Preliminary Analysis of Burnup Study on Different Pebble Arrangement inside MCNP Model of HTR Reactor Core
Wahid Luthfi1, a), Suwoto1, b), Topan Setiadipura1, c), Zuhair1, d)
1) Centre for Nuclear Reactor Technology and Safety - National Nuclear Energy Agency, 80th Building of Center for Science and Technology, South Tangerang, Indonesia 15310
Abstract
Further study to simplify the modeling of pebble bed high temperature reactor core (HTR) has been widely developed before. From last calculation on actual fueled pebble to dummy ratio, 57:43, some variation of TRISO unit and Pebble unit is modelled to achieve its first criticality configuration. In this paper, some model that use 27000 pebble with 57:43 ratio and 100% fueled pebble is created to be used on burnup calculation se we could compare its K-EFF and nuclide inventory of it. From this burnup calculation, we could see that SC TRISO unit gives us faster calculation time followed by HCP TRISO unit and then FCC TRISO unit. On the other hand, BCC pebble unit had some consistent deviation from other pebble unit, and we need more study to know the reason behind it. It could be seen that if there are some dummy pebbles inside the reactor, then the deviation would be higher than if there is just fueled pebble inside reactor. On 57:43 ratio, absolute average deviation of K-EFF on burnup calculation is lower than 2% and 10% for nuclide inventory (mass). On 100% fueled pebble, its below 0.15% on K-EFF absolute deviation and below 8% on nuclide inventory deviation.
Keywords: TRISO, Pebble, Modelling, MCNPX, K-EFF, Burnup
Topic: Nuclear and Radiation Computation