ANALYSIS OF MOD-1 HEATING SECTION EFFICIENCY IN THE RCCS TEST FACILITY OF HIGH TEMPERATURE REACTORS (Hendro Tjahjono a), Rahayu Kusumastuti, Mulya Juarsa, Dedy Haryanto, Surip Widodo, Andi Sofrany Ekariansyah, Susyadi, Mukhsinun Hadi Kusuma)

Abstract. In order to develop the design of Reactor Cavity Cooling System (RCCS) from High Temperature Reactors
(HTRs), Center for Nuclear Reactor Technology and Safety (PTKRN) has built an RCCS experimental facility aimed for
supporting the development of methods in designing a RCCS for a larger scale. This facility refers to the basic design of the
RCCS of a 10 MWth Non-Commercial Power Reactor (RDNK) with a scale of 1/1 for height and 1/15 scale for width. With
the availability of this experimental facility, characterization needs to evaluate whether the facility has functioned as
planned. Especially for heating section, the initial design made called the Mod-1 is a model that is still open on all sides
without insulation except on the back of the heating plate. The objective of this analysis is to determine the efficiency of this
section. Analysis is carried out through numerical and analytical calculations by developing an calculation program based on
Matlab. Two analysis conditions are evaluated such as normal condition and accident condition. The result shows that in
normal condition, the efficiency of heating section is only 11.34%, and increase to 13,55% in accident conditions. It means
that the heat released by the heating plate that is effectively received by cooling water through 5 riser pipes is very small. So,
the heating section Mod-1 of RCCS Test Loop has very low efficiency and needs to be improved.
Keywords: RCCS Test Loop, heating section Mod-1, HTR, RDNK.