| by-product materials and cover materials. Radon emissions from cover materials should be estimated as part of developing a closure plan for each site. The standard, however, applies only to emissions from by-product materials to the atmosphere. (q) In computing required by-product material cover thicknesses, moisture in soils in excess of amounts found normally in similar soils in similar circumstances may not be considered. Direct gamma exposure from the by-product material should be reduced to background levels. The effects of any thin synthetic layer may not be taken into account in determining the calculated radon exhalation level. Cover may not include materials that contain elevated levels of radium. Soils used for near-surface cover must be essentially the same, as far as radioactivity is concerned, as that of surrounding surface soils. If non-soil materials are proposed as cover materials, the licensee must demonstrate that such materials will not crack or degrade by differential settlement, weathering, or other mechanisms over the long term. (r) As soon as reasonably achievable after emplacement of the final cover to limit releases of radon-222 from uranium by-product material and prior to placement of erosion protection barriers of other features necessary for long-term control of the tailings, the licensee must verify through appropriate testing and analysis that the design and construction of the final radon barrier is effective in limiting releases of radon-222 to a level not exceeding 20pCi/m2 s averaged over the entire pile or impoundment using the procedures described in Appendix B, method 115 of 40 CFR Part 61, or another method of verification approved by the agency as being at least as effective in demonstrating the effectiveness of the final radon barrier. (s) When phased emplacement of the final radon barrier is included in the applicable reclamation plan, as defined in §336.1105(25) of this title, the verification of radon-222 release rates required in subsection (dd) of this section must be conducted for each portion of the pile or impoundment as the final radon barrier for that portion is emplaced. (t) Within 90 days of the completion of all testing and analysis relevant to the required verification in subsection (dd)(3) and (dd)(4) of this section, the uranium recovery licensee must report to the agency the results detailing the actions taken to verify that levels of release of radon-222 do not exceed 20 pCi/m2 s when averaged over the entire pile or impoundment. The licensee must maintain records documenting the source of input parameters, including the results of all measurements on which they are based, the calculations and/or analytical methods used to derive values for input parameters, and the procedure used to determine compliance. These records must be maintained until termination of the license and shall be kept in a form suitable for transfer to the custodial agency at the time of transfer of the site to the state or federal government in accordance with §336.1131 of this title (relating to Land Ownership of By-Product Material Disposal Sites). (u) Near-surface cover materials may not include waste, rock, or other materials that contain elevated levels of radium. Soils used for near-surface cover must be essentially the same, as far as radioactivity is concerned, as surrounding surface soils. This is to ensure that surface radon exhalation is not significantly above background because of the cover material itself. (v) The design requirements for longevity and control of radon releases apply to any portion of a licensed and/or disposal site unless such portion contains a concentration of radium in land averaged over areas of 100 square meters (m2 ), that, as a result of by-product material, does not exceed the background level by more than: (1) 5 picocuries per gram (pCi/g) of radium-226, or in the case of thorium by-product material, radium-228, averaged over the first 15 centimeters (cm) below the surface; and (2) 15 pCi/g of radium-226, or in the case of thorium by-product material, radium-228, averaged over 15-cm thick layers more than 15 cm below surface. (w) The licensee must also address the nonradiological hazards associated with the waste in planning and implementing closure. The licensee must ensure that disposal areas are closed in a manner that minimizes the need for further maintenance. To the extent necessary to prevent threats to human health and the environment, the licensee shall control, minimize, or eliminate post-closure escape of nonradiological hazardous constituents, leachate, contaminated rainwater, or waste decomposition products to groundwater or surface waters or to the atmosphere. (x) For impoundments containing uranium by-product materials, the final radon barrier shall be completed as expeditiously as practicable considering technological feasibility after the pile or impoundment ceases operation in accordance with a written reclamation plan, as defined in §336.1105(25) of this title, approved by the agency, by license amendment. (The term "As expeditiously as practicable considering technological feasibility" includes "Factors beyond the control of the licensee.") Deadlines for completion of the final radon barrier and applicable interim milestones shall be established as license conditions. Applicable interim milestones may include, but are not limited to, the retrieval of windblown by-product material and placement on the pile and the interim stabilization of the by-product material (including dewatering or the removal of freestanding liquids and recontouring). The placement of erosion protection barriers or other features necessary for long-term control of the by-product material shall also be completed in a timely manner in accordance with a written reclamation plan approved by the agency by license amendment. (y) The agency may approve by license amendment a licensee's request to extend the time for performance of milestones related to emplacement of the final radon barrier if, after providing an opportunity for public participation, the agency finds that the licensee has adequately demonstrated in the manner required in subsection (r) of this section that releases of radon-222 do not exceed an average of 20 pCi/m2 s. If the delay is approved on the basis that the radon releases do not exceed 20 pCi/m2 s, a verification of radon levels, as required by subsection (r) of this section, shall be made annually during the period of delay. In addition, once the agency has established the date in the reclamation plan for the milestone for completion of the final radon barrier, the agency may by license amendment extend that date based on cost if, after providing an opportunity for public participation, the agency finds that the licensee is making good faith efforts to emplace the final radon barrier, the delay is consistent with the definition of "Available technology," and the radon releases caused by the delay will not result in a significant incremental risk to the public health. (z) The agency may authorize by license amendment, upon licensee request, a portion of the impoundment to accept uranium by-product material, or such materials that are similar in physical, chemical, and radiological characteristics to the uranium mill tailings and associated wastes already in the pile or impoundment, from other sources during the closure process. No such authorization will be made if it results in a delay or impediment to emplacement of the final radon barrier over the remainder of the impoundment in a manner that will achieve levels of radon-222 releases not exceeding 20 pCi/m2 s averaged over the entire impoundment. The verification required in subsection (r) of this section may be completed with a portion of the impoundment being used for further disposal if the agency makes a final finding that the impoundment will continue to achieve a level of radon-222 release not exceeding 20 pCi/m2 s averaged over the entire impoundment. After the final radon barrier is complete except for the continuing disposal area, only by-product material will be authorized for disposal, and the disposal will be limited to the specified existing disposal area. This authorization by license amendment will only be made after providing opportunity for public participation. Reclamation of the disposal area, as appropriate, must be completed in a timely manner after disposal operations cease in accordance with subsection (p) of this section. These actions are not required to be complete as part of meeting the deadline for final radon barrier construction. (aa) The licensee's closure plan must provide reasonable assurance that institutional control will be provided for the length of time found necessary by the agency to ensure the requirements of subsection (p) of this section are met. (bb) Prior to any major site construction, a preoperational monitoring program must be conducted for one full year to provide complete baseline data on the site and its environs. Throughout the construction and operating phases of the project, an operational monitoring program must be conducted to measure or evaluate compliance with applicable standards and rules; to evaluate performance of control systems and procedures; to evaluate environmental impacts of operation; and to detect potential long-term effects. Cont'd... |
