1. U.S. Low-Level Radioactive Waste Classification System 10 CFR Part 61 - Basis, Updates, and Issues
Boby Abu-Eid, Ph.D.
SLS Advisor
Division of Decommissioning, Uranium Recovery and Waste Programs
U.S. Nuclear Regulatory Commission
April 17, 2019
LLW Forum Meeting –Alexandria, VA

2. Topics
Applicability and Basis of LLW Classification under 10 CFR Part 61:
Applicability
Waste class limits under §61.55 Tables 1&2
Comparison with International waste classification (e.g.; GSG-1)
Waste classes limits and NRC ongoing activities:
Site-Specific Analysis & Waste Acceptance Criteria
Alternative Disposal Requests
VLLW
GTCC
Key Issues, Summary, and Conclusion

3. Applicability of 10 CFR Part 61
10 CFR Part 61 (Licensing Requirements for Land Disposal of Radioactive Waste):
Applies to Radioactive Waste (RW) containing byproduct, source, and special nuclear material (SNM).
Doesn’t apply to: HLW, Transuranic (TRU), Spent Nuclear Fuel (SNF), U/Th tailings, and licensed byproduct material under 10 CFR
Waste containing radionuclides exceeding §61.55 Table 1 limits or limits in Table 2, Column 3, (designated GTCC) are not generally acceptable for near surface disposal.
I note that the current definition of "waste" in 10 CFR 61.2, which excludes TRU, is based upon a law enacted in The 1980 law was superseded in its entirety by a 1985 law. The 1985 law changed the definition of LLRW; that definition no longer excludes TRU from the scope of LLRW. Thus, in any future Part 61 rulemaking, the NRC will most likely revise the definition of waste to include TRU (or at least some form or concentration level of TRU).
I also add that the Commission can allow for land disposal of GTCC waste on a case-by-case basis per 10 CFR 61.55(a)(2)(iv).

4. Basis of 10 CFR Part 61 Tables 1 & 2 Limits: Approach & Methodology
Set protection limits; derive scenarios for exposure; perform inverse calculations, and apply other factors to modify derived concentrations.
Waste classification tables were based on a 500 mrem (whole-body) exposure or other specific organ dose limits.
NUREGs-0782/0945 primarily considered two concentration-limited and one activity-limited intruder scenarios.
Concentration Limited Scenarios: Intruder-Construction (acute); and Intruder- Agriculture (chronic).
Common assumptions include: (a) institutional controls breakdown temporarily; (b) inadvertent intruder directly contacts waste; (c) intrusion occurs into last disposal cell constructed, and (d) waste remains locally dispersed.
Mention bullet #5 is based on 1981 analysis to support 1982 Ruke-making

5. Radionuclides Considered in the Waste Source
Four different sites described in Appendix J of DEIS.
Sites selected to represent a range of environmental conditions.
Divided based on NRC regions: Northeast, Southeast, Midwest, West.
Reference disposal facility – humid, Eastern site: Mainly based on where the waste would be generated.
Reference source term – 20 years, 1E6 m3
Environmental conditions for Southeastern site: Expected groundwater impacts to be largest.

6. Intruder Normal Activities Scenarios
Dwelling Construction
Drilling for Water
Agriculture

7. Dose Conversion Factors (DCFs) Calculations
Intruder Construction PDCFs: NUREG-0782, Tables G.4 and G.7
Intruder Agriculture PDCFs: NUREG-0782, Tables G.5 through G.7
Calculated in NUREG/CR-1759 (1981), Vol. 3, App. B
DCFs
Inhalation DCFs from Health Physics 12, 173 (1966) and ICRP 19 (1972).
Ingestion DCFs from Reg. Guide 1.109, Rev.1 (1977) and NUREG-0172 (1977).
Direct gamma (volume) DCFs calculated from equations in HASL-195 (1968) with emitted gamma energy characteristics in Table of Isotopes, 6th Ed. (1967).
Direct gamma (air) DCFs are from NUREG-0456 (1978).
No dilution of I-129 with natural iodine.
All of above use dosimetry from ICRP 2 (1959).

8. 10 CFR 61.55 Waste Classification Tables 1 & 2
Class A Waste: less than 0.1 of Table 1 values and less than Table 2 Column 1 values.
Class B: Table 2: Concentration exceeds Column 1 but less than column 2 of Table 2
Class C: Concentration exceeds 0.1 the values in Table 1 but does not exceed Column 1 values in Table 1; It also exceeds the value in Table 2 but does not exceed the value in Table 2 column 3.
GTCC: radionuclides concentrations exceeds the values in Table 1 or the value in Table 2, column 3;
Sum-of-fraction concept is used.

9. IAEA GSG-1 Generic Waste Classification Scheme and Illustrative Examples of Waste Categories for Sealed Sources
Note that the lines between the classes of waste in GSG-1 were fuzzy on purpose as the actual lines are based on site-specific considerations (what is possible between the total waste in a country (including waste form, volume, concentrations, etc) and disposal media available (e.g.; not every country has arid sites).

10. Example of Disused Sealed Sources Classes Based on IAEA GSG-1
Example Half-life Activity Volume Example Waste Class
i <100 d MBq Small Y-90, Au-198 VSLW
(brachytherapy)
ii <100 d TBq Small Ir VSLW (brachytherapy)
iii <15 a <10 MBq Small Co-60, H-3 LLW (tritium targets), Kr-85
iv <15 a <100 TBq Small Co-60 LLW (irradiators)
v <30 a <1 MBq Small Cs LLW (brachytherapy, moisture density detectors)
vi <30 a <1 PBq Small Cs ILW (irradiators) Sr (thickness gauges, RTGs)
vii >30 a <40 MBq Small, but may Pu, Am, Ra (static ILW
be large number eliminator)
viii >30 a <10 GBq large numbers of Am-241, Ra ILW
sources (gauges)
Example of Disused Sealed Sources Classes Based on IAEA GSG-1
This slides was modified from IAEA GSG-1 to provide perspective of range of total activity and examples for each waste category for disused sealed sources. Note that in most cases with significant total activity, waste containing radionuclides with t1/2 >30 y is placed in the ILW category.

11. U.S. NRC Waste Categories
International Atomic Energy Agency Waste Categories
U.S. NRC Waste Categories
High Level Waste
Intermediate Level Waste
Greater-than-Class C LLW
Low Level Waste (LLW)
Class A, Class B and C LLW
A portion of GTCC?
Very Low Level Waste
Class A
Very Short Lived Waste
Material held for decay storage
Exempt Waste
Liquids/Air: Effluent releases
Solids: Case-by-case analysis
Comparison of IAEA
Waste Management Categories with
U.S.
Comparison between IAEA and NRC is approximate
Note that the lines between the classes of waste in GSG-1 were fuzzy on purpose as the actual lines are based on site-specific considerations (what is possible between the total waste in a country (including waste form, volume, concentrations, etc) and d
disposal media available (e.g.; not every country has arid sites).
I have the following recommendations and comments:
Notes to read:
1) Under its current regulation, 10 CFR 61.55(a)(2)(iv), the NRC states that the default disposal path for GTCC waste is a geologic repository, although the Commission may approve a Part 61 land disposal alternative on a case-by-case basis. As such, I recommend that the HLW box under U.S. (NRC) Waste Categories should be "High Level Waste, GTCC." However, this will be confusing since LLW is defined by exclusion of HLW.
3) The NRC has not defined, in its Part 61 regulations, "intermediate level waste." I recommend that you mention that (could be in a talking point). Based upon my discussions with technical staff, there is a fairly good conception of intermediate level disposal and that such disposal may be a viable option for many if not all GTCC waste streams. Thus, I recommend that you delete the question mark after GTCC in the intermediate level waste row.
4) Given the Commission tasking to develop a draft regulatory basis for the near-surface disposal of GTCC (SRM-SECY ), I recommend, in the LLW row, that the second line be revised to read as follows "Potential GTCC (subject of draft regualtory basis to be issued in May/June 2019)."

12. Waste Class Limits: Site-Specific Analysis
New limits based on site-specific analysis could be established based on:
Use of different dose conversion factors
Use of site-specific exposure scenarios
Use of site-specific physical input parameters
Use of updated models/codes
Use of risk-informed probabilistic approach (inputs & results)
All of above would lead to different waste acceptance criteria
Limits established in Tables I & II wouldn’t be applicable to site-specific analysis.
Emphasize:
The licensee will have the option to use the Tables or the site-specific analysis to develop their WAC,
Ongoing activities related to part 61 supplemental rulemaking as well as GTCC

13. Waste Class Limits: Alternative Disposal Request (ADR) Reviews
ADR for disposal of licensed materials of usually low-activity and quantity waste under 10 CFR
§ does not have specific dose limits. However, NUREG-1757, Vol. 1 Section refers specifically to on-site disposal of 0.05 mSv/y (5 mrem/y) and use of risk-informed probabilistic approach using updated dosimetry and models.
Licensees may request approval for disposal of waste off-site under §  in a landfill. The derived radionuclide concentrations and inventories may represent a significant fraction of Class A lower limits.
Exempt waste category and/or conditional clearance materials may be disposed under ADR using site-specific analysis on a case-by-case bases.
Based on safety criteria only, a fraction of Class A waste may disposed under ADR.
Bullet 2: has an upper limit in it which is 100 mrem/y public dose limit. As a matter of policy, we approve individual request generally at 5 mrem/y.
Although §  does not specify a dose limit, as stated above and in Section 7.2.1, guidance in NUREG-1757, Vol. 1, references “a few mrem” per year (i.e., 0.05 mSv per year (5 mrem per year)) as one potential guideline for on-site disposals. While NUREG-1757, Vol. 1, Section refers specifically to on-site disposals, 0.05 mSv per year (5 mrem per year) may be and has previously been used as a benchmark for off-site disposals. Nonetheless, acceptable values for the dose may vary based on unique scenarios for both on-site and off-site disposals and are evaluated on a case-by-case basis. The dose guidelines for evaluating requests for § 40.13(a) disposals are described in detail in Section
Licensees may request approval to disposal of waste off-site under §  or § 40.13(a). Off-site disposals are most often at a disposal facility with a State or Federal permit that is not a licensed LLW disposal facility.

14. Waste Class Limits: Very Low-Level Waste (VLLW) Scoping Study
IAEA GSG-1 defines VLLW as:
Waste that does not meet the criteria of exempt waste, but does not need a high level of containment and isolation, and, therefore, is suitable for disposal in a near surface landfill type facility with limited regulatory control.
The NRC currently does not have a formal regulatory definition for VLLW.
Options that may be considered in the VLLW Scoping Study: (a) limited scope rulemaking; (b) developing guidance specific to VLLW including modifying the ADR guidance; and (c) status quo. See also 83 Fed. Reg

15. Waste Classes Limits: GTCC
GTCC LLW is defined based on the upper limits of Class C waste.
Licensees or applicants may request on a case-by-case approval (61.55(a)(2)(iv) using similar methodology to Part 61, but using updated DCFs, models, scenarios and probabilistic analysis approach;
Site-specific analysis may result in different case-by-case approved GTCC volumes/inventories because of site differences;
NRC is currently evaluating whether some or all of GTCC can be disposed in the near surface. A draft regulatory basis is planned to be issues in the next few months.
Upper limits may be changed based on updated DCFs. Based on a cse-by-case basis

16. Waste Acceptance Criteria
Licensees would review their waste acceptance program at least annually
Ensures that the program continues to be adequate and is being implemented in a way that continues to protect public health and safety
RefeTo follow up on Ian's comment above, I recommend that you add to either the slide title or add a bullet point stating that the WAC is based upon the staff's proposed rule, which will be re-issued as either a re-proposed rule or a supplemental proposed rule.
Also, please note that SRM-SECY prescribed the draft final rule--any statements on these slides should be consistent with the Commission direction in SRM-SECY
This comment also applies to the next slide.rence NUREG-2175
Draft NUREG-2175

17. 10 CFR Part 61 Waste Acceptance Criteria
Allowable Limits on Radioactivity
Waste-form Characteristics and Container Specifications
Restrictions and Prohibitions
To follow up on Ian's comment above, I recommend that you add to either the slide title or add a bullet point stating that the WAC is based upon the staff's proposed rule, which will be re-issued as either a re-proposed rule or a supplemental proposed rule.
Also, please note that SRM-SECY prescribed the draft final rule--any statements on these slides should be consistent with the Commission direction in SRM-SECY
This comment also applies to the next slide.Reference NUREG-2175
Draft NUREG-2175

18. Key Issues in 10 CFR Part 61 Classification
Considering a generic LLW disposal facility concentration limits in Tables 1 and 2 that are not up-to-date because they are:
Based on superseded dosimetry ICRP 2 (1959)
Based on superseded models/codes, and software
Based on risk to intruder using deterministic approach
Considered disposal options under the stringent Part 61 requirements for all waste, no lower limits for exemptions, clearance, or short-lived nuclides
10 CFR Part 61 did not consider certain waste streams such as DU ,
International “Waste Acceptance Criteria” is typically based on site -specific analysis.
However LLW disposal sites under Part 61 are protective and safe.

19. Summary & Conclusion
Current LLW classification system has provided adequate safety measures; however, there are several potential enhancements.
The concept of deriving waste classes limits based on a generic site with stringent requirements for all waste categories continues to be useful, but alternate risk-informed, performance-based approach could be viable.
ADR process allows for disposal of waste onsite or in RCRA facilities.
NRC is currently evaluating whether some or all of GTCC waste can be disposed of in a near surface facility.
The concept that GTCC waste cannot be disposed, on generic basis, in a land disposal facility should be revised.
The proposed Part 61 rulemaking has made changes to the rule that may allow use of site-specific waste acceptance criteria.
The Commission has directed staff to change the definition of LLW to be consistent with the 1985 Low-Level Waste Policy Act Amendments.
Are the statements in this slide official agency positions? I ask because they appear to do more than summarize the presentation. These statements contain policy positions, e.g., revisions to the rules are needed, revisions to Commission policy are needed, the NRC should be flexible. If these are not official agency positions, then you'll need to revise them to either be statements of fact and/or accurate restatements of official agency positions.
agency position that the NRC should be "flexible" in reviewing and granting and 40.13(a) requests. Rephrase this bullet to say "ADR process allows for disposal of waste categories onsite or in RCRA facilities.

20. Backup Slides

21. Site-Specific Analysis
NUREG-2175 (Guidance for Conducting Technical Analyses for 10 CFR Part 61) provides:
Flowcharts, NRC staff recommendations, and examples for how licensees can develop high-quality technical analyses
Guidelines for what licensees or applicants should include and what regulators should review for each type of analysis
Suggested references, screening tools, and case studies
DRAFT final version made publically available in ADAMS and on the public website

22. 10 CFR Part 61 Dose Impact Calculation
The scenarios employ common expressions for dose equivalent, H (mrem):
H = ∑i,j PDCF x Ca, where:
PDCF ≡ Pathway Dose Conversion Factor,
(mrem per Ci/m3)
Ca ≡ [Radionuclide]access point, (Ci/m3)
i ≡ Radionuclide index
j ≡ Pathway index

23. Dose Impacts Calculations (Cont’d)
Ca = I x Cw, where:
Cw ≡ [Radionuclide]waste, (Ci/m3)
I = fo x fd x fw x fs, where:
I ≡ Interaction Factor, (-)
fo ≡ Time-delay factor, (-)
fd ≡ Site design and operation factor, (-)
fw ≡ Waste form and package factor, (-)
fs ≡ Site selection factor, (-)
Interaction factors:
Used to translate concentrations in waste to concentrations at exposure points.
Many interaction factors are derived in the analyses.
Today would likely be replaced by models and data.
See backup slides for examples.
Computer codes used:
Five computer codes used for DEIS: INTRUDE, OPTIONS, GRWATER, INVERSI, and INVERSW.
Two modified versions added for FEIS: OPTIONR and GRWATRR.
See Appendix D of NUREG-0945.
INTRUDE – radiological impacts resulting from potential human intrusion into a selected disposal facility location and design containing waste processed through one of the aforementioned waste spectra.
OPTIONS – waste volume-averaged inadvertent intruder impacts, impacts resulting from exposed waste scenarios, as well as impacts resulting from operational accidents.
GRWATER – individual exposures resulting from use of contaminated water drawn from various human access locations such as a well that may become contaminated.
INVERSI – calculates limiting concentrations in waste to meet a specific dose criterion for a specific design.
INVERSW – same as INVERSI but for groundwater migration and specific environmental conditions.