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

Comment
Number
3-15 3-16
Comment
Number
If overcoring is necessary to remove canisters, activation of 3.c.24 General Comment
the disposal media may result in radioactive dust. Occupational The discussion of costs and capacities for each medium and fuel cycle is
exposures should be estimated. confusing. Some of the data appears contradictory. For example:
o In order to have retrievability, all main entries (corridors), Table 1.5 (GEIS)
storage rooms and exhaust airways need to be kept open. Based Unit power costs (5 year retrievability) mill/kwh
on present day mining technology, this should not be a problem
in granite and basalt. However a repository in shale will Spent Fuel U + Pu recycle
require massive support requirements to maintain retrievability Salt 0.45 0.50
and retrievability in salt is questionable. There is signifi- Granite 0.51 0.58
cant evidence that salt rock behavior under thermal and mechanical Shale 0.46 0.59
stress is such that rapid closure rates can be expected. It may Basalt 0.53 0.63
be impossible to maintain integrity of seals under such closure
rates. (Closures of 2 feet may reasonably be expected - TM-44,
Table 5.12).
l.c.22 General Comment Table 3.1.26 (GEIS)
The rationale for the thermal and thermomechanical limits on which repository Construction Costs Including Decommissioning 106 $ (1978)
designs are based is missing from GEIS and should be provided. Spent Fuel U + Pu recycle
Salt 1000 1200
3.c.23 General Comment Granite 2600 2000
The statement is made that criteria for the performance of the mined Shale 1300 1300
repository have not yet been established. Instead several local criteria Basalt 3100 2300
such as limits on thermal loading, limits on area of the repository,
limits on geometry (single level repository) etc. have been imposed on the
design process. This appears to be a process of local optimization. It
appears that imposing these limits on different geologic media results in
noncomparable containment of the waste. For example: With the design Table 1.2 (GEIS)
process and argument presented in GEIS, would a repository in granite Total Repository Acreage Required for 10,000 GWe-y Economy
200 m below the surface contain the wastes with the same level of effective- Spent Fuel U + Pu recycle
ness as the repository in salt at a depth of 580 m? Given the knowledge Salt 16,000 12,000
that large chambers in granite are feasible, different repository designs Granite 6,000 12,000
and waste storage designs should be considered. Shale 12,000 20,000
Basalt 6,000 12,000
o