Potensi bahaya reaktor riset lebih rendah dibandingkan reaktor daya. Namun sebahagian besar reaktor riset dibangun beberapa dekade lalu, dimana persyaratan desain belum sepenuhnya memenuhi persyaratan keselamatan sebagaimana halnya RSG-GAS yang sudah beroperasi selama 28 tahun dan berlokasi dekat dengan pemukiman penduduk. Sebagai masukan dari kecelakaan Fukushima perlu dilakukan pengkajian ulang analisis keselamatan RSG-GAS. Analisis keselamatan meliputi tahapan identifikasi potensi bahaya, mengkarakterisasi kejadian pemicu, menentukan probabilitas kegagalan dan mengukur konsekuensi. Penelitian ini hanya terbatas pada sistem pendingin primer. Kegagalan sistem primer dapat menimbulkan kejadian terparah, yaitu melelehnya bahan bakar reaktor. Berdasarkan identifikasi dan analisis bahaya pada sistem pendingin primer dengan menggunakan metode HAZID (Hazard Identification) dan HAZOP (Hazard and Operability Analysis) didapatkan lima kejadian pemicu yaitu: kehilangan pendingin karena kebocoran pipa pendingin primer area setelah katup isolasi, kehilangan pendingin karena pecahnya casing pompa karena kegagalan impeller, kehilangan pendingin karena kebocoran alat penukar panas, kehilangan aliran pendingin karena kegagalan pompa primer kehilangan aliran pendingin karena kegagalan katup isolasi primer. Setiap kejadian terdiri dari skenario sukses-gagal beberapa fungsi keselamatan yang tersedia, dan dihasilkan empat puluh delapan skenario dari ke lima kejadian yang ada. Menggunakan perangkat lunak Item ToolKit, disusun skenario kejadian terhadap sistem keselamatan yang tersedia menggunakan Metode Event Tree Analysis (ETA) dan didapatkan hasil probabilitas kejadian dengan nilai terbesar 5,12.10-6/tahun. Seluruh skenario berdasarkan CDF dan CDS, berada dalam kategori Medium Risk dan Low Risk, sehingga dapat dinyatakan bahwa reaktor aman untuk di operasikan.

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The research reactor has lower hazard potential than the power reactor. However, most research reactor was built a few decades ago, when the design requirement was not completely fulfilled the safety requirement as well as the Reaktor Serba Guna G. A Siwabessy (RSG - GAS) that has been operating for 28 years and located close to the housing resident. Learning from Fukushima accident, it is necessary to assess the safety analysis of RSG - GAS. The safety analysis including the identification of potential hazard, characterization of the postulated initiating event, determination of failure probability, and measuring the frequency.

This paper will be focused on the primary cooling system. The worst effect, as a result of the failure of primary system, because of the fuel of the reactor melts. Based on identification and hazard analysis of the primary cooling system using HAZID (Hazard Identification) and HAZOP (Hazard and Operability Analysis) method, there are five initiating events : loss of coolant accident (LOCA) because the leakage of the primary coolant boundary beyond the isolation valves, LOCA because the rupture of a pump casing due to impeller failure, LOCA because heat exchanger leakage, loss of flow accident (LOFA) because the loss of primary pump, and LOFA because the inadvertent closure of the primary isolation valves.

Each event consists of success - fail scenario from several available safety function, and there are fourty eight scenarios obtained from five events available. By using Item ToolKit Software, the event scenario arranged towards safety system avalaible by Event Tree Analysis (ETA) method and the frequency of each event is obtained, i.e the maximum value of event of 5.12E-6/year. All scenario based on CDF and CDS are in Medium Risk and Low Risk, so that the reactor is safe to operated.