ML19308C509
| ML19308C509 | |
| Person / Time | |
|---|---|
| Site: | Crane  |
| Issue date: | 11/15/1979 |
| From: | Schwendiman L Battelle Memorial Institute, PACIFIC NORTHWEST NATION |
| To: | Thompson W NRC OFFICE OF NUCLEAR MATERIAL SAFETY & SAFEGUARDS (NMSS) |
| Shared Package | |
| ML19308C510 | List: |
| References | |
| NUDOCS 8001280382 | |
| Download: ML19308C509 (2) | |
Text
4 RELATED CORRESPONDENCE O
OBattelle 79 \\-
November 15, 1979 4
Pacific Northwest Laboratories
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P.O. Box 999
/
g9 Richland, Washington U.S.A. 99352
$cC " 40 Telepnone t509:
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Telex 154874 I
'4 Mr. W. E. Thompson o
Fuel Cycle Technology MP 4 R)
Assessment Branch to efAg
/
Nuclear Regulatory Commiss W
s Mail Stop 396-SS
\\ "6 Washington, D.C.
20555
Dear Bill:
RADON EMISSION FROM UNDERGROUND URANIUM MINES This letter is to confirm our telephone conversation of November 14 regard-ing radon releases from underground mines.
I told you of our conclusions regarding radon release per RRY based on many additional radon measurements i
in 27 mines which included the mines used in PNL-2888 Rev.
It is important
{
to remember, in perspective, that the calculated curies per RRY are wholly l
contingent on knowledge of U 08 production from individual mines in the 3
sample.
The ore production listed in Table IV, PNL-2888 Rev. for the seven mines was obtained from the mine management. We accepted and used these mine production data and the estimate of 0.2% U 0s in the ore to arrive at 3
the value of 15.9 Ci exhausted in ventilation air per ton of U 03 8 produced.
At this point, we have made direct measurements of the radon emission from 27 underground uranium mines, (including those mines in Table IV, PNL-2888 Rev.)
whose production constitutes 59% of the 1978 U.S. production from underground uranium mining. With these data, we feel that we are in a reasonably good position to estimate the curies of radon per RRY from underground uranium mining in the U.S.
We must caution, however, that there are still a few assump-tions that need to be verified before our best estimate can be made.
These include the fact that radon emission seems to be independent of activity within the uranium mines.
Data on radon emission versus time from uranium mine vents are being analyzed to determine variations with time that occur. There may be some significant seasonal variation in radon emission and this is also being investigated.
Other factors which affect our estimate involve the fact that some uranium mines are being ventilated although there is no ore produc-tion taking place. The reason for this is apparent that these mines have connections with other underground mines which are being worked and ventilation is therefore required to avoid seepage of radon into active uranium mines.
All these factors appear at this point to be minor, so we therefore still have confidence that our measurement of radon release from the 27 mines that we have studied is reasonably representative of the uranium industry.
These 27 mines are located in the Ambrosia Lake, Church Rock, and Mariano Lake area of 50 Years of Service 8 0 0128 0_3 d5 2___,_
m 9-W 9 W
W.E. Thompson Nov.15,1979 page 2 New Mexico, the Uravan area,.of Colorado, the Moab area of Utah, and in the Four Corners region (Colorado, Utah, Arizona, and New Mexico).
The following information has been used in calculating the radon emission per RRY:
Total production from the 27 mines for 1978 (obtained from the DOE Grand Junction office) was 3,600,000 tons of uranium ore, 11,500,000 pounds of U 0s (5215 metric tons) or 28.7. RRY for 182 metric tons 3
per RRY.
Our measurements of the total radon emission from these 27 mines is 151,000 curies of radon per year.
151,000 e 28.7 = 5261 curies of radon per RRY.
(We'd round this to 5260.)
This value of 5260 curies of radon per RRY is for radon emission in the vents from uranium mines.
In addition, we estimate that 100 curies of radon per RRY will be emitted from aboveground ore storage at the mine mouths.
Thus, our best estimate is 5360 curies of radon per RRY from underground uranium mining.
The back-up documentation for these numbers is being included in our next topical report on underground mining which is currently being prepared.
The large difference in this curies of radon per RRY value compared with our earlier value of 3340 curies of radon per RRY in NUREG/CR-0627 (PNL-2888 Rev.)
September 1979, is due to the lower average current production for this group of mines compared to the production cited by the mine managers for October,1976 and which we used for arriving at the radon release per RRY.
In checking with the mine operator for each of these seven mines, it appears that there actually has been a substantial decrease in production rates over the past three years.
This decrease in production may have taken place slowly over a period of time.
We did make numerous attempts to obtain production rates during these series of measurements but were only able to obtain this information for Mines 1 and 2 which are listed in Table IV of the above report.
The earlier curies of radon per RRY value is thus based on the information which we were able to obtain from the mine operators provided to NRC by the mine operators in 1976.
We do feel now that the information from the DOE Grand Junction office is as reliable as can be obtained and therefore, we feel that our current estimate of 5360 curies of radon 'per RRY will not be subject to a major modification as we obtain further information in this study.
Very truly yours, de. k n~ w L. C. Schwendiman Atmospheric Sciences Department dj
.