Off-Gas Nuclide Analysis System

2013 ◽  
Author(s):  
Yoshinobu Sakakibara ◽  
Hitoshi Kuwabara ◽  
Takahiro Tadokoro ◽  
Mikio Koyama
Keyword(s):  
Nuclear Power ◽  
Gamma Ray ◽  
Cooling System ◽  
Early Stage ◽  
Moving Average ◽  
Detection Sensitivity ◽  
Ge Detector ◽  
Fuel Leakage ◽  
Analysis System ◽  
Periodic Check

In the nuclear power plant, the off gas linear monitor had been installed for the purpose of a detection of fuel leakage. However, its sensitivity to detect the early stage of fuel leakage was not enough, because it measured only the gross gamma-ray. So a high sensitive off gas monitor has been desired. HITACHI, Ltd., is commercialized the Off-Gas Nuclide Analysis System which can be accurately detected radioactive noble gases as a index to fuel leakage, and delivered it in 19 plants since 2002. It has been continuously working well and able to detect the early stage of fuel leakage 7 times. It can be detected the minute fuel leakage, so it is possible to operate the plant till next periodic check of the plant by executing PST*. And even if it is the case in which the plant must be stopped, the extent of pollution by fuel failure can be minimized. Main features of the Off-Gas Nuclide Analysis System are followings: (1) Maintenance-free continuous measurement is enabled by adopting electricity cooling system for a Ge detector. By attempting the miniaturization of the system, a compact field implementation plan is realized and also a periodic check can be simplified. (2) Thickness of a Ge detector is optimized to detect Xe-133 (80keV) as a main index nuclide to fuel leakage, so detection sensitivity is improved. (3) By adopting the mass flow control system wcich can control the flow stably in low, it is possible to reduce a volume and length of a decay tube for 13N which is the main interference nuclide, then a installation of the system is able to be simplified. (4) Moving average method which is effective to reduce noise is applied to a trend display of nuclides measured value, and it can be set at optimum time for the PST execution by flexibly setting a moving average time. *PST: Power Supression Test

scholarly journals Long-Term Monitoring of Radiocesium Concentration in Sediments and River Water along Five Rivers in Minami-Soma City during 2012–2016 Following the Fukushima Dai-ichi Nuclear Power Plant Accident

2018 ◽  
Vol 8 (8) ◽  
pp. 1319 ◽  
Author(s):  
Kiyoshi Shizuma ◽  
Wim Ikbal Nursal ◽  
Yushi Sakurai
Keyword(s):  
River Water ◽  
Nuclear Power ◽  
Gamma Ray ◽  
137Cs Concentration ◽  
Flow Conditions ◽  
High Accumulation ◽  
Ge Detector ◽  
Long Term Monitoring ◽  
Term Monitoring

Radiocesium monitoring in sediments and river water has been conducted along five rivers in Minami-Soma City during 2012–2016 to clarify the temporal changes of radiocesium contamination in these rivers. Sampling has been performed annually under normal flow conditions. Sediment and river water samples were collected from four or five sampling sites along each river. Gamma-ray measurements of sediments were performed using a low-background Ge detector and unfiltered river water was utilized to determine radiocesium concentration using a well-type Ge detector. The 137Cs concentration in sediments was highest at upstream sites and slowly decreased to downstream sites for all rivers reflecting the high radioactive contamination in the upstream area. Temporal decrease of the 137Cs concentration was observed in sediments and river water for each river. The effective half-lives were 1.3–2.1 y for sediments, and 0.9–2.1 y for river water from rivers with upstream dams. On the undammed river, the effective half-lives were 4.7 y and 3.7 y for sediment and river water, respectively. Much longer effective-half-lives might reflect the direct transfer of radiocesium from forests and plains to the river. The 137Cs concentration in riverbed was low in downstream areas, however, accumulation of 137Cs over the floodplain was observed. Rapid decrease of 137Cs contamination through rivers will put residents at ease, but high accumulation of radiocesium over floodplains should be noted for future river decontamination.

Automated high-resolution microscopy: the approaches so far

1987 ◽  
Vol 45 ◽  
pp. 58-61
Author(s):  
W. O. Saxton
Keyword(s):  
High Resolution ◽  
Early Stage ◽  
Automatic Recording ◽  
Microprocessor Control ◽  
Alternative Systems ◽  
Electron Image ◽  
Complete Automation ◽  
Analysis System ◽  
High Resolution Microscopy

Recent commercial microscopes with internal microprocessor control of all major functions have already demonstrated some of the benefits anticipated from such systems, such as continuous magnification, rotation-free diffraction and magnification, automatic recording of mutually registered focal series, and fewer control knobs. Complete automation of the focusing, stigmating and alignment of a high resolution microscope, allowing focal series to be recorded at preselected focus values as well, is still imminent rather than accomplished, however; some kind of image pick-up and analysis system, fed with the electron image via a TV camera, is clearly essential for this, but several alternative systems and algorithms are still being explored. This paper reviews the options critically in turn, and stresses the need to consider alignment and focusing at an early stage, and not merely as an optional extension to a basic proposal.

Human reliability in non-destructive inspections of nuclear power plant components: modeling and analysis

2019 ◽  
Vol 7 (2B) ◽  
Author(s):  
Vanderley Vasconcelos ◽  
Wellington Antonio Soares ◽  
Raissa Oliveira Marques ◽  
Silvério Ferreira Silva Jr ◽  
Amanda Laureano Raso
Keyword(s):  
Power Plant ◽  
Nuclear Power Plant ◽  
Human Factors ◽  
Nuclear Power ◽  
Power Plants ◽  
Failure Modes ◽  
Cooling System ◽  
Human Reliability ◽  
Non Destructive ◽  
Plant Components

Non-destructive inspection (NDI) is one of the key elements in ensuring quality of engineering systems and their safe use. This inspection is a very complex task, during which the inspectors have to rely on their sensory, perceptual, cognitive, and motor skills. It requires high vigilance once it is often carried out on large components, over a long period of time, and in hostile environments and restriction of workplace. A successful NDI requires careful planning, choice of appropriate NDI methods and inspection procedures, as well as qualified and trained inspection personnel. A failure of NDI to detect critical defects in safety-related components of nuclear power plants, for instance, may lead to catastrophic consequences for workers, public and environment. Therefore, ensuring that NDI is reliable and capable of detecting all critical defects is of utmost importance. Despite increased use of automation in NDI, human inspectors, and thus human factors, still play an important role in NDI reliability. Human reliability is the probability of humans conducting specific tasks with satisfactory performance. Many techniques are suitable for modeling and analyzing human reliability in NDI of nuclear power plant components, such as FMEA (Failure Modes and Effects Analysis) and THERP (Technique for Human Error Rate Prediction). An example by using qualitative and quantitative assessesments with these two techniques to improve typical NDI of pipe segments of a core cooling system of a nuclear power plant, through acting on human factors issues, is presented.

scholarly journals Comparison of saliva with healthcare workers- and patient-collected swabs in the diagnosis of COVID-19 in a large cohort

2021 ◽  
Vol 21 (1) ◽  
Author(s):  
Mitnala Sasikala ◽  
Yelamanchili Sadhana ◽  
Ketavarapu Vijayasarathy ◽  
Anand Gupta ◽  
Sarala Kumari Daram ◽  
...  
Keyword(s):  
Healthcare Workers ◽  
Early Stage ◽  
Cost Effective ◽  
Hospitalized Patients ◽  
Detection Sensitivity ◽  
Nasopharyngeal Swab ◽  
Predictive Values ◽  
Qrt Pcr ◽  
Asymptomatic Patients ◽  
Sensitivity Specificity

Abstract Background A considerable amount of evidence demonstrates the potential of saliva in the diagnosis of COVID-19. Our aim was to determine the sensitivity of saliva versus swabs collected by healthcare workers (HCWs) and patients themselves to assess whether saliva detection can be offered as a cost-effective, risk-free method of SARS-CoV-2 detection. Methods This study was conducted in a hospital involving outpatients and hospitalized patients. A total of 3018 outpatients were tested. Of these, 200 qRT-PCR-confirmed SARS-CoV-2-positive patients were recruited for further study. In addition, 101 SARS-CoV-2-positive hospitalized patients with symptoms were also enrolled in the study. From outpatients, HCWs collected nasopharyngeal swabs (NPS), saliva were obtained. From inpatients, HCWs collected swabs, patient-collected swabs, and saliva were obtained. qRT-PCR was performed to detect SARS-CoV-2 by TAQPATH assay to determine the sensitivity of saliva detection. Sensitivity, specificity and positive/negative predictive values (PPV, NPV) of detecting SARS-CoV-2 were calculated using MedCalc. Results Of 3018 outpatients (asymptomatic: 2683, symptomatic: 335) tested by qRT-PCR, 200 were positive (males: 140, females: 60; aged 37.9 ± 12.8 years; (81 asymptomatic, 119 symptomatic). Of these, saliva was positive in 128 (64%); 39 of 81 asymptomatic (47%),89 of 119 symptomatic patients (74.8%). Sensitivity of detection was 60.9% (55.4–66.3%, CI 95%), with a negative predictive value of 36%(32.9–39.2%, CI 95%).Among 101 hospitalized patients (males:65, females: 36; aged 53.48 ± 15.6 years), with HCW collected NPS as comparator, sensitivity of saliva was 56.1% (47.5–64.5, CI 95%), specificity 63.5%(50.4–75.3, CI95%) with PPV of 77.2% and NPV of 39.6% and that of self-swab was 52.3%(44–60.5%, CI95%), specificity 56.6% (42.3–70.2%, CI95%) with PPV 77.2% and NPV29.7%. Comparison of positivity with the onset of symptoms revealed highest detection in saliva on day 3 after onset of symptoms. Additionally, only saliva was positive in 13 (12.8%) hospitalized patients. Conclusion Saliva which is easier to collect than nasopharyngeal swab is a viable alternate to detect SARS-COV-2 in symptomatic patients in the early stage of onset of symptoms. Although saliva is currently not recommended for screening asymptomatic patients, optimization of collection and uniform timing of sampling might improve the sensitivity enabling its use as a screening tool at community level.

Design, calibration, and application of an airborne gamma spectrometer system in Switzerland

Geophysics ◽  
1997 ◽  
Vol 62 (5) ◽  
pp. 1369-1378 ◽  
Author(s):  
Georg F. Schwarz ◽  
Ladislaus Rybach ◽  
Emile E. Klingelé
Keyword(s):  
Power Plant ◽  
Nuclear Power ◽  
Power Plants ◽  
Gamma Ray ◽  
Point Sources ◽  
Swiss Alps ◽  
Artificial Radioactivity ◽  
Radiation Level ◽  
Satellite Navigation System ◽  
Emergency Situations

Airborne radiometric surveys are finding increasingly wider applications in environmental mapping and monitoring. They are the most efficient tool to delimit surface contamination and to locate lost radioactive sources. To secure radiometric capability in survey and emergency situations, a new sensitive airborne system has been built that includes an airborne spectrometer with 256 channels and a sodium iodide detector with a total volume of 16.8 liters. A rack mounted PC with memory cards is used for data acquisition, with a GPS satellite navigation system for positioning. The system was calibrated with point sources using a mathematical correction to take into account the effects of gamma‐ray scattering in the ground and in the atmosphere. The calibration was complemented by high precision ground gamma spectrometry and laboratory measurements on rock samples. In Switzerland, two major research programs make use of the capabilities of airborne radiometric measurements. The first one concerns nuclear power plant monitoring. The five Swiss nuclear installations (four power plants and one research facility) and the surrounding regions of each site are surveyed annually. The project goal is to monitor the dose‐rate distribution and to provide a documented baseline database. The measurements show that all sites (with the exception of the Gösgen power plant) can be identified clearly on the maps. No artificial radioactivity that could not be explained by the Chernobyl release or earlier nuclear weapons tests was detected outside of the fenced sites of the nuclear installations. The second program aims at a better evaluation of the natural radiation level in Switzerland. The survey focused on the crystalline rocks of the Central Massifs of the Swiss Alps because of their relatively high natural radioactivity and lithological variability.

Verification of Alarm Displays for the Nuclear Power Plant With Two Modular High-Temperature Gas-Cooled Reactors

2018 ◽  
Author(s):  
Jia Qianqian ◽  
Guo Chao ◽  
Li Jianghai ◽  
Qu Ronghong
Keyword(s):  
High Temperature ◽  
Power Plant ◽  
Nuclear Power Plant ◽  
Nuclear Power ◽  
Modular Design ◽  
Early Stage ◽  
Integrated System ◽  
Alarm System ◽  
Control Room ◽  
High Temperature Gas

The nuclear power plant with two modular high-temperature gas-cooled reactors (HTR-PM) is under construction now. The control room of HTR-PM is designed. This paper introduces the alarm displays in the control room, and describes some verification and validation (V&V) activities of the alarm system, especially verification for some new human factor issues of the alarm system in the two modular design. In HTR-PM, besides the regular V&V similar to other NPPs, the interference effect of the alarm rings of the two reactor modules at the same time, and the potential discomfort of the two reactor operators after shift between them are focused. Verifications at early stage of the two issues are carried on the verification platform of the control room before the integrated system validation (ISV), and all the human machine interfaces (HMIs) in the control room, including the alarm system are validated in ISV. The test results on the verification platform show that the alarm displays and rings can support the operators understand the alarm information without confusion of the two reactors, and the shift between the two reactor operators have no adverse impact on operation. The results in ISV also show that the alarm system can support the operators well.

scholarly journals Testing for presence of radioactivity in BC Pacific Ocean’s seafood supply

2014 ◽  
Author(s):  
Amy Luan ◽  
BCIT School of Health Sciences, Environmental Health ◽  
Bobby Sidhu ◽  
Abderrachid Zitouni
Keyword(s):  
Pacific Ocean ◽  
Gamma Radiation ◽  
Nuclear Power ◽  
Gamma Ray ◽  
Gamma Ray Spectrometer ◽  
The Pacific ◽  
Two Samples ◽  
Seafood Products ◽  
The Pacific Ocean ◽  
Fish And Shellfish

  Abstract: Due to the Fukushima Daiichi Nuclear power plant incident in March 2011, large quantities of contaminated water were released to the Pacific Ocean in Japan. The severity of contamination on the marine environment is unclear, therefore, the public is concerned with the possible internal radiation exposure from ingesting contaminated seafood products caught in the Pacific Ocean. This study was aimed to investigate the presence or absence of gamma radioactivity in commonly consumed seafood products from B.C. In total, ten different species of fish and three different species of shellfish were selected for analysis. For each species of fish, two samples were collected and each sample was from a different local seafood market. For each species of shellfish, ten samples were collected from three different sources. Using the portable GR-135 Plus gamma ray spectrometer, the samples were tested and analyzed for the presence of Fukushima radionuclides, particularly Cesium-137 (Cs-137) and Cesium- 134 (Cs-134).Based on the analyzed fish and shellfish, no gamma radiation was detected. The detector did not identify any gamma radiation over the normal background readings.  

scholarly journals Kabul River Flow Prediction Using Automated ARIMA Forecasting: A Machine Learning Approach

2021 ◽  
Vol 13 (19) ◽  
pp. 10720
Author(s):  
Muhammad Ali Musarat ◽  
Wesam Salah Alaloul ◽  
Muhammad Babar Ali Rabbani ◽  
Mujahid Ali ◽  
Muhammad Altaf ◽  
...  
Keyword(s):  
Machine Learning ◽  
Water Level ◽  
River Flow ◽  
Early Stage ◽  
Moving Average ◽  
Weather Prediction ◽  
Maximum Level ◽  
Information Criterion ◽  
Water Levels ◽  
Kabul River

The water level in a river defines the nature of flow and is fundamental to flood analysis. Extreme fluctuation in water levels in rivers, such as floods and droughts, are catastrophic in every manner; therefore, forecasting at an early stage would prevent possible disasters and relief efforts could be set up on time. This study aims to digitally model the water level in the Kabul River to prevent and alleviate the effects of any change in water level in this river downstream. This study used a machine learning tool known as the automatic autoregressive integrated moving average for statistical methodological analysis for forecasting the river flow. Based on the hydrological data collected from the water level of Kabul River in Swat, the water levels from 2011–2030 were forecasted, which were based on the lowest value of Akaike Information Criterion as 9.216. It was concluded that the water flow started to increase from the year 2011 till it reached its peak value in the year 2019–2020, and then the water level will maintain its maximum level to 250 cumecs and minimum level to 10 cumecs till 2030. The need for this research is justified as it could prove helpful in establishing guidelines for hydrological designers, the planning and management of water, hydropower engineering projects, as an indicator for weather prediction, and for the people who are greatly dependent on the Kabul River for their survival.

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