scholarly journals Radiological characterization of a German pressurized water reactor based on a highly resolved method for activity analysis and dose rate calculation

2021 ◽  
Vol 1 ◽  
pp. 25-26
Author(s):  
Markus Nolden ◽  
Agnes Scaramus ◽  
Rahim Nabbi ◽  
Frank Charlier ◽  
Klaus Fischer-Appelt
Keyword(s):  
Power Plant ◽  
Nuclear Power Plant ◽  
Dose Rate ◽  
Nuclear Power ◽  
Neutron Fluence ◽  
Radiation Transport ◽  
Source Terms ◽  
Activity Distribution ◽  
Radiological Characterization

Abstract. The amendment to the atomic act in 2011 results to phase out nuclear energy in Germany until the end of 2022. Subsequently, the licensee of the nuclear power plant is responsible for decommissioning and dismantling. During operation, activation of structures near the core of the reactor occur which govern the amount of radioactive waste, the dose rate distribution and dismantling strategies. Thus, a detailed radiological characterization of in-core and out-core structures is required to optimize decommissioning processes regarding the quantification and minimization of radioactive waste, radiation protection and reducing radiation exposure. These objectives are achieved using an innovative and efficient method developed and applied at the Chair of Repository Safety (Lehrstuhl für Endlagersicherheit, ELS) RWTH Aachen University. Within the framework of the joint project „Development of a methodology for activity analysis and dose rate estimation“, funded by the Federal ministry of Education and Research, approaches the objective to develop a standardized and highly resolved method to calculate time-dependent activity of components and structures near the reactor core based on operating history of the nuclear power plant and neutron fluence distribution. The approach requires the development of a detailed model for Monte-Carlo simulations which provides the basis to neutron fluence, neutron spectra and radiation transport simulations. To calculate the nuclide specific 3-Dimensional (3D) activity distribution of the entire facility, a facility-dependent activation cross section library is produced which focuses on recent nuclear databases (ENDF/B-VIII.0). A highly resolved and space-dependent 3D activity distribution of the entire facility is obtained using a modular program package, developed at ELS, including the activation code ORIGEN2. The results are produced in the form of detailed 3D activity maps. The source terms are generated on the basis of the space-dependent 3D activity distribution using an additional module of the program package. The combination of recent nuclear databases focusing on ENDF/B-VII.1 and complemented by JEFF-3.3 ensures a comprehensive characterisation of source terms. Subsequently, source terms are prepared for 3D radiation transport simulation using the Monte-Carlo method and the computer code MCNP. The simulations are conducted separately for each individual component obtaining the partial contribution of all in-core and out-core structures as well as the dose rate distribution of the entire facility. Similar to the activity calculation, the simulation results are used to generate 3D gamma flux and dose rate maps using the graphic module of the whole program system. On the basis of the radiological characterisation and in view of a high-level radiation protection these maps allow the optimum planning and realisation of the decommissioning and dismantling process of the nuclear power plant.

scholarly journals Ecosystem model-based approach for modeling the dynamics of <sup>137</sup>Cs transfer to marine plankton populations: application to the western North Pacific Ocean after the Fukushima nuclear power plant accident

2016 ◽  
Vol 13 (2) ◽  
pp. 499-516 ◽  
Author(s):  
M. Belharet ◽  
C. Estournel ◽  
S. Charmasson
Keyword(s):  
Power Plant ◽  
Nuclear Power Plant ◽  
Pacific Ocean ◽  
Dose Rate ◽  
North Pacific ◽  
Nuclear Power ◽  
Western North Pacific ◽  
North Pacific Ocean ◽  
Ecosystem Model ◽  
Western North Pacific Ocean

Abstract. Huge amounts of radionuclides, especially 137Cs, were released into the western North Pacific Ocean after the Fukushima nuclear power plant (FNPP) accident that occurred on 11 March 2011, resulting in contamination of the marine biota. In this study we developed a radioecological model to estimate 137Cs concentrations in phytoplankton and zooplankton populations representing the lower levels of the pelagic trophic chain. We coupled this model to a lower trophic level ecosystem model and an ocean circulation model to take into account the site-specific environmental conditions in the area. The different radioecological parameters of the model were estimated by calibration, and a sensitivity analysis to parameter uncertainties was carried out, showing a high sensitivity of the model results, especially to the 137Cs concentration in seawater, to the rates of accumulation from water and to the radionuclide assimilation efficiency for zooplankton. The results of the 137Cs concentrations in planktonic populations simulated in this study were then validated through comparison with the data available in the region after the accident. The model results have shown that the maximum concentrations in plankton after the accident were about 2 to 4 orders of magnitude higher than those observed before the accident, depending on the distance from FNPP. Finally, the maximum 137Cs absorbed dose rate for phyto- and zooplankton populations was estimated to be about 5  ×  10−2 µGy h−1, and was, therefore, lower than the predicted no-effect dose rate (PNEDR) value of 10 µGy h−1 defined in the ERICA assessment approach.

Natural variation of ambient dose rate in the air of Izu-Oshima Island after the Fukushima Daiichi Nuclear Power Plant accident

2015 ◽  
Vol 168 (4) ◽  
pp. 561-565 ◽  
Author(s):  
Fumihiko Maedera ◽  
Kazumasa Inoue ◽  
Masato Sugino ◽  
Ryosuke Sano ◽  
Mai Furue ◽  
...  
Keyword(s):  
Power Plant ◽  
Nuclear Power Plant ◽  
Dose Rate ◽  
Nuclear Power ◽  
Natural Variation ◽  
Nuclear Power Plant Accident ◽  
Fukushima Daiichi ◽  
Ambient Dose

scholarly journals V　Characteristics of Air Dose Rate Distribution in the Environment around the Fukushima Nuclear Power Plant site

RADIOISOTOPES ◽  
2015 ◽  
Vol 64 (9) ◽  
pp. 589-607
Author(s):  
Satoshi MIKAMI ◽  
Norihiro MATSUDA ◽  
Masaki ANDOH ◽  
Sakae KINASE ◽  
Mitsuaki KITANO ◽  
...  
Keyword(s):  
Power Plant ◽  
Nuclear Power Plant ◽  
Dose Rate ◽  
Nuclear Power ◽  
Rate Distribution ◽  
Plant Site

In situ gamma spectrometry using portable HPGe detector. Radiological characterization and environmental surveillance around an operating nuclear power plant. Possibilities and limits

2021 ◽  
Author(s):  
Jose Angel Corbacho ◽  
A Baeza
Keyword(s):  
Power Plant ◽  
Nuclear Power Plant ◽  
Gamma Spectrometry ◽  
Nuclear Power ◽  
Power Plants ◽  
Activity Concentration ◽  
Versatile Tool ◽  
Ge Detector ◽  
Radiological Characterization

Abstract In situ technique for measuring radionuclides in the soil using a portable Ge detector is a highly versatile tool for both the radiological characterization and for the monitoring of operating nuclear power plants. The main disadvantage of this technique is related to the lack of knowledge of the geometry of the source whose activity concentration is to be determined. However, its greatest advantage is the high spatial representability of the samples and the lower time and resource consumption than gamma spectrometry lab measurements. In this study, the possibilities and limits offered by in situ gamma spectrometry with a high resolution gamma portable detector in two common uses are shown: First, the radiological background characterization and its relationship with the geology of an area of 2700 km2 are assessed; Secondly, its potential for monitoring man-made activity concentration in soils located around an operating nuclear power plant in Spain for surveillance purposes is evaluated. Finally, high accuracy radiation maps have been prepared from the measurements carried out. These radiation maps are essential tools to know the radioactive background of an area, especially useful to assess artificial radioactive deposits produced after a nuclear accident or incident.

Estimation of the Dose Rate of Spent Fuel-Related Components of Lingao Nuclear Power Plant Using ORIGEN2 and MCNP5

2019 ◽  
Vol 24 (1) ◽  
pp. 64-70
Author(s):  
Mingliang Xie ◽  
Fei Xie ◽  
Fuchang Shan ◽  
Zhengquan Xie ◽  
Mingrui Li ◽  
...  
Keyword(s):  
Power Plant ◽  
Nuclear Power Plant ◽  
Dose Rate ◽  
Nuclear Power ◽  
Spent Fuel

Model of a Dry Storage Facility for a Medium Nuclear Power Plant

2001 ◽  
Author(s):  
Mile Bace ◽  
Kresimir Trontl ◽  
Dubravko Pevec
Keyword(s):  
Power Plant ◽  
Nuclear Power Plant ◽  
Radiation Dose ◽  
Dose Rate ◽  
Nuclear Power ◽  
Storage Facility ◽  
Spent Fuel ◽  
Radiation Dose Rate ◽  
Dry Storage ◽  
Fuel Assemblies

Abstract The intention was to model a dry storage facility that could satisfy the needs of a medium nuclear power plant similar to the NPP Krsko. The attention has been focused on radiation dose rate analyses and criticality calculations. Using the SCALE 4.4 code package and modified QAD-CGGP code, we modeled a facility that satisfies the basic criteria for public radiation protection. The capacity of the storage is 1,400 spent fuel assemblies which is adequate for a forty years medium NPP lifetime.

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