ML20041D064
| ML20041D064 | |
| Person / Time | |
|---|---|
| Issue date: | 02/10/1982 |
| From: | Silling S NRC OFFICE OF NUCLEAR MATERIAL SAFETY & SAFEGUARDS (NMSS) |
| To: | Knapp M NRC OFFICE OF NUCLEAR MATERIAL SAFETY & SAFEGUARDS (NMSS) |
| References | |
| REF-WM-1 WMHL:3109, NUDOCS 8203040185 | |
| Download: ML20041D064 (2) | |
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FEB 101982 0istribution: WM-82-080 A MHL file
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WMHL: 3109.5 HJMiller MJBell J0 Bunting MEMORANDUM FOR: flalcolm R. Knapp SASilling & r/f High-Level Waste Licensing peg l
Management Branch l
Division of Waste Management e
A C
FROM:
Stewart A. Silling l
High-Level Waste Licensing RECElVED 9
l ilanagement Branch t
Division of Waste Management 1
FEB 171982a-
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SUBJECT:
REVIEW 0F EEG-11 (WM-82-080)
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I have reviewed the report " Calculated Radiation Doses from
.s Brought to the Surface if Future Drilling Intercepts the WIPP Repository and Pressurized Brine" by %mes K. Channel of the State of New Mexico l
Environmental Evaluation Group (EEG-11).
The report analyzes a type of double-borehore scenario at the WIPP site.
l The first borehore penetrates the repository and an assumed underlying pocket of brine.
The brine floods the repository, accelerating corrosion of the waste canisters and leaching part of the waste.
The second borehole allows the contaminated brine to reach the surface in the course-i of drilling. The brine accumulates in a pond and evaporates, leaving a contaminated residue.
Part of the residue is transported by atmospheric suspension and dispersion to a farm where man is exposed through inhalation, external dose, and consumption of milk, produce, and meat.
The report also considers exposure of the crew drilling the second borehole.
The maximum individual dose predicted is 12 rem to bone and 0.3 rem to the whole body, which occurs if the second hole is drilled 400 years after closure.
Higher doses are predicted if the hole is drilled at 1000 years, but the author states that these doses are "not considered plausible," although he does not adequately explain why. The highest dose occurs through the inhalation pathway. The doses to the drilling crew worker and to the maximum exposed individual in the public are nearly equal.
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The maximum population exposure is 220 man-rem to bone and 5.9 rem to the whole body. The report states that this dose might cause 1 or 2 cancer deaths over 1500 years.
The author is aware that the scenario analyzed is a sequence of fairly unlikely events and is really a worst-case analysis. The report estimates a probability of 3E_5 of exceeding the EPA release limits.
Considering the small predicted health consequences of this unlikely scenario, DOE could reasonably cite this report as evidence that brine pockets are not a serious impediment to successful isolation of the waste at WIPP.
It should be noted that the assumed leach rates in the report of IE-4/yr for actinides and 1.2E-3/yr for cesium exceed the rate permitted by 10 CFR 60,1E-5/yr. Also, the canisters are assumed to fail prior to 1000 years.
ORIGIIIAL SIGNF.D EY Stewart A. Silling High-level Waste Licensing Management Branch
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