20.500.12556/DKUM-58515 Preveritev in posodobitev izgorevanja goriva z uporabo ISOlib knjižnice v CORD-2 programu Validation and modification of fuel burnup with the use of ISOlib library in the CORD-2 program Na Inštitutu Jožef Stefan se računalniški paket CORD-2 uporablja za preračune sredice lahkovodnih reaktorjev. CORD-2 se uporablja že od leta 1990 in je bil že večkrat verificiran za izdelavo projektnih izračunov Nuklearne elektrarne Krško. V ta namen smo znotraj doktorskega dela razvili postopke, s katerimi smo zamenjali obstoječi WIMSD-5B transportni modul za celični izračun z Monte Carlo programom Serpent 2. Razvili smo postopek efektivne homogenizacijske metode (EDH) za izračun presekov na modelu osnovne celice, ki se trenutno uporablja v CORD-2 programskem paketu. Z uporabo novega računskega orodja Serpent-GNOMER smo preverili izvedbo projektnih izračunov za Nuklearno elektrarno Krško. Izračune smo primerjali z eksperimentalnimi in vzporednimi CORD-2 preračuni, kjer smo opravili primerjavo ključnih parametrov. Rezultati analize so pokazali, da metoda Monte Carlo še ni primerna za rutinsko uporabo, lahko pa služi kot referenčna rešitev za preveritev determinističnih izračunov. CORD-2 obravnava zgorevanje goriva z uporabo predhodno generirane knjižnice izotopske sestave, tako imenovano knjižnico ISOlib. Le ta je generirana v odvisnosti od povprečnih obratovalnih pogojev med zgorevanjem. V trenutni verziji programa CORD-2 ne moremo upoštevati efekta hlajenja med remontom. Zato smo izpeljali faktorje hlajenja s katerimi izboljšamo izotopsko sestavo goriva. Izpeljali smo splošno obliko faktorjev, ki so odvisni od časa hlajenja, obogatitve goriva in končne zgorelosti goriva. Z uporabo empiričnih popravkov na enostavnem konzervativnem modelu dosežemo, da se razlika zaradi efekta hlajenja zmanjša. At the Jožef Stefan Institute the CORD-2 simulator is used for core design calculations of PWR's. The CORD-2 system has been validated for nuclear design calculations and has been used for the verification of the NPP Krško reload cores since 1990. New approach was developed where the existing WIMSD-5B code for lattice cell calculations was replaced with Monte Carlo code Serpent 2. The homogenization procedure was developed using the same methodology currently used in the CORD-2 system, namely the effective diffusion homogenization method (EDH), to obtain the cell homogenized cross sections and to use them in fuel assembly calculations. In this work the reactor core analysis of the Krško NPP has been performed using newly developed core simulator Serpent-GNOMER. The comparison versus measurements and CORD-2 calculations for the key core parameters is performed. The results indicate that replacing the present transport solver with a Monte Carlo solver is (still) out of the question for routine calculations but it can be treated as a reference case for validating and fine-tuning of the deterministic computational scheme. The treatment of burnup in CORD-2 is based on a predefined library of isotopic composition vectors called the ISOlib library. This library is constructed as a function of average fuel assembly operating conditions during burnup. Changes in the isotopic composition during outage were not accounted for in the original CORD-2 calculations. The cooling factor method was developed to improve the prediction of the isotopic composition. Derived cooling factors are in general form and they are dependent on cooling period, fuel enrichment and final burnup. We have demonstrated that derived corrections diminish the error in the calculated reactivity for a simple geometry model which represents the conservative approach. Monte Carlo homogenizacija deterministični pomnoževalni faktor porazdelitev moči izotopska sestava reaktorski izračuni računalniški programi hlajenje goriva zgorevanje goriva tlačnovodni lahkovodni reaktor Monte Carlo homogenization deterministic multiplication factor power distribution isotopic composition reactor calculations computer codes fuel cooling fuel burnup pressurized light water reactor true true false [D. Ćalić] Slovenski jezik Angleški jezik Doktorsko delo/naloga 2016-04-21 08:33:15 2016-08-31 08:24:52 2022-06-17 03:06:19 2019-07-11 10:42:24 2016 0 Maribor 0 0000-00-00 NiDoloceno NiDoloceno NiDoloceno 0000-00-00 0000-00-00 0000-00-00 [004.4:536.911]:621.039.524.44(043.3) 19753750 URN:SI:UM:DK:EUGDGJKJ DOK_Calic_Dusan_2016.pdf DOK_Calic_Dusan_2016.pdf 1 64AF1AC320C00C5B3E856D41E45079E9 813219e01946b39c54ea00ab3d430c7033bbb60807a87d15bc0b8ad8ce780330 297a61e1-7c0d-11eb-bb7a-00155d0001ca https://dk.um.si/Dokument.php?lang=slv&id=100616 Fakulteta za gradbeništvo, prometno inženirstvo in arhitekturo 0 0 0