The definitions, abbreviations, and acronyms in this section and in WAC 246-220-010 apply throughout this chapter unless the context clearly indicates otherwise.

(1) "Aquifer" means a geologic formation, group of formations, or part of a formation capable of yielding a significant amount of groundwater to wells or springs. Any saturated zone created by uranium or thorium recovery operations would not be considered an aquifer unless the zone is, or potentially is (a) hydraulically interconnected to a natural aquifer, (b) capable of discharge to surface water, or (c) reasonably accessible because of migration beyond the vertical projection of the boundary of the land transferred to long-term government ownership and care in accordance with WAC 246-252-030(11).

(2) "As expeditiously as practicable considering technological feasibility," for the purposes of Criterion 6A, means as quickly as possible considering: The physical characteristics of the tailings and the site; the limits of available technology; the need for consistency with mandatory requirements of other regulatory programs; and factors beyond the control of the licensee. The phrase permits consideration of the cost of compliance only to the extent specifically provided for by use of the term "available technology."

(3) "Available technology" means technologies and methods for emplacing a final radon barrier on uranium mill tailings piles or impoundments. This term shall not be construed to include extraordinary measures or techniques that would impose costs that are grossly excessive as measured by practice within the industry (or one that is reasonably analogous), (such as, by way of illustration only, unreasonable overtime, staffing, or transportation requirements, considering normal practice in the industry; laser fusion of soils), provided there is reasonable progress toward emplacement of the final radon barrier. To determine grossly excessive costs, the relevant baseline against which cost shall be compared is the cost estimate for tailings impoundment closure contained in the licensee's approved reclamation plan, but costs beyond these estimates shall not automatically be considered grossly excessive.

(4) "Closure" means the activities following operations to decontaminate and decommission the buildings and site used to produce by-product materials and reclaim the tailings or waste disposal area.

(5) "Closure plan" means the department approved plan to accomplish closure.

(6) "Compliance period" begins when the department sets secondary groundwater protection standards and ends when the owner or operator's license is terminated and the site is transferred to the state or federal agency for long-term care.

(7) "Dike" means an embankment or ridge of either natural or man-made materials used to prevent the movement of liquids, sludges, solids, or other materials.

(8) "Disposal area" means the area containing by-product materials to which the requirements of Criterion 6 apply.

(9) "Existing portion" means that land surface area of an existing surface impoundment on which significant quantities of uranium or thorium by-product materials had been placed prior to September 30, 1983.

(10) "Factors beyond the control of the licensee" means factors proximately causing delay in meeting the schedule in the applicable reclamation plan for the timely emplacement of the final radon barrier notwithstanding the good faith efforts of the licensee to complete the barrier in compliance with paragraph (a) of Criterion 6A. These factors may include, but are not limited to:

(a) Physical conditions at the site;

(b) Inclement weather or climatic conditions;

(c) An act of God;

(d) An act of war;

(e) A judicial or administrative order or decision, or change to the statutory, regulatory, or other legal requirements applicable to the licensee's facility that would preclude or delay the performance of activities required for compliance;

(f) Labor disturbances;

(g) Any modifications, cessation or delay ordered by state, federal, or local agencies;

(h) Delays beyond the time reasonably required in obtaining necessary government permits, licenses, approvals, or consent for activities described in the reclamation plan proposed by the licensee that result from agency failure to take final action after the licensee has made a good faith, timely effort to submit legally sufficient applications, responses to requests (including relevant data requested by the agencies), or other information, including approval of the reclamation plan; and

(i) An act or omission of any third party over whom the licensee has no control.

(11) "Final radon barrier" means the earthen cover (or approved alternative cover) over tailings or waste constructed to comply with Criterion 6 of WAC 246-252-030 (excluding erosion protection features).

(12) "Groundwater" means water below the land surface in a zone of saturation. For the purposes of this chapter, groundwater is the water contained within an aquifer as defined above.

(13) "Leachate" means any liquid, including any suspended or dissolved components in the liquid, that has percolated through or drained from the by-product material.

(14) "Licensed site" means the area contained within the boundary of a location under the control of persons generating or storing by-product materials under a department license.

(15) "Liner" means a continuous layer of natural or man-made materials, beneath or on the sides of a surface impoundment which restricts the downward or lateral escape of by-product material, hazardous constituents, or leachate.

(16) "Milestone" means an action or event that is required to occur by an enforceable date.

(17) "Operation" means that a uranium or thorium mill tailings pile or impoundment is being used for the continued placement of by-product material or is in standby status for such placement. A pile or impoundment is in operation from the day that by-product material is first placed in the pile or impoundment until the day final closure begins.

(18) "Point of compliance" is the site specific location in the uppermost aquifer where the groundwater protection standard must be met.

(19) "Reclamation plan," for the purposes of Criterion 6A, means the plan detailing activities to accomplish reclamation of the tailings or waste disposal area in accordance with the technical criteria of WAC 246-252-030. The reclamation plan must include a schedule for reclamation milestones that are key to the completion of the final radon barrier including as appropriate, but not limited to, wind blown tailings retrieval and placement on the pile, interim stabilization (including dewatering or the removal of freestanding liquids and recontouring), and final radon barrier construction. (Reclamation of tailings must also be addressed in the closure plan; the detailed reclamation plan may be incorporated into the closure plan.)

(20) "Surface impoundment" means a natural topographic depression, man-made excavation, or diked area, which is designed to hold an accumulation of liquid wastes or wastes containing free liquids, and which is not an injection well.

(21) "Uppermost aquifer" means the geologic formation nearest the natural ground surface that is an aquifer, as well as lower aquifers that are hydraulically interconnected with this aquifer within the facility's property boundary.