Gerhard Proehl:
Okay. So, let me talk a little bit about safety standards for the management of radioactive
waste. IAEA, International Atomic Energy Agency, is a UN organization which was found in
1957, and one of tasks is to establish or to ensure safety of nuclear applications. And this isalready set in the statute, to establish standards of safety for protection of health and forthe application of the standards. So, the IAEA, they have developed a number of safety
standards which have a hierarchical structure. On top of this hierarchy, there is so calledfundamentals, these are only 10 main objectives to ensure safety and protection of people
from nuclear applications. Of course, we have a wide range of nuclear applications and so,for any specific application or for a group of applications at least, there are so called safety
requirements, which means what to do in general to ensure safety, for example, in the fieldof predisposal management of waste.
This is still a high-level document, which covers more general issues and topics to beaddressed to ensure safe management of waste. And to give more guidance, there are socalled safety guides, which give more detailed guidance what to do for the application of thespecific activity, and it is related to best practice on experienced in member states and tomeet the requirements, how to do, what requirements request. For example, one standard
is disposal of radioactive waste, and there are more but general safety of facilities andactivities, and then they address the different aspects of management of waste. Predisposal
management means any activity which occurs before the waste is disposed and then thedisposal, then during disposal. Also with the commissioning of facilities, there is a lot ofwaste will be generated.
Waste disposal covers wide spectrum of activities. Waste management covers a widespectrum of activities. These are all administrative and operational activities which areinvolved in handling, pretreatment, treatment, conditioning of waste, transport, storage,
and finally also the disposal of radioactive waste. So, the disposal is the last and very
important activity of a long list of activities in-between. So, why do we need disposal? Of
course, it is quite simple. The alternative could be storage, and storage can always be only
a temporary solution.
Radioactive waste contains probably very long-lived radionuclides, which live much longer
than (0:05:00) 100 or 1000 years, and this means storage is not sustainable in the long

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term because it requires active control for safety and security, and there are ongoing
responsibilities and costs, and this would mean that also future generation would have to be
responsible and would have to spend resources on the waste that is produced andgenerated in present.
As you see there are events and developments, which could have an impact on safety andstorage. First of all, wars and terrorism where everything gets out of control but also urban
growth, natural events like storms, floods, earthquakes, or volcanic eruptions. So, disposal
is really a need. Therefore, disposal facilities is also a key topic of the IAEA, within the IAEA
safety standards. This specific safety guide gives an overview of the geological disposal andits implementation, about legal and organizational infrastructure, about the safety case andsafety assessment, and also it illustrates a stepwise approach to the development of ageological disposal facility. Stepwise approach is needed because usually such setup ofdisposal facility takes very long time, and so different steps are defined to go forward.
Another point I would like to explain is the safety case, may be you have not heard so far.
The safety case is a comprehensive evaluation of the safety assessment and in particularevaluates the findings of the safety assessment and provides statement of the confidence of
these findings. It will also address weak points of the safety assessment and how toovercome those weak points. So, the safety case and safety assessment go hand in hand.
The safety case, so to say, comprehensive, holistic view on the safety of disposal facility.
Coming back to the stepwise approach, here you have a timeline, we have several periods,
preoperational period, the operational period, and the post-closure period. This shows thedifferent activities, for example, preconstruction activities, construction activities, tooperation, closing, and then post-closing activities. And post-closing activities also includes,
at least for a limited time, some institutional control. On the long term, disposal facility has
to be designed as such that no institutional control is needed. And to give you an idea about
this timeline, can I mention that before – so preconstruction activities is about at least 10years, construction may be another 10 years, operation is usually something like 50, maybe
to 100 years, it depends on the host rock and also specific design but at least some decades.
Closure will be done probably a bit faster and by the end of the day, post closure issomething for eternity but here no longer institutional interventions are needed. (0:10:00)

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So, the requirements for safe disposal. First of all, there is a site characterization, and thisis to support a general understanding of the characteristics of the site and because we haveto look at long timeframes, also how the site will evolve over time. There are several
possibilities depending on the site. For example, the Swedish site will be constructed on anarea, which is undergoing an uplift since the last Ice Age. So, whole area is lifted by 6 mm
per year. The implications of such developments have to be addressed and have to bestudied in the site characterization.
The next one is design and, of course, the facility shall be designed in such a way to provide
operational and post-closure safety. This is what disposal is about. The construction of thisfacility has to be such that this objective is fulfilled under any circumstances. The operation,
I mean the disposal facility during operation is a normal nuclear facility, and so it has to beoperated in accordance with the IAEA safety standards or with relevant national regulations.
And the closure, I mean the facility shall be closed to provide the safety function shown inthe safety case, which are important for safety over long period of time.
So, to demonstrate long-term safety requires a safety assessment, and safety assessment
is a key activity of the IAEA to provide guidance, to ensure safety for wide range of facilities,
and disposal is one of them. And within the safety assessment, this requires the evaluationof the overall performance of a disposal system, and this disposal system comprises of thehost rock, the area where the waste is stored, the overlaying rock, and then the biosphere.
And the safety assessment requires a systematic assessment of all radiation hazards andalso to quantify radiological impact both in operation and post closure.
This is a scheme of such a disposal system. This is confinement of the waste and the waste
is usually packed in some additional matrix overpack, then they are sealed. So the idea is toisolate the waste for a long time from the biosphere. Nevertheless, in all safety assessments,
fancy ideas or scenarios are considered, which might cause in the far future, a migration ofradionuclides from the confinement area to the biosphere. Based on this data, on thisprediction, what activity could appear in the biosphere, an assessment of doses to people ismade who live in this area, which could be affected in the far future. (0:15:00)
The safety assessment is a complex document, and this is just an idea what all is necessary,
what all has to be considered and addressed in the safety assessment. So, is themanagement system internal, whether the company who is responsible for the waste does aPage 3 of 6good job, and we have some non-environmental impact, we have operational safety, andthe site and engineering and to estimate post-closure radiologic impact, the scenarios,
models, and calculations have to be described in detail.
Within our problem, what we have within the inner problem, we are not looking in detail to
all these effects and phenomenon which occur in the underground, we focus more on thebiosphere part and on the assessment of potential doses to people who live in this area. So,some guidance for this problem is also given in this safety standard. Regarding radiation
protection objective in the post-closure period, the following and the safety objective is thatthe site, design, and construct, operate, and close the disposal facility. So, protection isalways ensured, and it has also been demonstrated that doses and risks in the long term
will not exceed the dose constraints and risk constraints which are used as a design criteria.
Coming to the criteria for members of the public, for any facility which is planned, the doselimit is 1 mSv per year, and also this criteria should not be exceeded in the future. This 1mSv per year is the exposure from all nuclear facilities in an area. It might well be that inan area, there are two facilities or three but by the end of the day, each individual should
not receive more than 1 mSv per year. Therefore, a dose constraint is introduced, which isthe dose limit for specific installation rather than for all nuclear installations on a specificsite. At this point, 1 mSv per year, according to the risk factors published by the ICRP,
that’s International Commission on Radiological Protection, this is a risk of 10-5 per year.
Let us look for some criteria in national disposal facility project for Sweden, which iscurrently undergoing licensing. There is a risk constraint of 10-6 per year, and this isapproximately equivalent to an annual dose of 20 µSv. For comparison, the exposure fromnatural background is about 2.4 mSv per year. So, it is about 1% of the natural exposure.
Finland has different criteria. The doses to the most exposed people should be below 0.1
mSv per year and for those who are not most exposed, the dose should be very, very low,
insignificantly low. (0:20:00). And for the timeframe, that is required to look for theassessment for several thousand years and then Finland said there are no longer detailed
dose assessment is necessary, but they give a constraint on the radioactive release to theenvironment and these releases because these are very long-term processes could beaveraged over 1000 years.

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Coming back to Sweden, with regard to the timeframe considered for the first year, aquantitative assessment is required and for times longer than 1000 years, a sequence ofpossible developments should be considered, and these assessments should be as long as
12-year function of the disposal is required, but it should be at least 10,000 years. You see
all these radiologic criteria remain below 1 mSv per year, but the details differ from country
to country. France says the risk constraint is equivalent to a dose of 0.25 mSv per year, and10,000 years should be looked at for safety demonstration. In Germany, the dose criteria is
still under discussion, so far the criteria for high level waste disposal facility is 10 µSv peryear, which is even lower than Sweden and the timeframe of disclosure is also underdiscussion, that for 10,000 years detailed assessment should be made and then for a million
years, a more stylized, a more simplified assessment can be done to demonstrate this longterm safety.
So, this is SSG-14 recordings of post-closure safety assessment. It is said that radiation
exposure is a major safety issue, and it has to be developed, and also confidence in themodeling has to be provided. And confidence is often provided if all assumptions are very
conservative, it means very pessimistic. However, another requirement here is that theconservatism should be reasonable, shouldn’t be overly conservative, so as to have somedegree of realism. It is also said that any approach to make an acceptance easier because
we look at long timeframes and to look over long periods of time to complex systems is very
difficult. That’s why it is suggested to try to look for simple approaches. Serial approach is,of course, someone which benefits simplicity, conservatism and realism. This is consideredas the best starting point, this is also kind of a best wish.
For looking for the dose assessment, looking for compliance with safety objectives andcriteria, it is assumed that in estimating doses to individuals in the future due to a disposal
facility, people will be present locally, even if it is (0:25:00) in the middle of a desert but
people have to be around, otherwise, there is no dose. And it should also be assumed thatpeople make some use of the local resources that may contain radionuclides originatingfrom the waste of the disposal facility. So, there is requirement to look specifically to thosescenarios which could cause the migration of radionuclides from the disposal area to thebiosphere. However, since it is not possible to predict behavior of people in the future withany certainty, it is suggested that assessment models need to be stylized, simplified.

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There was an IAEA project, which was called BIOMASS in the 2000 years, and the BIOMASS
project discusses in detail the rationale and possible approaches to modeling the biosphereand the estimation of doses arising from waste disposal facilities. And this BIOMASSmethodology, they have different flowchart with different steps. First of all, it deals withassessment context, where is the disposal site and what kind of waste will be disposed off
there. It provides a detailed description of disposal system, develop scenarios, adjusted
scenarios for the assessment of exposures to people, develop appropriate assessment
models, do calculations and analysis of the doses, and then the question is does this model
address appropriately the site, if yes, then comparison with the criteria and, if no, do it
again. Details about this methodology will be given in one of the next presentations. The
report has been prepared of the BIOMASS project on the development of referencebiosphere for solid radioactive waste disposal.
So, finally, I have some conclusions. We have seen that the IAEA has developed safety
standards on the disposal of radioactive waste. The safety assessment for waste disposal
facility has to cover all components and aspects of a facility, including the host rock, waste
packages and confinement, geology and hydrology and exposures to people and thebiosphere. So, radiological criteria in the post closure period are well below 1 mSv, and thetimeframes to be considered are up to 1 million years, and this depends on the country. TheIAEA has developed methodology to set up assessment models for exposures in the farfuture.
Thank you very much.

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