Perhitungan Ketebalan Optimal Perisai Radiasi Micro Reactor Heat Pipe (MRHP) dengan Paket Perangkat Lunak MCNPX

Sangaji Nurfauzi Kinarso, Dr. Ir. Haryono Budi Santosa, M.Sc.; Dr.Ing. Ir. Kusnanto

2023 | Skripsi | TEKNIK NUKLIR

Perancangan PLTN mikro berpendingin garam lebur menggunakan pipa kalor berlangsung di Indonesia. Rancangan konseptual ini disebut Micro Reactor Heat Pipe (MRHP).  Untuk meningkatkan rancangan konseptual MRHP ke dasar desain perlu dilakukan penentuan spesifikasi perisai radiasi reaktor. Data daya atenuasi, geometri fisik, dan jumlah material perisai dengan material berbeda diperlukan untuk melengkapi spesifikasi ini.

Penelitian dilakukan melalui perhitungan simulasi transport partikel.  Keseluruhan gedung reaktor beserta teras dimodelkan pada perangkat lunak MCNPX. Korelasi ketebalan perisai terhadap laju dosis diperoleh melalui simulasi terhadap model yang divariasikan ketebalan perisainya.  Korelasi ini digunakan untuk menentukan daya atenuasi dan geometri optimal perisai radiasi. Perhitungan dilanjutkan dengan penentuan total jumlah material yang dibutuhkan berdasarkan data geometri optimal perisai.

Penelitian menunjukkan data terkait ketebalan optimal dan jumlah massa perisai dari masing-masing material agar tercapai nilai batas dosis yang berlaku. Perisai radiasi berbahan beton iron-portland didapati memiliki tebal optimal paling rendah yatu sebesar 150,0 cm. Perisai berbahan AISI 1018 memiliki ketebalan perisai paling tebal yaitu sebesar 402,4 cm. Perisai berbahan beton barit didapati memiliki massa paling rendah yaitu sebesar 96,7 ton. Perisai berbahan AISI 1018 memiliki massa paling besar yaitu 395,9 ton

Design of a molten filled-heat pipes micro nuclear reactor is underway in Indonesia. The conceptual design is called Micro Reactor Heat Pipe (MRHP). To elevate MRHP from the conceptual design to the design basis stage, it is necessary to determine the reactor radiation shielding specifications. Data on attenuation characteristics, physical geometry, and the required amounts of materials of shields with different materials are needed to complete the shielding specifications.

The research is conducted through particle transport simulation calculations. The entire reactor building and core were modeled on MCNPX software. The correlation of shield thickness to dose rate was obtained through simulations of models by varying the shield thickness. This correlation is used to determine the attenuation characteristics and optimal geometry of the radiation shield. The total amount of material needed can then be calculated based on the optimal shielding geometry data.

The study showed data related to the optimum thickness and the amounts of materials required to achieve the dose limit value. The radiation shield made of iron-portland concrete was found to have the lowest optimal thickness of 150,0 cm.The shield made out of AISI 1018 has the thickest shield thickness of 402,4 cm. The radiation shield made of barite concrete was found to have the lowest mass of 96,7 metric ton. The shield made out of barit concrete has the thickest shield thickness of 495,9 metric ton.

Kata Kunci : MRHP, perisai, ketebalan, massa