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

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106<br />

CONSEQUENCE ANALYSIS<br />

would depend on specific cask construction and behavior. Surface dose rates for casks are<br />

designed to not exceed 1000 mr/hr following Type B packaging qualification tests described<br />

in 49 CFR 173.398.<br />

The assumption made by the commenter when comparing releases from Accidents 6.2.8 and<br />

6.2.7 is that they are related. However, Accident 6.2.8 is based on Accident 6.2.6. The<br />

mixed fission product and actinide releases discussed in 6.2.7 are due to impact damage to<br />

the fuel. A severe impact was not postulated for either Accident 6.2.6 or 6.2.8.<br />

Table 4.1.1-10 in DOE/ET-0029 does consider releases <strong>of</strong> mixed fission products with the<br />

cask coolant for Accident 6.2.6. The inclusion <strong>of</strong> actinides in this table is in error.<br />

Excluding plutonium and curium would reduce the dose expected for this accident. Revised<br />

Tables 4.1.2-7 and 4.1.1-11 from DOE/ET-0029 are included here. The mixed fission product<br />

contribution to the dose from Accident 6.2.8 was negligible.<br />

Estimates <strong>of</strong> particulate releases from a spent fuel cask involved in a severe accident<br />

are different for DOE/ET-0028 and PNL-2588 (Elder et. al. 1978). DOE/ET-0028 assumed that<br />

particulates were only generated in an impact environment and that a small fraction would<br />

escape the cask cavity. PNL-2588 assumes that impacts and rapid outgassing <strong>of</strong> fuel elements<br />

during creep rupture can release particulates to the cask cavity. A higher fraction <strong>of</strong> par-<br />

ticulates released to the cask cavity were conservatively assumed to reach the atmosphere<br />

in PNL-2588 (Elder et. al. 1978). Differences in actinide and particulate releases in the<br />

two documents are due to both the assumption <strong>of</strong> releases during creep rupture and the frac-<br />

tion <strong>of</strong> nuclides that escape the cask cavity. Particulates were not the largest dose con-<br />

tributor in PNL-2588 (Elder et. al. 1978).<br />

TABLE 4.1.2-7. One-Year Dose and 70-Year Dose Commitment to the<br />

Maximum Individual Resulting from a Moderate<br />

Accident During Truck Transport <strong>of</strong> Spent Fuel<br />

Dose, rem<br />

Organ 1-Year 70-Year<br />

Total Body 1.4 x 10- 5 7.6 x 10- 5<br />

Thyroid 2.5 x 10- 6 2.5 x 10- 6<br />

Lung 6.8 x 10- 4 9.4 x 10- 4<br />

Bone 1.1 x 10- 4 3.9 x 10 - 4 *<br />

Skin 4.5 x 10 - 6 4.5 x 10<br />

*Original value was in error in Table 4.1.2-7<br />

- 6

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