Studi Pengaruh Fraksi Coated Fuel Particle pada Desain Pebble Bed Reactor 40 MWt Berbahan Bakar Uranium

Coated Fuel Particle (CFP) adalah tipe elemen bakar mikro berdiameter lebih kecil dari 1 mm, yang di dalamnya terdapat material fisil yang dilapisi oleh beberapa lapisan karbon. Pebble Bed Reactor (PBR) menggunakan konsep CFP untuk elemen bakarnya. CFP dimasukan ke dalam bola elemen bakar berukuran 6 cm dan disebar di dalam zona elemen bakar. Tujuan penelitian ini adalah untuk mempelajari pengaruh dari fraksi CFP terhadap beberapa parameter neutronik penting seperti faktor multiplikasi efektif, spektrum energi neutron, perubahan densitas material fisil dan fertil, serta tingkat utilisasi material fisil. Analisa dilakukan untuk pada sistem PBR berdaya 40 MWt dengan menggunakan kode Monte Carlo MVP/MVP-BURN, dengan fraksi CFP yang dianalisa berkisar antara 5-60%. Dari penelitian ini didapatkan bahwa fraksi CFP sebesar 10% memberikan nilai optimal untuk beberapa parameter neutronik terkait dan dapat dijadikan acuan untuk desain Pebble Bed Reactor berdaya 40 MWt dengan elemen bakar uranium.

The Effects of the Number of Coated Fuel Particles on the Neutronic Aspects of 25 MWt Pebble Bed Reactor with Thorium Fuel

High-Temperature Gas Reactor (HTGR) is a type of reactor that continues to be developed because of its advantages in terms of economic aspects, proliferation resistance, and safety aspects. One of the safety aspect improvements is due to the use of the Coated Fuel Particle (CFP). A coated fuel particle is a fuel with a diameter smaller than 1 mm and is protected by several carbon layers. In the Pebble Bed Reactor (PBR) type of HTGR design, the CFP is placed in a 6 cm fuel ball. How much CFP is put into the fuel ball will determine the neutronic characteristics of the reactor. In this study, the effect of the amount of CFP in the fuel ball on the 25 MWt PBR design using Thorium fuel and its impact on several important neutronic aspects, such as the effective multiplication factor, the amount of fuel enrichment, the utilization of fissile material, and the density of the fissile material formed. The calculation was performed by the Monte Carlo MVP / MVP-BURN code. This study found that the coated fuel particle fraction of 15% was the optimum value for the studied neutronic parameters.