Global environmental transport models for tritium [electronic resource].
- Oak Ridge, Tenn. : Oak Ridge National Laboratory, 1985.
Oak Ridge, Tenn. : Distributed by the Office of Scientific and Technical Information, U.S. Dept. of Energy.
- Physical Description:
- Pages: 14 : digital, PDF file
- Additional Creators:
- Oak Ridge National Laboratory and United States. Department of Energy. Office of Scientific and Technical Information
- Restrictions on Access:
- Free-to-read Unrestricted online access
- In this paper we discuss some of the obstacles to the construction of credible models of global tritium transport for use in dose assessments. We illustrate these difficulties by comparing model predictions of environmental tritium levels with measurements. Monitoring of tritium has shown that specific activities in precipitation over land are typically higher by a factor of three to four than those in precipitation over the oceans. Experience with modeling CO/sub 2/ turnover in the oceans has led to the conclusion that two-box reservoir models of the ocean often give unsatisfactory representations of transient solutions. Failure to consider these factors in global models can lead to distorted estimates of collective dose and create difficulties in validation of the model against real data. We illustrate these problems with a seven-box model recommended by the National Council on Radiation Protection and Measurements in which we forced the atmospheric compartment to reproduce an exogenous function based on historic observations of HTO in precipitation at 50/sup 0/N. The fresh water response underestimates data from the Ottawa River by a factor of about five, and the ocean surface response overestimates tritium data from the surface waters of the Northern Pacific by nearly an order of magnitude. Revision of the model to include (1) separate over-land and over-ocean compartments of the atmosphere and (2) a box-diffusion model of the subsurface ocean brings the discrepant responses into good agreement with the environmental data. In a second exercise, we used a latitudinally disaggregated model and replaced a tropospheric compartment in the northern hemisphere by historic precipitation data. The model's response greatly underestimates the tritium specific activity in the southern hemisphere. These exercises lead us to doubt that a proper global transport model for tritium is available at present for collective dose assessment. 12 refs., 3 figs.
- Report Numbers:
- E 1.99:conf-850405-7
- Other Subject(s):
- Earth Atmosphere
- Radionuclide Migration
- Surface Waters
- Radioecological Concentration
- Atmospheric Precipitations
- Experimental Data
- Global Aspects
- Mathematical Models
- Beta Decay Radioisotopes
- Beta-Minus Decay Radioisotopes
- Ecological Concentration
- Environmental Transport
- Hydrogen Isotopes
- Light Nuclei
- Mass Transfer
- Numerical Data
- Odd-Even Nuclei
- Years Living Radioisotopes
- Published through SciTech Connect.
2. national topical meeting on tritium technology in fission, fusion and isotopic applications, Dayton, OH, USA, 30 Apr 1985.
Kocher, D.C.; Killough, G.G.
- Funding Information:
View MARC record | catkey: 14149710