Analysis Of Main Steam Line Break Accident Outside Containment On PWR

ANALYSIS OF MAIN STEAM LINE BREAK ACCIDENT OUTSIDE CONTAINMENT ON PWR

Andi Sofrany Ekariansyah
Pusat Teknologi Reaktor dan Keselamatan Nuklir - BATAN
PTRKN-BATAN, Kawasan PUSPIPTEK Gd. 80, Serpong, Tangerang, 15310
ABSTRACT
ANALYSIS OF MAIN STEAM LINE BREAK ACCIDENT OUTSIDE CONTAINMENT ON PWR. An analysis of main steam line break (MSLB) accident on PWR using RELAP/SCDAPSIM/Mod3.2 code has been done. Accident analysis is important to be performed because it is contained in the Safety Analysis Report (SAR) before the nuclear power plant construction for assessing the safety of reactor facility. The purposes of analysis are to know the accident sequence characteristics and any parameter changes important for safety. The Tsuruga Unit 2 with 1160 MWe output is used as reference. One main steam pipe located at one loop outside the containment is assumed to experience a double-ended steam pipe break. Analysis is performed for 2 cases, which are one MSIV of one secondary loop is failed to close (Case 1) and all MSIVs of 4 secondary loop are failed to close (Case 2). The results show that the excessive core cool down on Case 2 is higher than on Case1, shown by the higher decrease of primary pressure, decrease of pressurize water level into empty condition, and the higher decrease of average core temperature. There are no coolant condition at upper vessel and voids at core channel, which is disappeared along with the safety injection from ECCS. An increase of core reactivity and thermal power are indicated, but no differences between the two cases. From the safety point of view, the success of reactor protection system to trip the reactor and operability of safety injection from ECCS is able to maintain the core in a safe and cool condition according to the safety criteria.

Keywords: Main steam line break, PWR, RELAP/SCDAPSIM/Mod3.2
Published : Proceeding "SEMINAR NASIONAL PENGEMBANGAN ENERGI NUKLIR II 2009", Jakarta, 25 Juni 2009