scholarly journals Analysis on radiation control and the impact of land pipeline leakage of offshore nuclear power plant on groundwater

2021 ◽  
Vol 2083 (2) ◽  
pp. 022021
Author(s):  
Lianghui Liu ◽  
Jiahuan Yu ◽  
Yueping Xu

Abstract Using the groundwater migration and dispersion analytical model, combined with the topography and groundwater characteristics along the land drainage pipeline of an offshore nuclear power plant, the migration and dispersion of six radionuclides (3H, 14C, 137Cs, 134Cs, 60Co, 90Sr, etc.) in groundwater under the condition of pipeline breach accident are predicted. The scope of impact of radionuclides and the annual effective dose caused by drinking water pathways to the public are analyzed. By summarizing the radionuclide concentration and dose index requirements for groundwater at home and abroad, the corresponding environmental impact assessment is given. The prediction results show that the radionuclide concentration and public effective dose at the same distance first increase and then decrease with time, and the peak radionuclide concentration and maximum public effective dose gradually decrease with distance increasing, in other words, the impact of the breach accident on the distance above 30 m is limited.

2020 ◽  
Vol 2020 ◽  
pp. 1-8
Author(s):  
K. Gyamfi ◽  
S. A. Birikorang ◽  
E. Ampomah-Amoako ◽  
J. J. Fletcher

Atmospheric dispersion modelling and radiological safety analysis have been performed for a postulated accident scenario of a generic VVER-1000 nuclear power plant using the HotSpot Health Physics code. The total effective dose equivalent (TEDE), the respiratory time-integrated air concentration, and the ground deposition concentration are calculated considering site-specific meteorological conditions. The results show that the maximum TEDE and ground deposition concentration values of 3.69E – 01 Sv and 3.80E + 06 kBq/m2 occurred at downwind distance of 0.18 km from the release point. This maximum TEDE value is recorded within a distance where public occupation is restricted. The TEDE values at distances of 5.0 km and beyond where public occupation is likely to be found are far below the annual regulatory limits of 1 mSv from public exposure in a year even in the event of worse accident scenario as set in IAEA Safety Standard No. GSR Part 3; no action related specifically to the public exposure is required. The released radionuclides might be transported to long distances but will not have any harmful effect on the public. The direction of the radionuclide emission from the release point is towards the north east. It is observed that the organ with the highest value of committed effective dose equivalent (CEDE) appears to be the thyroid. It was followed by the bone surface, lung, red marrow, and lower large intestine wall in order of decreasing CEDE value. Radionuclides including I-131, I-133, Sr-89, Cs-134, Ba-140, Xe-133, and Xe-135 were found to be the main contributors to the CEDE.


2021 ◽  
Vol 2021 ◽  
pp. 1-8
Author(s):  
Boldsaikhan Purevsuren ◽  
Juyoul Kim

It has been well known that nuclear power plant and coal-fired power plant release some amount of radioactive materials during their normal operations. The purpose of this study was to compare radiation exposure doses to the public as a consequence of airborne effluents released from nuclear and coal-fired power plants under the normal operation. NRCDose3 was used to estimate radiation exposure doses to the public from gaseous effluents of nuclear power plant during its normal operation while CAP88-PC was used to calculate doses to the public living around coal-fired power plant. The results showed that radiation exposure doses from nuclear power plant were less than those from coal-fired power plant and regulatory annual limits. Effective dose by external exposure, skin equivalent dose, and organ equivalent dose from gaseous effluents of nuclear power plant were 2.93 × 10−4 mSv/y, 2.90 × 10−3 mSv/y, and 1.78 × 10−2 mSv/y, respectively. On the contrary, the corresponding effective dose by external exposure, external skin dose, and organ dose from coal-fired power plant were 1.13 × 10−2 mSv/y, 5.33 × 10−2 mSv/y, and 1.17 × 10−1 mSv/y, respectively.


2021 ◽  
Vol 2083 (2) ◽  
pp. 022020
Author(s):  
Jiahuan Yu ◽  
Xiaofeng Zhang

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.


Author(s):  
Sang-Nyung Kim ◽  
Sang-Gyu Lim

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.


2019 ◽  
Vol 2019 ◽  
pp. 1-7
Author(s):  
Zhigang Lan

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.


Author(s):  
H. Boonstra ◽  
A. C. Groot ◽  
C. A. Prins

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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