scholarly journals Nuclear Power Plant Infrastructure Evaluations for Removal of Spent Nuclear Fuel

2021 ◽  
Author(s):  
Steven Maheras ◽  
Lauren SB Rodman ◽  
Ralph Best ◽  
Adam Levin ◽  
Steven Ross ◽  
...  
Author(s):  
Takashi Kamei

Even after the huge impact of Fukushima Daiichi nuclear power plant accident, Japan has to establish its energy supply system satisfying requirements of both global warming and resistibility of natural disaster. Nuclear power has a potential to reduce carbon emission but large-scale and centralized nuclear power plant may lose large volume of electricity supply at once. Small-scale nuclear power plants will bring solution in Japan. Thorium molten-salt reactor (MSR) is selected to simulate implementation capacity of small reactors in Japan. In order to use thorium as nuclear fuel, fissionable isotope is indispensable since natural thorium does not include fissile material. Japan owns plutonium in spent nuclear fuel of uranium usage. Quantitative evaluation of implementing capacity of thorium MSR in Japan by using plutonium accumulated in Japan. Implementation capacity of thorium MSR will be about 38 GWe and 11.2 GWe in the maximum and minimum cases at 2050, respectively.


Author(s):  
Yung-Shin Tseng ◽  
Jong-Rong Wang ◽  
Chi-Hung Lin ◽  
Chunkuan Shin ◽  
F. Peter Tsai

Chinshan Nuclear Power Plant (CSNPP) is a two-unit BWR4 plant with 1804MWt power per unit. Taipower Co., the owner of the plant is preparing the life extension procedure to extend the CSNPP operation time. In order to meet the life extension requirement, many issues need to be solved before life extension licensing, such as the spent nuclear fuel management, structure aging etc. For the spent nuclear fuel management, ROC Atomic Energy Council (ROCAEC) certified method is employed to analyze the thermal behaviors of Dry Storage System (DSS). This method uses ANSYS coupled with RELAP5-3D to solve the thermal characteristic and successfully accomplish the licensing procedure of the Chinshan Nuclear Dry Storage Project. However, further validation results demonstrate that the coupled method still exists uncertainty and deficiency. In this study, a new Computational Fluid Dynamics (CFD) numerical model for spend nuclear fuel (NSF) dry storage system (DSS) has been developed to improve the accuracy of DSS thermal analysis results. Its accuracy has been validated by comparing the temperature predictions with the experimental results of VSC-17 DSS. It has been found that the thermal behaviors and physical phenomena in the DSS could be predicted with good agreement for the measurements. Moreover, the uncertainty and reasonableness of results in previous method can be improved by the new thermal analyses methodology.


2020 ◽  
Author(s):  
Laurynas Butkus ◽  
Rūta Barisevičiūtė ◽  
Žilvinas Ežerinskis ◽  
Justina Šapolaitė ◽  
Evaldas Maceika ◽  
...  

<p>Nuclear Power Plants (NPPs) and nuclear fuel reprocessing sites are main producers of anthropogenic radiocarbon. Anthropogenic <sup>14</sup>C can be released into the environment in gaseous forms, with liquid effluents or with spent nuclear fuel [1]. During photosynthesis radiocarbon can be easily assimilated into the plants. As a result, carbon-14 can be transported through the food chain and accumulate in a human body. Therefore, radiocarbon is considered a primary source of increased human radiation dose from industrial nuclear activities [2].</p><p>Main goal of this research was to evaluate the influence Ignalina NPP on carbon-14 content in the Lake Druksiai. The sediment core was collected from the Lake Druksiai. The ages of sediment layers were estimated using <sup>137</sup>Cs and <sup>210</sup>Pb dating methods. ABA (acid-base-acid) chemical pretreatment procedure was used to extract humin (HM) and humic acid (HA) fractions from the sediments. Chemically pretreated samples were graphitized with the Automated Graphitization Equipment AGE 3 (IonPlus AG). Carbon-14 measurements in prepared samples were performed using the single stage accelerator mass spectrometer (SSAMS, NEC, USA).</p><p>Radiocarbon content was measured in the sediment core which covers all phases of the NPP exploitation (commissioning, operation and decommissioning). These measurements in HM and HA fractions showed that after the start of the operation of the Ignalina NPP in 1983, the <sup>14</sup>C concentration in these organic fractions increased by 4 pMC and 3 pMC, respectively. In addition, a sharp increase of radiocarbon content (concentration almost doubled) in HA fraction was observed in the year 1999. Similar increase in <sup>14</sup>C activity in fish samples from Lake Druksiai was measured. In HM fraction such drastic changes in radiocarbon concentration were not observed. These results suggest that <sup>14</sup>C enriched effluents were released from the Ignalina NPP in 1999.</p><p>[1] Z. Ezerinskis et al., Annual Variations of 14C Concentration in the Tree Rings in the Vicinity of Ignalina Nuclear Power Plant, Radiocarbon 60, 1227–1236 (2018).</p><p>[2] IAEA, Generic Models for Use in Assessing the Impact of Discharges of Radioactive Substances to the Environment (2001).</p>


Author(s):  
J. A. Korchova ◽  
N. V. Harbachova ◽  
N. D. Kuzmina ◽  
N. V. Kulich

The purpose of the study is calculation research of the radiation characteristics of fission products and actinides at different phases of spent nuclear fuel (SNF) management of the Belarusian Nuclear Power Plant (NPP). The study is aimed at the scientific support of the government decision as determined by the “On approval of the spent nuclear fuel management Strategy of the Belarusian nuclear power plant”. А probabilistic forecasting model and an effective code CUB for the spent nuclear fuel radioactivity inventory assessment were developed by the authors. Radionuclides activities as function of nuclear fuel burnup for nuclear fuel with the initial enrichment on the 235U equals to 4.81 % on the base of approximation relations of Regulation RB-093-14 (Moskow, 2014) have been calculated. Basic relations between specific activities of the main hazardous fission products and actinide, the SNF burnup and initial degree of fuel enrichment were analyzed. The rates of decrease of individual and total fission products and actinides activities of the Units №1 and 2 of the Belarusian NPP were obtained depending on the specific phase of spent SNF management. The results are of value for decision-making on ecology acceptable SNF management option introduced by Spent Nuclear Fuel Management Strategy of the Belarusian NPP.


2018 ◽  
Vol 4 (4) ◽  
pp. 251-256 ◽  
Author(s):  
Sergey Shcheklein ◽  
Ismail Hossain ◽  
Mohammad Akbar ◽  
Vladimir Velkin

Bangladesh lies in a tectonically active zone. Earlier geological studies show that Bangladesh and its adjoining areas are exposed to a threat of severe earthquakes. Earthquakes may have disastrous consequences for a densely populated country. This dictates the need for a detailed analysis of the situation prior to the construction of nuclear power plant as required by the IAEA standards. This study reveals the correlation between seismic acceleration and potential damage. Procedures are presented for investigating the seismic hazard within the future NPP construction area. It has been shown that the obtained values of the earthquake’s peak ground acceleration are at the level below the design basis earthquake (DBE) level and will not lead to nuclear power plant malfunctions. For the most severe among the recorded and closely located earthquake centers (Madhupur) the intensity of seismic impacts on the nuclear power plant site does not exceed eight points on the MSK-64 scale. The existing predictions as to the possibility of a super-earthquake with magnitude in excess of nine points on the Richter scale to take place on the territory of the country indicate the necessity to develop an additional efficient seismic diagnostics system and to switch nuclear power plants in good time to passive heat removal mode as stipulated by the WWER 3+ design. A conclusion is made that accounting for the predicted seismic impacts in excess of the historically recorded levels should be achieved by the establishment of an additional efficient seismic diagnostics system and by timely switching the nuclear power plants to passive heat removal mode with reliable isolation of the reactor core and spent nuclear fuel pools.


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