Decontamination of the Special Drainage System at NPP A-1

2001 ◽  
Author(s):  
Ján Rezbárik ◽  
Dušan Majerský ◽  
Stanislav Sekely
Keyword(s):  
Power Plant ◽  
Nuclear Power Plant ◽  
Nuclear Power ◽  
Specific Activity ◽  
Drainage System ◽  
Solid Particles ◽  
Technological Systems ◽  
Solid Product ◽  
High Tendency ◽  
First Time

Abstract The first Czecho-slovak nuclear power plant A-1 was shut down after an accident in 1977 and it is now under decommissioning. In spite of that, some technological systems in nuclear power plant must remain in operation. The planned service life of these systems has already been exceeded and their technical design is not suitable for present requirements. These operated technological systems must be repaired and reconstructed. The special drainage system is one of the technological systems that must be in operation during the decommissioning process. After twenty-nine-year’-s of operation it became necessary to carry out the repairs, adaptations and replacements of some parts of this system with the aim to ensure more reliable operation and higher safety. Radioactive sludge from the bottom of the collecting tank and drain pit was pumped out using an ejector and it was caught in drums. The fixed contamination on the inner surface of the collecting tank was removed by the chemical loop decontamination method using an external circulating decontamination device. The surface of the drain pit was decontaminated with evenly spread decontamination gel that disrupted the fixed contamination. The contamination was then washed down using a water jet system with attached rotary brushes. At NPP A-1, an immobilisation method for the treatment of radioactive sludge and solid particles based on the addition of silicates was successfully used by AllDeco for the first time. This sludge is often sticky with the high tendency to settle out the liquid and has a specific activity three orders of magnitude higher than are the limits for the Conditioning Centre (with high content of alpha radionuclides) and because it is not sound and effective to treat it by technologies generally used for another type of wastes. The immobilisation of the sludge was performed at room temperature. The resulting solid product has suitable properties for temporary storage. Procedures for the verification of the treatment of further sludge from NPP A-1 have been started.

Research of Screening and Grading Method of Ageing Sensitive Objectives in Nuclear Power Plant

2014 ◽  
Vol 543-547 ◽  
pp. 858-861
Author(s):  
Xiao Tian Liu ◽  
Yong Wang ◽  
Shao Rui Niu ◽  
Yan Zhao Zhang ◽  
Zhen Hao Shi ◽  
...  
Keyword(s):  
Fuzzy Logic ◽  
Power Plant ◽  
Nuclear Power Plant ◽  
Nuclear Power ◽  
Power Plants ◽  
Lessons Learned ◽  
Nonlinear Coupling ◽  
Highly Nonlinear ◽  
Ageing Management ◽  
First Time

This first step of ageing management in nuclear power plant is to determine the objectives and their priorities. The characteristics of the objectives are complex and highly nonlinear coupling. A fuzzy logic based screening and grading method have been developed in this research for the first time which combined the genetic ageing lessons learned and field expert experience to resolve the problem. The method have been approved of highly applicability and applied to ageing management in multiple nuclear power plants.

Terrestrial Distribution of 14C in the Vicinity of Qinshan Nuclear Power Plant, China

Radiocarbon ◽  
2013 ◽  
Vol 55 (1) ◽  
pp. 59-66 ◽  
Author(s):  
Zhongtang Wang ◽  
Yuanyi Xiang ◽  
Qiuju Guo
Keyword(s):  
Power Plant ◽  
Nuclear Power Plant ◽  
Nuclear Power ◽  
Specific Activity ◽  
Background Level ◽  
Food Samples ◽  
Pine Needles ◽  
Activity Levels ◽  
Heavy Water Reactor ◽  
Rice Samples

We used accelerator mass spectrometry (AMS) to study radiocarbon-specific activity levels in agricultural and botanical samples (moss and pine needles) distributed within a 6.5-km radius of the Qinshan Nuclear Power Plant (NPP). The 14C-specific activity in moss samples (ranging from 265.6 to 223.0 Bq/kg C) decreased with increased distance from the stacks of Plant III (heavy water reactor) and reached the background level (223.8 Bq/kg C) at 6.5 km distance. Compared to the pine needles, the moss was a better indicator for investigating the 14C distribution near Qinshan NPP. The 14C-specific activity distribution in moss samples showed that the diffusion of 14C discharged from the Qinshan NPP was affected by both geographical and meteorological factors. Excess 14C-specific activity in the food samples ranged from 8.5 to 13.0 Bq/kg C (except for rice samples), resulting in a minimal radiation dose of 0.5 μSv per year to the public.

scholarly journals Considerations and challenges in the ICRP dialogues

2016 ◽  
Vol 45 (2_suppl) ◽  
pp. 119-122
Author(s):  
T. Hanzawa
Keyword(s):  
Power Plant ◽  
Nuclear Power Plant ◽  
Nuclear Power ◽  
International Commission ◽  
Radiological Protection ◽  
Simultaneous Interpretation ◽  
Fukushima Daiichi ◽  
The University ◽  
Dialogue Seminar ◽  
First Time

‘Yes I tried to explain, but residents couldn’t understand …’ This was the title of my presentation at the first International Commission on Radiological Protection (ICRP) dialogue seminar in November 2011 held at the Fukushima Prefectural Government office. The accident at Fukushima Daiichi nuclear power plant was triggered by the tsunami caused by the Great East Japan Earthquake of March 2011. Initially, it was thought that Date city, 50–60 km away from the accident, would be safe, but unfortunately this was not the case due to the direction of the wind at the time of the accident. I reported on decontamination in the aftermath of the accident at the ICRP dialogue seminar, following an invitation from Dr. Niwa of the University of Kyoto and a member of ICRP. There were many participants from overseas, and it was the first time that I had attended a meeting with simultaneous interpretation. I still remember that I was slightly bewildered.

scholarly journals Particle-laden flow around an obstacle in a square pipe: experiments and modeling

2020 ◽  
Vol 21 (5) ◽  
pp. 517
Author(s):  
Ouardia Ait Oucheggou ◽  
Véronique Pointeau ◽  
Guillaume Ricciardi ◽  
Élisabeth Guazzelli ◽  
Laurence Bergougnoux
Keyword(s):  
Power Plant ◽  
Nuclear Power Plant ◽  
Steam Generator ◽  
Nuclear Power ◽  
Particle Deposition ◽  
Three Dimensional ◽  
Vertical Tube ◽  
Nuclear Industry ◽  
Solid Particles ◽  
Complex Nature

Particle trapping and deposition around an obstacle occur in many natural and industrial situations and in particular in the nuclear industry. In the steam generator of a nuclear power plant, the progressive obstruction of the flow due to particle deposition reduces the efficiency and can induce tube cracking leading to breaking and damage. The steam generator then loses its role as a safety barrier of the nuclear power plant. From a fundamental standpoint, dilute and concentrated particulate flows have received a growing attention in the last decade. In this study, we investigate the transport of solid particles around obstacles in a confined flow. Experiments were performed in a simplified configuration by considering a laminar flow in a vertical tube. An obstacle was inserted at the middle height of the tube and neutrally-buoyant particles were injected at different locations along the tube. We have investigated first the trajectories of individual particles using particle tracking (PT). Then, the particle trajectories were modeled by using the Boussinesq-Basset-Oseen equation with a flow velocity field either measured using particle image velocimetry (PIV) or calculated by the Code_Saturne software in order to account for the three-dimensional (3D) character of the obstacle wake. This paper presents a comparison between the experimental observations and the predictions of the modeling for an obstacle consisting of a rectangular step at a Reynolds number of ≈100 and evidences the importance of accounting for the 3D complex nature of the flow.

scholarly journals 14C Levels in Tree Rings Located Near Qinshan Nuclear Power Plant, China

Radiocarbon ◽  
2012 ◽  
Vol 54 (2) ◽  
pp. 195-202 ◽  
Author(s):  
Zhongtang Wang ◽  
Yuanyi Xiang ◽  
Qiuju Guo
Keyword(s):  
Power Plant ◽  
Nuclear Power Plant ◽  
Tree Rings ◽  
Nuclear Power ◽  
Specific Activity ◽  
Background Level ◽  
Relative Increase ◽  
Pine Tree ◽  
Discharge Management ◽  
Excess Value

Specific activities of radiocarbon in annual tree rings corresponding to 1980-2009 are reported for a pine tree located 2 km from the Qinshan Nuclear Power Plant (Qinshan NPP), China. While a negligible enhanced 14C activity due to operation of the Qinshan NPP Plant I is evident, a relative increase (1.8–62.6 Bq/kg C) was observed in the specific activity after operation of the Qinshan NPP Plant II in 2002 and Plant III in 2003. The enhanced values were primarily affected by the 14C discharged from Plant III (CANDU-type reactor), and a good correlation was found between the 14C discharged from Plant III in the growing season and the 14C excess value. The excess 14C activities peaked in 2005 (at 302.0 Bq/kg C, which is 62.6 Bq/kg C above the “clean air” 14C level), and then declined due to the improvement in 14C discharge management of Plant III. In 2009, the 14C-specific activity was near the background level.

scholarly journals Analysis of Heat Transfer in The VVER-1200 Reactor’s Heat Channel

2017 ◽  
Vol 33 (3) ◽  
Author(s):  
Thin Dinh Van ◽  
Loat Van Bui ◽  
Hong Thi Bui
Keyword(s):  
Heat Transfer ◽  
Power Plant ◽  
Nuclear Power Plant ◽  
Nuclear Power ◽  
High Reliability ◽  
Modern Method ◽  
Safe Operation ◽  
The World ◽  
The Government ◽  
First Time

In early 2015, the Government of Vietname has decided to choose VVER-1200 Russian-made technology for building at the Nuclear Power Plant in Ninh Thuan 1, this is the advanced reactor generation III + and the only one has been completed for the first time in the world in August 2016. Vietnam is facing a major challenge, which is how to ensure the acquired technology transfer process, then the safe operation of thisunit. This article analyzes some of the heat changes occur in reactor when there are changes of the heatflux. This is an issue directly related to the workof predictingincidents and give ways to fix the problem when the plant is in conditions such as  startup, normal and abnormaloperations. For analysis, the authors used CFD methods, this is a very modern method and have high reliability. The results received have fit well when compared with the safety analysis report of Rosatom published.

scholarly journals The analysis of radioecological monitoring results in the vicinity of the Kursk Nuclear Power Plant

2020 ◽  
Vol 13 (2) ◽  
pp. 19-30 ◽  
Author(s):  
V. K. Kuznetsov ◽  
A. V. Panov ◽  
N. I. Sanzharova ◽  
N. N. Isamov ◽  
N. V. Andreeva ◽  
...  
Keyword(s):  
Power Plant ◽  
Nuclear Power Plant ◽  
Nuclear Power ◽  
Specific Activity ◽  
Natural Radionuclides ◽  
Agricultural Products ◽  
Artificial Radionuclides ◽  
Radioecological Monitoring ◽  
The Impact ◽  
Maximum Content

The research presents the data of long-term observations of the impact of the Kursk Nuclear Power Plant operation on the radioecological situation in the region of its location. The dynamics of the content of natural and artificial radionuclides in the components of agricultural ecosystems was studied due to the data based on the information from the radioecological monitoring network developed in 2003. Samples of soils, agricultural products and animal feeds were taken at 11 control sites located on arable lands and grasslands in the vicinity of the Kursk Nuclear Power Plant, and, in settlements, locally produced food was sampled. It was shown that for the period of studies of 2003-2019, the average specific activity of 90Sr in the soils of agroecosystems of the 10 km influence zone of the Kursk Nuclear Power Plant varied within 2.7-4.3 Bq/kg, and specific activity of 137Cs was 14.6-40.8 Bq/kg. At the same time, there were found no trends of increase in the content of artificial radionuclides in soil over time and at different distances from the NPP, and the increased specific activity of 137Cs in soil compared to the global background is explained by the Chernobyl fallout. The variability of the average content of natural radionuclides in the soil for 40K was 481-625 Bq/kg, 226Ra – 20.6-29.5 Bq/ kg, 232Th – 28.2-39.2 Bq/kg, which corresponded to all-Russian data. The average specific activity of 90Sr in grain was 0.24-0.43 Bq/kg, and 137Cs – 0.19-0.37 Bq/kg. Even the maximum levels of artificial radionuclides in grain were 44 times for 90Sr and 85 times for 137Cs lower than the current SanPiN standards. The highest specific activity values of 137Cs and 90Sr in potatoes, vegetables, and gourds were 160 times lower than the SanPiN standards. It was noted that the maximum content of 90Sr in milk was more than 540 times lower than the SanPin standard, and for 137Cs this difference was 330 times. The maximum content of 137Cs in beef turned out to be over 850 times lower than the SanPiN standard for this radionuclide. About 70 Bq/a of 90Sr and 200 Bq/a of 137Cs enter the population diet with locally produced food, which is almost 400 times for 137Cs and 200 times for 90Sr lower than the annual limit. Milk (46%), meat (31%), potatoes and vegetables (14%) make the main contribution to the formation of the internal dose from agricultural products containing 137Cs, and contribution to dose from 90Sr is made by milk (14%) and crop products (potatoes, vegetables, bread) – up to 78%. In general, we concluded that over the past 17 years, the operation of the Kursk Nuclear Power Plant did not lead to a deterioration of the radioecological situation in the region of its location, because during the survey period there was no significant increase in the content of artificial radionuclides in agricultural products, foods and environmental components.

scholarly journals 14C Levels in Tree Rings Located Near Qinshan Nuclear Power Plant, China

Radiocarbon ◽  
2012 ◽  
Vol 54 (02) ◽  
pp. 195-202 ◽  
Author(s):  
Zhongtang Wang ◽  
Yuanyi Xiang ◽  
Qiuju Guo
Keyword(s):  
Power Plant ◽  
Nuclear Power Plant ◽  
Tree Rings ◽  
Nuclear Power ◽  
Specific Activity ◽  
Background Level ◽  
Relative Increase ◽  
Pine Tree ◽  
Discharge Management ◽  
Excess Value

Specific activities of radiocarbon in annual tree rings corresponding to 1980-2009 are reported for a pine tree located 2 km from the Qinshan Nuclear Power Plant (Qinshan NPP), China. While a negligible enhanced14C activity due to operation of the Qinshan NPP Plant I is evident, a relative increase (1.8–62.6 Bq/kg C) was observed in the specific activity after operation of the Qinshan NPP Plant II in 2002 and Plant III in 2003. The enhanced values were primarily affected by the14C discharged from Plant III (CANDU-type reactor), and a good correlation was found between the14C discharged from Plant III in the growing season and the14C excess value. The excess14C activities peaked in 2005 (at 302.0 Bq/kg C, which is 62.6 Bq/kg C above the “clean air”14C level), and then declined due to the improvement in14C discharge management of Plant III. In 2009, the14C-specific activity was near the background level.

The Thermal Balance Calculation of AP1000 Turbine Roll-Up by Non-Nuclear Steam

2013 ◽  
Author(s):  
Shunda Wang ◽  
Xiuli Li
Keyword(s):  
Power Plant ◽  
Nuclear Power Plant ◽  
Time Use ◽  
Nuclear Power ◽  
Design Parameters ◽  
Primary System ◽  
Big Picture ◽  
Critical Zones ◽  
First Time ◽  
Important Test

The initial turbine non-nuclear steam roll-up is an important test during nuclear power plant startup. The purpose of the test is to discover and solve turbine problem before reactor achieve critical. The benefit of this test is milestone may be shorter and save time. Use AP1000 equipments design parameters to calculate the basement of this test, by the way, we can find a safe method to startup. In this test, the heat is produced by reactor coolant pumps and PZR heaters. During roll-up, to avoid critical zones of turbine and reduce thermal stress, we hold on some speed points. At low speed period we can make up heat to make sure we can achieve the purpose of this test. So the calorimetric balance between primary side and second side is very important. Non-nuclear steam has many benefits for nuclear power plant startup. First, the secondary loop completes build before the primary system, but as one of the most important equipments, turbine must be examined to make sure it can roll-up and operation without no disease, so before primary system equipments installation finished we can save lots of time to solve turbine problems; the second one, during this duration, all of equipments of primary system can perform their function in the first time, we also make sure system function can perform correctly and timely. So, as a big picture, the milestone of startup can be shorter by replace nuclear steam rolling-up the turbine.

Specific activity of243Am and243Cm in the fuel of the 4th power-generating unit of the Chernobyl nuclear power plant

Atomic Energy ◽  
1999 ◽  
Vol 87 (5) ◽  
pp. 788-790 ◽  
Author(s):  
V. A. Ageev ◽  
S. L. Vyrichek ◽  
A. P. Lashko ◽  
T. N. Lashko ◽  
A. A. Odintsov
Keyword(s):  
Power Plant ◽  
Nuclear Power Plant ◽  
Nuclear Power ◽  
Specific Activity ◽  
Chernobyl Nuclear Power Plant ◽  
Power Generating Unit
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