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

You also want an ePaper? Increase the reach of your titles

YUMPU automatically turns print PDFs into web optimized ePapers that Google loves.

332<br />

ALTERNATIVE DISPOSAL CONCEPTS<br />

As presented in the final Statement (Section 6.1.2), the reference case use <strong>of</strong> 3 cav-<br />

ities, each approximately 20 m in diameter (6000 m 3 volume) was selected on the basis <strong>of</strong><br />

engineering judgment and would be subject to extensive review if the option were pursued.<br />

Factors which entered in the judgment were numerous; e.g. ease <strong>of</strong> excavation, desired spa-<br />

cing to prevent interaction between cavities, the likelihood <strong>of</strong> a geologic formation <strong>of</strong><br />

appropriate size, etc. Many <strong>of</strong> the judgments were influenced by technical conservatism.<br />

It should be noted that there is probably some as yet undetermined minimum size <strong>of</strong><br />

cavity (corresponding to a maximum number <strong>of</strong> cavities) that will be required to accumulate<br />

a sufficient quantity <strong>of</strong> liquid waste. Smaller quantities, with very low attendent heat<br />

contents would not adequately melt the rock.<br />

Further details <strong>of</strong> the basis for selection <strong>of</strong> the cavity size can be obtained from the<br />

various documents listed in Appendix M <strong>of</strong> Volume 2 <strong>of</strong> the final Statement.<br />

Draft pp. 3.4.1-22<br />

Issue<br />

The treatment <strong>of</strong> "Rock Melt" in the GEIS misleads the reader as to the depth <strong>of</strong> inves-<br />

tigation which has been completed. For example in the first paragraph on p. 3.4.4 <strong>of</strong> the<br />

GEIS, it is stated: "The concept has been assessed and reviewed (4,5) and preliminary labor-<br />

atory scale investigations have been performed (6,7)." The workshop referred to as Refer-<br />

ence 5, as productive as it may have been, fell far short <strong>of</strong> assessing "Rock Melt." The<br />

laboratory scale investigations were designed to study the descent <strong>of</strong> solid containers by<br />

rock melting, not the molten cavity concept. (208-NRC)<br />

Response<br />

Section 6.1.2.3 <strong>of</strong> the final Statement more properly describes the status <strong>of</strong> knowledge<br />

regarding the rock melt concept. It is agreed that the original referenced text was<br />

misleading.<br />

Draft p. 3.4.1-22<br />

Issue<br />

While the potential for reduced cost certainly exists with this concept, it is hard to<br />

see how it could conceivably stand up to a "Circular 779" litany "uncertainties." In parti-<br />

cular, we cannot conceive <strong>of</strong> NRC licensing this concept for spent fuel--criticality ques-<br />

tions alone would doom the project. This entire section seems to be a rather blase treatment<br />

that not only reduces the concept's credibility but jeopardizes the credibility <strong>of</strong> the<br />

analyses <strong>of</strong> all the concepts. Some <strong>of</strong> the ideas and objectives are not bad, but achieving<br />

them with assurance seems very doubtful. This concept obviously lacks multiple barriers,<br />

control, retrievability, and opportunities for implementing contingency plans were things

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

Saved successfully!

Ooh no, something went wrong!