23.04.2013 Views

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

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

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

SHOW MORE
SHOW LESS

Create successful ePaper yourself

Turn your PDF publications into a flip-book with our unique Google optimized e-Paper software.

7<br />

WASTE PROGRAM<br />

the attention <strong>of</strong> the decisionmakers, as has been done in this Statement (see final Sec-<br />

tions 4.7, 5.4, 7.5). Further refinements in the estimates <strong>of</strong> use <strong>of</strong> resources will be<br />

developed for site specific statements.<br />

Issue<br />

Several commenters stated that program approaches and geologic disposal choices should<br />

require retrievability <strong>of</strong> wastes after emplacement (i.e., to take advantage <strong>of</strong> improvements<br />

intechnology or discovery <strong>of</strong> a more acceptable site, to provide availability <strong>of</strong> access in<br />

case <strong>of</strong> malfunction, and to take advantage <strong>of</strong> the potential future resource value <strong>of</strong> the<br />

waste). (3, 27, 45, 96, 151, 164, 187, 196, 205)<br />

Response<br />

DOE defines retrievability as the removal <strong>of</strong> waste following emplacement in a repos-<br />

itory but prior to closure <strong>of</strong> the repository system (backfilling <strong>of</strong> rooms and shafts). The<br />

initial emplacement <strong>of</strong> wastes so that they can be retrieved for periods <strong>of</strong> five and up to<br />

twenty-five years following placement, is a basis for the analysis <strong>of</strong> geologic repositories<br />

in this Statement. Further discussion <strong>of</strong> retrievability is in Section 5.3 and a description<br />

<strong>of</strong> requirements for five and twenty-five year ready retrievability is provided in<br />

Appendix K. The exact period <strong>of</strong> retrievability that will be required for a waste repository<br />

has not yet been determined.<br />

Initial emplacement <strong>of</strong> waste in at least the first repository will permit retrievab-<br />

ility for some initial period <strong>of</strong> time to allow for removal <strong>of</strong> emplaced wastes if unexpected<br />

phenomena are observed which could lead to the failure <strong>of</strong> the repository system to provide<br />

the required isolation or containment <strong>of</strong> the radioactive wastes.<br />

Since the radioactive wastes are continually undergoing radioactive decay, the heat<br />

emission and radiation levels will be constantly decreasing. Consequently, the period<br />

immediately following waste emplacement will provide the most severe conditions on the<br />

nearfield environment. At the same time, accelerated tests will be performed at the repos-<br />

itory level with artificially heated or concentrated waste forms, probably in closer arrays,<br />

to seek out any unpredicted phenomena. After an initial period <strong>of</strong> operations, much greater<br />

confidence in the understanding <strong>of</strong> the interaction between the waste and the repository<br />

structure will have been gained and permission to abandon the ability for ready retrieval<br />

will be sought from the NRC.<br />

Issues<br />

Several commenters expressed concern about the multiple barrier concept:<br />

e More research and development is needed in the area <strong>of</strong> rock mechanics. (21)<br />

7,

Hooray! Your file is uploaded and ready to be published.

Saved successfully!

Ooh no, something went wrong!