Radioactive Waste Storage Facility Research Articles

Legal Aspects of the Safety of the Techa Cascade of Reservoirs—Liquid Radioactive Waste Storage Facilities

In Russia in 1950–1960 solutions for the localization and storage of large volumes of liquid radioactive waste produced during defensive tasks were accomplished using natural and man-made water objects. At present, they are non-isolated from the environment and radioactive waste storage facilities constitute a serious potential menace. These objects are not allowed by the current legislation of the Russian Federation on environmental protection and safety. However, they do exist and there are no definite and approved engineering solutions regarding their removal. One of these objects is the Techa Cascade of Reservoirs (TCR) of the Mayak plant. In this article, TCR protection requirements are based on and formalized taking into account the legislation of the Russian Federation and the biospheric approach to the radiation protection of humans and the environment. Special safety requirements are needed because the standard argument “from human exposure to discharge standards” is invalid owing to the fact that the possibility of using water objects that have had contact with the TCR is restricted by law.

Environmental Injustice in Siting Nuclear Plants

Abstract The mining, fuel enrichment-fabrication, and waste-management stages of the US commercial nuclear-fuel cycle have been documented as involving environmental injustices affecting, respectively, indigenous uranium miners, nuclear workers, and minorities and poor people living near radioactive-waste storage facilities. After surveying these three environmental-injustice problems, the article asks whether US nuclear-reactor siting also involves environmental injustice. For instance, because high percentages of minorities and poor people live near the proposed Vogtle reactors in Georgia, would siting new reactors at the Vogtle facility involve environmental injustice? If so, would this case be an isolated instance of environmental injustice, or is the apparent Georgia inequity generally representative of environmental injustice associated with nuclear-reactor siting throughout the US? Providing a preliminary answer to these questions, the article uses census data, paired t-tests, and z-tests to compar...

Radiological protection regulation during spent nuclear fuel and radioactive wastemanagement in the Western Branch of the Federal State Unitary Enterprise ‘SevRAO’

The site of temporary storage of spent nuclear fuel and radioactive waste, situated atAndreeva Bay in Northwest Russia, was developed in the 1960s, and it has carried outreceipt and storage of fresh and spent nuclear fuel, and solid and liquid radioactive wastegenerated during the operation of nuclear submarines and nuclear-powered icebreakers.The site is now operated as the western branch of the Federal State UnitaryEnterprise, SevRAO. In the course of operation over several decades, the containmentbarriers in the Spent Nuclear Fuel and Radioactive Waste storage facilities partiallylost their containment effectiveness, so workshop facilities and parts of the sitebecame contaminated with radioactive substances. This paper describes work beingundertaken to provide an updated regulatory basis for the protection of workers duringespecially hazardous remediation activities, necessary because of the unusual radiationconditions at the site. It describes the results of recent survey work carried outby the Burnasyan Federal Medical Biophysical Centre, within a programme ofregulatory cooperation between the Norwegian Radiation Protection Authority and theFederal Medical–Biological Agency of Russia. The survey work and subsequentanalyses have contributed to the development of special regulations setting outradiological protection requirements for operations planned at the site. Within theserequirements, and taking account of a variety of other factors, a continuing needarises for the implementation of optimisation of remediation at Andreeva Bay.

Radioactive contamination of groundwater at the Andreeva Bay Shore Technical Base, Northwest Russia

The Andreeva Bay Shore Technical Base is one of the largest, most contaminated nuclear legacy sites in Northwest Russia. Radioactive contamination at the site stems from servicing and maintenance activites for Russian Northern Fleet nuclear submarine. Studies of groundwater contamination have been conducted using measurements taken at different boreholes around the site. Results indicate that groundwater contamination has occurred in some areas of the Andreeva Bay facility. These areas are primarily located near Building 5 where accidental releases occurred in 1982 during storage of spent nuclear fuel (SNF) and near the liquid and solid radioactive waste (LRW and SRW) storage facilities which have been infiltrated by precipitation waters.

On-site radioactive soil contamination at the Andreeva Bay shore technical base, Northwest Russia

The radioactive waste (RAW) storage site at Andreeva Bay in the Russian Northwest has experienced radioactive contamination both as a result of activities carried out at the site and due to incidents that have occurred there in the past such as accidental releases of radioactive materials. The site is an interesting case study for decommissioning due to the extremely large amounts of radioactivity present at the site and the conditions under which it is stored; very little has been previously published in the scientific literature about this site. This paper complements the paper describing dose rates at Andreeva Bay which is published in this issue of Journal of Environmental Radioactivity by the same authors. This study presents new data related to the activity concentrations of 137Cs and 90Sr in surface soils and measurements of α- and β-particle fluxes taken at different areas around the site. Limited data on 60Co is also presented. The results of the study indicate that the main areas of site contamination are associated with the former spent nuclear fuel storage facility at Building 5, due to accidental discharges which began in 1982. Substantial contamination is also observed at the solid radioactive waste storage facilities, probably due to the ingress of water into these facilities. More than 240 samples were measured: maximum contamination levels were 1 × 10 6 Bq/kg 137Cs (mean value 4.1 × 10 5 Bq/kg) and 4 × 10 6 Bq/kg 90Sr (mean value 1.2 × 10 5 Bq/kg). Localised patches of α and β contamination were also observed throughout the site.

On-site gamma dose rates at the Andreeva Bay shore technical base, northwest Russia

The spent nuclear fuel (SNF) and radioactive waste (RAW) storage facility at Andreeva Bay shore technical base (STB) is one of the largest and most hazardous nuclear legacy sites in northwest Russia. Originally commissioned in the 1960s the facility now stores large amounts of SNF and RAW associated with the Russian Northern Fleet of nuclear powered submarines. The objective of the present study was to map ambient gamma dose rates throughout the facility, in particular at a number of specific sites where SNF and RAW are stored. The data presented here are taken from a Norwegian–Russian collaboration enabling the first publication in the scientific literature of the complete survey of on-site dose rates. Results indicate that elevated gamma dose rates are found primarily at discrete sites within the facility; maximum dose rates of up to 1000 μSv/h close to the ground (0.1 m) and up to 3000 μSv/h at 1 m above ground were recorded, higher doses at the 1 m height being indicative primarily of the presence of contaminated equipment as opposed to ground contamination. Highest dose rates were measured at sites located in the immediate vicinity of buildings used for storing SNF and sites associated with storage of solid and liquid radioactive wastes. Elevated dose rates were also observed near the former channel of a small brook that became heavily contaminated as a result of radioactive leaks from the SNF storage at Building 5 starting in 1982. Isolated patches of elevated dose rates were also observed throughout the STB. A second paper detailing the radioactive soil contamination at the site is published in this issue of Journal of Environmental Radioactivity.

How the Radiologic and Nuclear Medical Communities Can Improve Nuclear Security

Highly enriched uranium (HEU) is used to manufacture technetium-99m, the most widely used medical radioisotope in the world. Highly enriched uranium is also used to make nuclear bombs; 50 kg of HEU is enough to make a Hiroshima-type bomb. It is generally agreed that this technology is within the reach of a terrorist group; the main obstacle is acquiring HEU. Currently, as a legacy of the US and Soviet Atoms for Peace Program, there are civilian users of HEU in 40 countries, and about 1,000 kg are still being shipped each year. Unfortunately, the major international manufacturers of technetium-99m have been refusing to convert their production facilities to use low-enriched uranium (LEU), which cannot be used to make a nuclear bomb. Only 1% to 2% of the HEU is consumed in the process of producing technetium-99m. The remainder is accumulating in radioactive waste storage facilities. The radiologic and nuclear medical communities could make a tremendous contribution to a safer world by supporting the replacement of HEU with LEU in the production of technetium-99m. Low-enriched uranium is just as cost effective as HEU for the manufacture of technetium-99m and does not contribute to the risk for nuclear terrorism.

06/01639 Commissioning and operation of high level radioactive waste vitrification and storage facilities: the Indian experience: Raj, K. International Journal of Nuclear Energy Science and Technology, 2005, 1, (2–3), 148–163

A simulated high level waste (HLW) containing 4 mass% chrome oxide, whose overall composition is representative of the high chrome oxide wastes at Hanford WA USA, was easily vitrified in a phosphate glass at temperatures ranging from 1150 °C, for waste loadings of 55 mass%, to 1250 °C for waste loadings of 75 mass%. Even at these high waste loadings, these wasteforms had an excellent chemical durability. The best chemical durability was achieved when the O/(Si + P) atomic ratio was between 3.5 and 3.8. These wasteforms were also resistant to crystallization although trace amounts of crystalline Cr2O3 were present in wasteforms containing more than 70 mass% HLW. It is concluded that up to 45 mass% of the total HLW at Hanford, especially that containing as high as 4.5 mass% chrome oxide, could be directly vitrified into an iron phosphate glass, that meets all of the current chemical durability requirements by simply adding 25–35 mass% P2O5 to the waste and melting the mixture at 1150–1250 °C for a few (<6) hours.

Seismic Hazards Assessment for Radioactive Waste Disposal Sites in Regions of Low Seismic Activity

A comparative tectonic quiescence and lack of earthquakes make the stable centres of continents attractive for siting long-term radioactive waste storage facilities. The low rates of deformation in such regions, however, make it difficult to characterize their long-term seismotectonic behaviour, leading to uncertain estimates for the very low probability hazard estimates required by society. In an attempt to overcome the deficiency of both contemporary seismicity and paleoseismic data in central Canada, we have used earthquake histories from regions with similar seismotectonic characteristics from around the world. Substituting space for time, we estimate a long-term rate per 106 km2 of 0.004 magnitude ≥6 earthquakes per annum, of which 33–100% might rupture to the surface.

Modelling of the shielding capabilities of the existing solid radioactive waste storages at ignalina NPP

There is only one nuclear power plant in Lithuania--Ignalina NPP (INPP). The INPP operates two similar units with design electrical power of 1500 MW. The units were commissioned in 1983 and 1987 respectively. From the beginning of the INPP operation all generated solid radioactive waste was collected and stored at the Soviet type solid radwaste facility located at INPP site. The INPP solid radwaste storage facility consists of four buildings, namely building No. 155, No. 155/1, No. 157 and No. 157/1. The buildings of the INPP solid radwaste storage facility are reinforced concrete structures above ground. State Nuclear Safety Inspectorate (VATESI) has specified that particular safety analysis must be performed for existing radioactive waste storage facilities of the INPP. As part of the safety analysis, shielding capabilities of the walls and roofs of these buildings were analysed. This paper presents radiation shielding analysis of the buildings No. 157 and No. 157/1 that are still in operation. The buildings No. 155 and No. 155/1 are already filled up with the waste and no additional waste loading is expected.

Bioindication-based Estimation of Technogenic Impact on Pinus sylvestris L. Populations in the Vicinity of a Radioactive Waste Storage Facility

The spectrum and frequency of cytogenetic aberrations in the reproductive (seeds) and vegetative (foliage) organs of Scotch pine (Pinus sylvestris L.) have been studied in the vicinity of the LSK Radon facility for radioactive waste storage and processing and in a 30-km zone around the Chernobyl Nuclear Power Plant. The results indicate that the pine populations of these regions are exposed to mutagenic factors. In contrast to the 30-km Chernobyl zone, the increased environmental mutagenicity in the vicinity of LSK Radon and in the center of the city of Sosnovyi Bor is mainly accounted for by chemical factors. The results of additional acute γ-irradiation have shown an increased radiation resistance of Scotch pine seeds from the LSK Radon and Sosnovyi Bor populations. Regression analysis demonstrated a significant increase in the cytogenetic aberration rate in plants from the experimental plots throughout the study period (1997–2002).

Bio-monitoring the genotoxicity of populations of Scots pine in the vicinity of a radioactive waste storage facility

Results of a long-term (1997–2002) study of the Scots pine populations growing in the vicinity of the radioactive waste storage facility (‘Radon’ LWPE) are presented. Cytogenetic disturbances in reproductive (seeds) and vegetative (needles) tissues sampled from Scots pine populations were studied to examine whether Scots pine trees have experienced environmental stress in areas with relatively low levels of pollution. The data clearly indicate the presence of mutagenic contaminants in the environment of the pine trees. An increased number of mitotic abnormalities, especially multipolar mitoses was found in the pine tree populations submitted to man-made exposure, which suggests that the cytogenetic damage is mainly caused by chemical contamination. A higher radioresistance of the Scots pine seeds from the impacted populations was shown by use of acute γ-irradiation. During the observation period 1997–2002, pine trees exposed to anthropogenic pollution showed a steady increase of cytogenetic alterations in the root meristem cells.

Commissioning and operation of high level radioactive waste vitrification and storage facilities: the Indian experience

In India, R&D work for management of high-level radioactive liquid waste (HLW) was started along with inception of the Indian Atomic Energy Programme. This culminated in the setting up of the first vitrification facility at the Waste Immobilisation Plant (WIP) at Tarapur. The second vitrification facility has been commissioned at WIP at Trombay and the third such facility is being set up at Kalpakkam. Vitrified waste product (VWP) canisters generated from both Tarapur and Trombay are destined for storage at solid storage surveillance facility (SSSF) at Tarapur, which is the first Indian facility for interim storage vitrified waste product. This paper presents the details of commissioning and operation of these facilities along with work being done on long-term characterisation of vitrified waste product and future vitrification programme.

Investigating Pu and U isotopic compositions in sediments: a case study in Lake Obuchi, Rokkasho Village, Japan using sector-field ICP-MS and ICP-QMS

The objectives of the present work were to study isotope ratios and the inventory of plutonium and uranium isotope compositions in sediments from Lake Obuchi, which is in the vicinity of several nuclear fuel facilities in Rokkasho, Japan. Pu and its isotopes were determined using sector-field ICP-MS and U and its isotopes were determined with ICP-QMS after separation and purification with a combination of ion-exchange and extraction chromatography. The observed (240)Pu/(239)Pu atom ratio (0.186 +/- 0.016) was similar to that of global fallout, indicating that the possible early tropospheric fallout Pu did not deliver Pu from the Pacific Proving Ground to areas above 40 degrees N. The previously reported higher Pu inventory in the deep water area of Lake Obuchi could be attributed to the lateral transportation of Pu deposited in the shallow area which resulted from the migration of deposited global fallout Pu from the land into the lake by river runoff and from the Pacific Ocean by tide movement and sea water scavenging, as well as from direct soil input by winds. The (235)U/(238)U atom ratios ranged from 0.00723 to 0.00732, indicating the natural origin of U in the sediments. The average (234)U/(238)U activity ratio of 1.11 in a sediment core indicated a significant sea water U contribution. No evidence was found for the release of U containing wastes from the nearby nuclear facilities. These results will serve as a reference baseline on the levels of Pu and U in the studied site so that any further contamination from the spent nuclear fuel reprocessing plants, the radioactive waste disposal and storage facilities, and the uranium enrichment plant can be identified, and the impact of future release can be rapidly assessed.

Radiation streaming and skyshine evaluation for a proposed low-level radioactive waste assured isolation facility.

Texas is investigating the idea of building a long term waste storage facility, also known as an Assured Isolation Facility. This is an above-ground, retrievable low-level radioactive waste storage facility. A preliminary, scoping-level analysis has been extended to consider more complex scenarios of radiation streaming and skyshine by using MCNP to model the facility in greater detail. Using bounding source term assumptions, the radiation doses and dose rates are found to exceed applicable limits by an order of magnitude. By altering the facility design to fill in the hollow cores of the prefabricated concrete slabs used in the roof over the "high-gamma" rooms where the waste with greatest gamma radiation intensity is stored, dose rates outside the facility decrease by an order of magnitude. With the modified design, the annual dose at the site fenceline is less than the 1 mSv annual limit for exposure of the public. Within the site perimeter, modifying the roof results in an order of magnitude drop in the dose rate for personnel outside the facility and on the facility roof, as well as a significant drop inside the facility. Radiation streaming inside the facility can be lowered almost two orders of magnitude by placing operational restrictions to keep at least two rows of waste containers in front of the high-gamma room to cut down on the size of the path for streaming.

Retrospective dosimetry: dose evaluation using unheated and heated quartz from a radioactive waste storage building.

In the assessment of dose received from a nuclear accident, considerable attention has been paid to retrospective dosimetry using heated materials such as household ceramics and bricks. However, unheated materials such as mortar and concrete are more commonly found in industrial sites and particularly in nuclear installations. These materials contain natural dosemeters such as quartz, which usually is less sensitive than its heated counterpart. The potential of quartz extracted from mortar in a wall of a low-level radioactive-waste storage facility containing distributed sources of 60Co and 137Cs has been investigated. Dose-depth proliles based on small aliquots and single grains from the quartz extracted from the mortar samples are reported here. These are compared with results from heated quartz and polymineral fine grains extracted from an adjacent brick, and the integrated dose recorded by environmental TLDs.

Dose reconstruction system for the exposed population living along the Techa River.

The Mayak Production Association, which began operation in 1948, was the first facility in the former Soviet Union for the production of plutonium. Significant worker and population exposure occurred as a result of failures in the technological processes in the late 1940's and early 1950's. Members of the public were exposed via discharge of about 1017 Bq of liquid wastes into the Techa River during 1949-1956, an explosion in the radioactive waste-storage facility in 1957, and gaseous aerosol releases within the first decades of the facility's operation. Residents of many villages downstream on the Techa River were exposed via a variety of pathways; the more significant included drinking of water from the river and external gamma exposure due to proximity to sediments and shoreline. The specific aim of this project is to enhance the reconstruction of external and internal radiation doses for individuals in the Extended Techa River Cohort. The purpose of this paper is to present the details of the methods that are being used in this enhanced dose-reconstruction effort and to provide example and representative results of the calculations. The methods of dose assessment currently being developed for the exposed population [termed the Techa River Dosimetry System-2000 (TRDS-2000)], which are a significant improvement on past methods (TRDS-1996), are presented. The new TRDS-2000 doses from the ingestion of radionuclides are substantially higher for the gastrointestinal tract, due to consideration of short-lived radionuclides. The TRDS-2000 doses from external exposure are substantially lower due to improvements in several factors. Assessment of uncertainty and validation of the "new" doses are significant issues currently under investigation.

Sensitivity of protective barrier performance to changes in rainfall rate

Single- or multi-layered surface barriers are used for protecting the underlying hazardous or radioactive waste storage facility and for reducing the risk of dispersion of contaminants to the ground water. To assess the effect of variations in net rainfall rate (total rainfall minus evapotranspiration) on the hydraulic response of a multi-layered barrier, a series of flow simulations were performed. Water fluxes in different layers of the barrier were numerically calculated for three net rainfall rates, i.e. 0.0255, 0.0742, and 0.141 cm/day. These rates correspond to dry, average, and wet climatological conditions in Belgium. Results show that for dry conditions, almost 45% of the water infiltrating the top of the barrier is laterally evacuated. When the net rainfall rate increases from 0.0255 to 0.0742 cm/day, more water is being laterally diverted, and only 22% of the applied rainfall percolates through the barrier. If the rainfall rate is increased from 0.0255 to 0.141 cm/day, the percolation becomes 14% of the applied rainfall. This indicates that fluxes leaving the bottom of the repository increase only slightly, although the rainfall rate for wet conditions is approximately 5 times larger than for dry conditions. Under dry conditions a slightly negative pressure develops in the bottom of the low-permeability clay layer. However, this desaturation does not affect the integrity of the clay.

Anion Scavengers for Low-Level Radioactive Waste Repository Backfills

Minimization of 129/− and 99 TcO4 − transport to the biosphere is critical to the success of low level radioactive waste (LLRW) storage facilities. Here we experimentally identify and classify potential sorbent materials for inclusion in LLRW backfills. For low pH conditions (pH 4-5), Cu-sulfides and possibly imogolite-rich soils provide Kd's (distribution coefficients) of roughly 103 mL g−1 for /−, and 102 mL g−1 for TcO4 −. At near neutral pH, hydrotalcites, Cu-oxides, Cu-sulfides, and lignite coal possess Kd's on the order of 102 mL g−1 for both /− and TcO4 −. At high pH (pH>10), such as might occur in a cementitious LLRW facility, calcium monosulfate aluminate Kd's are calculated to be roughly 102 mL g−1 for both both /− and TcO4 −.

Potential Negative Impacts of Nuclear Activities on Local Economies: Rethinking the Issue

Surveys of public opinion about perceptions of risk associated with the nuclear fuel cycle have shown that the public professes a widespread feeling of dread, a fear of associated stigmas, and a concern about possible catastrophic nuclear accidents. Various interest groups and state governments that oppose congressionally mandated siting of centralized high‐level radioactive waste (HLW) storage and disposal facilities are using this negative imagery to create a powerful, emotional obstacle to the siting process. From statistical analyses of images and location preferences, researchers have claimed that possible significant economic losses could potentially accompany the siting of HLW facilities. However, several paradoxes, or self‐contradictory statements, apparently exist between the responses expressed in surveys and the actual economic and demographic behavior evidenced in the marketplace. Federal policymakers need to evaluate whether the request for a change in siting policy is based on subjective fear of a potential negative economic effect or on proven negative effects. Empirically observed behavior does not support predicted negative economic effects based on survey responses.