On August 29, 2016, the U.S. Nuclear Regulatory Commission (NRC) announced that additional questions and answers (Nos. 22, 23, and 24) regarding implementation of the revised Branch Technical Position on Concentration Averaging and Encapsulation (CA BTP) have been posted to the NRC public website at http://www.nrc.gov/waste/llw-disposal/llw-pa/llw-btp.html.
Overview
The regulatory requirements for licensing a low-level radioactive waste disposal facility describe a system for classifying low-level radioactive waste for near-surface disposal. Classification of low-level radioactive waste is based on the concentrations of certain radionuclides, and 10 CFR § 61.55(a)(8) specifically allows for averaging of concentrations in determining the waste class. The CA BTP expands on those regulatory requirements by describing acceptable averaging methods that can be used in classifying waste.
Additional Questions and Answers
On August 29, 2016, NRC posted the following additional questions and answers about implementation of the CA BTP to the public website:
- Section 3.2.1 of the CA BTP states that if blendable waste fills 90 percent or more of a package, average radionuclide concentrations can be based on the entire interior volume of the container. If a resin liner has the fill bar (inlet connection point) at the 85% full mark, could the liner be filled with other “blendable” radioactive material to achieve a volume of 90 percent full, thereby allowing the concentration to be based on the entire internal volume?
Yes, if the final package meets the disposal site waste acceptance criteria, the liner could be filled to 90 percent full with other blendable radioactive waste and the concentration could then be based on the entire internal volume. As discussed in the response to Question 7, small amounts of non-radioactive material also could be used.
The CA BTP states containers of blendable waste should be at least 90% full to take credit for the entire internal volume of the container in averaging. Alternately, the waste volume or mass should be used. This guidance is similar to the 1995 CA BTP position for soils and contaminated trash. It was extended to all blendable waste in the 2015 CA BTP for simplicity, so that there would be one position for blendable wastes. NRC staff notes that 10 CFR 61.56(b)(3) requires licensees to minimize void spaces within waste (and between waste and its package) to the extent practical.
- Section 3.2.3 of the CA BTP states that if multiple waste streams of a single waste type generated at a licensee’s facility are aggregated for the purposes of operational efficiency, occupational safety, or occupational dose reduction, the aggregated waste can be treated as a single waste stream for the purposes of the CA BTP. Does this mean that multiple waste streams (e.g., primary resin and secondary resin) placed in the same liner could be considered to be a single waste stream, thereby allowing the 90 percent fill provision of Section 3.2.1 to be used?
Yes, if primary and secondary resins are combined at a generating facility for operational efficiency, occupational safety, or occupational dose reduction, they can be treated as one waste stream and the 90 percent fill provision of Section 3.2.1 of the 2015 CA BTP can be applied.
- Does the treatment of multiple waste streams as a single waste stream discussed in Question 23 contradict the definition of a waste stream as defined in Section 1.1.1 of the 2015 BTP?
No. The 1995 CA BTP allowed waste streams aggregated at a generating facility for the purposes of operational efficiency or occupational dose reduction to be combined without being subject to any 1995 CA BTP constraints on “mixing”. The corresponding provision in the 2015 CA BTP is very similar to the text of the 1995 CA BTP except that it adds “occupational safety” (i.e., non-radiological industrial safety considerations) as an acceptable basis for applying the provision. The provision does not contradict the definition of a waste stream. Rather, it recognizes that different waste streams are being combined but allows them to be averaged as if they are a single waste stream if they are combined for specific purposes (i.e., operational efficiency, occupational safety, or occupational dose reduction).
Background
10 CFR Part 61, “Licensing Requirements for Land Disposal of Radioactive Waste,” provides licensing procedures, performance objectives, and technical requirements for the issuance of licenses for the land disposal of low-level radioactive waste. Four performance objectives, including protection of an inadvertent intruder into the waste disposal site, define the overall level of safety to be achieved by disposal. Intruder protection is provided in part by the waste classification concentration limits in 10 CFR § 61.55, which are designed to ensure that an inadvertent intruder is not exposed to unsafe levels of radiation. All low-level radioactive waste must be classified in accordance with the waste classification tables in 10 CFR § 61.55. Concentrations of radionuclides that are used to determine the waste classification may be averaged over the volume or weight of the waste, in accordance with 10 CFR § 61.55(a)(8).
NRC staff has published guidance that defines acceptable approaches for such concentration averaging. In 1983, the NRC issued, “Low-Level Waste Licensing Branch Technical Position on Radioactive Waste Classification,” one of the first guidance documents supporting Part 61. The waste classification technical position paper describes overall procedures acceptable to NRC staff that may be used by licensees to determine the presence and concentrations of the radionuclides listed in § 61.55, and thereby classifying waste for near-surface disposal.
In 1995, the NRC revised, in part, the 1983 “Low-Level Waste Licensing Branch Technical Position on Radioactive Waste Classification.” The initial 1983 guidance established a technical position on radioactive waste classification. The initial guidance included a section, “Concentration Volumes and Masses,” that provided guidance to waste generators on the interpretation of 10 CFR § 61.55(a)(8), as it applies to a variety of different forms and types of low-level waste. The 1995 CA BTP expands on, further defines, and replaces the guidance that was provided in Section C.3 of the original 1983 technical position. The 1995 Technical Position represents acceptable methods by which specific waste streams or mixtures of these waste streams may be classified.
In 2007, the NRC staff performed a strategic assessment of the NRC’s regulatory program for low-level radioactive waste. The staff undertook this effort in recognition of significant new and emerging low-level radioactive waste disposal issues. The strategic assessment identified a need to update the CA BTP. The CA BTP has the potential to increase the flexibility of disposal of certain types of low-level radioactive waste—particularly sealed sources, ion exchange resins, and irradiated hardware. The strategic assessment stated that the staff will use risk-informed approaches and knowledge that were not available when the BTP was developed and last updated in 1995.
In SECY-10-0043, NRC staff provided the Commission with an analysis of issues related to low-level radioactive waste blending. In the Staff Requirements Memorandum (SRM) for SECY-10-0043 (SRM-SECY-10-0043), the Commission directed the staff to revise the blending position in the CA BTP to be risk-informed and performance-based. With this decision, the staff was in a position to update the entire CA BTP—not only addressing blending, but also the remainder of the CA BTP topics that addressed mathematical averaging of radioactivity concentrations. Revising the CA BTP aligned with the NRC’s position of moving towards a risk-informed performance-based regulatory approach. Refer to the NRC public website on low-level radioactive waste blending for more information on this topic.
The final version of the CA BTP was published in February 2015. (See LLW Notes, March/April 2015, pp. 41-45.) Volume 1 (ML12254B065) is the actual guidance document and Volume 2 (ML12326A611) contains responses to stakeholder comments and the technical basis.
NRC staff anticipates questions regarding implementation of the BTP; therefore, staff will post questions (with answers) as they are received. The current list of questions/answers can be found in ADAMS (ML16237A374).
For additional information, please contact Don Lowman, Project Manager for NMSS/DSFM/SFLB, at (301) 415-5452 or at Donald.Lowman@nrc.gov.