Metoda za analizu nesimetričnih kvarova u nuklearnim elektranama

doctoral thesis

• Title (english): Method for Analysis of Asymmetric Accidents in Nuclear Power Plants
• Author: Davor Grgić
• Mentor: Danilo Feretić (mentor)
• Committee member: Dubravko Pevec (član povjerenstva)
• Committee member: Danilo Feretić (član povjerenstva)
• Committee member: Željko Bogdan (član povjerenstva)
• Committee member: Neven Elezović (član povjerenstva)
• Committee member: Nikola Čavlina (član povjerenstva)
• Granter: University of Zagreb; Faculty of Electrical Engineering and Computing; (Department of Energy and Power Systems); Zagreb
• Defense date and country: 2001-10-30, Croatia
• Scientific / art field, discipline and subdiscipline: TECHNICAL SCIENCES; Electrical Engineering; Power Engineering
• Universal decimal classification (UDC): 621.3 - Electrical engineering

Abstract

Vezani trodimenzionalni neutronski i termohidraulički sistemski programi mogu unaprijediti točnost analiza reaktivnošću izazvanih akcidenata u slučajevima kad termohidrauličke povratne veze i utjecaj cijelog reaktorskog rashladnog sustava određuju brzinu nuklearnih reakcija. Vezani program je razvijen koristeći best-estimate termohidraulički sistemski program RELAP5/mod3.2, koji provodi termohidrauličku analizu za sve bitne komponente u postrojenju i uključuje realistični opis kontrolnih i zaštitnih sustava elektrane. Dva su programa korištena u neutronskom dijelu vezanog programa, coarse mesh trodimenzionalni neutronski difuzijski program QUABOX/CUBBOX–HYCA i trodimenzionalni nodalni difuzijski program PARCS. U vezanom programu RELAP5 računa sistemsku termohidrauliku, termohidrauliku i vođenje topline u srednjem kanalu reaktorske jezgre, dok QUABOX ili PARCS računaju samo 3D neutronsku kinetiku. Osnovni vezni moduli osiguravaju izmjenu podataka između neutronskog i termohidrauličkog dijela. Koristi se direktni eksplicitni tip povezivanja. RELAP5 ima vodeću ulogu u vezanom programu i odgovoran je za vremensku integraciju i organizaciju proračuna. Dodatno, razvijena je i verzija vezanog programa s subkanalnim modelom jezgre baziranim na programu COBRA. Sve tri verzije vezanog proračuna verificirane su na primjeru OECD TMI-1 MSLB benchmarka. Razvijena metoda za proračun asimetričnih akcidenata u reaktoru primjenjena je na HFP i HZP EOL analizu loma parovoda u NE Krško. Rezultati dobiveni vezanim proračunom demonstrirali su da lokalne povratne veze efikasno prigušuju porast snage za vrijeme akcidenta, rezultirajući u manjem povratku na snagu u odnosu na točkastu kinetiku.

Abstract (english)

Coupled three dimensional neutronic and thermal-hydraulic system codes can improve the accuracy of reactivity induced accidents analysis in cases where the thermal-hydraulic feedback effects and influence of whole reactor coolant system determines nuclear reaction rate. Coupled code is developed using best-estimate thermal-hydraulic system code RELAP5/mod3.2, which provides thermal-hydraulic analysis for all components in the plant and include realistic description of plant protection and control systems. Two codes were used as neutronic part of coupled code, coarse mesh three dimensional neutronic diffusion code QUABOX/CUBBOX–HYCA, and three dimensional neutronic nodal diffusion code PARCS. In the coupled code RELAP5 calculates system thermal hydraulics, average core channel thermal hydraulics and heat conduction while QUABOX, or PARCS, calculates only 3D neutron kinetics. Basic interface module provides the interchange of the data between the two codes. The direct explicit type of coupling is used. RELAP5 takes the leading role in the coupled code and it is responsible for time stepping and organization of the calculation. In addition, version of the coupled code with subchannel COBRA based thermal-hydraulic core model was developed. All three coupled code versions have been verified using OECD TMI-1 MSLB benchmark calculation. The developed method for asymmetric reactor accidents calculation was applied for NPP Krsko steam line break accident analysis at HFP and HZP EOL conditions. The results obtained with coupled code demonstrated that local feedback effects suppress fission power increase during accident, resulting in lower calculated global power compared to point kinetics case.

• Keywords: RELAP5; QUABOX; PARCS; COBRA; vezani program; trodimenzionalna kinetika; subkanalni program; nesimetrični tranzijenti; akcident loma parovoda; MSLB benchmark; best-estimate sigurnosne analize
• Keywords (english): RELAP5; QUABOX; PARCS; COBRA; coupled code; threedimensional kinetics; subchannel code; asymmetric transients; steam line break accident; MSLB benchmark; best-estimate safety analyses
• Language: croatian
• URN:NBN: urn:nbn:hr:168:815833
• Study programme: Title: Doctoral study programme "Electrical Engineering and Computing"; Study programme type: university; Study level: postgraduate; Academic / professional title: doktor/doktorica znanosti, po-dručje tehničkih znanosti (doktor/doktorica znanosti, po-dručje tehničkih znanosti)
• Type of resource: Text
• File origin: Born digital
• Access conditions: Closed access
• Created on: 2019-04-23 07:06:35