scholarly journals Long-Term Dynamics of Trophic State Indicators in Phytoplankton of the Cooling Reservoir of a Nuclear Power Plant

2021 ◽  
Vol 23 (1) ◽  
pp. 1-14
Author(s):  
Tatiana Novoselova ◽  
Sophia Barinova ◽  
Alexander Protasov

Abstract The dynamics of long-term indicators of trophicity in the cooling pond of a nuclear power plant in Ukraine was analyzed by phytoplankton biomass and bioindicators of trophicity. Greater species richness correlated with the number of species-indicators of greater trophicity. During the contourization processes caused by the introduction of filter-feeding mollusks and changes in the operating mode of the nuclear power plant, there was a decrease in the abundance of phytoplankton and trophic state. During decontourization, there was a sequential “return” of previously eliminated taxa and the restoration of the number of indicator species.

2021 ◽  
Vol 13 (3) ◽  
pp. 1073
Author(s):  
Bella Zubekhina ◽  
Boris Burakov ◽  
Ekaterina Silanteva ◽  
Yuri Petrov ◽  
Vasiliy Yapaskurt ◽  
...  

Samples of Chernobyl fuel debris, including massive corium and “lava” were collected inside the Chernobyl “Sarcophagus” or “Shelter” in 1990, transported to Leningrad (St. Petersburg) and stored under laboratory conditions for many years. In 2011 aged samples were visually re-examined and it was confirmed that most of them remained intact, although some evidence of self-destruction and chemical alteration were clearly observed. Selected samples of corium and “lava” were affected by static leaching at temperatures of 25, 90 and 150 °C in distilled water. A normalized Pu mass loss (NLPu) from corium samples after 140 days was noted to be 0.5 g/m2 at 25 °C and 1.1 g/m2 at 90 °C. For “lava” samples NLPu was 2.2–2.3 g/m2 at 90 °C for 140 days. The formation of secondary uranyl phases on the surface of corium and “lava” samples altered at 150 °C was confirmed. The results obtained are considered as an important basis for the simulation of fuel debris aging at Fukushima Daiichi nuclear power plant (NPP).


Radiocarbon ◽  
1989 ◽  
Vol 31 (03) ◽  
pp. 754-761 ◽  
Author(s):  
Ede Hertelendi ◽  
György Uchrin ◽  
Peter Ormai

We present results of airborne 14C emission measurements from the Paks PWR nuclear power plant. Long-term release of 14C in the form of carbon dioxide or carbon monoxide and hydrocarbons were simultaneously measured. The results of internal gas-proportional and liquid scintillation counting agree well with theoretical assessments of 14C releases from pressurized water reactors. The mean value of the 14C concentration in discharged air is 130Bqm-3 and the normalized release is equal to 740GBq/GWe · yr. > 95% of 14C released is in the form of hydrocarbons, ca 4% is apportioned to CO2, and <1% to CO. Tree-ring measurements were also made and indicated a minute increase of 14C content in the vicinity of the nuclear power plant.


2010 ◽  
Vol 99 (5) ◽  
pp. 639-648 ◽  
Author(s):  
B. Ya. Oskolkov ◽  
M. D. Bondarkov ◽  
S. P. Gaschak ◽  
A. M. Maksymenko ◽  
V. M. Maksymenko ◽  
...  

2020 ◽  
Vol 3 (1) ◽  
Author(s):  
Tatyana Novoselova ◽  
Anzhelika Sylaieva ◽  
Yuliya Gromova ◽  
Tanita Menshova ◽  
Irina Morozovskaya ◽  
...  

Author(s):  
Yasuyoshi Taruta ◽  
Satoshi Yanagihara ◽  
Takashi Hashimoto ◽  
Shigeto Kobayashi ◽  
Yukihiro Iguchi ◽  
...  

Abstract Decommissioning of Nuclear Power Plant is a long-term project during which generations are expected to change. Therefore, it is necessary to appropriately transfer knowledge, technology and skills to the next generation. In recent years, in the world of decommissioning, attempts have been made to apply advanced technologies such as utilization of knowledge management and digital technology. This study describes adaptation in decommissioning from viewpoint of utilizing IT technology called digital twin and aspect of knowledge management.


Author(s):  
Horst Rothenhöfer ◽  
Andreas Manke

The safety relevant components of nuclear power plant Neckarwestheim 1 — in service since 1976 — have been reviewed and updated for long-term operation (LTO). The actions included hardware retrofits as well as updates of analysis according to the latest state of the scientific and technical knowledge. For large piping such as the steam lines, the established pipes have been retained while the supports have been optimized. All shock absorbers (snubbers) including corresponding inertia have been eliminated resulting in a defined guidance and statically defined displacements. The integrity analyses for the optimized steam lines, including break preclusion, have been validated successfully with comprehensive measurements. The verification has delivered an extra high level of credibility, exceeding the “standard” requirements to achieve fitness for service in long-term operation. Measurement and validation, which are the main focus of this paper, range from monitoring of service loads to the static and dynamic measurements of pressure, local temperatures and displacements during initial start-up after implementation of the design modifications. The proper function of supports has been proved and the quality of the simulation models has been confirmed. Some expected and some unexpected dynamic events have been detected during blow-down tests. It was demonstrated that the amplitudes of all dynamic loads stay within limits. The validation of analyses with comprehensive measurement has been an important proof of quality and delivered the redundancy required for the integrity of a nuclear power plant in service, enhancing the high level of safety even more.


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