Researches on the Simulation of the Degasifying Column Used in Nuclear Power Plant

2013 ◽  
Author(s):  
Jianhua Xie ◽  
Quanliu Ye ◽  
Jinchun Yang
Keyword(s):  
Power Plant ◽  
Nuclear Power Plant ◽  
Nuclear Power Station ◽  
Nuclear Power ◽  
Aspen Plus ◽  
The Other ◽  
Power Station ◽  
Simplified Models ◽  
Simulation Results ◽  
Aspen Simulation

The degasifying column is an important unit in nuclear power station. In order to verify the performance of the column, the degasifying process has been simulated by using the well-known software ASPEN Plus and on a basis of some proper hypothesizes and simplified models. Degasifying column is found that it has good capability on taking out key components such as krypton and oxygen from reactor coolant. On the other side, it’s difficult to carry out radioactive gas experiment on site which is seriously enslaved to the potential radioactive harm on operators. Simulation by using ASPEN Plus is a good way to solve this problem. Furthermore, three kinds of experiments such as ASPEN simulation, deoxidation experiment and radioactive gas experiment on site which are used for validating the performance of column are compared. The comparison shows that ASPEN simulation has less risk and less costs, but the simulation results are more exact and credible. Moreover, the debugging process of the column can be inducted and improved according to the simulation.

Lessons From an Operational Small Leakage at Tsuruga Nuclear Power Station

2015 ◽  
Author(s):  
Hiroyuki Kobayashi ◽  
Osamu Urabe ◽  
Takushi Fujino
Keyword(s):  
Power Plant ◽  
Nuclear Power Plant ◽  
Nuclear Power Station ◽  
Nuclear Power ◽  
The Other ◽  
Leak Test ◽  
Power Station ◽  
Long Time ◽  
Short Time ◽  
Repair Techniques

Operational small leakage is occasionally observed in a nuclear power plant, and the leak forces an operator to decide whether to shut down the plant or not. Even if the leakage is just a little, it might draw the considerable attention in the society, so that the operator sometimes gets into the situation to judge more severely than technical judgment. Furthermore, at the time of plant restart and the system leak test just after maintenance, even the operator doesn’t accept any leakage considering the long management for the leakage up to the next outage. On the other hand, once the operator shut down the plant, it sometimes takes long time to restart again because of the difficulty to obtain new pipes and valves in short time. The temporary repair techniques referred to the JSME code might be able to be applied to maintain the plant operation, however some difficulties exist in a practical process. One of the authors has faced with many cases in which the operational small leakage had to be dealt at Tsuruga nuclear power station. This paper shows some cases of them and discusses lessons which are related to the codes and standards.

Analysis of the Safety of Nuclear Power Plants

2013 ◽  
Vol 724-725 ◽  
pp. 692-695 ◽  
Author(s):  
De Wen Liu ◽  
Jian Xun Zheng ◽  
Zhi Ke Chen ◽  
Liang Kun Liu
Keyword(s):  
Power Plant ◽  
Nuclear Power Plant ◽  
Nuclear Power Station ◽  
Nuclear Power ◽  
Nuclear Energy ◽  
Energy Utilization ◽  
Human Beings ◽  
Power Station ◽  
Modern Development ◽  
The World

Nuclear energy is a carbon-free, clean and efficient energy. It is very important in the progress of human civilization and modern development of the world, however, there are still some problems such as nuclear leak and nuclear waste. In this paper, the worlds nuclear energy utilization and nuclear power plant constructions are reviewed and plans are forecasted. The basic reason of previous nuclear power plant accidents in history is summarized. Taking 2011 Tohuku earthquake-fukushima nuclear power station accident as an example,threats to the nuclear power plant by earthquake are investigated and impacts on social, economic and ecological environment caused by nuclear power station accident are analyzed. This paper drew lessons from previous accidents and put forward a variety of countermeasures which are from both the technical and management aspects. We also appeal people all over the world to respect the nature, enjoy the nature, and to create and enjoy the new civilization of human beings.

Radiation Dose of Airborne Radioactive Material in Nuclear Power Plant Conventional Operating Conditions

2017 ◽  
Author(s):  
Liu Zhanyang ◽  
Tao Naigui ◽  
Chen Yang ◽  
Tao Yunliang
Keyword(s):  
Power Plant ◽  
Nuclear Power Plant ◽  
Nuclear Power Station ◽  
Nuclear Power ◽  
Operating Conditions ◽  
Power Station ◽  
Atmospheric Diffusion ◽  
Radioactive Effluent ◽  
Plant Site ◽  
Ground Deposition

In this paper, air-immersion, ground deposition, ingestion and inhalation of airborne radioactive effluent released from nuclear power plant under normal operating conditions is studied according to the atmospheric diffusion and ground deposition patterns and parameters that are suitable for the environmental characteristics of the nuclear power plant site, and the public living habits and food chain parameters around the site. Based on the Gaussian plume model, with a radius of 80 kilometers we divide 1, 2, 3, 5, 10, 20, 30, 40,50,60,70,80 km concentric circles around the nuclear power plant site. The 16 compass azimuth axial are the sector center-line, forming a total of 192 sub-regions, atmospheric diffusion of radionuclides is simulated in the assessment area of the region. The annual average atmospheric dispersion factor is calculate by using hourly observation data of wind direction, rainfall and atmospheric stability of the meteorological tower and the ground station, taking into account the ground reflection during transmission, the the decay of the radionuclide, and the loss brought by the wet and dry settling that caused by gravity and rain washing. The airborne radioactive effluent is deposited on the ground or plant surface by dry settling and wet settling in the process of atmospheric environment changing and diffusion. Radioactivity of per unit area brought about by dry settling and rain fall settling is described by the deposition coefficient and deposition speed. The long-term ground deposition factor and ground annual concentration in the evaluation area were calculated under the situation of airborne radioactive effluents in the nuclear power station mixing emission, and the calculated result of radionuclide concentration in the air and soil was compared with the natural background value and the actual monitoring value. Based on the radionuclide deposited on the ground and air through the terrestrial food radioactive transfer mode, together with a large number of environmental surveys data on the population distribution, agriculture, farming, animal husbandry and people’s living and eating habits in the 80km around nuclear station, combing with the actual situation of nuclear power station, the calculation model is amended accordingly. Using reasonable dose mode to calculate the maximum individual and entire public effective dose of the residents in the assessment area, and the results will be compared with other human activities. By comparing the calculated results of radionuclide concentration and radiation dose, it provide quantitative reference information for us understanding the influence of nuclear power station on the surrounding radiation environment, and to meet the requirements of nuclear power plant influence on surrounding environment and people under normal operating conditions.

Evaluation on Radiological Consequence Induced by MSLB Accident With Alternative Source Term

2010 ◽  
Author(s):  
Jingxi Li ◽  
Gaofeng Huang ◽  
Lili Tong
Keyword(s):  
Power Plant ◽  
Nuclear Power Plant ◽  
Nuclear Power ◽  
Power Plants ◽  
Nuclear Power Plants ◽  
Source Term ◽  
Control Room ◽  
Power Station ◽  
Alternative Source ◽  
Radiological Consequence

The major threat that nuclear power plants (NPPs) pose to the safety of the public comes from the large amount radioactive material released during design-basis accidents (DBAs). Additionally, many aspects of Control Room Habitability, Environmental Reports, Facility Siting and Operation derive from the design analyses that incorporated the earlier accident source term and radiological consequence of NPPs. Depending on current applications, majority of Chinese NPPs adopt the method of TID-14844, which uses the whole body and thyroid dose criteria. However, alternative Source Term (AST) are commonly used in AP1000 and some LWRs (such as Beaver Valley Power Station, Units No. 1 and No. 2, Calvert Cliffs Nuclear Power Plant, Unit Nos. 1 And 2, Kewaunee Power Station and so on), so it is attempted to adopt AST in radiological consequence analysis of other nuclear power plants. By introducing and implementing the method of AST defined in RG 1.183 and using integral safety analysis code, a pressurized water reactor (PWR) of 900 MW nuclear power plant analysis model is constructed and the radiological consequence induced by Main Steam Line Break (MSLB) accident is evaluated. For DBA MSLB, the fractions of core inventory are assumed to be in the gap for various radionuclides and then the release from the fuel gap is assumed to occur instantaneously with the onset of assumed damage. According to the assumptions for evaluating the radiological consequences of PWR MSLB, dose calculation methodology is performed with total effective dose equivalent (TEDE) which is the criteria of dose evaluation. Compared with dose criteria of RG 1.183, the dose of control room, exclusion area boundary and outer boundary of low population zone are acceptable.

Countermeasures Derived From the Lessons of the Fukushima Daiichi Nuclear Power Plant Accident

2013 ◽  
Author(s):  
Tadashi Narabayashi
Keyword(s):  
Power Plant ◽  
Nuclear Power Plant ◽  
Pacific Ocean ◽  
Electric Power ◽  
Nuclear Power ◽  
Safety Evaluation ◽  
Lessons Learned ◽  
The Other ◽  
Nuclear Accidents ◽  
Fukushima Daiichi

On March 11, 2011, Tokyo Electric Power Company’s Fukushima Daiichi Nuclear Power Plant (NPP) was hit by a tsunami caused by the Tohoku-Pacific Ocean Earthquake, resulting in nuclear accidents in Units #1 to #4. With the aim of improving the safety of NPPs worldwide, we summarize the lessons that have been learned following a thorough analysis of the event and make specific proposals for improving the safety of such facilities. The author has been involved in investigating the causes of the accidents and developing countermeasures for other NPPs in Japan as a member of the Committee for the Investigation of Nuclear Safety of the Atomic Energy Society of Japan [1], an advisory meeting member of NISA with regard to technical lessons learned from the Fukushima Daiichi NPP accidents, and a Safety Evaluation Member of NISA for the other NPPs in Japan [2].

Deposition Fractions of Fission Product and Heavy Elements on Soil in Fukushima Dai-Ichi Nuclear Power Plant Accident

2013 ◽  
Author(s):  
Toru Yamamoto
Keyword(s):  
Power Plant ◽  
Nuclear Power Plant ◽  
Nuclear Power ◽  
Soil Samples ◽  
Heavy Elements ◽  
Severe Accident ◽  
Accident Analysis ◽  
Radioactivity Measurement ◽  
Power Station ◽  
The Core

Based on radioactivity measurement of soil samples in the site of Fukushima Dai-Ichi Nuclear Power Station, radioactivity of Sr, Nb, Mo, Tc, Ru, Ag, Te, I, Cs, Ba, La, Pu, Am, and Cm isotopes were compiled as radioactivity ratios to 137Cs. By exponentially fitting or averaging, the radioactivity ratios at the core shutdown were estimated. They were divided by those of the fuel of the core at the shutdown to obtain a deposited radioactivity fractions of the nuclides as relative values to 137Cs, which also correspond to deposition fractions of the elements as relative values to Cs. They were estimated to be orders of 10−4 to 10−3 for Sr, 10−4 for Nb, 10−2 to 10−1 for Mo, 10−1 for Ag, 10−1 to 100 for Te, 100 for I, 10−3 for Ba, 10−6 to 10−5 for Pu, 10−6 to 10−5 for Am, and 10−6 for Cm. The observed radioactivity ratios to 137Cs were compared with those obtained by severe accident analysis to assess the validation of the analysis.

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