scholarly journals Modeling of 14C Vertical Distribution in Bottom Sediments of the Ignalina Nuclear Power Plant Cooling Reservoir

Water ◽  
2021 ◽  
Vol 13 (10) ◽  
pp. 1397
Author(s):  
Rūta Barisevičiūtė ◽  
Evaldas Maceika ◽  
Laurynas Juodis ◽  
Algirdas Pabedinskas ◽  
Justina Šapolaitė ◽  
...  
Keyword(s):  
Power Plant ◽  
Nuclear Power Plant ◽  
Vertical Distribution ◽  
Nuclear Power ◽  
Dissolved Inorganic Carbon ◽  
Lake Ecosystem ◽  
High Temporal Resolution ◽  
Model Calculations ◽  
Organic Sediment ◽  
The Impact

The Ignalina Nuclear Power Plant (INPP) in Lithuania is a rare case when lake water is used instead of river or sea water for cooling. Lake Drūkšiai with water residence time of 3–4 year and undisturbed sediment layers is a unique system to assess the impact of a nuclear facility on the aquatic ecosystem with a sufficiently high temporal resolution. We constructed a model of radiocarbon cycling processes in lake ecosystem which evaluates the 14C specific activity vertical distribution in two organic sediment fractions: alkali-soluble and alkali-insoluble. Model calculations proved that during the first 15 years of operation since 1983, 14C annual aqueous releases from the INPP were in water dissolved inorganic carbon form and varied in the range of 2.4 ÷ 3.7 × 108 Bq/year. The results of the modeling of hypothetic scenarios also showed that there was the only one episode of elevated releases from the INPP in 2000–2001, which changed the interaction between the two organic sediment fractions for the period of 2000–2006. It was caused most probably by released chemicals from INPP but not by 14C contamination. Interaction processes between both sediment fractions recovered to its original state after 2006, indicating that the released additional chemical compounds lake ecosystem have been cleaned-up.

Investigation of reservoir age variations in Lake Druksiai caused by anthropogenic factors

2021 ◽  
Author(s):  
Laurynas Butkus ◽  
Rūta Barisevičiūtė ◽  
Justina Šapolaitė ◽  
Žilvinas Ežerinskis ◽  
Evaldas Maceika ◽  
...  
Keyword(s):  
Power Plant ◽  
Nuclear Power Plant ◽  
Bottom Sediments ◽  
Nuclear Power ◽  
Dissolved Inorganic Carbon ◽  
Anthropogenic Factors ◽  
Past Century ◽  
Reservoir Effect ◽  
Age Variations ◽  
The Impact

<p>The reservoir effect (RE) is defined as the difference between the radiocarbon isotope ratio (<sup>14</sup>C/<sup>12</sup>C) in the terrestrial and aquatic samples. Both natural processes and anthropogenic activities affecting carbon cycle in the water ecosystem can lead to changes in the RE. Therefore, reservoir effect studies can help to assess the impact of external factors on a hydrological system [1].</p><p>The aim of this research was to evaluate the impact of anthropogenic <sup>14</sup>C contamination from Ignalina nuclear power plant (Ignalina NPP, INPP) on the Lake Drūkšiai system. The lake water was used to cool the reactors of the INPP. The lake sediment and fish (both benthic and pelagic) scale samples were collected from the Drūkšiai lake. ABA (acid-base-acid) chemical pretreatment procedure was used to extract humin (HM) and humic acid (HA) fractions from the sediments. Radiocarbon measurements in these samples were performed using the accelerator mass spectrometer (AMS).</p><p>In 1963, increased concentrations of radiocarbon due to the testing of nuclear weapons showed that atmosphere-lake CO<sub>2</sub> exchange accounted for about 22% carbon in bottom sediments. During the first 15 years of operation of the Ignalina Nuclear Power Plant, <sup>14</sup>C-enriched dissolved inorganic carbon (DIC) was continuously released into Lake Druksiai. During that period, an average of about 0.24 GBq of radiocarbon was released per year. Measurements of radiocarbon concentrations in fish confirm that the <sup>14</sup>C contamination was in dissolved inorganic form.</p><p>Around 2000, <sup>14</sup>C-enriched DIC (2.3 GBq radiocarbon) was released into Lake Druksiai from Ignalina NPP. In addition, organic compounds were additionally released in the same year. These compounds were not <sup>14</sup>C-enriched but affected the interaction between humic and humic acids. Almost a decade after the end of operation of the Ignalina NPP, there is still some <sup>14</sup>C pollution (from INPP) remaining in Lake Druksiai. The concentration of radiocarbon in the bottom sediments is still higher than in the atmosphere. </p><p> </p><p>[1] R. Barisevičiūtė et al., Tracing Carbon Isotope Variations in Lake Sediments Caused by Environmental Factors During the Past Century: A Case Study of Lake Tapeliai, Lithuania, Radiocarbon 61(4), 885–903, (2019).</p>

14C Distribution in Atmospheric and Aquatic Environments Around Qinshan Nuclear Power Plant, China

Radiocarbon ◽  
2014 ◽  
Vol 56 (3) ◽  
pp. 1107-1114 ◽  
Author(s):  
Zhongtang Wang ◽  
Dan Hu ◽  
Hong Xu ◽  
Qiuju Guo
Keyword(s):  
Power Plant ◽  
Nuclear Power Plant ◽  
Water Samples ◽  
Nuclear Power ◽  
Dissolved Inorganic Carbon ◽  
Tap Water ◽  
Surface Seawater ◽  
Pressurized Water ◽  
Specific Activities ◽  
Water Reactors

Atmospheric CO2 and aquatic water samples were analyzed to evaluate the environmental 14C enrichment due to operation of the Qinshan nuclear power plant (NPP), where two heavy-water reactors and five pressurized-water reactors are employed. Elevated 14C-specific activities (2–26.7 Bq/kg C) were observed in the short-term air samples collected within a 5-km radius, while samples over 5 km were close to background levels. The 14C-specific activities of dissolved inorganic carbon (DIC) in the surface seawater samples ranged from 196.8 to 206.5 Bq/kg C (average 203.4 Bq/kg C), which are close to the background value. No elevated 14C level in surface seawater was found after 20 years of operation of Qinshan NPP, indicating that the 14C discharged was well diffused. The results of the freshwater samples show that excess 14C-specific activity (average 17.1 Bq/kg C) was found in surface water and well water samples, while no obvious 14C increase was found in drinking water (groundwater and tap water) compared to the background level.

scholarly journals Comparison and Evaluation of Domestic and Foreign Radiation Environmental Standards for Nuclear Power Plants

2021 ◽  
Vol 2083 (2) ◽  
pp. 022020
Author(s):  
Jiahuan Yu ◽  
Xiaofeng Zhang
Keyword(s):  
Power Plant ◽  
Nuclear Power Plant ◽  
Nuclear Power ◽  
Power Plants ◽  
Nuclear Power Plants ◽  
The United States ◽  
Discharge System ◽  
Radioactive Effluent ◽  
Effluent Discharge ◽  
The Impact

Abstract With the development of the nuclear energy industry and the increasing demand for environmental protection, the impact of nuclear power plant radiation on the environment has gradually entered the public view. This article combs the nuclear power plant radiation environmental management systems of several countries, takes the domestic and foreign management of radioactive effluent discharge from nuclear power plants as a starting point, analyses and compares the laws and standards related to radioactive effluents from nuclear power plants in France, the United States, China, and South Korea. In this paper, the management improvement of radioactive effluent discharge system of Chinese nuclear power plants has been discussed.

Root Cause of Thermal Sleeve Loosening in a Korean Standard Nuclear Power Plant

2006 ◽  
Author(s):  
Sang-Nyung Kim ◽  
Sang-Gyu Lim
Keyword(s):  
Power Plant ◽  
Nuclear Power Plant ◽  
Nuclear Power ◽  
Power Plants ◽  
Measurement Data ◽  
Significant Loss ◽  
Design Modification ◽  
Root Cause ◽  
Explosive Expansion ◽  
The Impact

The safety injection (SI) nozzle of a 1000MWe-class Korean standard nuclear power plant (KSNP) is fitted with thermal sleeves (T/S) to alleviate thermal fatigue. Thermal sleeves in KSNP #3 & #4 in Yeonggwang (YG) & Ulchin (UC) are manufactured out of In-600 and fitted solidly without any problem, whereas KSNP #5 & #6 in the same nuclear power plants, also fitted with thermal sleeves made of In-690 for increased corrosion resistance, experienced a loosening of thermal sleeves in all reactors except KSNP YG #5-1A, resulting in significant loss of generation availability. An investigation into the cause of the loosening of the thermal sleeves only found out that the thermal sleeves were subject to severe vibration and rotation, failing to uncover the root cause and mechanism of the loosening. In an effort to identify the root cause of T/S loosening, three suspected causes were analyzed: (1) the impact force of flow on the T/S when the safety SI nozzle was in operation, (2) the differences between In-600 and In-690 in terms of physical and chemical properties (notably the thermal expansion coefficient), and (3) the positioning error after explosive expansion of the T/S as well as the asymmetric expansion of T/S. It was confirmed that none of the three suspected causes could be considered as the root cause. However, after reviewing design changes applied to the Palo Verde nuclear plant predating KSNP YG #3 & #4 to KSNP #5 & #6, it was realized that the second design modification (in terms of groove depth & material) had required an additional explosive energy by 150% in aggregate, but the amount of gunpowder and the explosive expansion method were the same as before, resulting in insufficient explosive force that led to poor thermal sleeve expansion. T/S measurement data and rubbing copies also support this conclusion. In addition, it is our judgment that the acceptance criteria applicable to T/S fitting was not strict enough, failing to single out thermal sleeves that were not expanded sufficiently. Furthermore, the T/S loosening was also attributable to lenient quality control before and after fitting the T/S that resulted in significant uncertainty. Lastly, in a flow-induced vibration test planned to account for the flow mechanism that had a direct impact upon the loosening of the thermal sleeves that were not fitted completely, it was discovered that the T/S loosening was attributable to RCS main flow. In addition, it was proven theoretically that the rotation of the T/S was induced by vibration.

scholarly journals Blowout Accident Impact Analysis Method for the Siting of Offshore Floating Nuclear Power Plant in Offshore Oil Fields

2019 ◽  
Vol 2019 ◽  
pp. 1-7
Author(s):  
Zhigang Lan
Keyword(s):  
Power Plant ◽  
Nuclear Power Plant ◽  
Nuclear Power ◽  
Power Plants ◽  
Impact Analysis ◽  
Oil Spills ◽  
Oil Field ◽  
Oil Fields ◽  
Offshore Oil ◽  
The Impact

Focused on the utilization of nuclear energy in offshore oil fields, the correspondence between various hazards caused by blowout accidents (including associated, secondary, and derivative hazards) and the initiating events that may lead to accidents of offshore floating nuclear power plant (OFNPP) is established. The risk source, risk characteristics, risk evolution, and risk action mode of blowout accidents in offshore oil fields are summarized and analyzed. The impacts of blowout accident in offshore oil field on OFNPP are comprehensively analyzed, including injection combustion and spilled oil combustion induced by well blowout, drifting and explosion of deflagration vapor clouds formed by well blowouts, seawater pollution caused by blowout oil spills, the toxic gas cloud caused by well blowout, and the impact of mobile fire source formed by a burning oil spill on OFNPP at sea. The preliminary analysis methods and corresponding procedures are established for the impact of blowout accidents on offshore floating nuclear power plants in offshore oil fields, and a calculation example is given in order to further illustrate the methods.

On the Feasibility of Nuclear Versus Combustion Gas Turbine Propulsion for High-Speed Cargo Ships

2004 ◽  
Author(s):  
H. Boonstra ◽  
A. C. Groot ◽  
C. A. Prins
Keyword(s):  
Power Plant ◽  
Nuclear Power Plant ◽  
Gas Turbine ◽  
High Speed ◽  
Nuclear Power ◽  
Parametric Design ◽  
Pebble Bed ◽  
Pressurized Water ◽  
Combustion Gas ◽  
The Impact

This paper presents the outcome of a study on the feasibility of a nuclear powered High-Speed Pentamaran, initiated by Nigel Gee and Associates and the Delft University of Technology. It explores the competitiveness of a nuclear power plant for the critical characteristics of a marine propulsion plant. Three nuclear reactor types are selected: the Pressurized Water Reactor (PWR), the Pebble-bed and Prismatic-block HTGR. Their characteristics are estimated for a power range from 100 MWth to 1000 MWth in a parametric design, providing a level base for comparison with conventional gas turbine technology. The reactor scaling is based on reference reactors with an emphasis on marine application. This implies that preference is given to passive safety and simplicity, as they are key-factors for a marine power plant. A case study for a 60-knot Pentamaran shows the impact of a nuclear power plant on a ship designed with combustion gas turbine propulsion. The Prismatic-block HTGR is chosen as most suitable because of its low weight compared to the PWR, in spite of the proven technology of a PWR. The Pebble-bed HTGR is considered too voluminous for High-Speed craft. Conservative data and priority to simple systems and high safety leads to an unfavorable high weight of the nuclear plant in competition with the original gas turbine driven Pentamaran. The nuclear powered ship has some clear advantages at high sailing ranges.

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