[Code of Federal Regulations]

[Title 40, Volume 24]

[Revised as of July 1, 2006]

From the U.S. Government Printing Office via GPO Access

[CITE: 40CFR197.31]



[Page 67-68]

 

                   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    (a) It is the volume of ground water that would be withdrawn 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;

    (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.



[[Page 68]]



                          Additional Provisions