ABSTRAK
Keselamatan PLTN menjadi sangat penting dan utama, mengingat
kecelakaan pada PLTN Fukushima Dhaiichi Jepang (2011) akibat gempa bumi
dan tsunami yang berujung pada kegagalan sistem keselamatan aktif pada PLTN,
saat ini hampir semua PLTN di dunia memakai sistem keselamatan aktif, namun
dalam sistem keselamatan aktif memiliki kelemahan yaitu harus digunakannya
pompa dalam mengalirkan fluida sedangkan pompa harus dialiri listrik dari
generator, hal ini dapat menyebabkan kegagalan sistem keselamatan jika ada
kendala pada pompa maupun generator. Sistem keselamatan yang lebih aman
terus dikembangkan oleh para peneliti yaitu sistem pasif. sistem pasif atau
sirkulasi alamiah bekerja dengan memanfaatkan panas pada teras reaktor, hal ini
dikarenakan perbedaan kerapatan fluida selama melewati teras reaktor salah
satunya disebabkan oleh perbedaan temperatur serta sistem ini bekerja dengan dua
hukum fisika yaitu grafitasi dan buoyancy. Penelitian ini bertujuan untuk
menentukan laju aliran massa air di dalam pipa pada bagian heater menggunakan
data hubungan karakteristik perubahan temperatur TH-IN dan TH-OUT
berdasarkan variasi daya 174,4 watt – 1752 watt. Metode penelitian dilakukan
secara eksperimental menggunakan alat Untai FASSIP-01 Mod.1 yang merupakan
fasilitas eksperimen di Laboratorium Eksperimental Termohidrolika di Pusat
Teknologi dan Keselamatan Reaktor Nuklir (PTKRN) Badan Tenaga Nuklir
Nasional (BATAN), dengan variasi daya BCH-02 dari 174,4 watt sampai 1752
watt untuk setiap 15 menit pada tekanan 1,5 bar di RCS. Hasil penelitian
menunjukkan bahwa laju aliran massa air dengan variasi daya 2,27 watt diperoleh
laju aliran massa air sebesar 0,00090 [kg/s], daya 5,34 watt diperoleh 0,00113
[kg/s], daya 9,29 diperoleh 0,00116 [kg/s], daya 13,77 watt diperoleh 0,00104
[kg/s], dan daya 19,08 watt diperoleh 0,00102 [kg/s]. Stabilitas aliran sirkulasi
alam pada air di bagian heater terjadi dengan variasi daya pada eksperimen
membutuhkan waktu yang berbeda untuk mencapai kondisi aliran yang stabil.
Kata kunci: Keselamatan PLTN, sirkulasi alam, sistem pasif, laju aliran massa,
BCH-02, FASSIP-01Mod.1
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ABSTRACT
Safety of nuclear power plants is very important and important, considering the
accident at the Fukushima Dhaiichi Japan nuclear power plant (2011) due to the
earthquake and tsunami which led to the failure of an active safety system in
nuclear power plants, now almost all nuclear power plants in the world use active
safety systems, but in active safety systems has a disadvantage, that is, the pump
must be used to drain fluid while the pump must be electrified from the generator,
this can cause a failure of the safety system if there are obstacles to the pump or
generator. Safer safety systems continue to be developed by researchers, namely
passive systems. Passive or natural circulation systems work by utilizing heat on
the reactor core, this is due to differences in fluid density over the reactor core,
one of which is caused by temperature differences and this system works with two
laws of physics, namely gravity and buoyancy. This study aims to determine the
flow rate of the mass of water in the pipe on the heater section using data on the
characteristics of TH-IN and TH-OUT temperature changes based on variations
in power of 174.4 watts - 1752 watts. The research method was carried out
experimentally using the Strand FASSIP-01 Mod.1 tool which was an
experimental facility at the Thermohydrolical Experimental Laboratory at the
Nuclear Reactor (PTKRN) Technology and Safety Center of the National Nuclear
Energy Agency (BATAN), with variations in power BCH-02 from 174.4 watts to
1752 watts for every 15 minutes at a pressure of 1.5 bar on the RCS. The results
showed that the mass flow rate of water with a 2.27 watt power variation obtained
a water mass flow rate of 0,00090 [kg / s], a power of 5.34 watts was obtained
0.00113 [kg / s], power 9.29 was obtained 0.00116 [kg / s], 13.77 watts of power
are obtained 0.00104 [kg / s], and 19.08 watts of power are obtained 0.00102 [kg
/ s]. The stability of the natural circulation flow in the water in the heater section
occurs with power variations in the experiment requiring different times to
achieve stable flow conditions.
Keywords:
Safety of nuclear power plants, natural circulation, passive
systems, mass flow rates, BCH-02, FASSIP-01Mod.1.