Accident Management Actions in a Lower Head SBLOCA With HPSI Failed

2012 ◽  
Author(s):  
J. Gonzalez-Cadelo ◽  
C. Queral ◽  
J. Montero ◽  
J. C. Martinez-Murillo
Keyword(s):  
High Pressure ◽  
Time Delays ◽  
Safety Assessment ◽  
Nuclear Safety ◽  
Safety Issues ◽  
Management Actions ◽  
Accident Management ◽  
Lower Head ◽  
Emergency Operating ◽  
Present Emergency

In the framework of CAMP and OECD/NEA ROSA projects a broad analysis of Lower Head SBLOCA with High Pressure Safety Injection (HPSI) unavailable in a Westinghouse PWR has been performed. The simulations have been performed with TRACE 5 patch1 and the selected methodology has been the Integrated Safety Assessment (ISA) methodology, developed by the Spanish Nuclear Safety Council (CSN), which allows obtaining the damage domain as a function of the operator actuation times. The objective of this work is to find the available time for accident management actions by means of ISA methodology. The main conclusions are that present emergency operating procedures are adequate for this kind of sequences and there is not necessary to modify them and also that, the ISA methodology is adequate to analyze safety issues that include time delays uncertainties.

scholarly journals Accident Management Actions in an Upper-Head Small-Break Loss-of-Coolant Accident with High-Pressure Safety Injection Failed

2011 ◽  
Vol 175 (3) ◽  
pp. 572-593 ◽  
Author(s):  
César Queral ◽  
Juan González-Cadelo ◽  
Gonzalo Jimenez ◽  
Ernesto Villalba
Keyword(s):  
High Pressure ◽  
Management Actions ◽  
Loss Of Coolant Accident ◽  
Accident Management ◽  
Loss Of Coolant

Some Applications of Piping Failure Database to Nuclear Safety Issues in Korea

2007 ◽  
Author(s):  
Sun Yeong Choi ◽  
Young Hwan Choi
Keyword(s):  
Safety Assessment ◽  
Nuclear Safety ◽  
Life Extension ◽  
Screening Criteria ◽  
Safety Issues ◽  
Event Frequency ◽  
New Strategy ◽  
Periodic Safety ◽  
Leak Before Break ◽  
Service Inspection

Korean applications of a piping failure database to some nuclear safety issues related to nuclear piping such as a domestic initiating event frequency for a probabilistic safety assessment (PSA), an enhanced in-service inspection (ISI) program, a new strategy for the ISI program, leak before break (LBB) screening criteria, a risk-informed ISI (RI-ISI) program, and aging management for a periodic safety review (PSR) and/or a life extension are introduced in this study. By using a piping rupture frequency and a piping damage frequency obtained from a piping failure database, a domestic initiating frequency for a PSA, an enhanced ISI program, and a new strategy for an ISI are established. Some safety issues such as the LBB screening criteria, ISI program, RI-ISI program, and the aging management of nuclear piping are reviewed based on the information and insights obtained from a case-by-case analysis of the piping failure events in the piping failure database.

scholarly journals Resilience trinity: safeguarding ecosystem services across three different time horizons and decision contexts

2019 ◽  
Author(s):  
H Weise ◽  
H Auge ◽  
C Baessler ◽  
I Bärlund ◽  
E.M. Bennett ◽  
...  
Keyword(s):  
High Pressure ◽  
Ecosystem Services ◽  
Conceptual Framework ◽  
Network Architectures ◽  
Management Actions ◽  
Time Horizons ◽  
Resilience Thinking ◽  
Imminent Threat ◽  
Resilience Mechanisms ◽  
Term Management

AbstractEnsuring ecosystem resilience is an intuitive approach to safeguard future provisioning of ecosystem services (ES). However, resilience is an ambiguous concept and difficult to operationalize. Focusing on resilience mechanisms, such as diversity, network architectures or adaptive capacity, has recently been suggested as means to operationalize resilience. Still, the focus on mechanisms is not specific enough because the usefulness of a mechanism is context-dependent. We suggest a conceptual framework, resilience trinity, to facilitate management of resilience mechanisms in three distinctive decision contexts and time-horizons. i) reactive, when there is an imminent threat to ES resilience and a high pressure to act, ii) adjustive, when the threat is known in general but there is still time to adapt management, and iii) provident when time horizons are very long and the nature of the threats is uncertain, leading to a low willingness to act. This emphasizes that resilience has different interpretations and implications at different time horizons which however need to be reconciled. The inclusion of time into resilience thinking ensures that longer-term management actions are not missed while urgent threats to ES are given priority.

IO, Coagency, Intractability, and Resilience

2013 ◽  
pp. 342-352 ◽  
Author(s):  
Erik Hollnagel
Keyword(s):  
Safety Assessment ◽  
Assessment Methods ◽  
Resilience Engineering ◽  
Safety Issues ◽  
Technological Developments ◽  
Technical Systems ◽  
Integrated Operations ◽  
Circulus Vitiosus

Technological developments continuously create opportunities that are eagerly adopted by industries with a seemingly insatiable need for innovation. This has established a forceful circulus vitiosus that has resulted in exceedingly complicated socio-technical systems. The introduction of Integrated Operations in drilling and off-shore operations is one, but not the only, example of that. This development poses a challenge for how to deal with risk and safety issues. Where existing safety assessment methods focus on descriptions of component capabilities, complicated socio-technical systems must be described in terms of relations or even functional couplings. In order to design, analyse, and manage such systems, it must be acknowledged that performance adjustments are a resource rather than a threat. Safety can no longer be achieved just by preventing that something goes wrong, but must instead try to ensure that everything goes right. Resilience engineering provides the conceptual and practical means to support and accomplish that change.

scholarly journals Assessment of Severe Accident Management for Small IPWR under an ESBO Scenario

2019 ◽  
Vol 2019 ◽  
pp. 1-10 ◽  
Author(s):  
Hao Yu ◽  
Minjun Peng
Keyword(s):  
High Pressure ◽  
Low Pressure ◽  
Lower Pressure ◽  
Severe Accident ◽  
Maximum Temperature ◽  
Pressurized Water ◽  
The Core ◽  
Severe Accidents ◽  
Accident Management ◽  
Degradation Studies

Interest in evaluation of severe accidents induced by extended station blackout (ESBO) has significantly increased after Fukushima. In this paper, the severe accident process under the high and low pressure induced by an ESBO for a small integrated pressurized water reactor (IPWR)-IP200 is simulated with the SCDAP/RELAP5 code. For both types of selected scenarios, the IP200 thermal hydraulic behavior and core meltdown are analyzed without operator actions. Core degradation studies firstly focus on the changes in the core water level and temperature. Then, the inhibition of natural circulation in the reactor pressure vessel (RPV) on core temperature rise is studied. In addition, the phenomena of core oxidation and hydrogen generation and the reaction mechanism of zirconium with the water and steam during core degradation are analyzed. The temperature distribution and time point of the core melting process are obtained. And the IP200 severe accident management guideline (SAMG) entry condition is determined. Finally, it is compared with other core degradation studies of large distributed reactors to discuss the influence of the inherent design characteristics of IP200. Furthermore, through the comparison of four sets of scenarios, the effects of the passive safety system (PSS) on the mitigation of severe accidents are evaluated. Detailed results show that, for the quantitative conclusions, the low coolant storage of IP200 makes the core degradation very fast. The duration from core oxidation to corium relocation in the lower-pressure scenario is 53% faster than that of in the high-pressure scenario. The maximum temperature of liquid corium in the lower-pressure scenario is 134 K higher than that of the high-pressure scenario. Besides, the core forms a molten pool 2.8 h earlier in the lower-pressure scenario. The hydrogen generated in the high-pressure scenario is higher when compared to the low-pressure scenario due to the slower degradation of the core. After the reactor reaches the SAMG entry conditions, the PSS input can effectively alleviate the accident and prevent the core from being damaged and melted. There is more time to alleviate the accident. This study is aimed at providing a reference to improve the existing IPWR SAMGs.

Explore the Self-Governance on Nuclear Safety Emergency - A Case Study of the 3rd Nuclear Power Plant

2012 ◽  
Vol 260-261 ◽  
pp. 103-106
Author(s):  
Yi Chun Lin ◽  
Yung Nane Yang
Keyword(s):  
Power Plant ◽  
Nuclear Power Plant ◽  
Alternative Energy ◽  
Nuclear Power ◽  
Power Plants ◽  
Nuclear Power Plants ◽  
Nuclear Safety ◽  
Security Issue ◽  
Safety Issues ◽  
Plant Safety

The ripples of the tsunami crisis in Japan triggered introspections of nuclear plant safety issues in the worldwide. Many countries have claimed the suspension of nuclear power plants. However, some countries such as Taiwan, under nearly 99% energy is exported, the disasters force government and citizen to face the importance of nuclear safety, especially the neighborhoods nearby the nuclear power plants. We have to face the nuclear safety since there is no other alternative energy presently. The 3rd nuclear power plant located in the south of Taiwan, which has the same geographic features with Fukushima, Japan. Presently, there is no precedent in Taiwan of precaution and rescue team and civil supervised mechanic on nuclear security issue. This paper will review according to transparent information, public participation and cross-organization cooperation to propose the execution and work division principles, including information monitor, educational propagation, hide and evacuation, emergence aid and care, rear and refuge service. The ultimate target is to establish self-governance inside nearby neighborhood to confront nuclear disaster at the critical moment.

Studies on Safety Assessment Method for Operating License Extension of Nuclear Power Plants in China

2017 ◽  
Author(s):  
Zhilin Chen ◽  
Ping Huang ◽  
Chunhui Wang ◽  
Zhiyuan Chi ◽  
Fangjie Shi ◽  
...  
Keyword(s):  
Nuclear Power ◽  
Safety Assessment ◽  
Power Plants ◽  
Nuclear Power Plants ◽  
Assessment Method ◽  
Nuclear Safety ◽  
Management Systems ◽  
Effect Evaluation ◽  
Environment Effect ◽  
Assessment Environment

It’s the trend to extend the operating license time, called Operating License Extension (OLE) in China, of nuclear power plants (NPPs) in the future. It needs to be adequately demonstrated by licensees and approved by the regulator to gain an extended license time, such as 20 years. The demonstration methods for OLE are different among countries due to the different management systems for NPPs. Safety assessment, environment effect evaluation and update of the final safety analysis report (FSAR) will be the main aspects during OLE demonstration of NPPs in China according to the technical policy issued by National Nuclear Safety Administration (NNSA). Technical methods for scoping and screening, aging management review and time-limited aging analyses, which are the main contents of safety assessment are established based on the technical policy drafted by NNSA and international experiences in order to assist the operators to implement the safety assessment for OLE of NPP.

Ex-Vessel Coolability Analysis for a Belgian NPP

2009 ◽  
Author(s):  
Jarne R. Verpoorten ◽  
Miche`le Auglaire ◽  
Frank Bertels
Keyword(s):  
State Of The Art ◽  
The State ◽  
Severe Accident ◽  
Research Projects ◽  
Specific Data ◽  
The Core ◽  
Core Damage ◽  
Accident Management ◽  
Lower Head ◽  
Core Cooling

During a hypothetical Severe Accident (SA), core damage is to be expected due to insufficient core cooling. If the lack of core cooling persists, the degradation of the core can continue and could lead to the presence of corium in the lower plenum. There, the thermo-mechanical attack of the lower head by the corium could eventually lead to vessel failure and corium release to the reactor cavity pit. In this paper, it is described how the international state-of-the-art knowledge has been applied in combination with plant-specific data in order to obtain a custom Severe Accident Management (SAM) approach and hardware adaptations for existing NPPs. Also the interest of Tractebel Engineering in future SA research projects related to this topic will be addressed from the viewpoint of keeping the analysis up-to-date with the state-of-the art knowledge.

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