نوع مقاله : مقاله پژوهشی

نویسندگان

1 گروه مهندسی هسته‌ای، دانشکده مهندسی مکانیک، دانشگاه شیراز، صندوق پستی: 84334-71946، شیراز ـ ایران

2 مرکز تحقیقات ایمنی، دانشگاه شیراز، صندوق پستی: 84334-71946، شیراز ـ ایران

10.24200/nst.2022.1455

چکیده

آنالیز درخت رویداد برای کمی کردن معیار ریسک فرکانس آسیب به قلب (CDF) و ارزیابی ریسک نیروگاه‌های هسته‌ای ناشی از وقوع رویدادهای آغازگر فرضی مختلف به کار گرفته می‌شود. جهت محاسبه این معیار، لازم است که حالت‌های مختلف عملکردی سیستم­های ایمنی  و اپراتور در برابر حادثه موردنظر، ارزیابی و تحلیل شوند. طبق مدارک ارزیابی ایمنی احتمالاتی رآکتور مورد نظر، محاسبه معیار فرکانس آسیب به قلب، توسط ابزارهای استاتیکی مانند درخت خطا و درخت رویداد استاتیکی انجام شده است. این روش، دینامیک حادثه و سناریوها را در نظر نگرفته و صرف عملکرد صحیح و ناصحیح سیستم‌های ایمنی و اپراتور را برای محاسبه فرکانس هر سناریو به کار می‌گیرد. در مقابل روش درخت رویداد دینامیکی، به‌طور هم‌زمان مدل‌های فیزیکی و احتمالاتی را برای تولید شاخه‌ها و سناریوها در درخت رویداد، محاسبه فرکانس وقوع سناریو، تعیین پروفایل زمانی آسیب به قلب و تغییرات زمانی پارامترهای فیزیکی نیروگاه برای هر سناریو به کار می‌گیرد. در این مقاله، ابتدا درخت رویداد دینامیکی برای حادثه SBOدر نیروگاه اتمی 446/V1000VVER- با استفاده از کدهای  5RELAP و RAVEN توسعه می‌یابد. سپس نتایج حاصل از آن با نتایج درخت رویداد استاتیکی مقایسه می‌گردد. نتایج نشان می‌دهد با توجه به فرضیات در نظر گرفته شده تعداد 3170 سناریو در درخت رویداد دینامیکی مورد ارزیابی قرار می‌گیرد، در حالی‌که در روش درخت رویداد استاتیکی تنها تعداد 33 سناریو از پیش تعیین شده مورد بررسی قرار می‌گیرد. هم‌چنین میزان فرکانس آسیب به قلب محاسبه شده در درخت رویداد استاتیکی و دینامیکی، به ترتیب 6-10×61/3 و 6-10×97/1 به ازای هر سال کارکرد رآکتور می‌باشد.

کلیدواژه‌ها

عنوان مقاله [English]

A comparison of static and dynamic event tree analyses for SBO accident in VVER-1000/V446 NPP

نویسندگان [English]

  • M.E. Amirsoltani 1 2
  • A. Pirouzmand 1 2
  • M.R. Nematollahi 1 2

1 Department of Nuclear Engineering, School of Mechanical Engineering, Shiraz University, P.O.BOX: 71946-84334, Shiraz - Iran

2 Department of Nuclear Engineering, School of Mechanical Engineering, Shiraz University, P.O.BOX: 71946-84334, Shiraz - Iran

چکیده [English]

Event tree analysis is applied to quantify the core damage frequency (CDF) and assess the risk of nuclear power plants (NPPs) resulting from various postulated initiating events. To calculate this criterion, it is necessary to generate the probable scenarios according to the function of safety systems and the operator's actions. The classical event tree is currently used in PSA analysis. This method does not consider the accident's dynamics and scenarios. It considers only the availability/unavailability of the safety system functions and the operator's actions to calculate the frequency of each scenario. In contrast, the dynamic event tree method applies physical and probabilistic models to generate branches in the event tree, calculate the frequency of each scenario, determine the time profile of core damage, and time variation of physical parameters of the NPP for each scenario. This paper develops the dynamic event tree for the SBO accident at the VVER-1000/V446 NPP using the RELAP5 and RAVEN codes. The results are then compared with the outputs of the classical event tree. The results show that according to the assumptions, 3170 scenarios are evaluated in the dynamic event tree, while only 33 predetermined scenarios are examined in the conventional event tree. The calculated core damage frequencies are 3.61×10-6 (yr-1) and 1.97×10-6 (yr-1) for conventional and dynamic event trees, respectively.

کلیدواژه‌ها [English]

  • Static Event Tree (ET)
  • Dynamic Event Tree (DET)
  • Station Black-Out (SBO) accident
  • VVER-1000/V446 NPP
  • RELAP5/mod3.2
  • Risk Analysis Virtual Environment (RAVEN)
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