Dear Bernard, Roger
JHPS would like to thank IRPA for providing the opportunity to submit comments on the draft of “IRPA Guiding
Principles on ‘Reasonableness’ in the Optimisation of Radiation Protection”. Optimization of protection is relevant
to all exposure situations and categories, and is undoubtedly a very important principle of the system of radiologicalprotection. The current regulations and protective measures may incorporate some reasonableness and rational
viewpoints, but it is important to judge whether they are sufficient or not. (For example, even if the dose is reduced
to some extent using some cost by optimisation considering this document, the judgment may be still controversial
whether the dose should be further reduced by additional cost, with taking the degree and uncertainty into
consideration.
Other factors should also be considered in an all-hazards approach, and the magnitude of resources devoted to themwill be based on a graded approach according to risk and social and economic impact. The issues to be considered in
the process are presented in the text, and this document has many suggestions for RP experts and stakeholders.
JHPS does support IRPA for tackling such a difficult task.
General comments:
Developing process of this document should also ensure transparency. For this purpose, JHPS suggests toestablish an IRPA Task Group to treat the optimization issue involving wide aspects of experts from theassociated societies.



JHPS also suggests to promote sharing specific information of optimization through case-by-case basis thatwould depend on the exposure situation and categories.



Clarification of expected readers of this document will be necessary. It is thought that the main readers will be
RP experts, regulators, medical professionals et al, but in some cases, the contents of this document should also
be understood by stakeholders who may be the members of the public when an optimisation process is
implemented for decision making.



To more improve this document, appropriate references throughout would be helpful in furthering understanding.



ICRP Publication 101(b) provides many important points for optimization. For example, para (33) “Optimisation
is a frame of mind”, para (66) “All aspects of optimisation cannot be codified; optimisation is more an obligationof means than of results.”. In this document, although it says “The above list of Guiding Principles covers
principles that should be applicable in all, or most, scenarios and situations, but cannot be taken as a complete
exhaustive set of factors.” in Conclusion, items listed in Table 3.1 in ICRP Publication 101(b) will also be helpful.

Specific comments:
Please see attached the file.

IRPA Guiding Principles on ‘Reasonableness’ in the Optimisation ofRadiation Protection (Draft v2 November 2020)
Introduction and Background
Optimisation of protection, including the inherent judgement on what is ‘reasonable’, is a cornerstoneof radiation protection. There is a very wide experience of its application in practice across all fields ofprotection. However, there are some concerns that the interpretation of what is ‘reasonable’ in
applying the ALARA concept has in some cases become too cautious and limiting, with a tendency inmany situations towards an approach of minimisation of exposure rather than exercising a balanced
judgement on what is ‘reasonable’. This is perhaps reflective of an embedded conservatism within theprofession, including within the regulatory community, and it is now very timely to reconsider ourfundamental approach to optimisation.
These concerns were expressed in the IRPA consultation on the system of protection1, and since thenthere have been several workshops and exercises to deliberate on ‘Reasonableness’. The French
Radiation Protection Society (SFRP) arranged two internationally-oriented workshops on this topic,
and published the proceedings2. The European ALARA Network has published guidance on
optimisation3, and recently the NEA held a workshop on ‘Rethinking the Art of Reasonableness’(Lisbon, January 2020)4.
In general terms these workshops and deliberations have been based around specific exposure
scenarios for the optimisation of protection, and many of the conclusions relate to the specifics of thechosen scenario. Whilst these outcomes are indeed very valuable, IRPA believes that it is also
necessary to have a clear understanding of the wider generic issues which underpin the process of
optimisation of protection for all exposure situations. IRPA has therefore prepared these Guiding
Principles, which have been developed through consultation with the Associate Societies, and which
therefore reflect the views of a wide range of radiation protection professionals and practitioners. The
views of many other international organisations have also been taken into account in thedevelopment of the guidance.
Optimisation of protection is one of three fundamental principles of radiation protection. It is often
referred to as ALARA – keeping exposures As Low As Reasonably Achievable, taking account of
economic and societal factors. Optimisation of protection is a wider picture than just consideration ofdose or exposure, although exposure is a key parameter in the concept. Experience has demonstrated
that the optimisation principle is the central pillar for the practical implementation of radiation
protection, and is the dominant factor controlling exposures in any well-developed system ofprotection.

削除: aExpenditure of huge resources to reduce trivial harm may be easily judged to be unreasonable.
However, as the cost increases when the risk is quite small, or public concern becomes a significant
factor, the judgment of reasonableness becomes much less clear. The complexity of optimisation canalso depend on the exposure situations, with emergency and existing exposure situations often being
more challenging than planned exposure. Every scenario needs its own specific considerations, but It
is also important to consider and discuss a broad understanding on how to judge what is ‘reasonable’in optimisation of protection across all situations – i.e. the common underpinning factors andprinciples.

削除: is

削除: fundamental

コメントの追加 [A1]: Adding reference will be helpful.

削除: as
削除: reduces, or
削除: increases

削除: haveThis IRPA guidance is addressed to all organisations and radiation protection professionals involved
across all fields of protection, including members of the public, operators, medical specialists,
regulators, governmental officials and advisers.

コメントの追加 [A2]: Is the member of the public also expected
as reader for this document?

Underpinning Considerations and Context
Optimisation of protection has been a fundamental component of the system of protection for many
years, and the concept of ‘reasonableness’ is integral to this approach. ICRP Publication 1015 outlines
some basic tenets of the approach, noting in particular the increasing role given to considerations ofequity, safety culture and stakeholder involvement. It emphasises that optimisation is notminimisation, and thus the best option is not necessarily the one with the lowest dose. ICRP
Publication 1386 defines reasonableness as ‘to make rational, informed, and impartial decisions that
respect other views, goals, and conflicting interests’.
In working towards a consensus on reasonableness it is helpful to provide for ongoing dialogues
between regulators, industry/sector groups and relevant professional bodies such as radiation
protection societies. This can provide a supporting national framework for the judgement anddecision-making process.

コメントの追加 [A3]: It is good that the scope of the guideline islimited to professionals, but the public should always be included in
the scope of the dialogue.

Before defining the key guiding principles for reasonableness it is helpful to explore someunderpinning considerations on which any guiding principles are based.
a) Radiation Protection Principles
Optimisation is the second of the three principles underpinning the system of protection - Justification,
Optimisation and Limitation - and cannot be seen in isolation. We must first demonstrate that the
exposure is justified: namely that it does more benefit than harm. The optimisation process needs tonote that this justification has already taken place, and not re-open that fundamental question.
It can also be helpful to note the role of dose reference levels, diagnostic reference levels and dose
constraints in the optimisation process. These are aimed at limiting the range of exposures in theinterest of ensuring equity amongst the exposed population. They are not direct limits, and mustnever be considered as such, but can be very useful in the iterative optimisation process and helpful tothe understanding of stakeholders.

コメントの追加 [A4]: Justification is about changing theexposure situation.
In the optimization process, the exposure situation may change due
to new methods, and each time this happens, a justification
decision will be included.
Therefore, it is not accurate to say here that the basic question ofjustification will not be addressed again, and the wording needs tobe modified.
This comment is also rerated to the sentence ”cannot be seen in
isolation” in the beginning.

b) LNT/Threshold
There is scientific uncertainty in the inferred risk posed by radiation in the key dose range of around a
few mSv/a, which is the situation where almost all practical decisions of protection are made.
Recognising this uncertainty, the system of protection in general use is based on the Linear No
Threshold (LNT) model, which assumes for the purposes of protection that the risks identifiable athigher doses (typically down to several tens of mSv) are extrapolated pro-rata to the low dose region.
There are other alternative concepts for the risk model for which there is some limited scientificsupport, in particular the concept of a threshold below which the risk would be zero (or even there
could be a hormetic response from such exposure).
It is clear that the concept of optimisation at low doses would not be applicable in a threshold model.
Whilst there are some strongly-held views in favour of such an approach, the widely accepted basis forthe system of protection adopts the LNT model. This IRPA guidance follows this approach.

コメントの追加 [A5]: Adding reference will be helpful.
This should not be “Identifiable risk” but “increase of cancer risk
can be significantly detectable by the epidemiological method”.
コメントの追加 [A6]: What is the reason to mention “several
tens of mSv”. This quantification should be prudent. Probably “lessthan 100-200mSv” may be accurate with reference of LSS study.？
削除: benefitIn practice there is a wide consensus that at these relevant low exposure levels, all we know is that if
there is a risk, then it is very small and is equivalent to risks that would normally be accepted in society.
In recognition of this we should accept that it is necessary at these low exposure levels to give careful
thought before allocating significant effort and resources to the pursuit of even lower doses.

コメントの追加 [A7]: Is it possible to quantitatively indicate“low level”?
コメントの追加 [A8]: Acceptable or unacceptable should not be
judged by risk alone, but should also take into account situation.

c) Ethical Values
Protection judgements must take account of the balancing of key ethical values as outlined in ICRP
Publication 1386, and the balance point will depend on circumstances:•

Prudence: This is the ability to make informed and carefully considered choices without thefull knowledge of the scope and consequences of actions. Whilst this is an important andessential concept, in practice it is often interpreted as a need for precaution, which in turnrequires careful judgement. In Publication 138 ICRP notes that prudence should not be taken
to be synonymous with caution, conservatism or never taking risks. In practical situations
where it is necessary to seek a balance between the ethical values, the weight given to
prudence and precaution should reflect the level of risk: the relative emphasis given toprecaution at for example tens of µSv should be lower than at tens of mSv, where risks are atleast a factor of one thousand higher.

•

Dignity and Justice: These values are related to fairness and limiting inequity, which lead tothe need to involve stakeholders in the judgement process, and also support the generalprinciple of optimisation. The values therefore support the introduction of equity and fairness
in the distribution of exposure among people exposed, which must be taken into accountduring optimisation.

•

Beneficence (in association with Non-Maleficence) - ‘To increase the direct and indirect
benefits for individual, community and the environment’ (ICRP 1386). In broad terms this
implies that we strive for the best value for society, with an expectation that the use ofresources should be seen to deliver appropriate benefits.

コメントの追加 [A9]: It should not be judged only by dose levels.
For example, exposure from radon is a few mSv, while exposure
from clearance materials is a few µSv, but they have completely
different meanings. We should not simply say that because thedose is 1,000 times different, the importance is 1,000 times
different. That is the ethics of protection, and that is what shouldbe emphasized in these guidelines.

In any specific optimisation situation it will be necessary to judge an appropriate balance between
these key ethical values, none of which are absolute in nature. In summary it can be said that the
ethical values in radiation protection support the concepts of proportionality, the engagement ofinterested parties, and the effective use of resources in the approach to reasonableness.
d) Context of risks and natural background exposure
Most radiation protection decisions involve doses less than ‘a few’ mSv/a, or indeed much lower. The
overwhelming majority of exposures are well within the variability of natural background exposure,and hence make very little difference to the total dose received by any individual, with total exposure
from all sources remaining within the normal range of natural background. As noted above, in this low
dose exposure range, little direct evidence of harm is obtained, hence giving uncertainty over the truerisk.
Whilst we cannot ignore the optimisation of such low dose exposures, we should nevertheless be
cognisant of society’s pragmatic ‘common sense’ approach to these variations of background exposurelevels. In normal day-to-day life the many individual decisions (and associated allocation of resources)
contributing to such exposure variations are not generally based on concerns or considerations ofradiation risks. Whilst such exposures are often classed as ‘voluntary’, and as such are taken to be lesssensitive than imposed risk, in practice for most situations the decisions are taken by individuals in the

コメントの追加 [A10]: From a) to c) above, ICRP publications
are cited as references. For d), it will be helpful to add UNSCEAR
report and ICRP Publication 60 as references to clearly indicate thatfrom a) to d) are the underpinning consideration.

削除: there isabsence of knowledge regarding radiation exposure, and any associated risks are therefore implicitly
deemed as acceptable by society.
Although such considerations may well not be universally applicable, it does nevertheless re-inforce
the need to ensure that the radiation protection decisions we make are seen to result in reasonablevalue for society. It also emphasises that it would be helpful for all parties (stakeholders) engaged in
the optimisation process to be aware of the context and perspective of natural background exposure.

Guiding Principles on ‘Reasonableness’
Putting some summary for previous section and explanation for the following text here will be helpful.

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JHPS suggests to categorize the following subsections by considering the characteristics of theircontents. For instance,
Current situation: 1, 2
Important points: 3, 4, 5, 8, 9Possible quantitative index: 6Open question: 7

書式変更: タブ位置: 20.89 字(なし)Regarding subsections 6 and 7, it will be appropriate to move them to appendix.

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1. Judgement Call
Optimisation of protection is a judgement call which is essentially situation-based, often termed‘taking account of the prevailing circumstances’ (which of course applies to all decisions in life). Whatis considered reasonable in one situation does not automatically determine, or necessarily strongly
influence, what may be reasonable in another situation. Whilst it is helpful to follow a structured
approach to assessing optimisation, nevertheless there can be no automatic judgement-free process
which leads to a decision. It is important that the specific circumstances are always taken into account;hence any generalised assertion that the lowest exposure for a particular activity is ‘best practice’, andmust therefore be achieved by all relevant practitioners, should not be made without properconsideration of all relevant circumstances.
2. Proportionality
It is widely acknowledged that the effort and resources allocated to optimisation should in broad
terms be proportionate to the level of risk (which may be judged in terms of individual dose andcollective dose as well as issues of perceived risk), and also take account of the potential degree of
exposure reduction. This aligns with pragmatic common sense approaches generally across society,and also with the regulatory principle of a graded approach.
Collective dose can be a valuable factor, particularly in occupational exposure considerations, but its
value in other situations may be limited – see further discussion in ICRP Publication 1015.
As noted by IAEAx, the incremental benefits to be obtained in terms of dose reduction decreaseprogressively as the associated expenditure increases. Even the cost of considering the ways in which
doses can be reduced can become significant compared with the benefit to be achieved.
3. Stakeholder Engagement

コメントの追加 [A11]: In the analysis of accidents, public
exposure should also be important. There seems to be little point insingling out occupational exposure.。

コメントの追加 [A12]: IAEA DS470 should not be used as areference here. ICRP Pub. 101 (b) is appropriate for this.
削除: At some stage, for low doses, the effort might not beworthwhile.

It is essential to involve all those parties potentially impacted by the outcome, usually termed‘stakeholders’, in judging what is reasonable in the particular circumstances. Stakeholder involvement
should be educative for all parties, and where some participants are not familiar with radiation risk it
is essential to take enough time to explore and engage cooperatively in order to share understandingof both the science and perception issues involved. Such an approach can help to address what seems
to be an inherent fear of radiation in some quarters. A key to informed decision-making is a sharedunderstanding of the science, related policies and perceived and actual risks.

コメントの追加 [A13]: There will be several issues other thanscience and perception.
コメントの追加 [A14]: Some key points, such as importance ofdialogue should be added (ICRP Publication 146)

It must be recognised that it might not always be possible to reach a full consensus on what isreasonable, and whilst all stakeholders must have the opportunity to express their own expectations
and concerns, it is important as far as possible to avoid strongly-held but singular opinions dominating
the process. The stakeholder process must be seen as open and fair, with clarity on the responsibility
for making the final decision – i.e. who has the decision authority, and what is the role of the otherinterested parties. The ideal objective of the stakeholder engagement process would be that all parties
accept that what is to be implemented is a fair outcome that is appropriately safe.
It is important to ensure that the party ultimately responsible for associated expenditure of resources
in implementing the decision outcome must be fully engaged and represented in the stakeholder
engagement process. This may involve careful consideration of who is really paying the true costs,
especially where it may involve imposed costs to customers/consumers or the use of wider society
resources. The funding party’s role and responsibilities in the optimisation process must be clearly
defined.

コメントの追加 [A15]: There is too much emphasis on cost.

ICRP 1015 notes that the extent of stakeholder involvement will vary from one situation to another.
Depending upon the circumstances, it may not be necessary to involve all stakeholders, or types of
stakeholders, in every aspect or phase of the optimisation process. Many radiological protection
decisions will not be complex or socially contentious, and thus will not need broad stakeholder
involvement.
Further guidance is contained in IRPA ‘s Guiding Principles for Radiation Protection Professionals on
Stakeholder Engagement7.
4. All Hazards Approach
The optimisation process should take account of all relevant hazards, and not necessarily focus solely
on radiation – i.e adopt an holistic ‘All Hazards’ approach. Indeed, a complete consideration should
address not just all hazards, but all negative considerations (detriments) such as expense or loss of
income, decrease or loss of services, social disruption, discrimination, the health risks of notundertaking medical radiological interventions, and so on. Furthermore, it must consider all benefits,
not just the abatement of hazards or other negative considerations. In some situations the total risk
could be increased when only radiation hazards are considered. Radiation is often not the mostsignificant hazard, although it often receives the most regulatory attention.
It is recognised that in some jurisdictions the scope/competence of a regulatory body may be limited
to radiation safety, and hence not formally encompass other risks which should be taken into accountin an All Hazards approach. In such situations it is important for the regulatory body to establish
working relations and practical agreements with other relevant regulatory authorities.
5. Avoidance of Over-Conservatism

コメントの追加 [A16]: This is not the comment for this draft but
JHPS suggest IRPA to promote sharing information of optimizationeven they are case-by-case basis depend on the exposure situationand categories.

It is very important that optimisation processes are based on realistic assessments of doses and otherrisks. The use of multiple conservative assumptions in assessments, which result in significant overestimates of exposure, or the use of ‘worst case scenarios’, are a misinterpretation of reasonablenessand can lead to a misallocation of resources. Where there is a range of possible outcomes for a
scenario, then careful judgement is necessary to determine the basis for assessments so that theoutcome may be considered as ‘reasonable’.
It is noted that in some cases an exposure assessment is undertaken solely to demonstrate compliancewith a defined criterion. In such cases it may be appropriate to use conservative parameters if thisapproach can easily demonstrate compliance. However, where it is important to determine the actual
exposure levels, such as in an optimisation assessment, then it is important to avoid overconservatisms.

コメントの追加 [A17]: Please clarify the “Other risks”.

コメントの追加 [A18]: The extent of over-conservatism will be
up to the situation. Adding some explanation on the preventive
principle may be also helpful in this subsection.

6. Value for Society
The concept of wider ‘value for society’ in the use of resources, as introduced in the above discussion
on ethical values and the risk context, should always be taken into consideration in optimisation
judgements. As noted in ICRP1048, based on general principles of good governance, governments haveobligations to pursue ‘the optimal use of societal resources’ and ‘not allow such resources to besquandered on unproductive legislation and fruitless regulatory control’. The concept of Value forSociety must include the use of financial resources as well as other concepts of societal value.
Previously in ICRP recommendations9, 10 there was an emphasis on Cost Benefit Analysis (CBA), with amonetary value placed on the personSv as a part of the judgement process. This was aimed at aligningsocietal Value for Money (VFM) across different options for resource spending. Over more recent
times there has been a growing emphasis placed on the equity issue raised by the uneven distributionof benefits and detriments through society, and on a consequent need to involve all stakeholders in
the optimisation process. These are important developments which are central to this guidance, but it
does seem that the consideration of financial factors in judging a balanced value for society has
become much less visible.
Whilst quantitative analysis such as CBA can provide important information, in practice the technique
has been limited both in scope and application, and rarely makes a significant contribution to
optimisation judgements. There are other quantitative techniques which can assist in the judgementof value for society, such as Multi Attribute Utility Analysis and related systems, and these can be
helpful.
There is evidence in other aspects of life where VFM considerations are quite central to societal
decision-making. In the healthcare sector there are several examples where decisions are made on
how to prioritise the spending of the national health budget. The use of the QALY concept (Quality
Adjusted Life Year), which in many ways has analogies with a CBA approach, has been adopted inseveral countries and has been proven as a valuable approach.
It is recognised that VFM judgements are in practice quite difficult, but it is important that they arerecognised as having a rightful place in the overall judgement of value for society. Financial
considerations are still an essential factor that stakeholders, regulators and authorities must consider.
This would be consistent with a ‘graded approach’ to optimisation and with the ethical value of
beneficence. The challenge is how to ensure that in practice these considerations are factored into

コメントの追加 [A19]: Please add some reference for this.

optimisation assessments. IRPA believes that further deliberation is necessary in order to ensure that
financial aspects are given due regard in the judgement of reasonableness.
7. De Minimis cut-off
Some consideration has previously been given to the concept of a minimum cut-off, below which nofurther efforts to address optimisation are necessary. Various proposals for such a threshold havecovered the range from 10µSv/a up to doses around 5-10% of the relevant worker or public dose limit.
Whilst this approach is understandable and has some rationale, it is difficult to apply in practice:•

The simple declaration of a fixed ‘de minimis’ value can be seen to carry an imputation thatabove this value it would indeed be necessary to take action, which may be totally
inappropriate.

•

Exposure situations are so varied that a single numerical minimum does not seem realistic,
and would be likely to lead to an inappropriate ‘lowest common denominator’ approach.

•Experience has shown that even at low doses there are often simple, realistic and inexpensive
actions that can still be taken to improve the exposure situation, often based on the ‘safety
culture’ concept.

IRPA’s view is that at small fractions of a dose limit, or significantly below reference levels, there
should be no ‘a priori’ expectation of dose reduction measures or formal demonstration of ALARA. Theinterpretation of the term ‘small fraction’ is inevitably judgemental, but would not exceed of the orderof one tenth. This does not imply that exposures above these levels should always be considered for
optimisation. Indeed, for many exposures this would be totally unrealistic.
However, as noted above, in some low dose situations there may be appropriate measures that could
reasonably be taken. For example to implement actions arising from safety culture considerations orfrom stakeholder engagement, where these improve overall confidence without imposing adisproportionate burden on society’s resources, even if there is no significant benefit in direct safety
terms. In such cases it would be helpful overtly to recognise the basis on which the decision is made.
This issue of a De Minimis approach is of wide interest and importance. IRPA believes that further
deliberation is necessary in order to further explore the concept.
8. Alignment with Radiation Protection Safety Culture
There is a very strong alignment between the key aspects of an ALARA process and the key attributesof a wider safety culture, of which radiation safety culture is an integral sub-set. A strong safety
culture should be an inherent feature of any organisation, covering all contributions to risk, including
radiation. The common essential components of a safety culture include:
•
•
•
•
•
•

Engaging with all parties involved in the activity
Implementing appropriate education and training
Maintaining an environment allowing openness and challenge
Learning and sharing from experience
Strong commitment from the leadership
Integration of the above commitments into a clear management system

コメントの追加 [A20]: Adding a reference will be needed.
コメントの追加 [A21]: Adding a reference will be needed.

コメントの追加 [A22]: This is not considered to be IRPA's view.
The basis of this document is that the extent of optimization
depends on the situation and should be considered with thestakeholders.
The quantitative content that appears in the next sentence, that it
will not exceed 1/10, is also unfounded.
In addition, this conclusion would be ambiguously positioned bybringing up the issue of safety culture.

These fundamental safety culture attributes apply irrespective of the level of risk/dose, and they
therefore provide a platform for ensuring appropriate attention in those lower dose situations wherea more formal assessment of optimisation is not appropriate.
There is good evidence for the success of safety culture approaches, especially in the cases ofoccupational exposure and for the totality of occupational and patient exposures in a healthcare
setting. Culture-based approaches are also applicable in many situations involving public exposure,especially where longer term stakeholder engagement is necessary. In such situations it is often
necessary to give greater attention to the process of engagement, due to the unfamiliarity of many
stakeholders with the concepts of radiation protection.
9. Audit Trail
In any specific optimisation scenario there are very many factors that need to be taken into account,and the outcome is often the result of a complex judgement process. As part of the process it is
helpful to declare and record the key factors which determined the decision. This will help to decide if
the optimisation process should be revisited when circumstances change, and it also makes visible
whether it is radiation risk itself, perception issues or other factors that have been key to the outcomein those specific situations. This can help inform other situations and is important in seeking to avoid
establishing inappropriate precedents, as well as ensuring that stakeholders are clearly aware of thedecision drivers.

コメントの追加 [A23]: Please add PDCA iterative process as aconcrete example for this.

Conclusions – What is ‘Reasonable’ in Optimisation of Protection?
Optimisation of protection is an essential component of radiation protection, and usually is thedominant factor controlling exposures in any well-developed system of protection. Each exposure
situation is individual, and must be addressed as such, and there is a wide range of factors whichshould be taken into account. Some of these factors may be common, or particularly important, in
specific exposure situations such as planned, emergency and existing exposures. Medical exposure
also has a particular set of common factors, for example relating to optimising imaging practicearound image quality. It is not possible for this IRPA guiding principles document to cover all thesedifferent detailed situations, however, some important points can be identified and sophisticatedowing to the valuable comments from the Associate Societies.
The above list of Guiding Principles covers principles that should be applicable in all, or most, scenariosand situations, but cannot be taken as a complete exhaustive set of factors. IRPA believes that theabove principles represent the key generic issues. Taking these into account in judgements ofreasonableness will lead to greater consistency in approach, greater confidence in the outcome andimproved transparency.

Specific remarks for the consultation on this v2 draft
There are two particular issues where there was strong support from the IRPA Associate Societies in thefirst round of consultation, but where the way forward is not clear and it was considered that further
reflection is important:•

De Minimis Cut-off: There was agreement on the need to avoid unproductive effort at very low
doses, as well as broad support for the de minimis concept, but there was a range of views on
how best to proceed.

削除: .

•

Value for Society: Specifically on how best to ensure that financial considerations are properly
taken into account.

Further reflections on these two issues are particularly welcome.

References
1. Coates et al, 2017 J. Radiol. Prot. https://doi.org/10.1088/1361-6498/aa9e5c
2. Lecomte et al, 2019 Radioprotection https://doi.org/10.1051/radiopro/2019037
3. Optimisation of Radiation Protection ALARA: A Practical Guidebook. 2019 European ALARA Networkwww.eu-alara.net
4. NEA Lisbon Workshop (reference to be added when available)
5. ICRP101:The Optimisation of Radiological Protection – Broadening the Process (2006)
6. ICRP138: Ethical Foundations of the System Radiological Protection (2018)
7. IRPA Guiding principles for Radiation Protection professionals on stakeholder Engagement (2008)
http://irpa.net/docs/IRPA%20Stakeholder%20Engagement%20Guiding%20Principles%20(2008).pdf
8. ICRP104: Scope of Radiological Protection Control Measures (2007)
9. ICRP 37: Cost Benefit Analysis in the Optimisation of Radiation protection (1983)
10. ICRP 55: Optimization and Decision-Making in Radiological Protection (1990)
X. IAEA DS470 (in draft) [to be confirmed]

Draft v2 November 2020