Naslov nad sažetkom na eng. jeziku: Aging of power cables in nuclear power plant due to influence of local temperature conditions

Magistarski rad obranjen je 2011-11-29

Bibliografija: str. 113-114. - Popis kratica i oznaka. - Sažetak na eng. i hrv. jeziku. - Životopis

SAŽETAK: Značajan broj nuklearnih elektrana koje su trenutno u pogonu, približavaju se kraju početno predviđenog životnog vijeka. S obzirom da dobro rade i konkurentne su, postoji interes za produljenjem njihove eksploatacije. Prije produljenja životnog vijeka, potrebno je utvrditi da li starenju izložene komponente, strukture i sustavi mogu ispuniti svoje projektom predviđene funkcije. Kabeli su važna komponenta u sigurnosti nuklearne elektrane iako sami po sebi nemaju aktivnu sigurnosnu funkciju (prenose signale za indikaciju, kontrolne i upravljačke naredbe ili energiju električkoj opremi koja izvršava sigurnosnu funkciju). Posljedično, funkcionalnost kabela nužnih za nuklearnu sigurnost je osiguravanje funkcionalnosti opreme važne za nuklearnu sigurnost. Zbog toga se rad bavi programom upravljanja starenjem kabela čiji je cilj identificiranje mehanizama i efekata starenja, te utvrditi da li su degradacije uzrokovane starenjem unutar predviđenih dopuštenih granica kako bi se osigurao siguran rad elektrane. Također, u radu se posebno analizira utjecaj promjene temperature okoline na promjenu životne dobi kabela u odnosu na kvalificiranu životnu dob. Kao ilustracija, korištenjem Arrheniusovog modela izvršen je proračun za ocjenu starenja kabela na mjestu s lokalno povišenom temperaturom. - KLJUČNE RIJEČI: Struktura kabela, starenje kabela, uzročnici starenja, mehanizmi starenja, nuklearna elektrana, vođenje topline, metoda konačnih elemenata, Arrheniusov model/jednadžba, proračun ostatnog životnog vijeka

ABSTRACT: A significant number of operating nuclear power plants is approaching the end of the initially estimated design life. Considering that plants are stable and competitive, it may be possible to extend design lives to 60 years (perhaps even longer). Before expending life time, ageing in NPPs must be effectively managed to ensure the availability of design functions throughout the plant service life. From the safety perspective, this means controlling ageing degradation and wear-out within acceptable safety limits so that adequate safety margins remain, i.e. integrity and functional capability in excess of normal operating requirements. Even though cables are not active component, they are vital components in NPPs since they link the system components with instruments and control equipment used to monitor and control the plant. Consequently, the functionality of the cable necessary for nuclear safety is necessity for ensuring the functionality of equipment relevant to nuclear safety. Since the cable ageing have been recognized as potential threat to safe operation of NPP, this thesis deals with ageing management program aimed at identifying the mechanisms and effects of aging and to determine whether the degradation caused by aging is within the stipulated tolerance limits to ensure safe operation of power plants. Also, it analyses the impact of ambient temperature changes on the cable ageing comparing to a qualified life. For an illustration, Arrhenius’s model was used to calculate cable ageing in hot spot with the increased local temperature. - KEYWORDS: Cable structure, materials, cable aging, aging stressors, aging mechanism, nuclear power plant, heat transfer, Arrhenius, finite element method