Numerical Study on Condensation in Immersed Containment System of Advanced SMR During Uncontrolled Depressurization

Abstract

NUMERICAL STUDY ON CONDENSATION IN IMMERSED CONTAINMENT SYSTEM OF ADVANCED SMR DURING UNCONTROLLED DEPRESSURIZATION.A number of Small Modular Reactor designs have been developed by several countries and mostly each comes with specific innovative improvements. One of them is NuScale reactor which implements a steel, small size immersed-in-pool containment system. This new approach derives new challenges as control for temperature and pressure inside the containment is conducted without any active system. Passive heat transfer and condensation is important parameter that needs to be investigated for this kind of containment design. Hence, this work examines the condensation, pressure and the effect of pool temperature on capability of the containment to remove heat and maintain integrity passively. The work is performed using numerical simulation by modeling the reactor in RELAP5 code. Calculation result shows that during depressurization, maximum pressure limit of 5.5 MPa is not exceeded. Besides, the containment design provides enough capability to transfer heat from the containment to water pool passively. This work also investigates sensitivity analysis of pool temperature which shows that for an increase of about 17 o C, heat removal from the containment to water pool is only slightly affected with value less than 3 percent.Keywords: Containment, Condensation, RELAP5, NuScale, Depressurization ABSTRAK STUDI NUMERIK PROSES KONDENSASI PADA SISTEM PENGUNGKUNG TERENDAM UNTUK SMR SAAT DEPRESURISASI TAK TERKENDALI. Sejumlah desain reaktor modular daya kecil (SMR) sedang dikembangkan dan dibangun oleh beberapa negara dan umumnya. Masing-masing reaktor tersebut memiliki inovasi tersendiri. Salah satunya adalah reaktor NuScale yang menggunakan sistem pengungkung ukuran kecil berbahan logam yang terendam dalam kolam air. Pendekatan baru ini memunculkan tantangan baru karena pengendalian temperatur dan tekanan dalam pengungkung dilakukan tanpa sistem aktif (peralatan bertenaga listrik

Simulation of Feed Water Temperature Decrease Accident in Nuscale Reactor

“…Publications related to this reactor mostly discussed the superiority of the design in dealing with severe accident and extreme event [3,4]. Besides, the response of containment system using simplified model has also been investigated [5].…”