[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: 40CFR197.12]

[Page 61-62]
 
                   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. 197.12  What definitions apply in subpart B?

    All definitions in subpart A of this part and the following:
    Accessible environment means any point outside of the controlled 
area, including:
    (1) The atmosphere (including the atmosphere above the surface area 
of the controlled area);
    (2) Land surfaces;
    (3) Surface waters;
    (4) Oceans; and
    (5) The lithosphere.
    Aquifer means a water-bearing underground geological formation, 
group of formations, or part of a formation (excluding perched water 
bodies) that can yield a significant amount of ground water to a well or 
spring.
    Barrier means any material, structure, or feature that, for a period 
to be determined by NRC, prevents or substantially reduces the rate of 
movement of water or radionuclides from the Yucca Mountain repository to 
the accessible environment, or prevents the release or substantially 
reduces the release rate of radionuclides from the waste. For example, a 
barrier may be a geologic feature, an engineered structure, a canister, 
a waste form with physical and chemical characteristics that 
significantly decrease the mobility of radionuclides, or a material 
placed over and around the waste, provided that the material 
substantially delays movement of water or radionuclides.
    Controlled area means:
    (1) The surface area, identified by passive institutional controls, 
that encompasses no more than 300 square kilometers. It must not extend 
farther:
    (a) South than 36 deg. 40[min] 13.6661[sec] north latitude, in the 
predominant direction of ground water flow; and
    (b) Than five kilometers from the repository footprint in any other 
direction; and
    (2) The subsurface underlying the surface area.
    Disposal means the emplacement of radioactive material into the 
Yucca Mountain disposal system with the intent of isolating it for as 
long as reasonably possible and with no intent of recovery, whether or 
not the design of the disposal system permits the ready

[[Page 62]]

recovery of the material. Disposal of radioactive material in the Yucca 
Mountain disposal system begins when all of the ramps and other openings 
into the Yucca Mountain repository are sealed.
    Ground water means water that is below the land surface and in a 
saturated zone.
    Human intrusion means breaching of any portion of the Yucca Mountain 
disposal system, within the repository footprint, by any human activity.
    Passive institutional controls means:
    (1) Markers, as permanent as practicable, placed on the Earth's 
surface;
    (2) Public records and archives;
    (3) Government ownership and regulations regarding land or resource 
use; and
    (4) Other reasonable methods of preserving knowledge about the 
location, design, and contents of the Yucca Mountain disposal system.
    Peak dose means the highest annual committed effective dose 
equivalent projected to be received by the reasonably maximally exposed 
individual.
    Performance assessment means an analysis that:
    (1) Identifies the features, events, processes, (except human 
intrusion), and sequences of events and processes (except human 
intrusion) that might affect the Yucca Mountain disposal system and 
their probabilities of occurring during 10,000 years after disposal;
    (2) Examines the effects of those features, events, processes, and 
sequences of events and processes upon the performance of the Yucca 
Mountain disposal system; and
    (3) Estimates the annual committed effective dose equivalent 
incurred by the reasonably maximally exposed individual, including the 
associated uncertainties, as a result of releases caused by all 
significant features, events, processes, and sequences of events and 
processes, weighted by their probability of occurrence.
    Period of geologic stability means the time during which the 
variability of geologic characteristics and their future behavior in and 
around the Yucca Mountain site can be bounded, that is, they can be 
projected within a reasonable range of possibilities.
    Plume of contamination means that volume of ground water in the 
predominant direction of ground water flow that contains radioactive 
contamination from releases from the Yucca Mountain repository. It does 
not include releases from any other potential sources on or near the 
Nevada Test Site.
    Repository footprint means the outline of the outermost locations of 
where the waste is emplaced in the Yucca Mountain repository.
    Slice of the plume means a cross-section of the plume of 
contamination with sufficient thickness parallel to the prevalent 
direction of flow of the plume that it contains the representative 
volume.
    Total dissolved solids means the total dissolved (filterable) solids 
in water as determined by use of the method specified in 40 CFR part 
136.
    Undisturbed performance means that human intrusion or the occurrence 
of unlikely natural features, events, and processes do not disturb the 
disposal system.
    Undisturbed Yucca Mountain disposal system means that the Yucca 
Mountain disposal system is not affected by human intrusion.
    Waste means any radioactive material emplaced for disposal into the 
Yucca Mountain repository.
    Well-capture zone means the volume from which a well pumping at a 
defined rate is withdrawing water from an aquifer. The dimensions of the 
well-capture zone are determined by the pumping rate in combination with 
aquifer characteristics assumed for calculations, such as hydraulic 
conductivity, gradient, and the screened interval.
    Yucca Mountain disposal system means the combination of underground 
engineered and natural barriers within the controlled area that prevents 
or substantially reduces releases from the waste.