Multiple Models Support in Probabilistic Safety Assessment Program RiskA (13033)
Shanqi CHEN, Jin WANG, Jiawen XU, Fang Wang, Liqin HU
Chinese Academy of Sciences
Probabilistic safety assessment (PSA) programs have been widely used for the fault tree analyses. However, the fault tree model formats of different programs are generally different, which will introduce difficulties in the comparison and verification among these PSA programs. RiskA, a reliability and probabilistic safety assessment program developed by FDS Team, can support multiple model formats of widely used PSA programs. Abundant benchmarks are tested and results are compared, which verified the accuracy and efficiency of the model conversion.
Design and Implementation of Probabilistic Safety Analysis Program B ased on C/S Architecture (13035)
Jiawen XU (1, 2), Jin WANG (1), Shanqi Chen (1, 2), Liqin HU (1, 2)
- Chinese Academy of Sciences,
- University of Science and Technology of China
Probability safety analysis (PSA) programs are necessary tools for the PSA analysis of large complicated systems. Architectur e is the basis of product software systems, the effectiveness and efficiency of the architect ure design determined the quality and performance of the product software. Most existing PSA software is standalone. In this paper, the design and implementation of the new Client/Server (C/S) architecture developed on the platform of PSA program RiskA will be introduced in detail. Combining with multilayer software system structure design method and integrating with module exploring idea, the new architecture can enhance reliability, efficiency and expandability of PSA software system.
The Andromeda Shell and Scripting Interface to Efficiently Treat PSA Models (12023)
Friedlhuber Thomas (1) , Mohamed Hibti (2), Antoine Rauzy (3)
- EdgeMind S.A.S, France,
- EDF R&D, France,
- Ecole Polytechnique, France
Working with large full scope PSA models may require appropriate to ols to browse the models, to allow their modication, documenta tion and to per form export/import and merge procedures that cover the needs of version management and validation processes of large PSA models or parts of them. In this paper we introduce a shell based language that provides appropriate shell commands to handle PSA models and allow scripting over PSA-Modules for systematic procedures and batch ope rations. This approach is based on an XML format between Scandpower RS-PSA format and the Open PSA Model Exchange Format.
The introduction of a shell based language reveals new efficient opportunities of automating any kind of procedures when working with PSA models. Scripts can be developed in a generic way, what all ows them to remain compact, readable and expressive at the same time. Their execution is reproducible, debug -able, testable and most important, ef ficient. Scripts can be considered for updating procedures (for instance for updating system fault trees when generated automatically via arti ficial intelligence tools), or for comparing and merging versions of a PSA models with divergent paths, for establishing the events cartography (to highlight dependencies over specifi c patterns), for revision and review procedures to allow easy and systematic and incremental search and validate procedures to ensure a better view of the nested structures within a PSA model and for easy documenting edition.
A Method to Compare PSA Models in a Modular PSA (12103)
Friedlhuber Thomas (1) , Mohamed Hibti (2), Antoine Rauzy (3)
- EdgeMind S.A.S, France,
- EDF R&D, France,
- Ecole Polytechnique, France
Most Probabilistic Safety Assessment (PSA) models are typically based on the fault tree and event tree approach . Since decades, these PSA models serve as important tool for safety demonstration and as support for regulatory issues. In some industries, for example in nuclear power plants, PSA models increased in size and complexity over the recent years as a consequence of the scope extension to external hazards, new applications and new requirements (due post-Fukushima insights and recommendations).
Therefore, for the purpose of quality assurance, it is worth to have a precise log of any model evolution s to guaranty compliance with standards and to ensure that models refl ect the reality of plants. However, in the database architecture of currently used PSA tools, only meta data information can be obtained concerning model modifi cations. Analysts (users), developers and reviewers may need to have deep insights on di fferent model transitions (set of modifi cations), and then go through details in order to verify and justify (for example to safety authorities) the set of modi fications applied to a PSA model. Currently, those activities are performed manually and can be time-consuming and error-prone since PSA models may contain dozens of thousands of model objects.
In this article, a method is presented to automatically compare PSA models. The method prov ides important feedback to model engineers for example to verify model modifications applied since an ancient model state, for checking or diagnosis purposes (for instance to understand the impact and importance o f individual model modi fications). Further, the result (the diff erences) can be used to automatically generate modifi cation reports to trace and justify model modifi cations. Finally, it can serve as preliminary step for the purpose of model fusion (the "combination" of models) w hich is an ultimate step to con current modeling. The comparison method has been implemented in Andromeda, a research software developed at EDF R&D to develop and test new modeling approaches in a so- called modular PSA". A modular PSA treats models by smaller pieces (the modules") what constitutes a crucial paradigm for the comparison method of this article.
Use of PSA M odel XML Standard Formats for V&V (12108)
Enrique Melendez Asensio Roberto Herrero Santos
Consejo de Seguridad Nuclear (Spain)
The Spanish Nuclear regulatory body (CSN) has implemented a regulatory system inspired by the USNRC Reactor Oversight Process (ROP). As such, the system makes use of PSA results and insights in several tasks. Inspection results are assessed by PSA quantification, determining the consequences of licensee performance deficiencies by mapping onto a PSA model any failures to comply with rules and regulations. A requantification of the model yields the impact of the performance deficiency in the plant risk. The outcome is used to t ake decisions on further regulatory actions. In addition, whenever applicable, inspection scope is driven by PSA importance, be it the baseline inspections or special inspections, reactive to events. This regulatory framework requires PSA information to be disseminated throughout the organization, even among non PSA experts. A web based information system has been brought up that presents PSA hypotheses, methods and results in a consistent manner for all Spanish plants. Inspectors have ready access to this information tool within CSN’s internal website. The information in the web based system stems from the licensees’ PSA models. Since the Spanish NPPs use several PSA codes, a common interface to feed the web base information system is required. T he OpenPSA initiative (http://www.open-psa.org/ ) proposed an XML standard format for PSA model exchange, dubbed OPSA -MEF. At CSN, an XML format derived from the OpenPSA work, suitable for the quantification tools used at CSN has been the choice. Mor eover, the OPSA-MEF is a platform for developing tools that convert PSA models between PSA codes, allowing the same model to be viewed, modified and quantified by different programs. This has been demonstrated by tools developed at CSN. Furthermore, as reg ulators, CSN staff need s independent views on licensee models. These can be best accomplished by in-house tools that perform batch checks for consistency of the models.