(1) Near-surface disposal facility operation and disposal site closure.

(a) Wastes designated as Class A pursuant to chapter 246-249 WAC shall be segregated from other wastes by placing in disposal units which are sufficiently separated from disposal units for the other waste classes so that any interaction between Class A wastes and other wastes will not result in the failure to meet the performance objectives of this chapter. This segregation is not necessary for Class A wastes if they meet the stability requirements in chapter 246-249 WAC.

(b) Wastes designated as Class C pursuant to chapter 246-249 WAC shall be disposed of so that the top of the waste is a minimum of five meters below the top surface of the cover or must be disposed of with intruder barriers that are designed to protect against an inadvertent intrusion for at least five hundred years.

(c) Except as provided in (l) of this subsection, only waste classified as Class A, B, or C shall be acceptable for near-surface disposal. All waste shall be disposed of in accordance with the requirements of (d) through (k) of this subsection.

(d) Wastes shall be emplaced in a manner that maintains the package integrity during emplacement, minimizes the void spaces between packages, and permits the void spaces to be filled.

(e) Void spaces between waste packages shall be filled with earth or other material to reduce future subsidence within the fill.

(f) Waste shall be placed and covered in a manner that limits the radiation dose rate at the surface of the cover to levels that at a minimum will permit the licensee to comply with all provisions of chapter 246-221 WAC at the time the license is transferred pursuant to WAC 246-250-140.

(g) The boundaries and locations of each disposal unit shall be accurately located and mapped by means of a land survey. Near-surface disposal units shall be marked in such a way that the boundaries of each unit can be easily defined. Three permanent survey marker control points, referenced to United States Geological Survey (USGS) or National Geodetic Survey (NGS) survey control stations, shall be established on the site to facilitate surveys. The USGS or NGS control stations shall provide horizontal and vertical controls as checked against USGS or NGS record files.

(h) A buffer zone of land shall be maintained between any buried waste and the disposal site boundary and beneath the disposed waste. The buffer zone shall be of adequate dimensions to carry out environmental monitoring activities specified in WAC 246-250-340(4) and take mitigative measures if needed.

(i) Closure and stabilization measures as set forth in the approved site closure plan shall be carried out as each disposal unit is filled and covered.

(j) Active waste disposal operations shall not have an adverse effect on completed closure and stabilization measures.

(k) Only wastes containing or contaminated with radioactive material shall be disposed of at the disposal site.

(l) Proposals for disposal of waste that is not generally acceptable for near-surface disposal because the waste form and disposal methods must be different and, in general, more stringent than those specified for Class C waste, may be submitted to the department for approval.

(2) (Reserved.)