STUDY OF THERMAL HYDRAULICS PARAMETERS OF TRIGA RESEARCH REACTOR UNDER NATURAL CONVECTION MODE OF COOLANT FLOW USING NCTRIGA COMPUTER CODE
Abstract
Abstract
A thermal-hydraulic analysis of the TRIGA Mark II Research Reactor operating at 500 kW under natural convection conditions was conducted using the NCTRIGA code utilizing SRAC2006 neutronics data, and results were benchmarked against MCNP4C calculations. The study focused on evaluating key thermal-hydraulic parameters along the axial length of the hottest fuel rod (C4) to ensure the reactor's safety. The Reynolds number exhibited a consistent increase with axial height. Conversely, heat flux, heat transfer coefficient, and fuel centerline temperature demonstrated a similar trend: increasing from the top of the core, peaking near the midpoint, and subsequently decreasing. Notably, fuel centerline temperatures remained significantly below established safety limits. Fuel surface temperatures remained relatively constant, while coolant temperature demonstrated a slow, incremental increase along the axial length from the top. While minor discrepancies were observed between the SRAC2006 and MCNP4C datasets, the peak values and their locations remained consistent across both.
Abstrak
Analisis terma-hidraulik bagi Reaktor Penyelidikan TRIGA Mark II yang beroperasi pada 500 kW di bawah keadaan perolakan semula jadi telah dijalankan menggunakan kod NCTRIGA yang menggunakan data neutronics SRAC2006, dan keputusan telah ditanda aras terhadap pengiraan MCNP4C. Kajian ini memberi tumpuan kepada menilai parameter terma-hidraulik utama sepanjang panjang paksi rod bahan api terpanas (C4) untuk memastikan keselamatan reaktor. Nombor Reynolds menunjukkan peningkatan yang konsisten dengan ketinggian paksi. Sebaliknya, fluks haba, pekali pemindahan haba, dan suhu garis tengah bahan api menunjukkan arah aliran yang sama: meningkat dari atas teras, memuncak berhampiran titik tengah, dan seterusnya menurun. Terutama, suhu garis tengah bahan api kekal jauh di bawah had keselamatan yang ditetapkan. Suhu permukaan bahan api kekal secara relatifnya tetap, manakala suhu penyejuk menunjukkan peningkatan yang perlahan dan bertambah sepanjang paksi dari atas. Walaupun percanggahan kecil diperhatikan antara set data SRAC2006 dan MCNP4C, nilai puncak dan lokasinya kekal konsisten di kedua-duanya.
