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Management of Commercially Generated Radioactive Waste - U.S. ...

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Response<br />

87<br />

CONSEQUENCE ANALYSIS<br />

Actual leach rates for HLW in glass used were<br />

1 x 10-4g/cm 2 / day - for first 10 days <strong>of</strong> leaching<br />

1 x 10-5g/cm 2 /day - for remainder <strong>of</strong> time<br />

This is equivalent to approximately 1% loss <strong>of</strong> material contacted per year by leaching<br />

assuming a density <strong>of</strong> waste in glass as 3 g/cm 3<br />

Draft p. 3.1.149<br />

Issue<br />

What is the source <strong>of</strong> the listed leach rate (1 x 10-4gm/cm 2 /day) for intermediate<br />

level and low-level waste? What waste forms are involved? (218-001)<br />

Response<br />

The values listed for intermediate-level and low-level wastes are unpublished concensus<br />

judgments <strong>of</strong> senior individuals at Battelle-Northwest Laboratory. Another individual<br />

believed that 1 x 10-3gm/cm 2 /day was more appropriate for wastes solidified with cement.<br />

In terms <strong>of</strong> radiological impact intermediate-level and low-level wastes are not significant<br />

in comparison with high-level wastes.<br />

Draft pp. 3.1.150-155<br />

Issue<br />

The annual doses to a maximum individual associated with the breach <strong>of</strong>.a salt reposi-<br />

tory are three to ten times the permissible annual dose for occupational exposures...Thus<br />

the calculated number <strong>of</strong> health effects attributed to this accident would range from 1 x 104<br />

to 3 x 105<br />

GEIS goes on to multiply these figures by 1/100 as the probability <strong>of</strong> failure <strong>of</strong> waste<br />

containment and by 4 x 10- 11 /yr as the probability <strong>of</strong> a new fault intersecting the reposi-<br />

tory to arrive at insignificant risk levels. The probability <strong>of</strong> an existing fault becoming<br />

permeable should also be considered. (208-NRC)<br />

Response<br />

The case presented was felt to be sufficient; site-selection criteria are expected to<br />

preclude the presence <strong>of</strong> existing faults. (However, see also EPA's comments regarding prob-<br />

ability <strong>of</strong> interaction with water).

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