Analisis terhadap Model Lepasan Radioaktif dan Tindakan Protektif untuk Kecelakaan Potensial PLTN

Dispersi lepasan produk fisi dari PLTN pada kondisi kecelakaan merupakan topik penting terkait dengan kecelakaan nuklir di Fukushima, karena konsekuensi radiologinya terhadap manusia dan lingkungan. Tujuan penelitian adalah mengkaji dan menganalisis model lepasan radioaktif dan tindakan protektif untuk kecelakaan potensial PLTN jika terjadi di Indonesia. Analisis dan pemodelan dilakukan pada PLTN dari PWR -1000 yang diaplikasikan untuk contoh tapak Semenanjung Muria dan Pesisir Banten. Postulasi kecelakaan adalah yang mengakibatkan teras meleleh dan kegagalan kontainmen reaktor untuk memitigasi lepasan radioaktif ke lingkungan. Dari penelitian ini diperoleh model lepasan radioaktif dan model tindakan protektif untuk dua contoh tapak di Indonesia yaitu tapak Semenanjung Muria dan Pesisir Banten, dengan postulasi kecelakaan yang sama. Analisis terhadap penggunaan model yang sama menghasilkan lepasan dan tindakan protektif yang tidak sama untuk kedua tapak tersebut; karena dipengaruhi oleh kondisi meteorologi tapak yang meliputi kecepatan angin, arah angin, dan stabilitas cuaca; dan kondisi lingkungan tapak berupa kerapatan dan distribusi penduduk, produksi pertanian dan peternakan penduduk lokal, dan konsumsi hasil pertanian dan peternakan setempat

Penentuan Zona Kedaruratan Nuklir Luar Tapak (Off-site) di Indonesia

THE DETERMINATION OF NUCLEAR EMERGENCY ZONE FOR OFF SITE IN INDONESIA. Learning from the Fukushima accident, especially in the nuclear emergencies management after the accident needs to be reviewed which improve Indonesian perceptions of nuclear power plant (NPP) safety. Zoning is very important for the nuclear emergency management, as it accelerates and more precise in taking protective actions on society and the environment. This paper aims to determine the nuclear emergency planning zone EPZ for off-site in Indonesia. The research methodology is to calculations for PWR- 1000 MWe (±3300 MWth) under abnormal conditions postulated as a design basis accident, DBA and beyond design basis accidents BDBA on the site of Ujung Lemah Abang, Bojanegara, West and South Bangka. Calculations and simulations using countermeasures module of PC-Cosyma programme. The result that Ujung Lemah Abang site has the simplest nuclear emergency planning zone EPZ. Site conditions is more influential than the magnitude of the activity radioactive releases, especially the meteorological and environmental conditions

A Backward Method to Estimate the Dai-ichi Reactor Core Damage Using Radiation Exposure in the Environment

The Fukushima accident resulted in the melting of the reactor core due to loss of supply of coolant when the reactor stopped from operating conditions. The earthquake and tsunami caused loss of electricity due to the flooding that occurred in the reactor. The absence of the coolant supply after reactor shutdown resulted in heat accumulation, causing the temperature of the fuel to rise beyond its melting point. In the early stages of the accident, operator could not determine the severity of the accident and the percentage of the reactor core damaged. The available data was based on the radiation exposure in the environment that was reported by the authorities. The aim of this paper is to determine the severity of the conditions in the reactor core based on the radiation doses measured in the environment. The method is performed by backward counting based on the measuring radiation exposure and radionuclides releases source term. The calculation was performed by using the PC-COSYMA code. The results showed that the core damage fraction at Dai-ichi Unit 1 was 70%, and the resulting individual effective dose in the exclusion area is 401 mSv, while the core damage fraction at Unit 2 was 30%, and the resulting individual effective dose was 99.1 mSv, while for Unit 3, the core damage fraction was 25% for an individual effective dose of 92.2 mSv. The differences between the results of the calculation for estimation of core damage proposed in this paper with the previously reported results is probably caused by the applied model for assessment, differences in postulations and assumptions, and the incompleteness of the input data. This difference could be reduced by performing calculations and simulations for more varied assumptions and postulations.Received: 30 October 2015 ; Revised: 29 March 2016; Accepted: 31 March 201