Nuclear Power Plants In Germany Research Articles

Experimental investigation of uranium release from spent nuclear fuels under conditions expected in a deep geological repository

Abstract. Direct disposal of spent nuclear fuel (SNF) in a deep geological repository is planned for the long-term management of the highly radioactive waste discharged from the light water reactors (LWRs) of nuclear power plants in Germany. The aim is to safely isolate the radionuclide inventory from the biosphere, ad infinitum, making use of a multi-barrier system consisting of technical, geotechnical and geological barriers interposed between the emplaced waste and the environment. Still, reversibility measures including retrievability of the waste products are considered in this concept. Internationally, in safety assessments for deep underground repositories (DGRs), the access of groundwater, followed by failure of canisters and finally loss of the SNF's cladding integrity is considered in the long term. Hence, the evaluation of the performance of SNF in the near field of a deep geological repository requires process understanding of SNF dissolution and rates, in addition to the quantification of the radionuclide release from SNF under reducing conditions of a breached container. With the aim to derive a radionuclide source term, the SNF dissolution and alteration processes can be assigned to two steps, namely the (i) instantaneous release of radionuclides upon cladding failure from gap and grain boundaries and (ii) a long-term release that results from the dissolution of the fuel grains themselves (Ewing, 2015). Since most radionuclides produced during irradiation of nuclear fuel in a reactor are trapped within the SNF matrix, understanding the processes leading to the dissolution of the matrix and its dissolution rates are of particular interest for post-closure safety assessments (Pastina and LaVerne, 2021). Research at the Institute for Nuclear Waste Disposal (INE) at the Karlsruhe Institute of Technology (KIT) has focused, for more than 25 years, on the behaviour of SNF (irradiated UO2 and mixed-oxide, MOX, fuels) under geochemical conditions (pH, redox milieu, gas atmosphere and ionic strength) representative of various repository concepts and radiolytic reactions on SNF dissolution mechanisms. This contribution will give an overview on the radionuclide release from dissolving SNFs under repository conditions. In particular, uranium released into solution from UO2 and MOX fuels during up to 1629 d of leaching in salt brines, granitic/bentonitic or cementitious groundwaters under Ar or Ar/H2 atmospheres. As observed in other published studies on SNF dissolution under reducing conditions, a large scatter of the uranium concentration is seen in the initial stages of our experiments. After about 1 year of leaching, the aqueous concentration of uranium slowly approaches the solubility limit of U(IV), independent of the type of studied SNF samples (various irradiated UO2 and MOX fuels). A similar behaviour is observed for other redox-sensitive actinides. The release rate of uranium decreases significantly in all experiments within first 400 d of leaching. Although the rate is very low, it is >0, and a continuous release is observed. A comparison of the results from SNF experiments under various redox conditions demonstrates that oxidative matrix dissolution is inhibited due to the presence of hydrogen. Our results are discussed in the context of the outcome of international research programmes on SNF corrosion. These findings are considered to be of relevance for the definition of source terms for various irradiated LWR fuels in safety investigations for a DGR in Germany.

Spatial Industrial Accident Exposure and Social Vulnerability Assessment of Hazardous Material Sites, Chemical Parks, and Nuclear Power Plants in Germany

Industrial accidents have shown that many people can be affected, such as in Seveso, Italy, in 1976. Industrial accidents in nuclear power plants have also led to fatalities and evacuations. To better guide preparedness against and mitigation of industrial accidents, an assessment is necessary to evaluate hazard exposure and the type of potentially vulnerable social groups that need to be taken into account. This study conducted a spatial assessment of three types of industrial facilities in Germany: facilities registered under the Seveso Directive, chemical parks, and nuclear power plants. The method consisted of a spatial assessment using a Geographic Information System of exposure around hazardous sites registered under the Seveso Directive in Germany and of census data to analyze social vulnerability. Hazards analyzed included industrial accidents and earthquakes. The results revealed that most industrial sites are in urban areas and that population density, the numbers of foreigners, and smaller housing unit sizes are higher in close proximity to these sites. The buffer zones analyzed in circles between 1 and 40 km show a decreasing vulnerability with more distance. This can guide emergency management planners and other stakeholders to better prepare for major accidents and better devise disaster risk reduction strategies specifically for different social groups.

Incidence of childhood leukemia before and after shut down of nuclear power plants in Germany in 2011: A population-based register study during 2004 to 2019.

The association between leukemia and proximity to nuclear-power-plants (NPPs) has been assessed in several countries with inconsistent results. A case-control study from Germany had shown an increased risk for childhood leukemia (diagnoses 1980-2003) near NPPs. Germany began shutting down nuclear reactors in 2011, following the Fukushima disaster. We tested whether the previously observed association between leukemia and proximity to NPP persisted despite the shutdown. We used an ecological study design to investigate the incidence of leukemia during 2004 to 2019 in children aged 0 to 14 years living near NPPs where at least one reactor was shut down in 2011. We defined study and control areas as municipalities whose surface area was at least 75% within 10km or between 10 and 50 km of NPPs, respectively. We calculated age-standardized rates and incidence rate ratios (IRR) using control-areas as the reference. We also computed standardized incidence ratios (SIR) separately for each NPP using incidence rates of the German population as a reference. IRR decreased from 1.20 (95% confidence interval: 0.81-1.77) in 2004 to 2011 to 1.12 (0.75-1.68) in 2012 to 2019. Analyses of single plants showed an excess of childhood leukemia during 2004 to 2019 for the Unterweser-NPP, based only on three cases, and the Krümmel-NPP (n=14; SIR: 1.98, 1.17-3.35). We found slightly decreasing of leukemia incidence rate ratios after the shutdown of nuclear reactors in 2011. Due to the small number of cases, risk estimates have large uncertainty. Further research including a longer follow-up is warranted. The consistent excess of incidence cases around Krümmel may require analytical epidemiological analysis.

Phasing out of nuclear - Phasing out of risk? Spatial assessment of social vulnerability and exposure to nuclear power plants in Germany

While nuclear power plants (NPP) are built back in Germany, the exposure risk will remain for some time being. This study conducts a geospatial analysis in exposure radii from 5 to 80 km around 41 NPP sites in and around Germany. The results show that 40 out of 113 major cities are exposed, and that vulnerability patterns vary. Foreigners and women live closer to NPPs, while it is the opposite with young and elderly people. This non-regular spatial distribution of population groups can be important to guide evacuation and emergency planning.

Relational territoriality and the spatial embeddedness of nuclear energy: A comparison of two nuclear power plants in Germany and France

The ongoing spatial turn of both energy research and transition studies have highlighted the need for a stronger understanding of spatial configurations to grasp the heterogeneity of energy transition pathways. While previous works predominantly focused on territorial context inhibiting or driving renewable energy development, the dynamics of incumbent energy systems remain understudied. This is particularly the case for nuclear power, which epitomizes the diversity of energy trajectories in decarbonization policies, swinging between “renaissance” and “decline”. Consistent with energy geographers’ call for new research characterizing the path dependencies which strengthen incumbent systems, this paper offers to assess the spatial embeddedness of nuclear power plants by comparing the closure of two facilities in Germany (Neckarwestheim) and France (Fessenheim). The two case studies were chosen for the divergent intensities of controversies triggered locally by their shutdown. We introduce Raffestin’s conception of relational territoriality, different from the behavioralist and Sackian approach previously used in energy geography, in order to identify and describe the spatial elements of nuclear power path dependencies. Results show more robust relational territorialities in Fessenheim than in Neckarwestheim. Opposition against closures appears stronger where the facility induced deeper forms of spatial embeddedness. The path dependency of nuclear power plants is co-produced by their territory preexisting spatial characteristics and social representations, the spatial transformative power of the monetary flow occasioned by the plants, the actions of the site’s workers and the normative elements governing its spatial existence. However, results show no direct influence of local communities on the elaboration of national nuclear policies.

Reactor safety research within the Helmholtz Association

Abstract The reactor safety research of the Helmholtz Association is an integral part of the national provident research. It focuses on the safety of nuclear power plants in Germany and abroad as well as on safety aspects of internationally developed innovative reactor concepts. The research in the three involved Helmholtz centers Forschungszentrum Jülich, Helmholtz-Zentrum Dresden-Rossendorf and Karlsruhe Institute of Technology covers important areas of design basis and beyond design basis accidents. A unique combination of code and model development supported by own large-scale experiments ensures the active preservation of the reactor safety competences. The research that is embedded in a strong international co-operation will be continued after the completion of the national phase-out from the use of nuclear energy for electricity production in 2022.

Hydro-climatic conditions and thermoelectric electricity generation – Part II: Model application to 17 nuclear power plants in Germany

In highly developed countries electricity generation is one of the largest water users. Water is mainly used in the cooling processes of thermal power plants. In as yet less developed countries, electricity requirements are also increasing in step with increasing production and standard of living. Renewable electricity generation is gaining more attention in both highly and less developed economies. However, many types of renewable electricity generation, e.g. wind or solar, are still unreliable due to their dependence on weather conditions. This is why electricity generation by thermal power plants will remain a substantial component of the overall energy system for the next decades.An approach is applied here for analysing links between water availability and water temperature, air temperature and electricity generation by power plants. A highly disaggregated level is used combining a power plant model and hydrological models. It is applied to analyse effects of climate change on 17 nuclear power plants in Germany. Although even under baseline conditions reduced electricity generation can be observed, any further increase in air temperatures reduces electricity output of almost all nuclear power plants. The different technological and environmental conditions of each plant site mean that specific models are necessary for the simulations.

Modeling the Merit Order Curve of the European Energy Exchange Power Market in Germany

An updating study concerning the analysis and modeling of the European Energy Exchange power market in Germany is urgently called for due to the dramatic transformations of the market in recent years. Based on careful data research, this paper provides a consolidated and detailed view concerning the development of the market and its mechanisms. This paper proposes a new analytical model of the merit order curve of the market. The model is designed to capture the occurrences of negative prices. It considers fuel prices and CO2 prices, and by taking into account the structural changes of the market such as the increasing energy in-feed from renewable sources and the moratorium of nuclear power plants in Germany, the model is robust to these changes of market fundamentals. The proposed merit-order-curve model constitutes a critical component in realistic fundamental models for the European Energy Exchange power market.

Independent assessor's report on the experience with preparation, managing, observing and evaluation of emergency exercises without prior notice in nuclear power plants

Abstract We inspect regularly the measures taken in terms of the plants operator emergency management organisation in supposed emergency situations and assess their effectiveness on behalf of the supervisory authorities under the atomic energy law. To this end corresponding exercises based on scenarios that have been prepared by ESN are carried out in the plants and followed by a group of independent observers. The course and effectiveness of measures initiated are assessed in the form of an expert's report. ESN prepared, managed, observed und evaluated more than 75 emergency exercises in nuclear power plants in the last twenty years. With this experience and particularly with the experience feedback between plants we contributed to the development of the internal emergency management for nuclear power plants in Germany. This paper at hand summarizes some of our experience.

Energy policy scenarios to reach challenging climate protection targets in the German electricity sector until 2050

In this article we demonstrate how challenging greenhouse gas reduction targets of up to 95% until 2050 can be achieved in the German electricity sector. In the analysis, we focus on the main requirements to reach such challenging targets. To account for interdependencies between the electricity market and the rest of the economy, different models were used to account for feedback loops with all other sectors. We include scenarios with different runtimes and retrofit costs for existing nuclear plants to determine the effects of a prolongation of nuclear power plants in Germany. Key findings for the electricity sector include the importance of a European-wide coordinated electricity grid extension and the exploitation of regional comparative cost effects for renewable sites. Due to political restrictions, nuclear energy will not be available in Germany in 2050. However, the nuclear life-time extension has a positive impact on end consumer electricity prices as well as economic growth in the medium term, if retrofit costs do not exceed certain limits.

Birth defects in the vicinity of nuclear power plants in Germany

Living in the vicinity of nuclear power plants (NPP) is discussed here in terms of adverse health effects. A prospective population-based cohort study was conducted to evaluate whether the prevalence of birth defects in the vicinity of NPPs is elevated and scrutinize a possible distance correlation. A birth cohort born to mothers living within 10km of two selected NPPs (study region) was compared to a region without NPP (comparison region), and an active surveillance of all live births, stillbirths, and induced abortions in the defined regions was performed. Between 01/2007 and 02/2008, all newborns were examined by specially trained study paediatricians according to the protocols of the Birth Registry Mainz Model. The cohort consisted of 5,273 infants (90% completeness). The outcome measure was an infant with birth defect(s). The prevalence of infants with birth defects was 4.5% in the study region and 4.7% in the comparison region, which corresponds to a relative risk (RR) of 0.94 (lower 95% confidence level (CL): 0.76). Thus, the prevalence of birth defects in the regions surrounding NPPs was not increased compared to those of the comparison region. Adjustment for potential confounders did not substantially change the result (RR 0.90, lower 95% CL 0.73). The adjusted and unadjusted distance approach (1/distance in km) did not show any correlation to vicinity to a NPP (p=0.38). Specifically, within the study region, the prevalence of birth defects showed no upward trend with decreasing distance. Birth defect prevalence and most descriptive parameters in the comparison region were identical to those in the Birth Registry Mainz Model.

Childhood Leukemia in the Vicinity of Nuclear Power Plants in Germany: Children Are Very Sensitive to Radiation

As a pediatrician I wish to point out children’s extreme sensitivity to radiation. The younger a child, the quicker it will be damaged even by low grade radiation. This is the key to understanding the results of the Epidemiological Study on Childhood Cancer in the Vicinity of Nuclear Power Plants (KiKK Study). On this basis, we urgently demand that permitted emissions should be adjusted to the risk for an embryo.

Childhood Leukemia in the Vicinity of Nuclear Power Plants in Germany: Confusion About Childhood Cancer Study

With their article, the authors are obviously attempting to play down the startling results of their own study. In the evaluation of data at the community level, the results from the Epidemiological Study on Childhood Cancer in the Vicinity of Nuclear Power Plants (KiKK Study), which found a notable increase in the leukemia risk in the vicinity of German nuclear power plants of 119%, shrunk to an unremarkable, non-significant 41%. The authors state that the discrepancy between the results is essentially due to the fact that the KiKK study accurately determined the distances between the childrens’ homes and the next nuclear power plant while the ecological study uses community midpoints.. But the authors also say that both statements actually reflect different perspectives, and hence, both statements are correct. In a sense we should be grateful to the authors for conducting this additional ecological study. It demonstrates that ecological studies are much less able to detect regional clusters than more elaborate case-control studies. When the authors refer to the results of a recent study from England that, in contrast to the KiKK study, has not shown a leukaemia increase in the vicinity of nuclear power stations, it has to be borne in mind that this study, again, is an ecological study. In England, eighteen cases of leukemia were counted in a 5 km radius, only about half as many as in the KiKK study. The leukemia risk there in the 5 km radius was about 50% higher than in the adjacent 5–10 km zone, but, due to small case numbers, the increase was not significant. Although the English results are remarkably consistent with the German results, the authors conclude that there was no proof that acute leukemias are more common in the vicinity of nuclear power plants in England.

Childhood Leukemia in the Vicinity of Nuclear Power Plants in Germany: The Environment Is Radioactively Contaminated

The long term study by Kaatsch et al showed a twofold increased risk (odds ratio 2.19) of leukemia in children up to 5 years of age living within a 5 km radius from a nuclear power station. However, the researchers subsequently call their own results into question by doubting an association between leukemia and ionizing radiation, since the levels of ionizing radiation were no higher in the vicinity of nuclear power stations than the existing natural radioactivity. The authors ask whether the children younger than 5 years were actually really permanently based within the 5 km radius, at the address where they were registered. Today’s small children are obviously so flexible that their permanent abode is questionable because of their nurseries, which in rural areas are open from 8 am to 12 noon only, and because of their long holidays, which might exclude any effect from the nuclear power station! The authors did not investigate the possibility of radioactive contamination of the environment by the nuclear power station. Nuclear power stations are large plants with contact to the soil via water; they have high chimneys, and many people go in and out all the time. There are multiple opportunities for radioactive contamination of the ground water, the air, and the people who work there. The possible cause of the increased number of cases of leukemia may not be ionizing radiation only, but also the environment of the power station. Through water and precipitation, radioactivity reaches the food chain—even small traces are sufficient to trigger leukemia in a toddler.

Childhood Leukemia in the Vicinity of Nuclear Power Plants in Germany: Ignorance Is a Curse

The authors noted an increase in the number of cases of leukemia in children younger than 5 years within a 5 km radius of nuclear power stations. Notably, they think that a causal association between raised leukemia incidence and additional radiation exposure through nuclear power stations is implausible. If this conclusion has been clear from the beginning, I don’t understand why the study was conducted in the first place. After the leukemia increase that was found, the usual dose estimate in children now needs to be questioned. And this is where ignorance is a curse. This is part of the highly complex area of biodosimetry and dosage equivalents, a highly technical terrain that neither a psychologist and occupational scientist (Professor Jungermann) nor an epidemiologist and informatics specialist (Dr Kaatsch) is qualified to comment on. The normal, extremely arbitrary dose estimates would need to be subjected to highly complicated tests. Finally, research would need to be conducted into what radiation load exactly an individual resident in the vicinity of a nuclear power plant receives, not only via environmental radiation but also via environmental air and the food chain; how the biological distribution in the body tissues works over time; and which bone seeking radionuclides administer which dosage to a child’s bone marrow. These questions would be worth studying and the computation models prestented by the German Commission on Radiological Protection would be worth verifying, and any insider knows exactly how very arbitrary the presented dose estimates are. What we do not need is a philosophical discourse about risk perception, nor repetitive emphasis on implausible causal associations compared with environmental radiation. What is required is careful checking of the dose estimates presented (allegedly only 1/1000 of environmental radiation). The studies required for this would have to conduct laborious nuclide measurements in the biotope and in the environmental air that the children breathe over the long term. The bone marrow of children who died due to leukemia in the vicinity of nuclear power plants would need to be compared in terms of its radionuclide uptake with that of children elsewhere. For knowledge to be interpreted and integrated, this knowledge has to be gained first of all!

Childhood Leukemia in the Vicinity of Nuclear Power Plants in Germany: In reply

Childhood Leukemia in the Vicinity of Nuclear Power Plants in Germany: In reply

Childhood Leukemia in the Vicinity of Nuclear Power Plants in Germany: Against All Logic

article is factually inaccurate and misleading. summary says: The question whether leukemia rates are increased near nuclear power plants is controversial. This statement is not correct. It is scientifically proven that the number of cancers and leukemias in children is higher the closer they live to a nuclear power plant. authors themselves have provided proof with their extraordinarily laborious study. statement that the causes of the cancers are unknown is equally misleading. In the context of the study, causes other than emissions from nuclear power plants were excluded. It was investigated whether the cancers were due to pesticides or other possible confounders. But no such confounder was found. The Epidemiological Study on Childhood Cancer in the Vicinity of Nuclear Power Plants (KiKK Study) explicitly investigated a causal association between radioactivity from nuclear power stations and cancers. This is the unequivocal message of a 2006 publication from the Mainz childhood cancer registry. study methods state that the individual distance of the residence of the children with cancer was used as a substitute for individual radiation exposure. In our opinion it contradicts any logic that the authors retrospectively exclude this part of the study design and thus do not accept their own findings. We therefore wish to ask for whose benefit the study was conducted. At least such a chiseled interpretation helps to keep nuclear power stations running.

Childhood leukemia in the vicinity of nuclear power plants in Germany.

The causes of leukemia are largely unclear. The question whether leukemia rates are increased near nuclear power plants is controversial. The German Childhood Cancer Registry has published an epidemiological case-control study on childhood cancer and nuclear power plants. The study was based on the distance of children's residences from nuclear power plants and addressed the question whether children under age 5 with cancer live closer, on average, to nuclear power plants than randomly selected controls. Odds Ratios (OR) for distance categories and standardized incidence ratios (SIR) were calculated. An association was found between the nearness of residence to nuclear power plants and the risk of leukemia (593 cases, 1766 controls). Within the 5-km zone, the OR for the development of leukemia in children under 5 years of age was 2.19 compared to the rest of the region, and this elevation of the OR was statistically significant. The incidence of leukemia in the overall study region was the same as that in Germany as a whole (SIR=0.99; 95% confidence interval 0.92-1.07). Based on the available information about radiation emissions from German nuclear power plants, a direct relation to radiation seems implausible. Many factors may conceivably cause leukemia, possibly operating in combination, and these factors may be present to a greater extent in the vicinity of German nuclear power plants.

Childhood leukaemia incidence below the age of 5 years near French nuclear powerplants

A recent study indicated an excess risk of leukaemia among children under the age of5 years living in the vicinity of nuclear power plants in Germany. We presentresults relating to the incidence of childhood leukaemia in the vicinity of nuclearpower plants in France for the same age range. These results do not indicatean excess risk of leukaemia in young children living near French nuclear powerplants.

Probabilistic Safety Assessment of External Flooding Protection for Nuclear Power Plants in Germany

Methods to systematically analyse existing nuclear power plants (NPP) regarding the adequacy of their existing protection equipment against external hazards, e.g. flooding, can be of deterministic as well as probabilistic nature. In the past the adequacy of the protection measures has been assessed only on a deterministic basis. The German regulatory body has issued probabilistic safety assessment (PSA) guidelines, which had been elaborated for a comprehensive integrated safety review of all NPP in operation. Amongst others the guidelines imply, that probabilistic considerations regarding external flooding are required. This paper presents a newly developed graded approach for the probabilistic assessment of external flooding. Main aspects are explained such as the underlying probabilistic considerations and the mathematical procedures for the calculation of exceedance frequencies, which have recently been developed and issued as part of the German Nuclear Safety Standard. Exemplarily it has been investigated if extreme events such as tsunami waves could be a hazard for NPP at coastal sites in Germany. Here it could be shown that due to limited source mechanisms and the specific morphological conditions in the North Sea no dedicated measures for protection against tsunamis in the German Bight are necessary.