1965 KB0 KB201320252024Avsec, JurijKelavić, Robertletnik:17številka:iss. 4str. 46-57ISSN:1855-5748COBISSID_HOST:228204803URN:URN:NBN:SI:doc-U0H12P2HenFakulteta za energetikoJournal of energy technologyfeedwater flow measurementfilm forming aminefilmski aminheat transferJedrske elektrarneKrško Nuclear Power Plantprenos toplotepretočni element venturijeve cevipretok napajalne vode merjenjeventuri flow elementFFA FW flow influence at NPP Krško| Vpliv FFA na meritev FW pretoka v NEK|The Krško Nuclear Power Plant (NEK) operates based on a Pressurised Water Reactor (PWR), which utilises three loops for heat transfer: primary, secondary, and tertiary. Heat generation occurs in the primary loop; steam production takes place in the secondary loop; and waste heat is discharged in the tertiary loop. During outages, which occur every 18 months, the secondary systems are exposed to the atmosphere, increasing the risk of corrosion. To prevent this, in 2021, the plant used a chemical solution, Film Forming Amine (FFA), which formed a protective hydrophobic layer on the inner surfaces of the pipelines. In March 2021, during the first use of FFA, deviations were observed in the main feedwater (FW) flow measurements. This affected the reactor power calculations, leading to a 0.4–0.5 % reduction in plant output (approximately 4 MWe). The main feedwater flow is a critical parameter for secondary calorimetric calculations, and has the largest impact on error in the event of deviations. The power reduction was confirmed by comparing various process parameters, including changes in the primary loop temperature differences (?T), main steam flow (MS), and generator output vs. condenser vacuum. Since the measurement of the main feedwater flow contributes the most to the uncertainty of primary flow and reactor calorimetric calculations, NEK is focused on improving its accuracy. Developing a numerical model in the computer-based programming environment is proposed as part of further research. This model would enable independent calculations of the main feedwater flow, to reduce the impact of the FFA chemicals on the measurement readout and its associated calculations. The model will be based on thermodynamic equations and algorithms for determining the flow with lower uncertainty than the current system. Using this model, correction factors should be obtained to adjust the current venturi meter readings. Ultimately, this approach will ensure better plant management, reduce energy losses, and increase revenues for NEK and its stakeholdersNuklearna elektrarna Krško (NEK) deluje na podlagi tlačnovodnega reaktorja (PWR), ki uporablja tri kroge za prenos toplote: primarni, sekundarni in terciarni. V primarnem krogu poteka proizvodnja toplote, v sekundarnem proizvodnja pare in odvajanje odpadne toplote v terciarnem. Med remonti, ki potekajo vsakih 18 mesecev, so sekundarni sistemi izpostavljeni atmosferi, kar povečuje tveganje za korozijo. Da bi to preprečili, je elektrarna leta 2021 uporabila kemično raztopino FFA (Film Forming Amine), ki je na notranjih površinah cevovodov tvorila zaščitni hidrofobni sloj. Marca 2021, ob prvi uporabi FFA, so se pojavila odstopanja pri meritvah pretoka glavne napajalne vode FW (Feedwater). To je vplivalo na izračun moči reaktorja in povzročilo upad zmogljivosti elektrarne za 0,4–0,5 % (približno 4 MWe). Pretok glavne napajalne vode je ključni parameter za sekundarni kalorimetrični izračun in ima največji vpliv na pogrešek v primeru odstopanja. Upad moči je bil potrjen s primerjavo različnih procesnih parametrov, kot so spremembe temperaturnih razlik v primarnem krogu (?T), s pretokom glavne pare (MS ? Main Steam) in meritvijo električne moči na generatorju. Ker meritev pretoka glavne napajalne vode prispeva največ k negotovosti izračuna pretoka primarnega sistema in kalorimetričnega izračuna sredice, smo v NEK osredotočeni na izboljšanje natančnosti te meritve. V sklopu nadaljnjega raziskovalnega dela se predlaga razvoj numeričnega modela v računalniško podprtem programskem okolju, ki bo omogočil neodvisen izračun pretoka glavne napajalne vode, z namenom zmanjšanja vpliva FFA kemikalije na meritev oziroma s tem povezane izračune moči reaktorja. Model bo temeljil na termodinamičnih enačbah in algoritmih za določanje pretoka z nižjo negotovostjo od sedanje. S pomočjo modela bi morali pridobiti korekcijske faktorje za prilagoditev trenutnih vrednosti venturijevih merilnikov. V končnici bo ta pristop zagotovil boljše upravljanje elektrarne, zmanjšal energetske izgube ter povečal prihodke za NEK in njene lastnikeTEXTznanstveno časopisjejournalsSlovenian National E-content AggregatorNational and University Library of SloveniaUniverza v Mariboru, Fakulteta za energetiko