Journal of environmental radioactivity最新文献

{"title":"Radionuclide Solid:liquid partitioning in an aged, reducing-grout wasteform recovered from a disposal facility","authors":"Daniel I. Kaplan , Philip M. Almond","doi":"10.1016/j.jenvrad.2024.107514","DOIUrl":"10.1016/j.jenvrad.2024.107514","url":null,"abstract":"<div><p>The Saltstone Disposal Facility on the Savannah River Site in South Carolina disposes of Low-Level Waste in a reducing-grout waste form. Reducing grout is presently being evaluated as a subsurface disposal waste form at several other locations in the United States, as well as in Europe and Asia. The objective of this study was to collect core samples directly from the Saltstone Disposal Facility and measure desorption distribution coefficients (<em>K</em><sub><em>d</em></sub>; radionuclide concentration ratio of saltstone:liquid; (Bq/kg)/Bq/L)) and desorption apparent solubility values (<em>k</em><sub><em>sp</em></sub>; radionuclide aqueous concentration (moles/L)). An important attribute of this study was that these tests were conducted with actual aged, grout waste form materials, not small-volume simulants prepared in a laboratory. The reducing grout is comprised of blast furnace slag, Class F fly ash, ordinary portland cement, and a radioactive salt waste solution generated during nuclear processing. The grout sample used in this study underwent hydrolyzation in the disposal facility for 30 months prior to measuring radionuclide leaching. Leaching experiments were conducted either in an inert (no oxygen) atmosphere to simulate conditions within the saltstone monolith prior to aging (becoming oxidized) or they were exposed to atmosphere conditions to simulate conditions of an aged saltstone. Importantly, these experiments were designed not to be diffusion limited, that is, the saltstone was ground finely and the suspensions were under constant agitation during the equilibration period. Under oxidized conditions, measured Tc <em>K</em><sub><em>d</em></sub> values were 10 mL/g, which was appreciably greater than the historical best-estimate value of 0.8 mL/g. This difference is likely the result of a fraction of the Tc remaining in the less soluble Tc(IV) form, even after extensive oxidation during the experiment. Under oxidized and reducing conditions, the measured Ba and Sr (both divalent alkaline earth metals) <em>K</em><sub><em>d</em></sub> value were more than an order of magnitude greater than historical best-estimate values of 100 mL/g. The unexpectedly high Ba and Sr <em>K</em><sub><em>d</em></sub> values were attributed to these radionuclides having sufficient time to age (form strong bonds) in the sulfur-rich saltstone sample. Apparent <em>k</em><sub><em>sp</em></sub> values under reducing conditions were 10<sup>−9</sup> mol/L Tc and 10<sup>−13</sup> mol/L Pu, consistent with values measured with surrogate materials. Measured apparent Ba, Sr, and Th <em>k</em><sub><em>sp</em></sub> values were significantly greater than historical best-estimates. The implications of the generally greater <em>K</em><sub><em>d</em></sub> values and lower <em>k</em><sub><em>sp</em></sub> values in these measurements is that these cementitious waste forms have greater radionuclide retention than was previously estimated based on laboratory studies ","PeriodicalId":15667,"journal":{"name":"Journal of environmental radioactivity","volume":"279 ","pages":"Article 107514"},"PeriodicalIF":1.9,"publicationDate":"2024-08-13","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"141978803","PeriodicalName":null,"FirstCategoryId":null,"ListUrlMain":null,"RegionNum":3,"RegionCategory":"环境科学与生态学","ArticlePicture":[],"TitleCN":null,"AbstractTextCN":null,"PMCID":"","EPubDate":null,"PubModel":null,"JCR":null,"JCRName":null,"Score":null,"Total":0}

{"title":"Effect of drying temperature on the quantitative analysis of 131I in algal samples by γ-spectrometry","authors":"Zeshu Li ,&nbsp;Fei Tuo ,&nbsp;Dezheng Yuan ,&nbsp;Qiang Zhou ,&nbsp;Weiguo Zhu ,&nbsp;Juncheng Liang ,&nbsp;Baolu Yang","doi":"10.1016/j.jenvrad.2024.107515","DOIUrl":"10.1016/j.jenvrad.2024.107515","url":null,"abstract":"<div><p>¹³¹I has been extensively utilized in nuclear medicine, resulting in its widespread detection in coastal algal samples due to its discharge. Therefore, it is essential to monitor ¹³¹I in the coastal algal samples. γ-spectrometry is an expeditious method for measuring ¹³¹I, but this method requires the pretreatment of the algal sample. The effect on ¹³¹I in the algal sample during the oven-drying treatment is unclear. In this study, the <em>Laminaria japonica</em> Areschoug and <em>Sargassum vachellianum</em> Greville were collected at two locations and analyzed for ¹³¹I using γ-spectrometry. Additionally, the content of iodine was measured using an Inductively Coupled Plasma-Mass Spectrometer (ICP-MS) to clarify the effect of ¹³¹I loss during drying treatment at different temperatures. The results demonstrated that the dried Laminaria and Sargassum samples had calculated ¹³¹I activity concentration relative standard deviations (RSDs) of 6.34 % and 16.31 %, respectively, while the fresh samples exhibited RSDs of 11.70 % and 15.57 %. Additionally, the iodine content RSDs in the dried samples were 9.19 % for Laminaria and 10.34 % for Sargassum. Significantly, discrepancies in ¹³¹I activity concentration between the fresh and dried Laminaria and Sargassum were 5.4 % and 10.3 %. These findings indicate that the temperature factor in drying has no effect on ¹³¹I loss in Laminaria and Sargassum in the range of 70 °C–110 °C.</p></div>","PeriodicalId":15667,"journal":{"name":"Journal of environmental radioactivity","volume":"278 ","pages":"Article 107515"},"PeriodicalIF":1.9,"publicationDate":"2024-08-11","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"141964162","PeriodicalName":null,"FirstCategoryId":null,"ListUrlMain":null,"RegionNum":3,"RegionCategory":"环境科学与生态学","ArticlePicture":[],"TitleCN":null,"AbstractTextCN":null,"PMCID":"","EPubDate":null,"PubModel":null,"JCR":null,"JCRName":null,"Score":null,"Total":0}

{"title":"Determination of the source location of anthropogenic radionuclides collected in Finland and Sweden in June 2020 using a multi-technology analysis","authors":"Ian Hoffman ,&nbsp;P. Mekarski ,&nbsp;A. Botti ,&nbsp;J. Yi ,&nbsp;A. Malo ,&nbsp;C. Cochrane ,&nbsp;V. Khotylev ,&nbsp;J. Kastlander ,&nbsp;A. Axelsson ,&nbsp;A. Ringbom ,&nbsp;M. Moring ,&nbsp;T. Karhunen ,&nbsp;A. Mattila ,&nbsp;M. Goodwin ,&nbsp;A. Davies ,&nbsp;K. Ungar","doi":"10.1016/j.jenvrad.2024.107508","DOIUrl":"10.1016/j.jenvrad.2024.107508","url":null,"abstract":"<div><p>In June 2020, observations of anthropogenic radionuclides in Estonia, Finland, and Sweden that were not related to any acknowledged environmental release led to a comprehensive investigation on the source and cause of the unusual emissions. Several of the observed radionuclides were on the list of Comprehensive Nuclear-Test-Ban Treaty (CTBT) relevant radionuclides as an indicator of a potential nuclear test, and warranted detailed investigation. While analysis of aerosol samples coupled with Atmospheric Transport and Dispersion Modelling (ATDM) is a standard approach for environmental particulate releases, several new techniques were employed to better characterize the samples that allowed for useful inferences to be made. These inferences were crucial in forming the ultimate hypothesis for determining the facility type and location of the release.</p></div>","PeriodicalId":15667,"journal":{"name":"Journal of environmental radioactivity","volume":"278 ","pages":"Article 107508"},"PeriodicalIF":1.9,"publicationDate":"2024-08-08","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"https://www.sciencedirect.com/science/article/pii/S0265931X24001401/pdfft?md5=fe0d1720a2f5761660eec17df8d09571&pid=1-s2.0-S0265931X24001401-main.pdf","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"141912895","PeriodicalName":null,"FirstCategoryId":null,"ListUrlMain":null,"RegionNum":3,"RegionCategory":"环境科学与生态学","ArticlePicture":[],"TitleCN":null,"AbstractTextCN":null,"PMCID":"OA","EPubDate":null,"PubModel":null,"JCR":null,"JCRName":null,"Score":null,"Total":0}

{"title":"Contributions of fossil and non-fossil fractions to total carbon in urban aerosols in Bratislava (Slovakia)","authors":"Ivan Kontul ,&nbsp;Alexander Cherkinsky ,&nbsp;Miroslav Ješkovský ,&nbsp;Jakub Kaizer ,&nbsp;Pavel P. Povinec ,&nbsp;Karol Sučák ,&nbsp;Jakub Zeman","doi":"10.1016/j.jenvrad.2024.107512","DOIUrl":"10.1016/j.jenvrad.2024.107512","url":null,"abstract":"<div><p>Radiocarbon measurements of total carbon (TC) fraction of aerosol samples collected at the campus of the Comenius University in Bratislava (Slovakia) during 2022–2023 were carried out. Based on radiocarbon activity of these samples and a source apportionment model we have determined the relative proportion of fossil and non-fossil carbon in collected atmospheric aerosols. The carbon from non-fossil sources (biomass burning and biogenic emissions) was dominant in this time period, on average it formed 72% of carbon present in the aerosols from the atmosphere of Bratislava. The whole range of determined non-fossil fraction was relatively small as it varied only from 0.67 (August–September) to 0.82 (December–January). These changes do not exhibit any significant seasonal variation as was previously observed in Bratislava during 2017–2018 in the elemental carbon (EC) aerosol fraction.</p></div>","PeriodicalId":15667,"journal":{"name":"Journal of environmental radioactivity","volume":"278 ","pages":"Article 107512"},"PeriodicalIF":1.9,"publicationDate":"2024-08-07","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"141906773","PeriodicalName":null,"FirstCategoryId":null,"ListUrlMain":null,"RegionNum":3,"RegionCategory":"环境科学与生态学","ArticlePicture":[],"TitleCN":null,"AbstractTextCN":null,"PMCID":"","EPubDate":null,"PubModel":null,"JCR":null,"JCRName":null,"Score":null,"Total":0}

{"title":"Low-level gamma ray counting on environmental samples","authors":"D. Mrdja,&nbsp;S. Forkapic,&nbsp;J. Hansman,&nbsp;J. Knezevic Radic,&nbsp;D. Velimirovic,&nbsp;K. Demirhan","doi":"10.1016/j.jenvrad.2024.107511","DOIUrl":"10.1016/j.jenvrad.2024.107511","url":null,"abstract":"<div><p>One of the major demands in gamma spectrometry of environmental samples is the accurate determination of activity concentration of present radionuclides (naturally occurring and those of artificial origin), due to the fact they are commonly of relatively low content. Thus, all these measurements have in common that the detection limit, in the spectral region of interest should be as low as possible. For this reason, the construction of a good passive, as well as active shield requires a detailed knowledge of the origin of the background events in the absence of an environmental sample. In addition, an analysis of the impact on detection limits due to the presence of the sample itself is also important. Also, the knowledge of the statistical basics for low-level counting is helpful to enable the best choice of detector characteristics (relative efficiency, peak to Compton ratio, resolution), measuring time, and required level of precaution against the different background contributions.</p><p>In this paper, the background spectra of several gamma spectroscopy systems (with passive and active veto shields) are analyzed and discussed, regarding their capabilities for measurements of environmental samples. Furthermore, various environmental samples are analyzed by low-level gamma spectrometry, including the sample measurements in the presence of an active veto shield against cosmic-ray muons. The disturbance of radioactive equilibrium between members of radioactive series in the samples is commented on, together with the possibility of use of certain gamma lines (including their interference and the corresponding intensities) for radionuclide activities determination.</p></div>","PeriodicalId":15667,"journal":{"name":"Journal of environmental radioactivity","volume":"278 ","pages":"Article 107511"},"PeriodicalIF":1.9,"publicationDate":"2024-08-02","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"141889406","PeriodicalName":null,"FirstCategoryId":null,"ListUrlMain":null,"RegionNum":3,"RegionCategory":"环境科学与生态学","ArticlePicture":[],"TitleCN":null,"AbstractTextCN":null,"PMCID":"","EPubDate":null,"PubModel":null,"JCR":null,"JCRName":null,"Score":null,"Total":0}

{"title":"Biokinetics of Americium-241 in the euryhaline diamond sturgeon Acipenser gueldenstaedtii following its uptake from water or food","authors":"Ross A. Jeffree ,&nbsp;Scott J. Markich ,&nbsp;Francois Oberhaensli ,&nbsp;Jean-Louis Teyssie","doi":"10.1016/j.jenvrad.2024.107503","DOIUrl":"10.1016/j.jenvrad.2024.107503","url":null,"abstract":"<div><p>Americium-241 whole body and internal biokinetics were experimentally investigated in the euryhaline diamond sturgeon <em>Acipenser gueldenstaedtii</em> during its uptake from water and food, in fresh (FW) and brackish water (BW; 9 psu). Whole-body uptake rates of ²⁴¹Am from water and subsequent depuration rates were quantified over 14 and 28 days, respectively, and assimilation efficiency (AE) of ²⁴¹Am from diet (chironomid) was determined over 28 days. FW reduced the biological half-life of ²⁴¹Am following aqueous uptake by an order of magnitude. In contrast BW greatly reduced ²⁴¹Am assimilation efficiency (AE) from diet (chironomid) by several orders of magnitude (from an AE of 8.5% (FW) down to 0.003% (BW)). Hence, salinity <em>per se</em> is indicated as a major environmental variable in determining the radiological exposure of <em>A. gueldenstaedtii</em> to ²⁴¹Am. During aqueous exposure BW appreciably increased ²⁴¹Am activity concentrations in most body components, but aqueous or dietary exposure pathway at either salinity did not determine marked differences in how ²⁴¹Am was distributed among six body components. The highly mineralized skin of <em>A. gueldenstaedtii</em> recurred as a major repository of ²⁴¹Am in all experimental treatments, as high as 50% among body components, due to its internal transfer from diet, surface adsorption and/or active absorption from water. The indicated prominence of the aqueous, compared to the dietary, exposure pathway for ²⁴¹Am accumulation by <em>A. gueldenstaedtii</em> suggests its radiological exposure would be enhanced by BW as it leads to its greater long-term retention, due to a much longer biological half-life.</p></div>","PeriodicalId":15667,"journal":{"name":"Journal of environmental radioactivity","volume":"278 ","pages":"Article 107503"},"PeriodicalIF":1.9,"publicationDate":"2024-07-31","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"141874985","PeriodicalName":null,"FirstCategoryId":null,"ListUrlMain":null,"RegionNum":3,"RegionCategory":"环境科学与生态学","ArticlePicture":[],"TitleCN":null,"AbstractTextCN":null,"PMCID":"","EPubDate":null,"PubModel":null,"JCR":null,"JCRName":null,"Score":null,"Total":0}

{"title":"Comparison between the Baltic Sea and Irish Sea level of Cs-137 contamination on benthic, demersal and pelagic fish species","authors":"Pedro Nogueira ,&nbsp;Ulrike Kammann ,&nbsp;Stefanie A.K. Schmied ,&nbsp;Marc-Oliver Aust","doi":"10.1016/j.jenvrad.2024.107510","DOIUrl":"10.1016/j.jenvrad.2024.107510","url":null,"abstract":"<div><p>The Irish Sea and the Baltic Sea are nowadays still the two most Cs-137 contaminated Seas worldwide. However, the origins of this contaminations are completely different. While the Baltic Sea was unintentionally contaminated due to global fallout after the accident in the Chernobyl nuclear powerplant in 1986, the Irish sea was intentionally used for low level liquid radioactive waste discharges from the Sellafield nuclear reprocessing facility (called Windscale until 1981) between the 1950s and 1990s. Nowadays, more than 30 years later, it is still possible to detect these contaminations in fish, water and sediments of both seas. Since fish are an important part of the human diet, monitoring Cs-137 levels in fish is essential for assessing the potential radiation exposure to humans. In 2019 and 2020 two surveys were dedicated to study the current levels of radioactive contamination in fish species from both Seas. During both surveys, fish samples were collected and analysed by gamma spectrometry later on. The results show that the average Cs-137 activity in benthic, demersal and pelagic fish species from the Baltic Sea are 2.7, 4.6 and 4.2, respectively, times higher than the corresponding values of the Irish Sea. Based on this and two other comparisons, it is concluded that the Baltic Sea is the most contaminated with Cs-137.</p></div>","PeriodicalId":15667,"journal":{"name":"Journal of environmental radioactivity","volume":"278 ","pages":"Article 107510"},"PeriodicalIF":1.9,"publicationDate":"2024-07-31","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"https://www.sciencedirect.com/science/article/pii/S0265931X24001425/pdfft?md5=f3ece612e8f1f15709f26db39eeb8a01&pid=1-s2.0-S0265931X24001425-main.pdf","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"141874986","PeriodicalName":null,"FirstCategoryId":null,"ListUrlMain":null,"RegionNum":3,"RegionCategory":"环境科学与生态学","ArticlePicture":[],"TitleCN":null,"AbstractTextCN":null,"PMCID":"OA","EPubDate":null,"PubModel":null,"JCR":null,"JCRName":null,"Score":null,"Total":0}

{"title":"Assessment of environmental impacts from authorized discharges of tritiated water from the Fukushima site to coastal and offshore regions","authors":"Jakub Kaizer ,&nbsp;Katsumi Hirose ,&nbsp;Pavel P. Povinec","doi":"10.1016/j.jenvrad.2024.107507","DOIUrl":"10.1016/j.jenvrad.2024.107507","url":null,"abstract":"<div><p>In August 2023, the long-planned discharging of radioactive wastewater from the Fukushima Dai-ichi Nuclear Power Plant (FDNPP) started after the confirmation of its feasibility and safety. As this water contains elevated amounts of tritium even after being diluted, a lot of resources have been invested in the monitoring of the Fukushima coastal region where the discharge outlet is located. We compare the first ³H surface activity concentrations from these measurements (up to the end of November 2023) with the available background values to evaluate a possible impact of the long-term discharging on humans and environmental levels of the radionuclide of interest in the same or nearby area. From our results, we can conclude that the joint effect of horizontal and vertical mixing has been significant enough to reduce tritium concentrations at the monitored locations in the region close to the FDNPP port two days after the end of the respective phase of the discharging beyond the detection limit of the applied analytical methods (∼0.3 Bq L⁻¹) which is by five orders of magnitude lower than safety limit for drinking water set by the World Health Organization (WHO). Moreover, the distant correlation analysis showed that tritium concentrations at stations located further than 1.4 km were very close to pre-discharge levels (∼0.4 Bq L⁻¹). We also estimated that the ³H activity concentration in the offshore Fukushima region would be elevated by 0.01 Bq L⁻¹ at maximum over a year of continuous discharging, which is in concordance with the already published modeling papers and much less than the impact of the FDNPP accident in 2011.</p></div>","PeriodicalId":15667,"journal":{"name":"Journal of environmental radioactivity","volume":"278 ","pages":"Article 107507"},"PeriodicalIF":1.9,"publicationDate":"2024-07-31","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"141874984","PeriodicalName":null,"FirstCategoryId":null,"ListUrlMain":null,"RegionNum":3,"RegionCategory":"环境科学与生态学","ArticlePicture":[],"TitleCN":null,"AbstractTextCN":null,"PMCID":"","EPubDate":null,"PubModel":null,"JCR":null,"JCRName":null,"Score":null,"Total":0}

{"title":"Time-dependent variations of groundwater radon: Insights from a twelve-year study in the Baikal region, East Siberia, Russia","authors":"Alexander K. Seminsky,&nbsp;Konstantin Zh Seminsky","doi":"10.1016/j.jenvrad.2024.107509","DOIUrl":"10.1016/j.jenvrad.2024.107509","url":null,"abstract":"<div><p>Time-dependent variations of ²²²Rn concentration (Q) in groundwater have been monitored for twelve years (2012–2023) at eight sites of groundwater discharge within the Baikal region in East Siberia, Russia. The concentrations of radioactive gas at different sites vary from 30% to 60% of average values (Q_av). The sampled waters are of three groups with Q_av ≈ 15 Bq/l (I), ≈30 Bq/l (II₁), and ≈50 Bq/l (II₂). Cluster analysis shows closest linkage between the two subgroups of group II due to similarity in the discharge mechanisms. Fourier analysis of periodic ²²²Rn behavior reveals major cycles of 365, 180, 126, and 30 days correlated with variations of air temperature and pressure, as well as with the patterns of groundwater discharge. In addition, radon anomalies are related with seismicity. Earthquakes are reflected in the radon field as three distinct anomaly types, occurring either subsequent to or prior to the seismic event. The anomalies responding to earthquake nucleation can be considered as precursors and used in earthquake prediction. The revealed trends make basis for a model designed to predict Q variations in groundwater of the area to 80% average efficiency. The external and internal factors that affect the concentration of radioactive gas in groundwater are linked in a hierarchic system and are classified according to the degree and type of their influence.</p></div>","PeriodicalId":15667,"journal":{"name":"Journal of environmental radioactivity","volume":"278 ","pages":"Article 107509"},"PeriodicalIF":1.9,"publicationDate":"2024-07-30","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"141859876","PeriodicalName":null,"FirstCategoryId":null,"ListUrlMain":null,"RegionNum":3,"RegionCategory":"环境科学与生态学","ArticlePicture":[],"TitleCN":null,"AbstractTextCN":null,"PMCID":"","EPubDate":null,"PubModel":null,"JCR":null,"JCRName":null,"Score":null,"Total":0}

{"title":"Improving the estimation of direct release rates and transport processes from the Fukushima Daiichi Nuclear Power Plant accident using higher-resolution oceanic dispersion model","authors":"Daisuke Tsumune ,&nbsp;Takaki Tsubono ,&nbsp;Kazuhiro Misumi","doi":"10.1016/j.jenvrad.2024.107500","DOIUrl":"10.1016/j.jenvrad.2024.107500","url":null,"abstract":"<div><p>A series of accidents at the Fukushima Daiichi Nuclear Power Station (F1NPS), following the 11 March 2011 earthquake and tsunami, resulted in the release of radioactive substances into the ocean. In particular, the release of large amounts of radioactive caesium has damaged the fishing industry, leading to voluntary restrictions on fishing and shipping. Oceanic dispersion simulations based on estimates of the pathways and fluxes of radioactive materials provide useful information for assessing the environmental impacts and formulating measures to mitigate the effects of the accident. For the direct release rate from the F1NPS site, an estimation method was developed using the results from nearby monitoring, and the seawater exchange rate was estimated in target volume using a numerical simulation. However, the influence of volume on the seawater exchange rate was not considered. Appropriate volumes must be considered when estimating the effects of future accidents. In addition, the directional coastal transport was underestimated in the simulations of the F1NPS accident because of the low resolution. To estimate the pathways and fluxes of radioactive material to the ocean and understand the distribution of the concentration of radioactive material based on ocean dispersion simulations, a study was conducted using a higher-resolution model. The horizontal resolution of the conventional ocean dispersion model Regional Ocean Modelling System (ROMS), was increased from 1 km to 200 m. The optimal settings of the seawater exchange rate were investigated, and the radioactive caesium transport process in the coastal direction was more accurately reflected. We found that the conventional volume for determining the seawater exchange rate, including the locations of release sources and observation points, is optimal. The validity of this finding was confirmed using experimental equations from previous oceanic tracer release experiments. To estimate future release rates, it an appropriate volume must be defined, for example, depending on the distance between the locations of the release sources and the observation point. In addition, improvements in the accuracy of the simulation of the coastal transport process were observed owing to the higher resolution, which increased reproducibility. However, with a horizontal resolution of 200 m, problems with repeatability near the harbours arose. A higher resolution, achieved using nesting or other methods, would be desirable to deal with releases smaller than those in the F1NPS accident.</p></div>","PeriodicalId":15667,"journal":{"name":"Journal of environmental radioactivity","volume":"278 ","pages":"Article 107500"},"PeriodicalIF":1.9,"publicationDate":"2024-07-30","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"141859875","PeriodicalName":null,"FirstCategoryId":null,"ListUrlMain":null,"RegionNum":3,"RegionCategory":"环境科学与生态学","ArticlePicture":[],"TitleCN":null,"AbstractTextCN":null,"PMCID":"","EPubDate":null,"PubModel":null,"JCR":null,"JCRName":null,"Score":null,"Total":0}