skip to main content
OSTI.GOV title logo U.S. Department of Energy
Office of Scientific and Technical Information

Title: Water and Regolith Shielding for Surface Reactor Missions

Abstract

This paper investigates potential shielding options for surface power fission reactors. The majority of work is focused on a lunar shield that uses a combination of water in stainless-steel cans and lunar regolith. The major advantage of a water-based shield is that development, testing, and deployment should be relatively inexpensive. This shielding approach is used for three surface reactor concepts: (1) a moderated spectrum, NaK cooled, Hastalloy/UZrH reactor, (2) a fast-spectrum, NaK-cooled, SS/UO2 reactor, and (3) a fast-spectrum, K-heat-pipe-cooled, SS/UO2 reactor. For this study, each of these reactors is coupled to a 25-kWt Stirling power system, designed for 5 year life. The shields are designed to limit the dose both to the Stirling alternators and potential astronauts on the surface. The general configuration used is to bury the reactor, but several other options exist as well. Dose calculations are presented as a function of distance from reactor, depth of buried hole, water boron concentration (if any), and regolith repacked density.

Authors:
; ;  [1];  [2];  [3]
  1. Nuclear Systems Design Group, Los Alamos National Laboratory, Los Alamos, New Mexico, 87545 (United States)
  2. School of Nuclear Engineering, Purdue University, West Lafayette, IN 47907 (United States)
  3. Department of Mechanical Engineering, University of Idaho, Moscow, ID (United States)
Publication Date:
OSTI Identifier:
20798029
Resource Type:
Journal Article
Resource Relation:
Journal Name: AIP Conference Proceedings; Journal Volume: 813; Journal Issue: 1; Conference: 10. conference on thermophysics applications in microgravity; 23. symposium on space nuclear power and propulsion; 4. conference on human/robotic technology and the national vision for space exploration; 4. symposium on space colonization; 3. symposium on new frontiers and future concepts, Albuquerque, NM (United States), 12-16 Feb 2006; Other Information: DOI: 10.1063/1.2169277; (c) 2006 American Institute of Physics; Country of input: International Atomic Energy Agency (IAEA)
Country of Publication:
United States
Language:
English
Subject:
75 CONDENSED MATTER PHYSICS, SUPERCONDUCTIVITY AND SUPERFLUIDITY; ALTERNATORS; BORON; POTASSIUM ALLOYS; POWER SYSTEMS; RADIATION DOSES; REACTOR MATERIALS; REACTORS; SHIELDING; SHIELDS; SODIUM ALLOYS; SPACE; SPACE VEHICLES; STAINLESS STEELS; SURFACES; TESTING; WATER

Citation Formats

Poston, David I., Sadasivan, Pratap, Dixon, David D., Ade, Brian J., and Leichliter, Katrina J. Water and Regolith Shielding for Surface Reactor Missions. United States: N. p., 2006. Web. doi:10.1063/1.2169277.
Poston, David I., Sadasivan, Pratap, Dixon, David D., Ade, Brian J., & Leichliter, Katrina J. Water and Regolith Shielding for Surface Reactor Missions. United States. doi:10.1063/1.2169277.
Poston, David I., Sadasivan, Pratap, Dixon, David D., Ade, Brian J., and Leichliter, Katrina J. Fri . "Water and Regolith Shielding for Surface Reactor Missions". United States. doi:10.1063/1.2169277.
@article{osti_20798029,
title = {Water and Regolith Shielding for Surface Reactor Missions},
author = {Poston, David I. and Sadasivan, Pratap and Dixon, David D. and Ade, Brian J. and Leichliter, Katrina J.},
abstractNote = {This paper investigates potential shielding options for surface power fission reactors. The majority of work is focused on a lunar shield that uses a combination of water in stainless-steel cans and lunar regolith. The major advantage of a water-based shield is that development, testing, and deployment should be relatively inexpensive. This shielding approach is used for three surface reactor concepts: (1) a moderated spectrum, NaK cooled, Hastalloy/UZrH reactor, (2) a fast-spectrum, NaK-cooled, SS/UO2 reactor, and (3) a fast-spectrum, K-heat-pipe-cooled, SS/UO2 reactor. For this study, each of these reactors is coupled to a 25-kWt Stirling power system, designed for 5 year life. The shields are designed to limit the dose both to the Stirling alternators and potential astronauts on the surface. The general configuration used is to bury the reactor, but several other options exist as well. Dose calculations are presented as a function of distance from reactor, depth of buried hole, water boron concentration (if any), and regolith repacked density.},
doi = {10.1063/1.2169277},
journal = {AIP Conference Proceedings},
number = 1,
volume = 813,
place = {United States},
year = {Fri Jan 20 00:00:00 EST 2006},
month = {Fri Jan 20 00:00:00 EST 2006}
}
  • If mass and heat transport properties in the top few cm of the lunar surface correspond, estimates of the daytime thermal conductivity based on the diffusivity calculated from in situ concentration gradients of low temperature volatile elements should be possible. Concentration gradients of Hg and Br in response to the diurnal heat pulse have been measured in samples from cores. The conductivity estimated is either ca 10/sup -3/ or ca 2 x 10/sup -4/W/cm-/sup 0/K depending on the assumptions made. The latter value is in agreement with near-surface daytime thermal properties calculated by Keihm et al. (1973) to explain themore » mean surface temperature. An activation energy for diffusion of Hg in the top few cm of the lunar surface is estimated to be ca 8 kcal/mole and suggests either vapor or surface migration. Fixation of the concentration gradient after the cores were extracted may be due to lack of a temperature gradient to act as a driving force or to disruption of grain contacts or their corrosion on exposure to air.« less
  • Earth’s terrestrial near-subsurface environment can be divided into relatively porous layers of soil, intact regolith, and sedimentary deposits above unweathered bedrock. Variations in the thicknesses of these layers control the hydrologic and biogeochemical responses of landscapes. Currently, Earth System Models approximate the thickness of these relatively permeable layers above bedrock as uniform globally, despite the fact that their thicknesses vary systematically with topography, climate, and geology. To meet the need for more realistic input data for models, we developed a high-resolution gridded global data set of the average thicknesses of soil, intact regolith, and sedimentary deposits within each 30 arcsecmore » (~ 1 km) pixel using the best available data for topography, climate, and geology as input. Our data set partitions the global land surface into upland hillslope, upland valley bottom, and lowland landscape components and uses models optimized for each landform type to estimate the thicknesses of each subsurface layer. On hillslopes, the data set is calibrated and validated using independent data sets of measured soil thicknesses from the U.S. and Europe and on lowlands using depth to bedrock observations from groundwater wells in the U.S. As a result, we anticipate that the data set will prove useful as an input to regional and global hydrological and ecosystems models.« less
    Cited by 18
  • Cited by 18
  • Earth’s terrestrial near-subsurface environment can be divided into relatively porous layers of soil, intact regolith, and sedimentary deposits above unweathered bedrock. Variations in the thicknesses of these layers control the hydrologic and biogeochemical responses of landscapes. Currently, Earth System Models approximate the thickness of these relatively permeable layers above bedrock as uniform globally, despite the fact that their thicknesses vary systematically with topography, climate, and geology. To meet the need for more realistic input data for models, we developed a high-resolution gridded global data set of the average thicknesses of soil, intact regolith, and sedimentary deposits within each 30 arcsecmore » (~ 1 km) pixel using the best available data for topography, climate, and geology as input. Our data set partitions the global land surface into upland hillslope, upland valley bottom, and lowland landscape components and uses models optimized for each landform type to estimate the thicknesses of each subsurface layer. On hillslopes, the data set is calibrated and validated using independent data sets of measured soil thicknesses from the U.S. and Europe and on lowlands using depth to bedrock observations from groundwater wells in the U.S. As a result, we anticipate that the data set will prove useful as an input to regional and global hydrological and ecosystems models.« less