skip to main content

Title: Thermal Performance Analysis of a Geologic Borehole Repository

The Brazilian Nuclear Research Institute (IPEN) proposed a design for the disposal of Disused Sealed Radioactive Sources (DSRS) based on the IAEA Borehole Disposal of Sealed Radioactive Sources (BOSS) design that would allow the entirety of Brazil’s inventory of DSRS to be disposed in a single borehole. The proposed IPEN design allows for 170 waste packages (WPs) containing DSRS (such as Co-60 and Cs-137) to be stacked on top of each other inside the borehole. The primary objective of this work was to evaluate the thermal performance of a conservative approach to the IPEN proposal with the equivalent of two WPs and two different inside configurations using Co-60 as the radioactive heat source. The current WP configuration (heterogeneous) for the IPEN proposal has 60% of the WP volume being occupied by a nuclear radioactive heat source and the remaining 40% as vacant space. The second configuration (homogeneous) considered for this project was a homogeneous case where 100% of the WP volume was occupied by a nuclear radioactive heat source. The computational models for the thermal analyses of the WP configurations with the Co-60 heat source considered three different cooling mechanisms (conduction, radiation, and convection) and the effect of mesh sizemore » on the results from the thermal analysis. The results of the analyses yielded maximum temperatures inside the WPs for both of the WP configurations and various mesh sizes. The heterogeneous WP considered the cooling mechanisms of conduction, convection, and radiation. The temperature results from the heterogeneous WP analysis suggest that the model is cooled predominantly by conduction with effect of radiation and natural convection on cooling being negligible. From the thermal analysis comparing the two WP configurations, the results suggest that either WP configuration could be used for the design. The mesh sensitivity results verify the meshes used, and results obtained from the thermal analyses were close to being independent of mesh size. The results from the computational case and analytically-calculated case for the homogeneous WP in benchmarking were almost identical, which indicates that the computational approach used here was successfully verified by the analytical solution.« less
Authors:
 [1]
  1. Savannah River Site (SRS), Aiken, SC (United States). Savannah River National Lab. (SRNL)
Publication Date:
OSTI Identifier:
1305138
Report Number(s):
SRNL-STI--2016-00457
TRN: US1601799
DOE Contract Number:
AC09-08SR22470
Resource Type:
Technical Report
Research Org:
Savannah River Site (SRS), Aiken, SC (United States). Savannah River National Lab. (SRNL)
Sponsoring Org:
USDOE Office of Environmental Management (EM)
Country of Publication:
United States
Language:
English
Subject:
12 MANAGEMENT OF RADIOACTIVE AND NON-RADIOACTIVE WASTES FROM NUCLEAR FACILITIES; 07 ISOTOPE AND RADIATION SOURCES; BOREHOLES; RADIOACTIVE WASTE DISPOSAL; NATURAL CONVECTION; RADIANT HEAT TRANSFER; THERMAL CONDUCTION; COBALT 60; CESIUM 137; CONFIGURATION; RADIOISOTOPE HEAT SOURCES; THERMAL ANALYSIS; BRAZIL; COOLING; PERFORMANCE; ANALYTICAL SOLUTION; COMPARATIVE EVALUATIONS; RADIATION SOURCES; BENCHMARKS; SENSITIVITY; COORDINATES; CALCULATION METHODS thermal analysis; borehole; waste package; DSRS