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.

6.110<br />

With the basic technology for injecting radioactive wastes into geologic strata already<br />

available, these research and development requirements can be categorized into several dis-<br />

crete areas <strong>of</strong> development, as described below.<br />

System Data Base. It would be essential that the total R&D program be supported by a<br />

data base that covered all the components that could affect performance <strong>of</strong> the disposal sys-<br />

tem. The data base would cover the waste form, its modification, storage and injection, and<br />

the characteristics <strong>of</strong> the disposal formation from near to far field.<br />

Development <strong>of</strong> Criteria for and Categorization <strong>of</strong> Siting Opportunities. The two types <strong>of</strong><br />

well injection disposal methods, liquid and grout injection, would require significantly dif-<br />

ferent but clearly definable disposal formation characteristics. Disposal site selection<br />

would have to proceed in stages, starting with the derivation and assembly <strong>of</strong> specific cri-<br />

teria, followed by successive narrowing <strong>of</strong> the field <strong>of</strong> choice to a specific site or sites.<br />

This approach would provide valuable generic hydrogeological data at an early stage for<br />

subsequent use in other R&D studies. The selection process could be undertaken initially<br />

using available geologic and hydrologic data and techniques. At the site-specific level,<br />

however, the use <strong>of</strong> yet-to-be developed "nonpenetrative" techniques might be required to<br />

minimize the amount <strong>of</strong> down-hole exploration.<br />

Liquid and Slurry <strong>Waste</strong>s. A key facet <strong>of</strong> well injection is pretreatment <strong>of</strong> the liquid or<br />

slurry to a form that would be both compatible with the receiving formation and also the best<br />

use <strong>of</strong> the potential <strong>of</strong> that formation to fix and retain the nuclides. Optimum forms and re-<br />

quisite admixtures would have to be identified. The R&D program would have to proceed from<br />

the generic to the specific when the geochemistry <strong>of</strong> the disposal formation is known.<br />

Techniques for Predicting the Configuration <strong>of</strong> Injected <strong>Waste</strong>s. Fundamental to the con-<br />

cept <strong>of</strong> "safe" disposal <strong>of</strong> waste is the necessity to predict, with a high degree <strong>of</strong> accuracy,<br />

the configuration that the injected wastes, whether liquid or grout-fixed slurry, would adopt<br />

in the disposal formation for both the short and long term. The technology should provide<br />

this capability.<br />

For the liquid injection method, predictive capability is currently limited by the ex-<br />

isting data base. Numerical simulation techniques are available, but these do not cover the<br />

range <strong>of</strong> conditions that might be encountered. Mathematical models for geohydrological and<br />

geochemical interaction studies would be needed.<br />

"Nonpenetrative" Exploration Techniques. The presence <strong>of</strong> a drill hole could impair the<br />

isolation <strong>of</strong> a disposal site. At present, the majority <strong>of</strong> exploratory techniques require<br />

drilling at least one hole (and <strong>of</strong>ten several) to obtain reliable information from geological<br />

strata. R&D would be needed to develop nonpenetrative exploration techniques, similar to<br />

other geologic disposal methods.<br />

Sealing Systems. It is assumed that the sealing system for well injection would have to<br />

meet the same time requirements for sealing penetrations that a mined repository must meet.<br />

The primary purpose <strong>of</strong> the seal is to inhibit water transport <strong>of</strong> radionuclides from the waste

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

Saved successfully!

Ooh no, something went wrong!