementing further techniques become grossly disproportionate to the benefits
gained. Even then, if the reduction of disposals resulting from the use of BAT does not
lead to environmentally acceptable results, additional measures have to be applied.
2.4 Application of BPM in Scotland
The use of BPM continues to be required by SEPA in authorisations issued under RSA 93.
BPM was defined in Command 2919
17
in relation to the release of radioactivity into the
environment. However, SEPA uses BPM in the wider context of keeping ionising radiation
exposures to the public ALARA. Therefore BPM is not restricted to minimising the release
of radioactivity to the environment. With this in mind SEPA has redefined BPM so that it
can be applied in a fashion which is consistent with BAT.
*
In England and Wales, this value supersedes the ‘threshold to optimisation’ of 20 µSv/y set out in Cmnd
2919, although this will continue to be used in Scotland. In all other respects, the requirements as laid out
for application of BAT are essentially identical to those currently identified for the demonstration of BPM.
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In order to satisfy the requirement to keep public exposures ALARA, SEPA requires
radioactive substances users to use BPM to minimise:
1. the activity and volume of radioactive waste generated
;
2. the total activity of radioactive waste that is discharged
to the environment;
3. the radiological effects
of such discharges on the environment and members of the
public.
Although it is individual exposures that should be minimised, the optimisation process
should take account of such factors as the availability and cost of relevant measures,
operator safety, the benefits of reduced disposals and other social and economic factors,
as appropriate. As with BAT applied in England and Wales, it is important to recognise that
selecting BPM to achieve the given objectives is not a one-off process. The users of
radioactive substances should keep their operations under review to ensure that they are
continuing to use BPM.
2.5 Protecting People and the Environment
There is a distinction between the requirement to
optimise
impacts to people (that is,
keeping exposures ALARA, having regard to social, economic and other factors) and the
requirement to
protect
the environment
e.g. 5
. Impacts on non-human biota are typically
assessed at the population level, based on reference organism types, although for
protected species or habitats, more detailed impact assessments may be required.
Text Box 4. Basis for Protecting People and the Environment
The Environment Agency
1
offers the following guidance on the regulation of radioactive
substance activities on nuclear licensed sites under the EPR.
“
Dose limits for people are set at a level intended to prevent those radiation effects in humans which
are known to occur above a certain level or threshold of dose (deterministic effects) and to ensure
that the incidence of those radiation effects for which it is assumed that there is no threshold and
that the risk of causing the effect increases with the level of the radiation dose (stochastic effects) is
not at an unacceptable level. Application of the optimisation principle and the use of constraints,
which are set below dose limits, further reduces this risk to as low as reasonably achievable
.”
With respect to protection of non-human species, a full framework for radiological protection is still
under development. In the meantime, an interim assessment approach has been developed
19,20
.
This uses models of the behaviour and transfer of radionuclides within ecosystems to predict
environmental concentrations, from which the radiation doses to reference organisms can be
estimated. These doses can then be compared to 'guideline values' to assess the level of risk.
In a discussion document, the IAEA
21
recognised that definitions of, and attitudes to protecting, the
environment are culturally based. Thus, the introduction of radioactivity or any other material, or
change in property of the physical environment may be deemed intrusive; even if there is no
perceptible resultant change in any part of the living environment. Similarly, the UK Discharge
Strategy
7
states that introduction of radioactivity to the environment is ‘undesirable’.
Advice from the ICRP
6
applies optimisation both to the protection of people and of the
broader environment. Whilst the recommendations of the ICRP in this respect may
influence assessments undertaken by site operators, it is not a regulatory requirement.
2.6 Role of Collective Dose in Optimisation
Permit conditions principally require that individual exposures should be optimised.
However, the Basic Safety Standards Directive
4
places a duty on Member States to
minimise the exposure risks faced by the general public, both individually and collectively.
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Consideration of exposure to the population as a whole is typically expressed through the
concept of collective dose.
Use of collective dose is not without its pitfalls, as it may aggregate very small doses
expressed over long periods of time in such a way as to exaggerate perceptions of
detriment
6
. As collective dose is highly dependent on the selection of an exposed
population and the timeframe over which exposures are received, the concept is best
suited to comparing options as part of an optimisation exercise. Guidance on the
determination and application of collective dose has been offered by the Health Protection
Agency
41
. In summary, the HPA favours the truncation of collective doses to a period of
500 years, with identification of specific populations and geographic regions (e.g. UK,
Europe, World).
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3 Drivers for BAT Beyond Permit Conditions
Site Permit Conditions specifically require the application of BAT as a means to
demonstrate optimisation
*
(Section 2 and Text Box 8, Section 5). In addition, there are
other drivers which use similar processes (see Figure 2 below and Appendix 1 for a
summary of legislative drivers).
Figure 2.
Interactions with BAT: strategy, principles and needs
Strategies and policies requiring a BAT (or equivalent) assessment include the following.
♦
UK Discharge Strategy
. The UK strategy for radioactive discharges
7
sets out how the
UK intends to implement the OSPAR Radioactive Substances Strategy. The Strategy,
which calls for continuous reductions in the discharges and emissions of radioactive
materials to the environment, requires operators to demonstrate the application of BAT
or BPM to manage any discharges during operations.
♦
Waste Strategy
. Government policy requires a Waste Strategy for the management
and disposal of radioactive wastes, including consideration of the non-radioactive
properties of the wastes. The NDA, for example, has established a specification
supporting the development of such documents
22
. It is considered good practice to
cover non-radioactive wastes in a similar way.
♦
Business Case and Options Appraisal
. The production of business cases to support
projects is a fundamental requirement placed on the NDA by government. The NDA
has produced guidance
23
supporting the production of business cases. Business cases
must be underpinned by options appraisal (Appendix 3).
♦
Radioactive Waste Management Case.
A RWMC is a mechanism to demonstrate the
long-term safety and environmental performance of the management of specific wastes
from their generation to their conditioning into the form in which they will be suitable for
storage and (in England and Wales) eventual disposal. The RWMC should detail the
*
In Scotland, equivalent requirements within Site Authorisations under RSA require the application of BPM
as a means to demonstrate optimisation.
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available options and processes considered and any reasons and assumptions used to
reject options. Preferred options should be identified on the basis of safety and
environmental performance. Proposed packaging and conditioning strategies should
be fully underpinned by BAT assessment to minimise long-term environmental impact
and ensure associated doses are ALARA
24
.
There are also a number of policies and strategies relating to environmental management
which do not explicitly require that BAT studies are undertaken, but where the need for
BAT assessments may be identified.
♦
Environmental Management Systems.
The majority of nuclear sites operate an
EMS. Such systems provide a framework for managing environmental responsibilities,
maintenance arrangements, etc.
♦
Environmental Impact Assessments.
Throughout the UK there is a statutory
requirement for the preparation of an EIA for a range of planning applications, in order
to ensure that the likely effects (both positive and negative) of a proposed development
on the environment are fully understood and taken into account. A key initial stage in
an EIA is an options appraisal, encompassing site selection and project design. A
planning applicant is required to identify the alternatives considered and reasoning for
the choices made. Measures to prevent, reduce or offset any significant adverse
effects must be described.
♦
Strategic Environmental Assessment.
Public sector plans and programmes that are
likely to have significant effects on the environment must have an SEA when they are
being prepared
25
. The SEA process requires that all reasonable alternatives to the plan
are identified and that all likely effects on the environment are assessed. Where
significant adverse effects are identified, information must be given as to how these will
be prevented, reduced or offset. The SEA process
26
requires objective definition,
context setting, options identification and evaluation.
♦
HAZOP
. A Hazard and Operability (HAZOP) study is a structured and systematic
examination of a planned or existing process or operation in order to identify and
evaluate problems that may represent risks to personnel or equipment, or prevent
efficient operation. Typically, a HAZOP is a qualitative technique carried out by a multi-
disciplinary team during a set of meetings. Individual components within a HAZOP
study may be underpinned by identification of BAT or,
vice versa
, a BAT study may
require a HAZOP analysis.
Documents you may be interested
Documents you may be interested
