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

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Comment
Comment
Number Number
final for such a large region and cannot be justified without detailed ~.e.8 Section 3.6.2.3
discussion.
This section starts off with the identification of the barriers to the
movement of radionuclides, then fails to discuss two of them: "any
A much more reasonable and specific statement is that made for fracture controlled modification of the medium," and "the benthic boundary layer."
zones in the mid-ocean ridge: "On the basis of present knowledge, A discussion of these barriers should be provided.
therefore, the fracture zones are not probable candidates as study sites."
4.e.9 p. 3.6.7
Similarly.the statement, "The abyssal plains...are therefore unacceptable Previous reports on the U.S. seabed disposal program have not included the
for further consideration." should be modified, water column as a design barrier. Is it.the program's intention to now
identify the water column as a primary design barrier to radionuclide
4.e.5 p. 3.6.4 migration, or rather to investigate its properties as a barrier only for
It is stated that: "Bottom currents in the MPG areas of the North Pacific unexpected releases? In other words, do the conceptual plans allow for
are generally weak and variable." A reference should be provided. How radionuclides to enter the water column during the period when they may
weak and variable bottom currents affect emplacement, radionuclide present a hazard to man or the ecosysteip? What is meant by inadvertant
migration, heat transfer, etc. should be discussed. release? Scenarios leading to inadvertant release should be described.
4.e.6 p. 3.6.4 4.e.10 p. 3.6.20
The sediment thickness is reported to be 50 to 100 meters, while in Under the discussion of the water column, it should be recognized that
Table 3.6.1 it is given as 100'to 300 meters. while the water column may not provide a barrier to migration, its
enormous capability to dilute such releases below significant concentrations
4.e.7 p. 3.6.4 cannot be overlooked as a mitigative feature (See comment 4.e.9).
A statement is made regarding waste disposal in trenches: "...a plate
being subducted would have moved only tens of kilometers during that time 4.e.11 p. 3.6.21
(250 to 500 thousand years) and would not be subducted fast enough for The research and development costs to support the penetrometer emplacement
waste disposal purposes." This conclusion does not follow from the concept are quoted as $250 million, on page 3.6.21, and as $60 million on
discussion proceeding it in the same paragraph. page 3.6.31. The components of each figure should be given. What is the
meaning of "state-of-the-art" (Figure 3.6.1) referring to penetrometer
a. How far would the waste have to move during that time to be subducti emplacement, given the quarter of a billion dollar research and
fact enough-for waste disposal purposes? Reference? development cost estimate?
b. What might the impact be of the waste not being subducted fast 4.e.12 p. 3.6.24
enough? It should be made clear that tsunamis could pose no danger to a ship that
was not in shallow, near shore waters, or near the source of tsunami.
Even a large tsunami would probably not be noticed by a ship in mid-ocean