scholarly journals Levels, Variations and Sources of 90sr and 137cs in Environmental and Food Samples Around Qinshan Nuclear Power Plant, China in 2012-2019

2021 ◽  
Author(s):  
Yiyao Cao ◽  
Zhixin Zhao ◽  
Xiaoming Lou ◽  
Shunfei Yu ◽  
Meibian Zhang ◽  
...  
Keyword(s):  
Power Plant ◽  
Nuclear Power Plant ◽  
Nuclear Power ◽  
Local Population ◽  
Temporal Variations ◽  
Food Samples ◽  
Nuclear Facilities ◽  
Local Facility ◽  
Radioactivity Monitoring ◽  
Radioactive Release

Abstract Environmental radioactivity monitoring in the surroundings of nuclear facilities is important to provide baseline data for effective detection in case of any radioactive release in the region. In this work, we report for the first time the long-term monitoring data of 137Cs and 90Sr in environmental and food samples around Qinshan Nuclear Power Plant (QNPP) in 2012-2019. The distribution levels, temporal variations and source terms of 137Cs and 90Sr in the investigated samples were discussed. The annual effective dose (AED) for the local population from the ingestion of foods was also evaluated. Peak values of 90Sr and 137Cs concentrations and 137Cs/90Sr radioactivity ratio were observed in total atmospheric deposition in 2016 and some water and food samples in the following years. This seems to be associated to an additional radioactive input, mostly likely from the operational release of a local facility. This demonstrates that 90Sr and 137Cs, especially the 137Cs/90Sr activity ratio, are sensitive indicators for detecting potential radioactive releases. Nevertheless, overall 90Sr and 137Cs activity concentrations measured during 2012-2019 in this work were at the background levels with average AED far below the internationally permissible limit and recommendation.

scholarly journals Long-term variation of 90Sr and 137Cs in environmental and food samples around Qinshan nuclear power plant, China

2021 ◽  
Vol 11 (1) ◽  
Author(s):  
Yiyao Cao ◽  
Zhixin Zhao ◽  
Peng Wang ◽  
Shunfei Yu ◽  
Zhongjun Lai ◽  
...  
Keyword(s):  
Power Plant ◽  
Nuclear Power Plant ◽  
Nuclear Power ◽  
Activity Ratio ◽  
Local Population ◽  
Temporal Variations ◽  
Food Samples ◽  
Nuclear Facilities ◽  
Local Facility

AbstractEnvironmental radioactivity monitoring in the surroundings of nuclear facilities is important to provide baseline data for effective detection in case of any radioactive release in the region. In this work, we report for the first time the long-term monitoring data of 137Cs and 90Sr in environmental and food samples around Qinshan nuclear power plant in 2012–2019. The distribution levels, temporal variations and source terms of 137Cs and 90Sr in the investigated samples were discussed. The annual effective dose (AED) for the local population from the ingestion of foods was also evaluated. Peak values of 90Sr and 137Cs concentrations and 137Cs/90Sr activity ratio were observed in total atmospheric deposition in 2016 and some water and food samples in the following years. This seems to be associated to an additional radioactive input, mostly likely from the operational release of a local facility. This demonstrates that 90Sr and 137Cs, especially the 137Cs/90Sr activity ratio, are sensitive indicators for detecting potential radioactive releases. Nevertheless, overall 90Sr and 137Cs activity concentrations measured during 2012–2019 in this work were at the background levels with average AED far below the internationally permissible limit and recommendation.

Use of Shear Lugs for Anchorage to Concrete

2009 ◽  
Author(s):  
Peter J. Carrato ◽  
Martin Reifschneider
Keyword(s):  
Power Plant ◽  
Nuclear Power Plant ◽  
Nuclear Power ◽  
Design Method ◽  
American Concrete Institute ◽  
Significant Activity ◽  
Lateral Loads ◽  
Nuclear Facilities ◽  
Shear Loads ◽  
Full Scale Tests

Anchoring structures, systems and components to concrete is a significant activity in the design and construction of a nuclear power plant. Early in this decade the Concrete Capacity Design method (CCD) was adopted by the American Concrete Institute (ACI) for use in the structural design for both commercial and nuclear facilities. This design method and associated qualification tests brings new challenges to designing efficient means for anchoring to concrete structures. Although the CCD method provides guidance on many aspects of concrete anchorage there are a few areas, pertinent to nuclear power plant construction, that are not covered or require significant interpretation of the most recent codes. This paper will focus on the design of shear lugs used to resist significant lateral loads. Results from laboratory tests of shear lugs are presented. These full scale tests considered the interaction of tension and shear loads on the performance of shear lug assemblies. Recommendations for the efficient use of shear lugs are provided.

Concept for the Guarantee of the Integrity of Bolted Flanged Connections in a German Nuclear Power Plant

2008 ◽  
Author(s):  
Manfred Schaaf ◽  
Friedrich Schoeckle ◽  
Jaroslav Bartonicek
Keyword(s):  
Power Plant ◽  
Nuclear Power Plant ◽  
Data Base ◽  
Nuclear Power ◽  
Test Laboratory ◽  
Third Party ◽  
Nuclear Facilities ◽  
Systematic Treatment ◽  
Bolted Flange ◽  
Test Loading

In nuclear facilities in Germany a systematic treatment of all sealing connections which are opened during the annual shutdowns is performed since several years. Special attention is paid to a design which meets specifications of the bolted flange connections (BFC’s). Apart from the use of suitable and certified materials this includes also the calculation of the required torques in accordance to the present rules. For the calculation procedure the nuclear code KTA 3211.2 (draft 2003) is applied which allows a tightness proof of the BFC, besides a stress analysis. For this calculation, experimentally achieved gasket characteristics according to DIN 28090-1 are required, which are either supplied by the gasket manufacturers or determined in the amtec test laboratory. The geometry and material data of each BFC are stored in a special data base. In addition, the data of the operating state as well as the design and test loading cases are included in the data base, so that all inputs for a later calculation are available. The results of the calculation which must be checked and approved by an expert third-party are stored in the flange data base, too (assembly state settings of each flange connection). On this base individual flange data sheets can be provided to the flange fitter teams that include all necessary information for assembly of each BFC (bolts, nuts, gasket, geometry and material specifications, lubricant, etc.).

Terrestrial Distribution of 14C in the Vicinity of Qinshan Nuclear Power Plant, China

Radiocarbon ◽  
2013 ◽  
Vol 55 (1) ◽  
pp. 59-66 ◽  
Author(s):  
Zhongtang Wang ◽  
Yuanyi Xiang ◽  
Qiuju Guo
Keyword(s):  
Power Plant ◽  
Nuclear Power Plant ◽  
Nuclear Power ◽  
Specific Activity ◽  
Background Level ◽  
Food Samples ◽  
Pine Needles ◽  
Activity Levels ◽  
Heavy Water Reactor ◽  
Rice Samples

We used accelerator mass spectrometry (AMS) to study radiocarbon-specific activity levels in agricultural and botanical samples (moss and pine needles) distributed within a 6.5-km radius of the Qinshan Nuclear Power Plant (NPP). The 14C-specific activity in moss samples (ranging from 265.6 to 223.0 Bq/kg C) decreased with increased distance from the stacks of Plant III (heavy water reactor) and reached the background level (223.8 Bq/kg C) at 6.5 km distance. Compared to the pine needles, the moss was a better indicator for investigating the 14C distribution near Qinshan NPP. The 14C-specific activity distribution in moss samples showed that the diffusion of 14C discharged from the Qinshan NPP was affected by both geographical and meteorological factors. Excess 14C-specific activity in the food samples ranged from 8.5 to 13.0 Bq/kg C (except for rice samples), resulting in a minimal radiation dose of 0.5 μSv per year to the public.

scholarly journals Historic Perspective on the Conversations to Restart the Kashiwazaki-Kariwa Nuclear Power Plant

2021 ◽  
Vol 10 (29) ◽  
pp. 147-172
Author(s):  
Andrea Carolina Ávalos Salgado ◽  
Keyword(s):  
Power Plant ◽  
Nuclear Power Plant ◽  
Nuclear Power ◽  
Nuclear Energy ◽  
Local Community ◽  
Nuclear Facilities ◽  
The Public ◽  
Before And After ◽  
The Government

Following the accident of Fukushima in 2011, nuclear facilities in Japan were shut down, and a new evaluation and restart process was developed. Despite the public safety concerns, the current administration expects nuclear energy to become a pillar for economic recovery in the coming years. This paper compares the historic context of restarting Kashiwazaki-Kariwa Nuclear Power Plant before and after Fukushima. The evolution is analyzed through a series of interviews in 2012 and 2013 in the community and with government officers, as well as a close follow-up of the official statements by TEPCO and the government agencies up until the end of 2020. It tackles the development in the relation between TEPCO, local authorities, and local community of this nuclear plant, before and after Fukushima. This historic relation has shown to be the key element in the restart process, even above the legal process.

scholarly journals Assessment of Adequate Margin to Liquefaction for Nuclear Power Plants

2018 ◽  
Vol 2018 ◽  
pp. 1-7 ◽  
Author(s):  
Tamás János Katona
Keyword(s):  
Power Plant ◽  
Nuclear Power Plant ◽  
Nuclear Power ◽  
Power Plants ◽  
Ground Acceleration ◽  
Design Basis ◽  
Essential Question ◽  
Radioactive Release ◽  
Adequate Margin

Design of nuclear power plant shall provide an adequate margin to protect items ultimately necessary to prevent an early large radioactive release in the case of earthquakes exceeding those considered in the design. An essential question is how large the margin should be to be accepted as adequate. In the practice, depending on the country regulation, a plant margin of at least 1.4 or 1.67 times the design basis peak ground acceleration is required to be demonstrated. The catastrophe at the Fukushima Daiichi Nuclear Power Plant revealed the fundamental experience that the plants designed in compliance with nuclear standards can survive the effects of the vibratory ground motion due to disastrous earthquake but may fail due to effects of phenomena accompanying or generated by the earthquakes. Liquefaction is one of those secondary effects of beyond-design basis earthquakes that should be investigated for NPPs at soil sites. However, the question has not been investigated up to now, whether a “margin earthquake”, vibratory effects of which the plant can withstand thanks to design margin, will not induce liquefaction at soil sites and will not result in loss of safety functions. In the paper, a procedure is proposed for calculation of the probability and margin to liquefaction. Use of the procedure is demonstrated on a case study with realistic site-plant parameters. Criteria for probability for screening and acceptable probabilistic margin to liquefaction are proposed. The possible building settlement due to margin earthquake is also assessed.

Recent Developments in D&D of Nuclear Facilities in Spain

2001 ◽  
Author(s):  
Juan L. Santiago ◽  
Sergio Vidaechea
Keyword(s):  
Power Plant ◽  
Nuclear Power Plant ◽  
Radioactive Waste ◽  
Nuclear Power ◽  
International Level ◽  
Final Phase ◽  
Nuclear Facilities ◽  
Recent Developments ◽  
Leading Position ◽  
Key Issues

Abstract Spain occupies a leading position at international level in the field of installation decommissioning. Decommissioning projects have already been performed in relation to uranium mills, the rehabilitation of disused uranium mines is currently in the final phase and the dismantling of the Vandellós-I Nuclear Power Plant is now under way. On the basis of this experience, this paper describes the key issues in decommissioning technology and presents the approaches adopted by ENRESA to tackle the decommissioning strategy in Spain. In particular practical dismantling and decontamination methods are described, and material and radioactive waste management are discussed.

Maximizing Value of Existing Nuclear Power Plant Generating Assets: A Case Study

2007 ◽  
Author(s):  
Komandur S. Sunder Raj
Keyword(s):  
Power Plant ◽  
Nuclear Power Plant ◽  
Nuclear Power ◽  
Fossil Fuels ◽  
Nuclear Facilities ◽  
Operation Performance ◽  
Generating Capacity ◽  
Greenhouse Effects ◽  
And Performance

The nuclear power industry is presently witnessing a renaissance. Global warming, greenhouse effects, concerns with use of as well as rising costs of fossil fuels, the desire to be weaned from foreign oil are all factors driving the need for increased reliance on nuclear power. Consequently, nuclear power plant owners are seeking to maximize the value of their generating assets through various means: improved operation, performance, capacity, availability, reliability and efficiency; license renewals, and; power uprates. Capacity factors are currently averaging well over 90% and, forced outage rates have decreased significantly, reflecting the maturation of operating and maintenance practices. In recognition of low fuel and relatively stable operating costs of their nuclear facilities, nuclear power plant owners have not only applied for license renewals, but have also upgraded the operation and, added electrical generating capacity to the operating units. Using a case study, this paper describes current efforts in maximizing the value of existing nuclear power plant generating assets. The focus of the paper is on maximizing benefits through improved operations and performance.

Analysis of temporal variations of Cs-137 discharge inventory from the port of Fukushima Daiichi Nuclear Power Plant over 9 years after the accident

2020 ◽  
Author(s):  
Susumu Yamada ◽  
Masahiko Machida ◽  
Ayako Iwata ◽  
Shigeyoshi Otosaka ◽  
Takuya Kobayashi ◽  
...  
Keyword(s):  
Power Plant ◽  
Nuclear Power Plant ◽  
Nuclear Power ◽  
Estimation Method ◽  
Coastal Region ◽  
Temporal Variations ◽  
Contaminated Water ◽  
Reactor Unit ◽  
Run Off ◽  
Fukushima Daiichi

<p>Just after Fukushima Daiichi Nuclear Power Plant (1F) accident occurred in March 2011, the direct discharges of highly-contaminated water from reactor Unit 2 and 3 into the 1F port followed. After the suppressions of the direct discharges, Kanda (Biogeosci. 10, 6107–6113, 2013) suggested that relatively small amounts of run-off of a radionuclide (Cs-137) from 1F port into Fukushima coastal region has continued based on his estimation method. However, Kanda’s estimation period was limited up to September 2012. Therefore, we expand the estimation period of the discharged inventory up to very recently, March 2020 with significant accuracy improvements by the present authors. As a result, we find that totally, in the period over 9 years, the discharged inventory has gradually diminished together with various characteristic fluctuations. In this presentation, we analyze the observed diminishing trends with temporal fluctuations and discuss their relationships with various suppression measures and constructions toward decommissioning of 1F. Furthermore, we estimate the annual discharged amount of Cs-137 and evaluate its impacts on the coastal area in terms of seawater concentrations.</p>

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