Safety Feature of EU-ABWR for Fukushima Accident

2014 ◽  
Author(s):  
Kazuhiro Kamei ◽  
Masatomo Kuroda ◽  
Yoshihiro Kojima ◽  
Kazuki Yano
Keyword(s):  
Severe Accident ◽  
Fukushima Accident ◽  
Safety Feature ◽  
Active Systems ◽  
Safety Requirements ◽  
Diversity Principle ◽  
European Nuclear ◽  
Safety Features ◽  
Safety Systems ◽  
The Eu

European Advanced Boiling Water Reactor (EU-ABWR) is developed by Toshiba. EU-ABWR accommodates an armored reactor building against Airplane Crash, severe accident mitigation systems, the N+2 principle in safety systems, the diversity principle and a large output of 1600 MWe. These features enable EU-ABWR’s design objectives and principles to be consistent with the safety requirements of Western European Nuclear Regulators’ Association (WENRA) and Finnish YVL guides. By designing safety features of the EU-ABWR based on Defense in Depth Principle, EU-ABWR has a capability to mitigate Design Extension Conditions like Fukushima Accident by using a combination of passive and active systems. Furthermore, a severe accident is mitigated passively without containment venting for at least 72 hours.

scholarly journals Simulation of a Station Blackout Accident for the SMART Using the CINEMA Code

2020 ◽  
Vol 8 ◽  
Author(s):  
Hyoung Tae Kim ◽  
Jin Ho Song ◽  
Rae-Joon Park
Keyword(s):  
Nuclear Power ◽  
Power Plants ◽  
Hydrogen Generation ◽  
Alternate Current ◽  
Reactor Vessel ◽  
Severe Accident ◽  
Fukushima Accident ◽  
Active Safety Systems ◽  
Station Blackout ◽  
Safety Systems

SMART is a small-sized integral type PWR containing major components within a single reactor pressure vessel. Advanced design features implemented into SMART have been proven or qualified through experience, testing, or analysis according to the applicable approved standards. After Fukushima accident, a rising attention is posed on the strategy to cope with a Station Blackout (SBO) accident, which is one of the representative severe accidents related to the nuclear power plants. The SBO is initiated by a loss of all offsite power with a concurrent failure of both emergency diesel generators. With no alternate current power source, most of the active safety systems that perform safety functions are not available. The purpose of SBO analysis in this paper is to show that the integrity of the containment can be maintained during a SBO accident in the SMART (System-integrated Modular Advanced ReacTor). Therefore, the accident sequence during a SBO accident was simulated using the CINEMA-SMART (Code for INtegrated severe accidEnt Management and Analysis-SMART) code to evaluate the transient scenario inside the reactor vessel after an initiating event, core heating and melting by core uncovery, relocation of debris, reactor vessel failure, discharge of molten core, and pressurization of the containment. It is shown that the integrity of the containment can be maintained during a SBO accident in the SMART reactor. It has to be mentioned that the assumptions used in this analysis are extremely conservative that the passive safety systems of PSIS and PRHRS were not credited. In addition, as ANS73 decay heat with 1.2 multiplier was used in this analysis, actual progression of the accident would be much slow and amount of hydrogen generation will be much less.

A Post Accident Safety Analysis Report of the Fukushima Accident — Future Direction of Evacuation: Lessons Learned

2013 ◽  
Author(s):  
Genn Saji
Keyword(s):  
Nuclear Power ◽  
Source Term ◽  
Cooling System ◽  
Lessons Learned ◽  
Effective Distance ◽  
Fukushima Accident ◽  
Station Blackout ◽  
Future Direction ◽  
Safety Features ◽  
Safety Systems

In nuclear safety, the source term is introduced to provide adequate isolation of the nuclear hazards from the public, by establishing a concept of ‘effective distance.’ This combines a geographical distance to the site boundary and an effective ‘distance’ with the use of engineered safety features (i.e., a containment system and its cooling system), combined with evacuation procedures to prevent radiation injury. Severe accidents occur when these safety systems failed to function. This basic safety approach was once again jeopardized by the Fukushima accident, which followed the Chernobyl accident. The factors that mitigated the effluent releases however depend greatly on the intrinsic safety features combined with the accident management. The multi-layered retention/decontamination factors that a nuclear power plant possesses should be incorporated in specifying the environmental source term. The Fukushima accident provides a reasonable upper bound with respect to environmental releases due to a LUHS (loss of ultimate heat sink), which triggered a prolonged SBO (station blackout). Due to the anticipated radiological consequences, the Japanese Government issued a series of evacuation orders, resulting in the evacuation of approximately 160,000 people from the Fukushima area. The prolonged evacuation is believed to be the cause of over one thousand “disaster-related (pre-mature) deaths (DRDs)” which have been reported among the evacuees due to psychosomatic effects (48%) and the disruption of medical and social welfare facilities (18%). In the future these types of deaths should be avoided.

Enhancement of Plant Availability by Outage Shortening in European Advanced Boiling Water Reactor (EU-ABWR)

2013 ◽  
Author(s):  
Kazuhiro Kamei ◽  
Kazuyoshi Kataoka ◽  
Kazuto Imasaki ◽  
Noboru Saito
Keyword(s):  
Boiling Water ◽  
Severe Accident ◽  
Boiling Water Reactor ◽  
Plant Availability ◽  
Control Rod ◽  
Water Reactor ◽  
Spray System ◽  
Maintenance And Inspection ◽  
Reactor Pool ◽  
Safety Systems

European Advanced Boiling Water Reactor (EU-ABWR) is developed by Toshiba. EU-ABWR accommodates an armored reactor building against Airplane Crash, severe accident mitigation systems, the N+2 principle in safety systems, the diversity principle and a large output of 1600 MWe. These features enable EU-ABWR’s design objectives and principles to be consistent with the requirements in the Finnish utility and the safety requirements of Finnish YVL guide. By adopting Scandinavian outage processes, the Plant Availability is aimed to be greater than 95%. ABWRs have an excellent design potential to acheive short outage duration (e.g., shortening of maintenance and inspection duration by applying Fine Motion Control Rod Drive and Reactor Internal Pump). In addition, the EU-ABWR applies following key design improvements to reduce a refueling outage duration; a) Direct Reactor Pressure Vessel (RPV) Head Spray System, b) Self-standing Control Rods and c) Water shielding reactor pool. In this paper, coolability of RPV due to application of the Direct RPV Head Spray System is also verified with numerical evaluations by Computation Fluid Dynamics (CFD) analysis.

scholarly journals FADEC Computer Systems for Safety Critical Application

1998 ◽  
Author(s):  
Friedrich Schwamm
Keyword(s):  
Fault Tolerant ◽  
Parallel Execution ◽  
Computer Design ◽  
Control Software ◽  
Computing Power ◽  
Safety Requirements ◽  
Engine Control System ◽  
Complex Functions ◽  
Hardware Overhead ◽  
Safety Features

One of the main requirements for modern FADEC systems is to implement great computing power with many interfaces and to keep the FADEC hardware effort to a minimum. On the other side the criticality potential of computer failures is considered as ‘hazardous’. The trend in FADEC development is to implement even more complex functions into the control software which consequently increases the authority and therefore the criticality potential of computer failures. In the mid 80’s a double computer system was used to performed a parallel execution of the control software with identical input parameters to output identical results. A difference in any one of these computer results causes the comparator hardware to output a failure indication. This was considered to have a 100% coverage of computer failures. The problem with this system was certainly the relatively large hardware overhead and the limited intelligence of the comparator logic. Some other FADEC systems have implemented only a Watch Dog Timer and Bus Access Supervisory hardware to detect computer malfunctions. With this method the proof for the achievements of the safety requirements have become almost impossible since adequate fault models of the computer components are difficult to establish due to their increasing functional complexity. This paper describes how to develop the safety features for the Computer Design from the Engine Control System Safety Requirements to achieve a full coverage of the potentially critical failure effects with fault tolerant failure recovery functions and a minimum of hardware overhead.

scholarly journals National Food Safety Systems in the European Union: A Comparative Survey

2013 ◽  
Vol 2 (1) ◽  
Author(s):  
Andreas Hadjigeorgiou ◽  
Elpidoforos S. Soteriades ◽  
Anastasios Philalithis ◽  
Anna Psaroulaki ◽  
Yiannis Tselentis ◽  
...  
Keyword(s):  
Risk Assessment ◽  
European Union ◽  
Food Safety ◽  
The European Union ◽  
Member States ◽  
Eu Member States ◽  
Comparative Survey ◽  
Safety Systems ◽  
Central Level ◽  
The Eu

This paper is a comparative survey of the National Food Safety Systems (NFSS) of the European Union (EU) Member-States (MS) and the Central EU level. The main organizational structures of the NFSS, their legal frameworks, their responsibilities, their experiences, and challenges relating to food safety are discussed. Growing concerns about food safety have led the EU itself, its MS and non-EU countries, which are EU trade-partners, to review and modify their food safety systems. Our study suggests that the EU and 22 out of 27 Member States (MS) have reorganized their NFSS by establishing a single food safety authority or a similar organization on the national or central level. In addition, the study analyzes different approaches towards the establishment of such agencies. Areas where marked differences in approaches were seen included the division of responsibilities for risk assessment (RA), risk management (RM), and risk communication (RC). We found that in 12 Member States, all three areas of activity (RA, RM, and RC) are kept together, whereas in 10 Member States, risk management is functionally or institutionally separate from risk assessment and risk communication. No single ideal model for others to follow for the organization of a food safety authority was observed; however, revised NFSS, either in EU member states or at the EU central level, may be more effective from the previous arrangements, because they provide central supervision, give priority to food control programs, and maintain comprehensive risk analysis as part of their activities.

scholarly journals Perspectives on a Severe Accident Consequences—10 Years after the Fukushima Accident

2021 ◽  
Vol 2 (4) ◽  
pp. 398-411
Author(s):  
Jinho Song
Keyword(s):  
Nuclear Reactor ◽  
Severe Accident ◽  
Accident Analysis ◽  
Fukushima Accident ◽  
The Public ◽  
Analysis Methodology ◽  
International Attention ◽  
Nuclear Reactor Safety ◽  
Term Monitoring

Scientific issues that draw international attention from the public and experts during the last 10 years after the Fukushima accident are discussed. An assessment of current severe accident analysis methodology, impact on the views of nuclear reactor safety, dispute on the safety of fishery products, discharge of radioactive water to the ocean, status of decommissioning, and needs for long-term monitoring of the environment are discussed.

scholarly journals The Fukushima accident was preventable

2015 ◽  
Vol 373 (2053) ◽  
pp. 20140379 ◽  
Author(s):  
Costas Synolakis ◽  
Utku Kânoğlu
Keyword(s):  
Emergency Preparedness ◽  
Nuclear Power ◽  
Hazard Analysis ◽  
Severe Accident ◽  
Regulatory Structure ◽  
Fukushima Accident ◽  
Critical Facilities ◽  
Safety Studies ◽  
New Research ◽  
Large Earthquakes

The 11 March 2011 tsunami was probably the fourth largest in the past 100 years and killed over 15 000 people. The magnitude of the design tsunami triggering earthquake affecting this region of Japan had been grossly underestimated, and the tsunami hit the Fukushima Dai-ichi nuclear power plant (NPP), causing the third most severe accident in an NPP ever. Interestingly, while the Onagawa NPP was also hit by a tsunami of approximately the same height as Dai-ichi, it survived the event ‘remarkably undamaged’. We explain what has been referred to as the cascade of engineering and regulatory failures that led to the Fukushima disaster. One, insufficient attention had been given to evidence of large tsunamis inundating the region earlier, to Japanese research suggestive that large earthquakes could occur anywhere along a subduction zone, and to new research on mega-thrusts since Boxing Day 2004. Two, there were unexplainably different design conditions for NPPs at close distances from each other. Three, the hazard analysis to calculate the maximum probable tsunami at Dai-ichi appeared to have had methodological mistakes, which almost nobody experienced in tsunami engineering would have made. Four, there were substantial inadequacies in the Japan nuclear regulatory structure. The Fukushima accident was preventable, if international best practices and standards had been followed, if there had been international reviews, and had common sense prevailed in the interpretation of pre-existing geological and hydrodynamic findings. Formal standards are needed for evaluating the tsunami vulnerability of NPPs, for specific training of engineers and scientists who perform tsunami computations for emergency preparedness or critical facilities, as well as for regulators who review safety studies.

On Miner's Location in Underground Mines

2021 ◽  
pp. 80-83
Author(s):  
A.V. Novikov ◽  
K.V. Panevnikov ◽  
I.V. Pisarev
Keyword(s):  
Coal Mine ◽  
Coal Mines ◽  
Underground Mines ◽  
Mine Safety ◽  
National Standard ◽  
Positioning Systems ◽  
Safety Requirements ◽  
Safety Regulations ◽  
Mining Safety ◽  
Safety Systems

To ensure industrial and mining safety the established safety rules for coal mines envisage the use of a number of complexes and systems, combined into multifunctional safety systems. These automated systems provide for people to be involved in the management of technological processes. The purpose of this paper is to assess how the coal mine safety requirements are aligned with other regulatory documents as they apply to modern safety systems in coal mines. To achieve this goal, the personnel location (positioning) and emergency alert systems in coal mine workings are analyzed for compliance with the requirements of the national standard for multifunctional safety systems in coal mines. It is shown that the current requirements for positioning systems are met by systems that have high accuracy in determining the location coordinates of people. It is suggested that positioning systems of the zonal type should be either upgraded to increase the number of readout devices to bring them up to the requirements of safety regulations in coal mines or replaced.

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