title: Interim storage of spent and disused sealed sources: optimisation of external dose distribution in waste grids using the MCNPX code.
abstract: Radioactive sealed sources are in use worldwide in different fields of application. When no further use is foreseen for these sources, they become spent or disused sealed sources and are subject to a specific waste management scheme. Portugal does have a Radioactive Waste Interim Storage Facility where spent or disused sealed sources are conditioned in a cement matrix inside concrete drums and following the geometrical disposition of a grid. The gamma dose values around each grid depend on the drum's enclosed activity and radionuclides considered, as well as on the drums distribution in the various layers of the grid. This work proposes a method based on the Monte Carlo simulation using the MCNPX code to estimate the best drum arrangement through the optimisation of dose distribution in a grid. Measured dose rate values at 1 m distance from the surface of the chosen optimised grid were used to validate the corresponding computational grid model.
authors.affiliation: Instituto Tecnológico e Nuclear, Departamento de Protecção Radiológica e Segurança Nuclear, Estrada Nacional 10, Apartado 21, 2686-953 Sacavém, Portugal. ipaiva@itn.mces.pt
authors.forename: I
authors.initials: I
authors.lastname: Paiva
authors.forename: C
authors.initials: C
authors.lastname: Oliveira
authors.forename: R
authors.initials: R
authors.lastname: Trindade
authors.forename: L
authors.initials: L
authors.lastname: Portugal
mesh_terms: D003198:Computer Simulation; D004867:Equipment Design; D019544:Equipment Failure Analysis; D015233:Models, Statistical; D009010:Monte Carlo Method; D009502:Neutrons; D009688:Nuclear Reactors / Q000295:instrumentation*; D017785:Photons; D011829:Radiation Dosage; D011834:Radiation Monitoring / Q000379:methods* / Q000592:standards; D011835:Radiation Protection / Q000295:instrumentation* / Q000379:methods; D011850:Radioactive Waste / Q000032:analysis*; D012542:Scattering, Radiation; D018505:Waste Management / Q000295:instrumentation* / Q000379:methods
chemical_list: D011850:Radioactive Waste