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Existing stores in Scotland are generally located on or very near to the surface. They will need to satisfy regulators as to their ability to meet health, safety, security and environmental requirements. For the purposes of the Policy near-surface for storage facilities means :. This is generally not the case for non-nuclear industries where the volumes of waste are much smaller and where it is not possible to provide long-term storage facilities on individual premises, for example in hospitals. Therefore there will not be a prescriptive definition of near to the site for storage facilities.

The presumption in the Policy is that storage facilities will be as near to the site where waste is produced as practicable. Decisions will be made on a case by case basis and will be subject to robust regulatory requirements and the principles underlying the Policy. This will require consideration of the environment, health, safety, security and transport requirements for storage options. This is consistent with the principles underpinning the Policy, particularly the Proximity Principle.

However, there may be circumstances, for example where large volumes of waste are being produced, where it will be appropriate for such non-nuclear industry waste producers to provide their own facilities. These facilities will be subject to the same requirements and robust regulatory controls that apply to waste from nuclear industry activities. Long-term does not mean indefinite storage but it may mean waste is stored for many decades. This means that a facility will have the capability to last for at least years, with the capability of extension beyond years, including the replacement or refurbishment of its structures and services.

The capability of these facilities will be reviewed at regular intervals, including by regulators, to ensure that they can be maintained for at least years and beyond, if necessary. For the purposes of the Policy disposal is placing the waste in a suitable specialised land-based facility without the intent to retrieve it at a later time. It is not that the waste cannot be retrieved, if that proved to be necessary, rather that there is no intention to retrieve it.

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It is not the facility which determines whether waste is regarded as stored or disposed of, it is the intention which determines whether a facility is for storage or disposal. The time waste is placed in a disposal facility is when disposal occurs, even if the facility is eventually closed many years later. Similarly, any monitoring requirements have reflected the fact that there was no intention to retrieve the waste.

However, whilst there may still be no intention to retrieve waste, many countries are now looking at the issues of monitoring and retrievability for long-term disposal facilities. The Policy does not specify what monitoring is required or how retrievability will be demonstrated. It will be for operators to demonstrate how this is to be done in the design and management plan for any disposal facility to the satisfaction of the regulators.

This reflects the GRA which provides guidance on the regulatory requirements and addresses both monitoring and retrievability. This is consistent with the GRA approach and reflects International examples of near-surface disposal facilities. The presumption in the Policy is that a disposal facility will be as near to the surface as practicable taking account of all factors.

For the purposes of the Policy near-surface for disposal facilities means :. The circumstances where waste is produced and where it can be disposed of may be in different locations, particularly for non-nuclear industry waste producers. Therefore there will not be a prescriptive definition of near to the site for disposal facilities. However, the presumption will be that disposal facilities will be as near to the site where waste is produced as practicable.

This will require consideration of the environment, health, safety, security and transport requirements for disposal options. It is not possible to put a specific time capability on such facilities in the same way as for storage facilities where, unlike disposal, there is always the intention to retrieve waste. Disposal facilities will need to be designed to contain waste for much longer periods. Developers will need to satisfy regulators that an environmental safety case can be met. Such an environmental safety case will need to comply with the principle that the level of protection provided to people and the environment against radiological hazards of the waste, both at the time of disposal and in the future, is consistent with the standards at the time of disposal.

In this context institutional control means that there will be control and monitoring of a disposal facility to the satisfaction of regulators to ensure that there is protection of the environment and people. The issue of active institutional control is addressed in the GRA. They will need to take account of the Policy in making their future planning assumptions, taking account of regulatory requirements.

Their assumptions will need to take account of their own individual decisions on long-term management options, including treatment or packaging options, and for either near-surface, near to the site storage or near-surface, near to the site disposal.

These decisions will be subject to robust regulatory requirements. Non-nuclear industry waste producers are still subject to robust regulatory controls but they have the option of considering the availability of any potential new treatment or storage or disposal options in Scotland, which are in proximity to them. Such arrangements will be subject to appropriate commercial agreements with facility providers. All parties involved in any proposals to provide new, or alter existing, facilities for treatment or storage or disposal will be expected to engage and consult with local, national, UK , EU and international stakeholders, in a manner appropriate for their proposals.

This Policy does not alter the existing legislative and regulatory arrangements. This includes complying with any applicable changes in legislation that occur whilst long-term management options are being considered or a facility is being maintained or developed.

Reversible Experiments: Putting Geological Disposal to the Test

Proposals will be scrutinised and regulated by the environment, health, safety, security and transport regulators, who will take account of best practice in Scotland and elsewhere in considering any permitting. It will also be for a developer to demonstrate how it has take account of such views.

Each multi-barrier state is the result of one or more scenarios that lead to this state. For each scenario the primary processes that attack or destroy the barriers that are bypassed in that state are identified. Secondary processes that influence the transport and the state of the radionuclides supplement the primary ones. The processes are chosen from a list of about so called FEPs Features, Events and Processes that are selected from existing literature. FEPs that are not relevant for the Dutch situation or that have a very low probability are left out. Although in most scenarios one or more barriers are at first not bypassed, eventually every scenario leads in the end to the release of radionuclides into the biosphere as a result of the natural geologic evolution of the site.

In this way a list of 22 scenarios is found that is assumed to cover the most important ways in which radionuclides might escape from the repository and reach the biosphere. The 22 scenarios are grouped into three distinct families. In subrosion subsurface dissolution scenarios the dominant process is the slow subsurface dissolution of rock salt in groundwater.

In flooding scenarios also called water intrusion scenarios the groundwater enters the repository through fractures in the salt body. In human intrusion scenarios the barriers are bypassed by future human activities like drilling, etc. Only 7 scenarios are selected for further analysis. Scenarios that contain processes for which no proper models are yet available are left out. This is the case for glaciation the effects of a glacial period and for gas production as a result of chemical processes around the containers.

This means that the results are expected to be the same. This is done for the scenarios where radiation damage plays a role. Radiation damage is the radio-chemical change of the crystal structure of the rock salt with the result that radiation energy from the waste is captured and stored in the surrounding salt.

Under some conditions the energy can be released explosively. It is assumed that these explosions only can occur in the first phase of the storage period the first thousand years. According to the PROSA study the effects are limited to the direct neighborhood of the waste so this will not result in cracks that extend to the groundwater system. Because of the creep of the rock salt these cracks will close again. So by the time that the groundwater reaches the burial place by the natural process of subrosion the effects of radiation damage are assumed to be gone.

Therefore the subrosion scenarios with radiation damage are expected to give the same results as the subrosion scenarios without radiation damage. PROSA is a probabilistic safety assessment. This means that probability distributions are used for various model parameters that are not known accurately. PROSA does not calculate probabilities of occurrence for the different scenarios. The question that PROSA tries to answer is: do scenarios exist that lead to an unacceptable radiological risk in the future?

For each scenario the radiological risk is calculated, assuming that the different steps of the scenario occur. The radiological risk is defined as the probability of a person to die as result of the exposure to radiation. Another aim of the report is to carry out a sensitivity analysis.

This means determining which input parameters for the different models have the strongest effect on the future exposure of human beings to radioactivity. Only for the human intrusion scenarios some estimates are given for the probability of occurrence, because these scenarios are the only ones that are found to lead to unacceptable levels of future exposure. These probabilities are used to estimate the risks of these scenarios. The conclusions of PROSA are that the subrosion scenarios and the flooding scenarios lead to very low to negligible radiological risks for future generations.

Only the risks for human intrusion scenarios are not negligible, although they are expected to be low. The sensitivity analysis leads to the identification of some characteristics of the repository and the geological formation that are most relevant for the safety of the system.

A low internal rise rate of the salt formation and the possibility of deep disposal are the safety relevant characteristics of the salt formation. The properties of the overburden the geological layers between the salt formation and the surface were considered not to be safety relevant characteristics. The interviewed experts provided valuable information about risk analysis from the viewpoint of their specific disciplines.

They also expressed their sometimes personal opinions about geological disposal of nuclear waste or related subjects. The method to use interviews as part of the field research is more often used in the social sciences than in the natural sciences, although there are examples in the natural sciences as well. For example V. Chernousenko[4] makes use of interviews to analyze in detail the causes of the nuclear accident at Chernobyl in The interview method used in this paper is based on the narrative interview that is developed in psychology see for example F.

Franke[6] further developed this method. In the narrative interview the interviewed persons are stimulated to express their opinions and also personal viewpoints on the subject. In this way apart from the factual information that is obtained, the interviewer also gets an impression of the viewpoints, tensions and interests within the scientific community and greater society in relationship with the subject.

Here follows a short introduction of the interviewed experts. The names of the experts are made fictitious to give them more freedom to express their opinions. The interviews were taken in Dutch. The citations were translated and edited by the author. The interview with Mr.

Brouwer took place in April He is a geologist and researched on location the geological characteristics of many salt formations and mines in the world. He showed a lot of motivation to express his views about the geological side of storage of nuclear waste. Here he showed more a practical then a theoretical attitude towards the subject. Van Dijk is a civil engineer. The interview took place in June He showed himself very engaged in the subject of nuclear waste. As a civil engineer he has a profound knowledge of the technical side of the subject, but he was also very aware of the social tensions.

He knew many arguments from proponents as well as opponents of underground storage and developed his own standpoint. He showed a lot of concern for a fruitful discussion between the various groups to develop workable solutions. The mathematician Mr. Froon was interviewed in August He is an expert in the field of model calculations. He showed himself to be a proponent of geological disposal of nuclear waste. He formulated clear and self-assured positions, with a somewhat detached attitude towards the subject. Jacobs is a physicist and works for an international environmental organisation.

He was interviewed in January He is specialised in nuclear energy and nuclear weapons. The opinions he expressed were well in accord with the standpoint of his organisation, as can be expected given his job. The interview with Mrs. Terbeek took place in May She is a chemical technologist and external safety advisor at an engineering office. In the interview she showed concern for the people that might be affected in the future by radiological risks. This motivated a critical attitude towards different research projects on the subject.

Viehoff was interviewed in October He is a mathematician and an expert on risk evaluation for water protection systems. During the interview he was very cautious to stay within the confines of his field of water protection. What he said was relevant for storage of nuclear waste, but he could not be persuaded to express any direct opinions about this subject.

The PROSA report uses the radiological risk criterion to evaluate the safety of underground repositories. The use of this criterion in the OPLA program was rather new in the discussion on the theme of geological disposal in the Netherlands. Before the proposed safety requirements for possible burial sites were of a geological nature like the depth of the salt formation, the existence and thickness of a caprock, the annual rising rate of the geological formation, etc.

With the initiation of the OPLA program by the Dutch government in the emphasis was put on the radiological risk criterion and the geological criteria were valued of secondary importance. It is mentioned that the initiation of the risk criterion had a profound influence on the societal discussion about geological disposal in the Netherlands that was going on from on. For example Damveld et al. With the shift from geological to radiological criteria the research programs and also the societal discussion had a tendency to become more abstract and general. Was the introduction of the radiological criterion an escape from the problematic geological criteria, or were there definite scientific reasons for its introduction and did it lead to a more reliable analysis?

I asked the mathematician Mr. Froon what according to his opinion was the reason why the researchers of the OPLA project started to use the radiological risk criterion. That is the goal of underground disposal. In the seventies we had no access to an integrated calculation model to investigate to what extent we could fulfil this demand. Therefore we used partial criteria. For each compartment of the disposal facility certain requirements were set and it was presumed that then the facility as a whole is safe enough in relation with isolating the waste from the people. But how do we weigh the relative importance of the partial criteria?

It may be that we reject a site because it does not meet the requirements of one of the partial criteria. But as a whole it may be that this site has the best shielding properties. What is of more importance, the fact that the containers have a thickness of 5 mm, that there exists a caprock on top of the salt formation, that the formation is moving a little bit, or that it has certain geohydrological properties?

At the moment we have the calculation tools to work with one integrated criterion we no longer need these partial criteria. It is then possible to evaluate every disposal concept in terms of future radiological exposure. I confronted my interview partner with the following fact.

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In the days of the geological criteria it was recognized that none of the geological sites considered met the requirements. They were all rejected[8]. The results of OPLA on the other hand showed that all disposal concepts that were studied fell well within the levels of acceptable risk. Can we say that now suddenly all these sites are found to be suitable after all? OPLA worked with very little site specific information. In fact three generic formations were studied: salt layers, salt pillows and salt pillars.

These formations, when they are big enough, were found in principle to be suitable for a safe and technically possible disposal of nuclear waste. When we look in the future at specific sites it is not certain of course, that they will meet the test. It is possible that strange unexpected facts will become known. In that sense your statement is not true. But on the other hand your black and white statement has more truth than is suggested from what I just said. On the basis of the earlier geologic criteria for each site there was something wrong with one or the other of the partial criteria.

But when we calculate the risk with our present models, on the basis of the same information, then we find that they all meet the test of having a very low radiological risk. Then I ask the question: on what where those earlier criteria based? So in Mr. Geological aspects of a formation are incorporated in this integral measure. But we must keep in mind that PROSA does not say anything about actual sites, it deals only with generic formations. How important is this aspect? The geologist Mr.

Brouwer has a definite opinion about this. There are large differences in depth of the salt formation, existence and composition of caprock, lithology of the rock formations above the salt, geohydrology, tectonic and geological history. Therefore it is impossible to judge if a formation is suitable for underground disposal without doing extensive research on location for several years. In my opinion it is a weak point of the OPLA project that no site specific research is done.

So it may very well be that the tendency of the discussion about geological disposal to become more abstract is not so much caused by the implementation of the risk criterion. It may be caused by the fact that the OPLA project only studied generic situations and in that way diverged from actual situations. The radiological risk criterion could also be applied to studies of actual disposal sites.

It is ironic that the environmental movement itself caused the rejection of research of actual sites, as was made clear by the civil engineer Mr. Only desk studies should be done, but no field studies. Only information was used that was already publicly known. Even results from drillings of oil companies that were not publicly known because of competition were not used. In fact it was initially intended to use this information, but the environmentalists resisted strongly. They occupied drilling plants, so the exploration of oil and gas became endangered.

The minister then decided that the information of oil and gas drillings should not be used. Under pressure of the environmentalists the most difficult decision, namely the carrying out of drillings, was postponed. OPLA followed the directive of the minister and did not carry out site specific research. Even non-penetrating methods like gravimetry were not used.

The risks that are calculated now are all very low, well below the standards set by the government. The result is that the risk criterion does not serve as a discriminating factor between different disposal concepts. Say the standard is 10 and we compare the results of two concepts with risks 0. There is a difference between these two figures, but compared to the standard of 10 the difference is hardly meaningful. So therefore the risk criterion does not work very well in discriminating between the two concepts. Therefore we need extra measures apart from the risk criterion.

Although the risk figures indicate that the isolation is all right, many people have the feeling that it is not. There is a big difference between the results of the calculations and the feeling of the people. It is important to develop measures that relate to the reasons why people think that it is not all right.

So it is possible to compare concepts that are the same in terms of risk, but not in terms of acceptance by the people. We can think of all kinds of disposal concepts, but they should be accepted. We need solutions that provide sufficient isolation and that can be carried out because they are accepted. What kind of extra measures do you think of?

Are they different from the earlier geological criteria? Think about retrievability, choices of host rock salt, clay, etc. Then we can say that we did our job better, we have a better option, although in terms of risk it may not be different. People fear the waste.

Nuclear Wastes: What, Me Worry? ( Original)

We do not yet succeed to catch that fear in the risk criterion. Apparently the fear is based on something else. People do not trust the results of the calculations. Maybe we can meet these feelings by showing that we did all that is possible, that we used all the present possibilities of technology, to make it as safe as possible. So we must try to weigh the concepts in terms of ability to realize them. Transmutation does not eliminate the need for a repository for high-level waste and spent fuel!

So we have an integrated criterion, calculated risks that are so low that we cannot compare different concepts, and even more public distrust. I asked an expert in industrial safety, the chemical technologist Mrs. Terbeek if the quantitative method of risk evaluation that was used in the PROSA study is a usual method in safety studies in industry. Safety reports in industry are structured in a uniform way according to manuals made by governmental organizations. The history of these procedures goes back to In that year the Dutch government issued the Large Accidents Resolution.

Companies handling hazardous materials were obliged to do a safety analysis. The analyses carried out by various different research institutions were very difficult to compare. The government felt the need to prescribe a uniform method. This method became the basis for obtaining licenses. Also various standards were set, for example the probability to die as the result of a certain industrial activity for an individual should be less than 10 -6 per year.

A probability of 10 -8 is regarded as negligible. The Netherlands has chosen a very quantitative approach to safety management. But remember that the meaning of the quantitative figures is the ability to compare results! If all research institutions use comparable methods, the results can be compared.

But the figures themselves depend very much on the application of models, failure probabilities, etc. There are many assumptions connected with these matters. If we choose them differently, the results are different. Do not take these figures too absolutely. The point is that we want people to act as safely as possible, within the limits of technology and economics. So do not pin yourself down on such figures. The matter is to compare alternatives, not more than that. It is also interesting to see that not always the same standards are used.

The figure of 10 -6 that I mentioned earlier is a workable standard in the industry. This standard is technologically and economically realistic. For safety in transport on the road of hazardous materials this standard is not useful. The risks in traffic are found to be higher, but we accept these risks. Therefore the standards in traffic are set a factor of 10 higher. We could do something like this in the case of nuclear waste, only in the other direction. Why should we use the standards of the industry?

Given the large number of uncertainties in connection with nuclear waste we could easily argue to use standards that are stronger. Standards are relative! So in the opinion of Mrs. Terbeek one should not take the calculated risk figures too absolutely. If we change our assumptions during the calculations, the figures change. The risk figures are mere instruments to compare results. Also the standards are relative. Here we may find the solution for the problem that Mr.

Froon mentioned in using the risk figures to compare disposal concepts. If we choose more stringent standards in case of geological disposal of nuclear waste it may become possible again to compare results. Setting more stringent standards is justified by the large number of uncertainties that are mentioned by Mrs.

Geological disposal of radioactive waste: induction video

Terbeek in the case of geological disposal of nuclear waste. Yucca was singled out for the country's first repository not because it had suitable geology, but rather because Nevada was seen as a politically vulnerable state. In fact, from until today, safety and environmental protection regulations have been repeatedly weakened or eliminated altogether to keep the ill-conceived, dangerous Yucca proposal afloat.

In conclusion we can say in connection with the reliability of risk analysis that the introduction of the radiological risk criterion has two sides. On the one hand the criterion allows an integrated analysis that can be regarded as more reliable. On the other hand the radiological risk parameters can be interpreted as too absolute, suggesting a more reliable result than can be justified. There are reasons to limit the use of the criterion to compare the results of calculations for different disposal concepts.

Also the standards are not absolute. In the case of disposal of nuclear waste there are reasons to adopt more stringent standards to account for the larger uncertainties. The reason why the discussion on disposal of nuclear waste became more abstract does not seem to have been caused by the introduction of the radiological risk criterion.

Instead it is due to the choice to study generic formations and not specific sites. The criterion could also be used in site-specific studies. Why is the disposal of nuclear waste thought to be connected with larger uncertainties than the more common industrial practices? We will deal with this question below. To evaluate the safety of a nuclear waste repository, we have to deal with very long periods of time.

The waste is dangerous for hundreds of thousands of years. These are geological time scales. To what extent is it possible to predict the development of the repository containing the waste over such long periods of time? Froon his opinion about the extrapolation of geological processes in the very far future.

Not all geologists endorse the statement anymore that one is able to predict the future on the basis of the past, one to one. I think most geologists accept that we can use the past and the present as information to know how geological processes will develop in the future. A principle that is generally accepted in physics is, that if the boundary conditions are unchanged, processes develop like they developed in the past.

So with disposal concepts we must take care that in the future the conditions will not be essentially different from the geological past. So the more we take care that temperature changes are sufficiently small, the stresses are small, etc.

II. special report by Neil A. Chapman

One expects the geology of the future to behave the same as in the past. For example one can design a model for the process of subrosion, the dissolution of the salt in the groundwater. This model can be validated with data from the past. Then one can reasonably expect that one can use this model for the calculation of the subrosion in the future. This does not mean that the rate of subrosion will stay the same as today.

In the past there were irregularities, and so one can expect this to be the case for the future.