Metodologija proračuna okolišnih uvjeta bitnih za funkcionalnost električne opreme nakon teške nesreće nuklearnoga reaktora

doctoral thesis

• Title (english): Methodology for calculation of environmental conditions important for electrical equipment survivability after severe nuclear reactor accident
• Author: Štefica Vlahović
• Mentor: Davor Grgić (mentor)
• Committee member: Igor Kuzle (predsjednik povjerenstva)
• Committee member: Siniša Šadek (član povjerenstva)
• Committee member: Daniel Rolph Schneider (član povjerenstva)
• Granter: University of Zagreb; Faculty of Electrical Engineering and Computing; Zagreb
• Defense date and country: 2024-01-10, Croatia
• Scientific / art field, discipline and subdiscipline: TECHNICAL SCIENCES; Electrical Engineering
• Universal decimal classification (UDC): 621.3 - Electrical engineering

Abstract

Nakon nesreće u nuklearnoj elektrani Fukushima Daiichi sve je više pažnje usmjereno području dokazivanja izdržljivosti opreme (engl. Equipment Survivability). Kako bi se spriječile i ograničile posljedice oslobađanja radioaktivnog materijala u slučaju teške nesreće, imperativ je izbor opreme koji osigurava njezino preživljavanje i funkcionalnost u tom scenariju. Kako bi se odabrala odgovarajuća oprema, potrebno je poznavati okolišne uvjete na lokaciji gdje je ta oprema smještena. Razvijena je metodologija određivanja okolišnih uvjeta, koja na jednom mjestu objedinjuje sve scenarije teških nesreća i modelira specifičnosti zgrada i soba u nuklearnoj elektrani. Kad su ti podaci poznati, metodologija je sljedljiva i može se primijeniti na bilo koju nuklearnu elektranu korištenjem ekvivalentnih računalnih programa. Okolišni uvjeti koji se promatraju su tlak, temperatura, relativna vlažnost, kemijski sastav okoline i doze i brzine doza ionizirajućeg zračenja. U sklopu metodologije su razvijena i dva modela koja su bila potrebna za njenu implementaciju. Prvi model je model radijativne izmjena topline između čeličnog kontejnmenta i okolnih zgrada/prostorija s naglaskom na novi način numeričkog računanja vidnih faktora. Drugi model je model za određivanje realističnog radioaktivnog inventara jezgre i odgovarajućih aktivnosti i neutronskih i gama izvora potrebnih za računanje doza na opremu.
Metodologija je primijenjena na konkretan program dokazivanja izdržljivosti opreme u nuklearnoj elektrani Krško.

Abstract (english)

Research in the field of Equipment Survivability came into focus after the accident in the nuclear power plant Fukushima Daiichi. To prevent and limit the consequences of the radioactive release, it is necessary to choose equipment that is capable of surviving and operating during and after severe accident. In order to choose the appropriate equipment, one needs to know the environmental conditions at the location where the equipment is located. In this doctoral dissertation, the methodology for calculating environmental conditions was developed, which incorporates relevant severe accident scenarios and models of buildings and rooms in a nuclear power plant. Once these data are known, the methodology is tractable and can be applied to any nuclear power plant using comparable computer programs. The observed environmental conditions are pressure, temperature, relative humidity, chemical composition, doses and dose rates of ionizing radiation.
As part of the methodology, two models have been developed that were necessary for methodology implementation. The first one is a model of radiative heat exchange between the steel containment and the surrounding buildings/rooms with an accent on a new way of numerical calculation of view factors. The second one is a model for determining a realistic radioactive core inventory and the corresponding activities of both neutron and gamma sources that are needed to calculate doses to equipment.
The methodology has been applied to the program of Equipment Survivability in the nuclear power plant Krško.

• Keywords: teška nuklearna nesreća; dokazivanje opstojnosti opreme; kvalifikacija električne opreme; metodologija proračuna okolišnih uvjeta; nuklearni računalni program; radijativna veza; radioaktivni sadržaj jezgre
• Keywords (english): Severe accident; Equipment Survivability; Equipment Qualification; nuclear code; radiation heat transfer; source term
• Language: croatian
• URN:NBN: urn:nbn:hr:168:362076
• Promotion: 2024
• 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
• Extent: 143 str. : graf. prikaz
• File origin: Born digital
• Access conditions: Open access
• Created on: 2024-05-10 13:37:02