ML20207N642
| ML20207N642 | |
| Person / Time | |
|---|---|
| Site: | Wood River Junction |
| Issue date: | 12/09/1986 |
| From: | Berger J OAK RIDGE ASSOCIATED UNIVERSITIES |
| To: | Crow W NRC OFFICE OF NUCLEAR MATERIAL SAFETY & SAFEGUARDS (NMSS) |
| References | |
| 27694, NUDOCS 8701140331 | |
| Download: ML20207N642 (3) | |
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/ M // W Oak Ridge Manpower Education, Associated Post Office Box 117 Research, and Training Universities Oak Ridge, Tennessee 37831-0117 Division o'
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December 9, 1986 RECENED %,-
c DEC 171986 P 9 y,MiUCtIAR REGULAT Mr. William Crow i
Division of Fuel Cycle & Material
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Washington, D.C.
20555 Subj ect: URANIUM. ISOTOPIC ANALYSES - UNC SOIL SAMPLES
Dear Mr. Crow:
Gamma spectrometry results on soil samples, collected during our September 26 followup survey at UNC - Wood River Junction, were reported in my letter of October 15, 1986. The isotopic uranium analyses on six selected samples have been completed and results are attached. The objective of the isotopic analyses was to confirm previously determined U-234/U-235 activity ratios rather than to remeasure the average U-235 and U-238 sample concentrations reported earlier. For this reason, ORAU did not grind, sif t, and homogize the entire 600 - 800 gram samples used for the gamma analysis. Only about 20 grams was removed from each sample and processed for isotopic analysis. Therefore, there are discrepancies in the U-235 concentrations, as measured by alpha spectrometry and gamma spectrometry; the largest difference is a factor of 2.5 for the sample from grid block D068.
U-234/U-235 ratios for individual samples ranged from 21.5 i 7.6 to 36.5 11.9.
The average. ratio of 28.5 1 4.9 is in good agreement with previously reported values of approximately 26.
Questions about this information should be referred to me at FTS 626-3305.
Sincerely, James D. Berger, Manager Radiological Site Assessment Program JDB/sj f m
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9 TABLE 1 RESULTS OF ISOTOPIC URANIUM ANALYSES ON SELECTED SAMPLES FROM FOLLOWUP SURVEY UNC - WOOD RIVER JUNCTION Grid Block Radionuclide Concentration (pCi/g)
U-234 U-235 U-238 U-234/U-235 B021 77.2 1 3.7 2.11 i 0.68a 1.03 10.42 36.5 i 11.9 B038 30.2 1 2.1 0.99 10.60 0.84 10.34 30.6 i 18.6 D068 220.5 i 5.4 8.0 1 1.3 1.61 10.60 27.6 1 4.4 D078 181 i 12 8.4 i 2.9 5.6 12.1 21.5 i 7.6 D089 38.2 1 2.8 1.3210.75 0.49 1 0.31 28.9 i 16.5 D094 997 38 38.2 i 8.4 7.9 i 3.4-26.1 1 5.8 Average U-234/235 activity ratio 28.5 i 4.9 aUncertainties are 2a based only on counting statistics.
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