[Code of Federal Regulations]
[Title 40, Volume 22]
[Revised as of July 1, 2003]
From the U.S. Government Printing Office via GPO Access
[CITE: 40CFR197.31]

[Page 64-65]
 
                   TITLE 40--PROTECTION OF ENVIRONMENT
 
         CHAPTER I--ENVIRONMENTAL PROTECTION AGENCY (CONTINUED)
 
PART 197--PUBLIC HEALTH AND ENVIRONMENTAL RADIATION PROTECTION STANDARDS 
FOR YUCCA MOUNTAIN, NEVADA--Table of Contents
 
    Subpart B--Public Health and Environmental Standards for Disposal
 
Sec. 197.31  What is a representative volume?

    (a) It is the volume of ground water that would be withdrawn 
annually from an aquifer containing less than 10,000 milligrams of total 
dissolved solids per liter of water to supply a given water demand. The 
DOE must project the concentration of radionuclides released from the 
Yucca Mountain disposal system that will be in the representative 
volume. The DOE must then use the projected concentrations to 
demonstrate a reasonable expectation to NRC that the Yucca Mountain 
disposal system complies with Sec. 197.30. The DOE must make the 
following assumptions concerning the representative volume:
    (1) It includes the highest concentration level in the plume of 
contamination in the accessible environment;

[[Page 65]]

    (2) Its position and dimensions in the aquifer are determined using 
average hydrologic characteristics which have cautious, but reasonable, 
values representative of the aquifers along the radionuclide migration 
path from the Yucca Mountain repository to the accessible environment as 
determined by site characterization; and
    (3) It contains 3,000 acre-feet of water (about 3,714,450,000 liters 
or 977,486,000 gallons).
    (b) The DOE must use one of two alternative methods for determining 
the dimensions of the representative volume. The DOE must propose its 
chosen method, and any underlying assumptions, to NRC for approval.
    (1) The DOE may calculate the dimensions as a well-capture zone. If 
DOE uses this approach, it must assume that the:
    (i) Water supply well(s) has (have) characteristics consistent with 
public water supply wells in the Town of Amargosa Valley, Nevada, for 
example, well-bore size and length of the screened intervals;
    (ii) Screened interval(s) include(s) the highest concentration in 
the plume of contamination in the accessible environment; and
    (iii) Pumping rates and the placement of the well(s) must be set to 
produce an annual withdrawal equal to the representative volume and to 
tap the highest concentration within the plume of contamination.
    (2) The DOE may calculate the dimensions as a slice of the plume. If 
DOE uses this approach, it must:
    (i) Propose to NRC, for its approval, where the location of the edge 
of the plume of contamination occurs. For example, the place where the 
concentration of radionuclides reaches 0.1% of the level of the highest 
concentration in the accessible environment;
    (ii) Assume that the slice of the plume is perpendicular to the 
prevalent direction of flow of the aquifer; and
    (iii) Assume that the volume of ground water contained within the 
slice of the plume equals the representative volume.

                          Additional Provisions