scholarly journals Determination of the Affected Steam Generator during Primary-to-Secondary Leakage in WWER-1000 Using a Geiger-Muller Counter

2020 ◽  
pp. 31-38
Author(s):  
Yu. Fylonych ◽  
V. Zaporozhan ◽  
O. Balashevskyi ◽  
V. Gerlyga ◽  
V. Tarasov

The main indicator of a primary-to-secondary leakage in WWER-1000 is the increased secondary side activity. Activity can be detected by radiation devices. Accordingly, the online monitoring of the secondary side activity allows the reactor operator to successfully determine the affected steam generator and implement appropriate actions to transfer the reactor in a safe state. The detectors are supposed to be installed behind the steam generator pipelines outside of the containment. The scattered photon spectrum, formed from N-16 decay in the detection area, is analyzed. The possibility of using a detection unit with a Geiger-Muller counter to register particles with energies that exceed the device energy range, which is indicated in the technical specifications, is confirmed. The paper indicates that the detector response is determined by two different approaches. In the first case, the absorbed dose rate is calculated by the energy deposition method (KERMA factor), and in the second case, the detector count rate is calculated by taking into account the secondary ionization processes. The calculation results of the detector response taking into account the dead time are presented. The dead time effect on the absorbed dose rate registered by the counter is analyzed. The calculated response coefficients of the detector for the main reference radionuclides of the primary side, which could be potentially transported into the detector’s registration volume, is obtained. Additionally, the paper provides for the maximum limit of the detected absorbed dose rate of BDMG-04-02B. The calculations were carried out using MCNP6 neutronic code focused on the analysis of the elementary particle interaction with surrounding materials.

2019 ◽  
Vol 188 (1) ◽  
pp. 98-108
Author(s):  
F O Wanjala ◽  
N O Hashim ◽  
D Otwoma ◽  
C Nyambura ◽  
J Kebwaro ◽  
...  

Abstract The activity concentration of radionuclides 238U, 232Th and 40K in soil and the absorbed dose rate (ADRA) at 1 m above the ground in Ortum was determined. The activity concentration in soils ranged from 33 to 85, 20 to 67 and 148–1019 Bq kg–1, respectively with an average of 40 ± 1.43, 56 ± 1.46 and 425 ± 19.24 Bq kg–1, respectively. The activity concentration of 232Th and 238U was found to reduce with increasing depth while that of 40K increased with increasing depth. The average activity concentration in soil was higher than the world average values. The average ADRA in air at 1 m above the ground was found to be 112 ± 29.6 nGy h–1. The soil and rocks in Ortum are recommended for use because the activity concentration of the terrestrial radionuclides is lower than the recommended threshold values.


2018 ◽  
Vol 53 (4) ◽  
pp. 265-278 ◽  
Author(s):  
S. Penabei ◽  
D. Bongue ◽  
P. Maleka ◽  
T. Dlamini ◽  
Saïdou ◽  
...  

In order to assess the levels of natural radioactivity and the associated radiological hazards in some building materials of the Mayo-Kebbi region (Chad), a total of nineteen samples were collected on the field. Using a high resolution γ-ray spectrometry system, the activity concentrations of radium (226Ra), thorium (232Th) and potassium (40K) in these samples have been determined. The measured average activity concentrations range from 0.56 ± 0.37 Bq kg−1 to 435 ± 7 Bq kg−1, 1.3 ± 0.6 Bq kg−1 to 50.6 ± 1.1 Bq kg−1 and 4.3 ± 2.0 Bq kg−1 to 840 ± 9 Bq kg−1, for 226Ra, 232Th and 40K, respectively. The highest 226Ra average activities is found in soil brick samples of Zabili. The highest mean value of 232Th and 40K concentrations are found in soil brick samples of Madajang. The activity concentration and the radium equivalent activity (Raeq) have been compared to other studies done elsewhere in the world. Their average values are lower than most of those of countries with which the comparison has been made. Were also evaluated, the external radiation hazard index, the internal radiation hazard index, the indoor air absorbed dose rate, the outdoor air absorbed dose rate, the activity utilization index, the annual effective dose, the annual gonadal dose equivalent, the representative level index, as well as, the excess lifetime cancer risk. In accordance with the criterion of the Organization for Economic Cooperation and Development, our results show that soil brick samples of Zabili and Madajang increases the risk of radiation exposure, thereby the possibility of developing cancer by people living in this environment. Based on these findings, brick samples from Zabili and Madajang are not recommended for construction purposes. All other sample materials have properties that are acceptable for use as building materials in terms of radiation hazard.


2001 ◽  
Author(s):  
J M Carson ◽  
P B Holman ◽  
R B K Shives ◽  
K L Ford ◽  
C T Harper ◽  
...  

2020 ◽  
Vol 24 (3) ◽  
pp. 435-442 ◽  
Author(s):  
M. Atipo ◽  
O. Olarinoye ◽  
B. Awojoyogbe ◽  
M. Kolo

Mineral mining and milling can be a source of national economic and technological development. However, mining of minerals has been confirmed to disturb the natural distribution of radioisotopes in the soil, air and water bodies in the biota. In an attempt to evaluate the radiological burden resulting from tin mining activities at Rayfield-Du area of Jos, the background gamma-radiation level in the mine was measured via a well calibratedhand-held dosimeter placed at 1 m above ground level. The mean absorbed dose rate, annual effective dose rate and excess lifetime cancer risk for the mine was 0.83 μSvh-1; 1.44 mSv-1 and 0.005 respectively. Generally, dose rates were higher in the mine pits and processing areas as compared to administrative areas of the mine. The mean measured dose rate and calculated dose parameters for the mine were all high when compared to the regulatory limit for public exposure. The potential of developing radiation-induced health defects as a result of high radiation absorbed dose rate by the miners and dwellers around the mine is highly probable.  Keywords: Gamma-radiation; mine; absorbed dose rate; radiation exposure.


2019 ◽  
Vol 188 (2) ◽  
pp. 174-180
Author(s):  
Chutima Kranrod ◽  
Supitcha Chanyotha ◽  
Phongphaegh Pengvanich ◽  
Rawiwan Kritsananuwat ◽  
Thamaborn Ploykrathok ◽  
...  

Abstract Natural background gamma radiation was measured along the main roads in the eastern, western and southern regions of Thailand using a car-borne survey system with a 3-in × 3-in NaI (Tl) scintillation spectrometer. The system was able to quickly survey a large area and obtain outdoor absorbed dose rate in air from a gamma ray pulse height distribution. A total of 19 219 data of the outdoor absorbed dose rate in air were collected. The average outdoor absorbed dose rate in air in the eastern, western and southern regions were found to be 8–127, 16–119 and 16–141 nGy h -1 , respectively. The highest outdoor absorbed dose rate in air was detected in the southern region of Thailand. The corresponding average outdoor annual effective dose to the public ranged from 11.7 to 80.8 μSv.


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