Analisis Eksperimental Fluks Kalor pada Celah Sempit Anulus Berdasarkan Variasi Suhu Air Pendingin Menggunakan Bagian Uji HeaTiNG-01

Eksperimen untuk mempelajari mekanisme perpindahan panas pendidihan pada celah sempit berdasarkan skenario kecelakaan parah PLTN TMI-2 perlu dilakukan untuk pemahaman terkait manajemen kecelakaan. Penelitian bertujuan untuk memperoleh nilai fluks kalor dan fluks kalor kritis (FKK) selama proses perpindahan panas pendidihan pada celah sempit anulus. Metode penelitian secara eksperimen menggunakan bagian uji HeaTiNG-01dengan fluida pendingin adalah air. Eksperimen dilakukan dengan memvariasikan suhu air pendingin pada suhu 75C, 85C dan 95C, dan memanaskan batang panas hingga mencapai suhu awal 650C. Kemudian proses pendidihan selama pendinginan direkam berdasarkan suhu transien pada batang panas. Data suhu digunakan untuk menghitung nilai fluks kalor dan wall superheat, hasilnya direpresentasikan melalui kurva didih. Hasil penelitian menunjukkan nilai FKK suhu pendingin 750C lebih rendah dibandingkan FKK suhu pendingin 85C dan 95C, dimana nilai FKK untuk suhu pendingin 85C dan 95C agak berdekatan. Nilai FKK maksimum untuk suhu 75C adalah 230 kW/m2, sedangkan untuk suhu 95C adalah 282 kW/m2. Meskipun demikian korelasi FKK terhadap posisi aksial batang panas pada berbagai variasi suhu mengikuti korelasi polynomial. Peristiwa pendidihan pada celah sempit tidak termasuk kategori didih kolam dengan membandingkan area didih film hasil eksperimen menggunakan korelasi Bromley. Kata kunci : kecelakaan parah, anulus, fluks kalor, FKK, celah sempit, didih kolam Experiment to investigate the mechanism of boiling heat transfer in a narrow gap on severe accident scenarios of TMI-2 nuclear power plant is necessary to develop the understanding of the related accident management.The present study aimed to obtain heat flux value and critical heat flux (CHF) during boiling heat transfer process in a narrow gap of annulus. The study was experimentally carried out using the HeaTiNG 01 test with water as cooling fluid which temperature was varied at 75C, 85C dan 95C. The rod was heated to 650C. The boiling process during cooling was investigated by recording the transient temperature of the heated rod. The data was used to calculate the heat flux and wall superheat which results were represented in a boiling curve. The experimental results showed that the CHF value of the cooling media at 75C was lower compared with that of at 85C and 95C. It was found that the values of CHF at 85C and 95C were close. The maximum CHF value at 75C was 230 kW/m2, while at 95C was 282 kW/m2. The CHF values at various position of heated rod was found to follow polynomial correlation. By comparing the boiling film areas from experimental results with that of Bromley correlation, it was concluded that boiling process in a narrow gap could not categorized as pool boiling process. Keywords: severe accident, annulus, heat flux, CHF, narrow gap, pool boilin