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

5.68
The 70-yr worldwide population dose from 3 H and 14C calculated for this case is
approximately 3.9 x 10- 18 man-rem, which is effectively zero when compared with
4.5 x 1010 man-rem received from naturally occurring sources.
Calculations of the effect of a drop of a fuel reprocessing waste canister down the
mine shaft indicated that this would be categorized as a moderate accident in terms of
release outside the repository. Some of the canistered waste is assumed to be released to
the mine atmosphere from four failed canisters in a time period of 1 hour. Canistered waste
will be one of three-forms:
* Solidified High-Level Wastes:
- Glass (175 kg/MTHM)--13 kg of particles less than 10 m in diameter will be
released to mine filters. Postulated frequency of occurrence is 7 x 10-7/yr.
- Calcine (52.5 kg/MTHM)--31 kg of particles less than 10 m will be released to
mine filters. Frequency of occurrence is 7 x 10- 7 /yr.
* RH-TRU Wastes--1.3 kg of Zircaloy fines less than 10 m in diameter will reach
the mine filters. The postulated frequency of occurrence is 2 x 10-6/yr.
The radioactive materials that would be released to the outside environment for the
various waste forms are presented in Tables 5.4.25. These releases were calculated assuming
that material released in the mine shaft passes through a roughing filter and two HEPA
filters (DF of 107) prior to escaping to the environment through a 110-m stack.
Doses to the maximum individual from these accidents are given in Table 5.4.26. The
doses in Table 5.4.26 are insignificant in terms of the radiation dose of 7 rem the
individual would have received from naturally occuring sources over the same time period.
TABLE 5.4.25. Radionuclide Releases for a Waste Canister Dropped Down
a Mine Shaft at a Repository for Reprocessing Wastes, Ci
Nuclide Glass Calcine Nuclide RH-TRU
90Y 3.9 x 10- 4 3.2 x 10- 3 3H - 1
2.5 x 10
9 0
Sr
4
3.9 x 10- 3.2 x 10- 3 14 C 4.4 x 10- 4
106Ru 4.4 x 10- 5 3.4 x 10- 4 6 0 Co 1.6 x 10- 6
125mTe 4.8 x 10- 6 4.0 x 10- 5 63Ni 1.6 x 10- 7
13 4 Cs 8.0 x 10- 5 1.3 x 10- 3 9 0 Sr 1.2 x 10- 8
137Cs 6.0 x 10- 4 4.8 x 10- 3 5 4 Mn 8.1 x 10- 8
144Ce 2.0 x 10- 5 1.6 x 10- 4 9 5 Nb 8.2 x 10- 8
154Eu 3.6 x 10- 5
2.8 x 10- 4 13 7 Cs 1.9 x 10- 8
23 8 Pu 5.6 x 10-7 4.4 x 10- 6 144Ce 4.8 x 10- 8
23 9 Pu 1.3 x 10- 8 1.0 x 10-7
23 8 Pu 1.1 x 10- 9
24 0 8
Pu 5.2 x 10- 4.0 x 10- 7 2 39 Pu 7.2 x 10-
241u 6.4 x 10- 6 4.0 x 10- 5 24 0 Pu 1.5 x 10- 10
24 1 6
Am 5.2 x 10- 4.0 x 10 5 24 1Pu 3.6 x 10- 8
24 4 Cm 4.4 x 10 - 5 3.5 x 10- 4 24 1 Am 1.4 x 10-10
242Cm 2.0 x 10-9
1 1
244 Cm 1.4 x 10- 9