Paper 26. In-situ measurements of corrosion deposits on the primary system at Paks nuclear power plant

Author(s):  
P. Ormai ◽  
T. Pintér ◽  
I. C. Szabó ◽  
T. Sztaricskai ◽  
G. Pető ◽  
...  
Author(s):  
Eltayeb Yousif ◽  
Zhang Zhijian ◽  
Tian Zhao-fei ◽  
A. M. Mustafa

To ensure effective operation of nuclear power plants, it is very important to evaluate different accident scenarios in actual plant conditions with different codes. In the field of nuclear safety, Loss of Coolant Accident (LOCA) is one of the main accidents. RELAP-MV Visualized Modularization software technology is recognized as one of the best estimated transient simulation programs of light water reactors, and also has the options for improved modeling methods, advanced programming, computational simulation techniques and integrated graphics displays. In this study, transient analysis of the primary system variation of thermo-hydraulics parameters in primary loop under SB-LOCA accident in AP1000 nuclear power plant (NPP) is carried out by Relap5-MV thermo-hydraulics code. While focusing on LOCA analysis in this study, effort was also made to test the effectiveness of the RELAP5-MV software already developed. The accuracy and reliability of RELAP5-MV have been successfully confirmed by simulating LOCA. The calculation was performed up to a transient time of 4,500.0s. RELAP5-MV is able to simulate a nuclear power system accurately and reliably using this modular modeling method. The results obtained from RELAP5 and RELAP5-MV are in agreement as they are based on the same models though in comparison with RELAP5, RELAP5-MV makes simulation of nuclear power systems easier and convenient for users most especially for the beginners.


Author(s):  
Jose Angel Corbacho ◽  
A Baeza

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.


2012 ◽  
Vol 2012 ◽  
pp. 1-17 ◽  
Author(s):  
Analia Bonelli ◽  
Oscar Mazzantini ◽  
Martin Sonnenkalb ◽  
Marcelo Caputo ◽  
Juan Matias García ◽  
...  

A description of the results for a Station Black-Out analysis for Atucha 2 Nuclear Power Plant is presented here. Calculations were performed with MELCOR 1.8.6 YV3165 Code. Atucha 2 is a pressurized heavy water reactor, cooled and moderated with heavy water, by two separate systems, presently under final construction in Argentina. The initiating event is loss of power, accompanied by the failure of four out of four diesel generators. All remaining plant safety systems are supposed to be available. It is assumed that during the Station Black-Out sequence the first pressurizer safety valve fails stuck open after 3 cycles of water release, respectively, 17 cycles in total. During the transient, the water in the fuel channels evaporates first while the moderator tank is still partially full. The moderator tank inventory acts as a temporary heat sink for the decay heat, which is evacuated through conduction and radiation heat transfer, delaying core degradation. This feature, together with the large volume of the steel filler pieces in the lower plenum and a high primary system volume to thermal power ratio, derives in a very slow transient in which RPV failure time is four to five times larger than that of other German PWRs.


Energies ◽  
2020 ◽  
Vol 13 (2) ◽  
pp. 359 ◽  
Author(s):  
Hrvoje Grganić ◽  
Davor Grgić ◽  
Siniša Šadek

Electromagnetic compatibility (EMC) in nuclear power plants today mostly relies on the qualification tests of the new equipment and adhering to some good installation practices. Diversity of the electromagnetic environment and different susceptibility of the plant equipment calls for a systematic classification of the EMC zones in a nuclear power plant. The paper proposes a methodology that uses a combination of the qualification tests, in situ and bench immunity tests, site survey measurements, operational experience, and numerical calculations to divide a nuclear power plant into a reasonable number of EMC zones. This would primarily help to have a better overview of the current EMC level in the plant and to unify emission and susceptibility requirements for the new equipment. In this paper, special attention is given to the preparation and performance of the in situ tests, which present the most challenging step of the methodology. In addition, the paper proposes some of the possible applications of the numerical calculations and addresses their challenges and limitations. The novel classification methodology, inspired by the equipment qualification program, is illustrated with examples from Krško Nuclear Power Plant, which recently performed a comprehensive EMC assessment.


Author(s):  
Shunda Wang ◽  
Xiuli Li

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.


2013 ◽  
Vol 54 (5) ◽  
pp. 832-839 ◽  
Author(s):  
R. Hristova ◽  
V. Hadjidekova ◽  
M. Grigorova ◽  
T. Nikolova ◽  
M. Bulanova ◽  
...  

Sign in / Sign up

Export Citation Format

Share Document