Low-level Radioactive Waste Disposal Facilities Research Articles

Cliff Retreat Rates Associated with a Low-Level Radioactive Waste Disposal Facility in Los Alamos, New Mexico, USA

We present an analysis and interpretation of potential cliff stability at a low-level waste disposal facility at Los Alamos National Laboratory, New Mexico, using cliff morphologic and fracture characteristics coupled with carbon-14 surface exposure dating. Our study is important as it directly bears on the licensing criteria for low-level radioactive waste sites. We find that future characteristic cliff failures will likely not breach disposal pits and shafts over the 1000-year minimum regulatory period. Further, we find, using a multivariate regression model, that slope angle and cliff face aspect are sub-equal in importance to predict regions of high risk of failure when combined with surface exposure ages and assuming that old exposure ages are most indicative of stability (instability) and therefore can aid decision making in final design implementation.

Basic Study on Applicability to Artificial Barriers for Radioactive Waste Disposal Facility for Various Zeolites

Artificial barriers are being considered for the burial disposal of low-level radioactive waste in Japan. The artificial barrier consists of i) a low permeable layer made of bentonite materials that suppresses migration of nuclides due to advection, and ii) a low diffusion layer that uses cementitious materials that suppresses migration of nuclides due to diffusion. In addition, as methods of disposing of radioactive waste generated by the accident at the Fukushima Daiichi Nuclear Power Station, controlled disposal and isolation-type disposal are being considered. We thought that it would be effective to add adsorption performance to the performance of suppressing migration of such radioactive substances. In this study, we designed and experimented on the adsorption performance of mortar mixed with various zeolites, which had never been examined. As evaluation methods, i) fluidity, ii) strength, iii) low diffusivity, and iv) distribution coefficient of cesium and iodine were obtained. Based on the results, we reexamined the composition and conducted experiments to examine the applicability to high-adsorption artificial barriers. As a result, it was confirmed that the mass transfer resistance tends to be low due to the zeolite being porous. It was also shown that the strength of mortar mixed with zeolite depends on the cement matrix. As a result of this research, the distribution coefficient of cesium in cementitious materials using zeolite with a high cation exchange capacity designed in this research is higher than that of cementitious materials for low-level radioactive waste disposal facilities currently in operation 1,500 times was obtained. On the other hand, we were able to discover the possibility of examining construction on a full-scale regarding fluidity and compressive strength. As a future task, it was found that it is necessary to investigate a more practical artificial barrier by increasing the strength and densification of the cement paste.

Site-specific characterisation of hydrogeological parameters for low-level solid radioactive waste disposal facility at Tarapur, India

Site-specific characterisation of hydrogeological parameters for low-level solid radioactive waste disposal facility at Tarapur, India

Tritium radioactivity estimation in cement mortar by heat-extraction and liquid scintillation counting

Tritium extraction from radioactively contaminated cement mortar samples was performed using heating and liquid scintillation counting methods. Tritiated water molecules (HTO) can be present in contaminated water along with water molecules (H2O). Water is one of the primary constituents of cement mortar dough. Therefore, if tritium is present in cement mortar, the buildings and structures using this cement mortar would be contaminated by tritium. The radioactivity level of the materials in the environment exposed to tritium contamination should be determined for their disposal in accordance with the criteria of low-level radioactive waste disposal facility. For our experiments, the cement mortar samples were heated at different temperature conditions using a high-temperature combustion furnace, and the extracted tritium was collected into a 0.1 M nitric acid solution, which was then mixed with a liquid scintillator to be analyzed in a liquid scintillation counter (LSC). The tritium extraction rate from the cement mortar sample was calculated to be 90.91% and 98.54% corresponding to 9 h of heating at temperatures of 200 °C and 400 °C, respectively. The tritium extraction rate was close to 100% at 400 °C, although the bulk of cement mortar sample was contaminated by tritium.

A long term baseline and variability of natural radionuclides in groundwater at the Vaalputs low-level radioactive waste disposal facility, Namaqualand, South Africa: regional implications

Abstract Vaalputs is the only South African nuclear waste disposal facility; it is licensed to dispose of low and intermediate level radioactive waste. Possible disposal of long-lived waste, potentially including spent fuel rods, prompted a study to establish a baseline of naturally-occurring radionuclides from the U and Th decay chains in the groundwater of Vaalputs. This baseline was created by investigating a dataset containing 25 years of analyses of the groundwater at the Vaalputs site. The behaviour over time, of 23 radionuclides in groundwater samples from 13 annually and three quarterly sampled boreholes, was evaluated and integrated in order to establish changing trends in the activities of radionuclides, the relative contributions of individual radionuclides to total radiation levels and how these were influenced by groundwater conditions. 238U levels showed a natural anomaly in the near-field of the disposal site that was attributed to the underlying basement rocks (granites) which are anomalously enriched in U. A set of duplicate samples from 2009 determined that the activity ratio of 234U/238U in the groundwater of Vaalputs is 4.1; this is ascribed to more rapid leaching of 234U relative to 238U, because of increased crystal structural damage around sites surrounding 234U atoms. High levels of 226Ra, unsupported by 238U, were found in groundwater from boreholes on the western side of the property: this groundwater yielded low values for 234U/238U, lower pH and stronger oxidizing conditions than groundwater from the rest of the area. The absence of overlying sedimentary rocks, which tend to ameliorate the effects of high radiation from granites by absorption, is suggested as the reason for the different geochemical conditions of the groundwater from boreholes in the west. This suggestion may apply to those boreholes elsewhere in Namaqualand with low published concentrations of 238U, but exceptionally high levels of α -and β-emitters. 232Th and its daughter radionuclides yielded radiation levels far below the guideline of 1 Bq.L-1 specified by the World Health Organization; this result is in line with the known low mobility of Th in groundwater systems.

The Core Agenda of Public Debate on the Cigéo Project in France

원자력 발전은 상대적으로 저렴한 발전비용으로 우리나라 경제성장의 밑거름이 되었던 에너지원으 로 알려져 있으나 방사성 폐기물 처리에 대해서는 논란이 지속적으로 발생하고 있다. 본 연구에서는 프랑스의 고준위 방폐장인 Cigéo의 설치에 대한 정책 수립과정과 공론화 과정을 살펴보고, 시맨틱네트워크 분석(Semantic Network Analysis)을 통해 프랑스의 고준위 방폐장 건설과정에서 제시되었던 여러 가지 핵심적인 의제들을 파악하였다. 분석결과 연결중심성이 높은 상위 10위의 주제어는 토론사업, 폐기물, 저장, 공공의, 질문, 위험, 시민, 참여, 부지 등이다. 프랑스의 사례를 볼 때 우리나라의 고준위 방폐장 설치단계에서 다양한 정책행위자들의 참여와 토론을 유도하고, 현세대와 미래세대간의 형평성을 고려해야 하는 한편, 사전적으로 관련 법제도를 정비해야 한다는 정책적 시사점을 제시할 수 있다.Nuclear power generation has been the cornerstone of economic growth due to low generation costs in Korea, but the disposal of radioactive waste continues to be controversial. Looking back on the controversy at the time of the establishment of low-level radioactive waste disposal facilities, it is expected that the establishment of high-level radioactive waste disposal facilities will lead to enormous social conflicts, urgently seeking social consensus. In this study, we examined the process of establishing the policy and public debate on the installation of Cigeo, a high-level radioactive waste disposal facility in France. In addition, through SNA (semantic network analysis), we identified several key agenda items which had been presented during the installation process, including debate, business, waste, storage, public, question, danger, citizen, participation, and site. Based on the case of Cigeo, we suggested several policy implications that it is necessary to promote participation and discussion of various policy actors and to consider intergenerational equity as well as preemptive legal action.

"Bad Faith": The Unsuccessful Attempt to Site a Low-Level Radioactive Waste Disposal Facility in Nebraska, 1982–2005

In 1982 Nebraska was one of five states to form the Central Interstate Low Level Radioactive Waste Compact. In 1987 the Compact Commission voted 4–1 in favor of Nebraska serving as the compact's disposal host. In 1998 state regulators denied US Ecology a license to construct a disposal facility in Boyd County, prompting waste generators and the commission to sue. In 2002 the presiding judge found in favor of the commission, observing that he could not conceive of a stronger case of bad faith in the performance of a contract. This article critically examines that failure, which has left lasting scars among local residents, in order to provide a comprehensive explanation of the siting attempt as well as a set of lessons learned that are applicable to any large infrastructure project that makes use of complex and hazardous technologies.

Educational Activity for the Radiation Emergency System in the Northern Part of Japan: Meeting Report on "The 3rd Educational Symposium on Radiation and Health (ESRAH) by Young Scientists in 2016".

In the northern part of Japan, close cooperation is essential in preparing for any possible emergency response to radiation accidents because several facilities, such as the Low-Level Radioactive Waste Disposal Facility, the MOX Fuel Fabrication Plant and the Vitrified Waste Storage Center, exist in Rokkasho Village (Aomori Prefecture). After the accident at Fukushima Daiichi Nuclear Power Plant in 2011, special attention should be given to the relationship between radiation and human health, as well as establishing a system for managing with a radiation emergency. In the area of Hokkaido and Aomori prefectures in Japan, since 2008 an exchange meeting between Hokkaido University and Hirosaki University has been held every year to have opportunities to discuss radiation effects on human health and to collect the latest news on monitoring environmental radiation. This meeting was elevated to an international meeting in 2014 titled "Educational Symposium on Radiation and Health (ESRAH) by Young Scientists". The 3rd ESRAH meeting took place in 2016, with the theme "Investigating Radiation Impact on the Environmental and Health". Here we report the meeting findings on the continuing educational efforts after the Fukushima incident, what was accomplished in terms of building a community educational approaches, and future goals.

Chemical Characteristics of Leachate in Low-Level Radioactive Waste Disposal Facilities

AbstractLeachate data from four low-level radioactive waste and mixed waste disposal facilities operated by the U.S. DOE for environmental restoration programs are presented and analyzed. Constitue...

Hydraulic Conductivity of Geosynthetic Clay Liners to Low-Level Radioactive Waste Leachate

AbstractHydraulic conductivity was evaluated for eight commercially available geosynthetic clay liners (GCLs) permeated with leachate characteristic of low-level radioactive waste (LLW) disposal facilities operated by the U.S. Department of Energy (DOE). Two of the GCLs (CS and GS) contained conventional sodium bentonite (Na-B). The others contained a bentonite–polymer mixture (CPL, CPH, GPL1, GPL2, and GPH) or bentonite–polymer composite (BPC). All GCLs (except GPL2 and GPH) were permeated directly with two synthetic LLW leachates that are essentially identical, except one has no radionuclides (nonradioactive synthetic leachate, or NSL) and the other has radionuclides (radioactive synthetic leachate, or RSL). Hydraulic conductivities to RSL and NSL were identical. For the CS and GS GCLs, the hydraulic conductivity gradually increased by a factor of 5–25 because divalent cations in the leachate replaced native sodium cations bound to the bentonite. The CPL, GPL1, and GPL2 GCLs with low polymer loading (1....

低レベル放射性廃棄物処分施設のコンクリート構築物のリスク論的安全評価におけるシナリオ選定

コンクリート構造物の計画，設計，建設，維持管理にあたっては，今後強く要請されてくると考えられるリスク論的考え方に基づく評価が必要となる。本稿では，低レベル放射性廃棄物処分施設のコンクリート構築物に焦点をあてて，リスク論的考え方に基づく安全評価を，シナリオの選定と関連させて解説する。東日本大震災の前年に原子力安全委員会で制定されたリスク論的考え方に基づく安全評価の方法に基づいているが，本シナリオの選定は，今後検討が急がされているリスク論的考え方に基づく一般のコンクリート構造物の安全性と信頼性の評価ならびに維持管理などに適用できるものと考えられる。

A two-stage approach to defining an affected community based on the directly affected population and the sense of community

Studies have demonstrated the inadequacy of relying on existing administrative boundaries or simple proximity to define an affected community. The proposal and siting of hazardous facilities can have a range of impacts upon people across wide areas, with some more affected than others as a result of living with the physical impacts of construction or the fear associated with perceived risk. We term those most affected the directly affected population and propose a two-stage model for identifying an affected community which places those most affected at the centre of the definition. The second stage is to identify the relationships those most affected have with the wider elements of the sense of community to discover the existing community or communities which are affected. Illustrated by the siting of a low-level radioactive waste disposal facility at Dounrey in the north of Scotland, we show that elements of the lived community experience may have very different shapes, extents and conflicting interests which pose challenges for their incorporation into a siting process. The two-stage model presented in this paper, by placing those most directly affected at the centre and working from there out into the existing communities, identifies issues early in any siting process to improve their incorporation and amelioration.

The spatial politics of siting a radioactive waste facility in Korea: A mixed methods approach

Low-level radioactive waste disposal facilities represent one of the most controversial Locally Unwanted Land-Uses (LULUs). In Korea in 2005, one of these disposal facilities was assigned to be placed in Gyeongju city after a competitive local referendum amongst four candidate cities took place. Many conflicts occurred between the residents living within and near the Gyeongju city following the decision. In this paper, we explore the spatial issues in the referendum system and aim to discover the reason behind these conflicts. To do so, we analyzed the spatial distribution of the acceptance rate in each ward of the four cities using several spatial statistical methods, Getis-Ord G and Gi*, and several types of interviews. We found that the referendum system has a problem with spatial inequity within and across its jurisdiction. Furthermore, the causes of the spatial outliers in the acceptance rate were verified by interviews. The results suggest that spatial matters should be considered to increase the local acceptance of LULUs.

Mineralogy of selected geological deposits from the United Kingdom and the Republic of Ireland as possible capping material for low-level radioactive waste disposal facilities

Solid low-level radioactive waste (LLW) is currently being disposed at a number of facilities in the United Kingdom (UK). The safety of these facilities relies to some extent on the use of engineered barriers, such as a cap and a liner, to isolate the waste and protect the environment. Generally, the material used as the barrier layer within such a cap should be of low permeability and it should retain this property over long timescales (beyond a few decades normally required for facilities containing non-radioactive wastes). The objective of this research is to determine the mineralogy of selected geological deposits from the UK and Republic of Ireland as part of a larger project to examine their suitability as a capping material, particularly on LLW sites. Mineral transformations, from weathering, may impact on the long-term performance of the cap and even the disposal facility. These transformations could be brought on or enhanced by climate change. X-ray diffraction (XRD) was carried-out on the sand, silt and clay fractions of the London Clay, Belfast Upper Boulder Clay, Irish Glacial Till, Belfast Sleech, and Ampthill Clay geological deposits. Minerals were present that could pose both positive and negative effects on the long-term performance of the cap. Smectite, which has a high shrink swell potential, may produce cracks in London Clay, Belfast Upper Boulder Clay and Ampthill Clay capping material during dry, hotter periods as a possible consequence of future climate change; thus, resulting in higher permeability. Ampthill Clay and Belfast Sleech had elevated amounts of organic matter (OM) at 5.93% and 5.88%, respectively, which may also contribute to cracking. Over time, this OM may decompose and result in increased permeability. Gypsum [CaSO 4] in the silt and sand fractions of Ampthill Clay may reduce the impact of erosion during wetter periods if it is incorporated into the upper portion of the cap. There are potential negative effects from the acidity created by the weathering of pyrite [FeS 2] present in the silt and sand fractions of Belfast Sleech and Ampthill Clay that could impede the growth of grasses used to stabilize the surface of the capping material if this material is used as part of the vegetative soil layer. Additionally, acidic waters generated from pyrite weathering could negatively impact the lower lying capping material and the disposal facility in general, because they could react with contaminants and weaken vessels storing contaminants. However, calcium carbonate [CaCO 3] present in the silt and sand fractions of these deposits, and dolomite [CaMg(CO 3) 2] in Belfast Sleech, may counter act the acidity.

Experience in Progressing the Planning Application for New LLW Disposal Facilities for Dounreay

AbstractAn integral part of decommissioning the Nuclear Decommissioning Agency's (NDA) Dounreay site is the management of the solid low level radioactive waste (LLW). The United Kingdom Atomic Energy Authority (UKAEA) has developed and progressed a technical and stakeholder programme that has enabled it to submit a robust Planning Application to Highland Council (HC) for New LLW Disposal Facilities at Dounreay and to submit substantive preliminary safety and environmental cases to the Nuclear Installations Inspectorate (NII) and the Scottish Environment Protection Agency (SEPA). To UKAEA’s knowledge this is the most advanced project in the UK for new LLW disposal facilities. Experience has been gained in progressing the Best Practicable Environmental Option (BPEO) Study, working with regulators in unfamiliar areas, and undertaking groundbreaking stakeholder consultation. Key lessons learnt are that stakeholders should be engaged in dialogue on the project as early as possible, documentation must be high quality and tailored to its audience, and internationally respected and credible consultants must be involved.

Reconsidering the law and economics of low-level radioactive waste management

Several countries are striving to ensure adequate long-run disposal space for low-level radioactive waste (LLRW). In the United States, the Low-Level Radioactive Waste Policy Act of 1980 and its 1985 amendments comprise a menu of incentives and penalties designed to motivate the construction of regional LLRW disposal facilities—the operating premise. Congress wished to intervene in the marketplace to bring about a more equitable solution to the LLRW management problem. Some investigators forewarned years ago that the federal law was both inefficient and inequitable. Additionally, however, the law has proved ineffectual, as only one new disposal facility has emerged and that one (at Clive, UT) was created outside of the federal incentive structure. This article (1) provides an argument as to why the LLRW Act of 1980 and its subsequent amendments failed to elicit the regional system of LLRW facilities it envisioned, and (2) complements this argument with a comprehensive model of LLRW management.

A study on the degree of deliberation and meditation of cyber poll respondents for nuclear-related decision making

Public participation is essential in each step of the nuclear-related decision-making process. Recently, the electronic systems using the Internet have become quite popular, and have emerged as a good medium for communicating with the public. In this study, a comprehensive utilization of electronic public participation was used to analyze public opinion on a given nuclear-related decision-making process. The degree of deliberation and meditation of the public participating in an electronic poll survey was evaluated, and the decision-making factors representing the personal characteristics of the poll respondents such as age, income, education, residence, degree of knowledge and concern were carefully incorporated when preparing the poll-survey questionnaire for its evaluation. Fuzzy analysis was used to assess and aggregate the responses to each decision-making factor. As a case study, this procedure was used to analyzing public opinion on the location of a low-level radioactive waste disposal facility on the campus of Seoul National University. The results show that there is a tendency of respondents who are on the negative side of the argument to be more deliberate and meditative in their decision-making process than those on the positive side. Knowledge and residence were found to be important decision-making factors.

Sorption and transport behavior of radionuclides in the proposed low-level radioactive waste disposal facility at the Hanford site, Washington

AbstractA series of batch sorption and column experiments was conducted to investigate sorption and transport behavior of99Tc,129I,79Se, and90Sr on and through borehole sediments collected from the proposed low-level radioactive waste disposal facility at the Hanford Site (200 East Area). Batch sorption experiments were conducted on Hanford sediment using uncontaminated Hanford groundwater and simulated glass leachates spiked with individual radionuclides. Strongest sorption occurred for90Sr, while79Se sorption was intermediate, and129I and99Tc showed the least sorption affinities on Hanford sediment among these radionuclides studied. The results of column experiments that measured transport behavior of these radionuclides through Hanford sediment were similar to the mobility that can be calculated from the batch sorption results, that is high mobility for99Tc and129I compared to the intermediate and strong retardation for79Se and90Sr, respectively. These contaminant sorption data on sediments from below the proposed disposal facility, especially the tests using simulated glass leachate, corroborate values obtained for sediments collected in the past from near by locations and for generic solutions such as regional groundwater. These new data should provide more technical defensibility for past performance assessment predictions that did not use site-specific sediments and leachates. Further, the new data will be incorporated into future performance assessment activities that will update and improve past predictions.

Parametric analyses of diffusion of activated sources in disposal forms

The primary objective of a low-level radioactive waste disposal facility is to isolate low-level radioactive waste from the public and the environment until the radionuclides in the waste have decayed to levels at which the hazard is negligible. Two fundamental concerns must be addressed when attempting to isolate low-level waste in a disposal facility on land. The first concern is isolating the waste from water, or hydrologic isolation. The second is preventing movement of the radionuclides out of the disposal facility, or radionuclide migration. Particularly, we have investigated here the latter scenario. Empirical curves describing the progression of the altered zone are obtained and they are used to define the correspondent altered thickness in the numerical calculations for a cement sample. Subsequent numerical analyses of diffusion of activated sources in waste disposals are considered for cemented containers. The adopted DAMAGE code takes into account a mass conservation equation and the linear momentum balance equation for the multiphase material. The mathematical model is based on the theory developed by Bazant for concretes and geomaterials; the fluid phases are considered as a unique mixture interacting with a solid phase. Short- and long-term diffusion analyses are performed for different characteristics of the grout and the results are presented in terms of radionuclides concentration. Indications on the minimum grout thicknesses able to resist to radioactive fluxes up to 1000 years are given.

The Uptake and Distribution of Buried Radionuclides by Pocket Gophers (Thomomys bottae)

Material Disposal Area G (Area G) at the Los Alamos National Laboratory is a low-level radioactive waste disposal facility. The noticeably high activity of pocket gophers on closed waste burial sites of various types at Area G resulted in the need to understand possible interactions between gophers and radioactive waste. Fossorial animals can influence the fate of contaminants by directly burrowing into waste trenches, pushing contaminated soil to the surface, or through indirect mechanisms such as consumption of contaminant-laden vegetation or the ingestion of soil. In our study, pocket gophers, mound soil, surface soil, and vegetation were collected at Area G and at offsite reference locations. The samples were analyzed for 241Am, 238Pu, 239Pu, 3H, and total U. It did not appear that gophers were responsible for any upward transport of radionuclides. Concentrations of 241Am, 238Pu, 239Pu, and 3H in some gophers, soil, and vegetation were higher than at reference sites; however, only 3H in gopher carcasses at only one of five sites within Area G was higher than a conservative ecological screening level.