Study of Station Blackout Accident Process in Taishan Nuclear Power Plant

2013 ◽  
Author(s):  
Yu Li ◽  
Huiyong Zhang ◽  
Yehong Liao ◽  
Jiming Lin ◽  
Dekui Zhan
Keyword(s):  
Power Plant ◽  
Nuclear Power Plant ◽  
Nuclear Power ◽  
Heat Removal ◽  
Final State ◽  
Primary Coolant ◽  
Station Blackout ◽  
Full Power ◽  
Diesel Generators

According to the design features of the nuclear power plant in Taishan, a station blackout (SBO) at full power is a complex sequence, induced by the loss of offsite power (LOOP) combined with the loss of the emergency diesel generators (EDGs). This paper shall be performed the deterministic safety analysis of SBO without PSA study, and it mainly analyzes an overheating event of primary coolant resulting in the temporary unavailability of the steam generators (SGs) feeding systems during the station blackout. The analysis of this accident is carried out using the CATHARE2 thermal hydraulic code. The analysis pointed out that the final state can be reached after the operator performs the main manual actions such as startup of the SBO diesel generators from the main control room; startup of the two ASG pumps of trains 1 and 4; Local opening of the ASG header downstream the ASG pumps to enable the two power supplied ASG pumps to feed all the four SGs; initiation of a manual cooldown via the VDA in order to ensure the long term protection of the RCP pumps seals with respect to the thermal and mechanical loads. It corresponds to the achievement of a stable heat removal conditions by the emergency feedwater system (ASG) and the atmospheric steam dump system (VDA).

Study on the SBO Coping Capability for Qinshan Phase II Unit 3

2013 ◽  
Author(s):  
Jian Deng ◽  
Bin Chen ◽  
Chunrui Deng ◽  
Ming Zhang
Keyword(s):  
Power Plant ◽  
Nuclear Power Plant ◽  
Nuclear Power ◽  
Heat Removal ◽  
Event Tree ◽  
Natural Event ◽  
Core Damage ◽  
Battery Capacity ◽  
Station Blackout

The accident in Japan on March 2011 was caused by a natural event (i.e., earthquake, and the induced tsunami) which was far more severe than the design basis for the Fukushima Dai-ichi nuclear power plant. The reactor cores of Dai-ichi unit 1 through 3 have been degraded due to the long term station blackout (SBO). Actually, a nuclear power plant is able to prevent the core damage despite the SBO event occurs, called “coping capability” or “coping time”. In this paper, the SBO coping capability is assessed for Qinshan II unit 3 based on the following: 1) reactor coolant inventory, 2) condensate inventory for decay heat removal, 3) class 1E battery capacity, 4) compressed air, 5) effects of loss of ventilation, 6) containment isolation. As a result, the SBO event tree is suggested to be updated and a few vulnerabilities have been identified and some modifications are proposed.

scholarly journals Effect of Coolant Inventories and Parallel Loop Interconnections on the Natural Circulation in Various Heat Transport Systems of a Nuclear Power Plant during Station Blackout

2008 ◽  
Vol 2008 ◽  
pp. 1-11 ◽  
Author(s):  
Avinash J. Gaikwad ◽  
P. K. Vijayan ◽  
Sharad Bhartya ◽  
Kannan Iyer ◽  
Rajesh Kumar ◽  
...  
Keyword(s):  
Power Plant ◽  
Nuclear Power Plant ◽  
Heat Transport ◽  
Nuclear Power ◽  
Natural Circulation ◽  
Heat Removal ◽  
Transport Systems ◽  
Critical Examination ◽  
Decay Heat ◽  
Station Blackout

Provision of passive means to reactor core decay heat removal enhances the nuclear power plant (NPP) safety and availability. In the earlier Indian pressurised heavy water reactors (IPHWRs), like the 220 MWe and the 540 MWe, crash cooldown from the steam generators (SGs) is resorted to mitigate consequences of station blackout (SBO). In the 700 MWe PHWR currently being designed an additional passive decay heat removal (PDHR) system is also incorporated to condense the steam generated in the boilers during a SBO. The sustainability of natural circulation in the various heat transport systems (i.e., primary heat transport (PHT), SGs, and PDHRs) under station blackout depends on the corresponding system's coolant inventories and the coolant circuit configurations (i.e., parallel paths and interconnections). On the primary side, the interconnection between the two primary loops plays an important role to sustain the natural circulation heat removal. On the secondary side, the steam lines interconnections and the initial inventory in the SGs prior to cooldown, that is, hooking up of the PDHRs are very important. This paper attempts to open up discussions on the concept and the core issues associated with passive systems which can provide continued heat sink during such accident scenarios. The discussions would include the criteria for design, and performance of such concepts already implemented and proposes schemes to be implemented in the proposed 700 MWe IPHWR. The designer feedbacks generated, and critical examination of performance analysis results for the added passive system to the existing generation II & III reactors will help ascertaining that these safety systems/inventories in fact perform in sustaining decay heat removal and augmenting safety.

scholarly journals Long-Term Aging of Chernobyl Fuel Debris: Corium and “Lava”

2021 ◽  
Vol 13 (3) ◽  
pp. 1073
Author(s):  
Bella Zubekhina ◽  
Boris Burakov ◽  
Ekaterina Silanteva ◽  
Yuri Petrov ◽  
Vasiliy Yapaskurt ◽  
...  
Keyword(s):  
Power Plant ◽  
Nuclear Power Plant ◽  
Mass Loss ◽  
Nuclear Power ◽  
Distilled Water ◽  
Chemical Alteration ◽  
Laboratory Conditions ◽  
Fukushima Daiichi ◽  
Important Basis

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).

scholarly journals 14C Release in Various Chemical Forms With Gaseous Effluents From the Paks Nuclear Power Plant

Radiocarbon ◽  
1989 ◽  
Vol 31 (03) ◽  
pp. 754-761 ◽  
Author(s):  
Ede Hertelendi ◽  
György Uchrin ◽  
Peter Ormai
Keyword(s):  
Power Plant ◽  
Nuclear Power Plant ◽  
Nuclear Power ◽  
Liquid Scintillation ◽  
Mean Value ◽  
Scintillation Counting ◽  
Pressurized Water ◽  
The Mean ◽  
Water Reactors

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.

scholarly journals Seismic safety evaluation during site selection for the nuclear power plants in Bangladesh

2018 ◽  
Vol 4 (4) ◽  
pp. 251-256 ◽  
Author(s):  
Sergey Shcheklein ◽  
Ismail Hossain ◽  
Mohammad Akbar ◽  
Vladimir Velkin
Keyword(s):  
Power Plant ◽  
Nuclear Power Plant ◽  
Nuclear Power ◽  
Power Plants ◽  
Nuclear Power Plants ◽  
Spent Nuclear Fuel ◽  
Heat Removal ◽  
Good Time ◽  
Diagnostics System ◽  
Seismic Impacts

Bangladesh lies in a tectonically active zone. Earlier geological studies show that Bangladesh and its adjoining areas are exposed to a threat of severe earthquakes. Earthquakes may have disastrous consequences for a densely populated country. This dictates the need for a detailed analysis of the situation prior to the construction of nuclear power plant as required by the IAEA standards. This study reveals the correlation between seismic acceleration and potential damage. Procedures are presented for investigating the seismic hazard within the future NPP construction area. It has been shown that the obtained values of the earthquake’s peak ground acceleration are at the level below the design basis earthquake (DBE) level and will not lead to nuclear power plant malfunctions. For the most severe among the recorded and closely located earthquake centers (Madhupur) the intensity of seismic impacts on the nuclear power plant site does not exceed eight points on the MSK-64 scale. The existing predictions as to the possibility of a super-earthquake with magnitude in excess of nine points on the Richter scale to take place on the territory of the country indicate the necessity to develop an additional efficient seismic diagnostics system and to switch nuclear power plants in good time to passive heat removal mode as stipulated by the WWER 3+ design. A conclusion is made that accounting for the predicted seismic impacts in excess of the historically recorded levels should be achieved by the establishment of an additional efficient seismic diagnostics system and by timely switching the nuclear power plants to passive heat removal mode with reliable isolation of the reactor core and spent nuclear fuel pools.

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