ML20246Q226
| ML20246Q226 | |
| Person / Time | |
|---|---|
| Issue date: | 05/12/1989 |
| From: | Lohaus P NRC OFFICE OF NUCLEAR MATERIAL SAFETY & SAFEGUARDS (NMSS) |
| To: | Matthews M ENERGY, DEPT. OF |
| References | |
| REF-WM-39 NUDOCS 8905220417 | |
| Download: ML20246Q226 (7) | |
Text
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1-4 MAY 121989 "Mr. Mark Matthews, Acting Project Manager Uranium Mill Tailings Project Office U.S.' Department of Energy P.O.. Box 5400 Albuquerque, New Mexico 87115
Dear Mr. Matthews:
In response to_your memorandum to me and others dated March 24, 1989, we have reviewed DOE's document entitled " Regulatory Alternatives for Groundwater-Compliance for the Department of Energy's UMTRA Project. Alternate -
Concentration Limits, Supplemental Standards, and Institutional Controls."
Based on our review, we conclude that the procedures described in the document are generally consistent with NRC's " Draft Technical Position on Information i
Needs to Demonstrate Compliance with EPA's Proposed Groundwater Protection Standards in 40 CFR Fart 192, Subpart A.C" and " Draft Technical Position on Alternate Concentration Limits for Uranium Mills." The enclosure provides specific comments and suggestions that you should consider in finalizing the Regulatory Alternatives document.
You may wish to defer revising the-document until after EPA promulgates final groundwater protection standards for the UMTRA Project.
This review was prepared by Michael Weber. Please contact him at telephone number FTS 492 0565 if you wish to discuss the enclosed comments and suggestions.
Sincerely, (SIGNED) PAULH.LOHAUS Paul H' Lohaus, Chief Operations Branch Division of Low-Level Waste Managenent and Decommissioning, NMSS
Enclosure:
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l NRC COMMENTS ON DOE'S DRAFT 1
"PEGULATORY ALTERNATIVES FOR GROUNDWATER STANDARDS FOR THE DOE'S UMTRA PROJECT - ALTERNATE CONCENTRATION LIMITS, SUPPLEMENTAL STANDARDS, AND INSTITUTIONAL CONTROLS" MAY 1989 General Based on its review, the NRC staff concludes that the procedures described in
" Regulatory Alternatives for Groundwater Standards for the DOE's UMTRA Project
- Alternate Concentration Limits, Supplemental Standards, and Institutional Controls" are generally consistent with NRC's " Draft Technical Position on Information Needs to Demonstrate Compliance with EPA's Proposed Groundwater Protection Standards in 40 CFR Part 192, Subpart A-C" and " Draft Technical Position on Alternate Concentration Limits for Uranium Mills."-
Specific 1.
Section 1.0, Page 3; Section 3.1, Page 48; Section 3.4, Page 58; Section 3.5, Page 60 The text states that three supplemental standard criteria apply to groundwater at UMTRAP sites. This description omits three other applicability criteria for supplemental standards that could apply for groundwater, including:
(1) Remedial actions required to satisfy Subparts A or B would pose a clear and present risk of injury to workers or to members of the public, notwithstanding reasonable measures to avoid or reduce risk [40 CFR-192.21(a)];
(2) There is no known remedial action [40 CFR 192.21(e)]; and (3) Radionuclides other than Radium-226 and its decay products are present in sufficient quantity and concentration to constitute a significant radiation hazard from residual radioactive materials [40 CFR 192.21(h)].
The Regulatory Alternatives document should be revised to include the three additional criteria listed above.
J 2.
Section 2.1, Page 7 The first paragraph of this section states that site-specific groundwater protection standards must establish concentration limits for each constituent i
of concern listed in either 40 CFR Part 192 or Appendix VIII of 40 CFR Part 261. This paraphrase of the' standards is incorrect because it'would require DOE to propose concentration limits for all of the hazardous constituents listed in Appendix VIII and 40 CFR Part 192 regardless of their presence in contaminated materials or groundwater at a given site. As provided in EPA's 1
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proposedstandardsin40CFRPart192.02(a)(3),hazardousconstituentssatisfy three criteria: (1) they'are listed in Appendix VIII of 40 CFR Part 261 or Subpart A of 40 CFR Part 192, (2) they are ex derived from the contaminated material, and (pected to be in or reasonably 3) they ha groundwater. Most cf the constituents listed in Arpendix VIII are generally.
not expected tc be in or derived from uranium mill.ailings. Thus, the list of hazardous constituents at a particular site would be expected to be-
-l considerably less than the combined lists of Appendix VIII and 40 CFR Part 192.
The Regulatory Alternatives document should be revised to paraphrase EPA's proposed standards correctly with respect to selecting hazardous constituents on a site-specific basis.
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3.
Section 2.1, Page 10 The terms " quantity" and " quality" in factors 3 and 6 have been inadvertently switched in the list of considerations for assessing potential adverse effects on groundwater quality. The Regulatory Alternatives document should be revised to list the considerations correctly es provided in 40 CFR Part 264.94(b).
i 4.
Figure 2.4, Page 29 1
The bottom block of the Risk Assessment Outline should state " Propose j
Acceptable Concentration Limit" or " Propose Health and Environmental Limit,"
rather than " Propose Alternate Concentration Limit." ACL proposals must demonstrate that proposed limits are as low.as reasonably achievable (ALARA).
j considering practicable corrective action, in addition to protection of humant and the environment. Thus, ACLs cannot be proposed based on risk assessment L
alone, contrary to the logic portrayed in Figure 2.4.
The Regulatory l
Alternatives document should be revised to correct the figure accordingly.
5.
Section 2.5.4, Page 40 This section should be revised to state that Figure 2.5 presents results for a hypothetical site.
In addition, actual benefit evaluations would be expected
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to consider combinations of alternatives in the range of alternative design configurations.
6.
Section 2.5.5, Page 42 i
The' text states that ACLs will be determined by selecting an ALARA design and then completing the risk assessment for each constituent. This approach may i
not produce acceptable ACLs unless the ALARA concentrations are less than or l
L equal to concentrations that are protective of human health and the environment. EPA's proposed standards in 40 CFR Part 192.02(a)(3)(v) provide l
l for the establishment of ACLs if they are ALARA and they prevent substantial I
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present or future hazards.to humans and the environment, as provided in 40 CFR Part264.94(b).
By pursuing the approach described in the Regulatory Alternatives document at an actual site, DOE may select an ALARA design that
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is inadequate to protect human health and the environment.
In such situations, DOE would then need to revise its ALARA design analysis to develop a design that adequately protects humans and the environment to comply with the ACL requirements. A preferred approach would be to first conduct the risk assessment to identify acceptable health and environmental limits and then to select an ALARA design, which protects humans and the environment from substantial present or future hazards.
Consequently, DOE should revise the Regulatory Alternatives document to provide procedures for performing the risk assessment either before the ALARA design analysis or in parallel with the analysis as illustrated in Figure 2.3 of DOE's document.
7.
Section 2.6, Page 43 Contrary to the text, licensees have applied for ACLs at active uranium mill (Title II) sites. NRC has encouraged the licensees to resubmit the applications in accordance with the guidance in the staff's technical position on ACLs because the original applications were inadequate or, in some cases, premature. The Regulatory Alternatives document should be revised to correct this error.
8.
Section 3.2, Page 50; Table 3.1, Page 59 The text and table describe information requirements for supplemental standards applications. Although the basis for applying supplemental standards varies from site to site, all supplemental standards applications for groundwater protection should have the same fundamental components as described in Section 5.5 of NRC Staff Technical Position " Standard Format ar.d Content for Documentation of Remedial Action 3 election Documentation at Title I Uranium 1989. These components include: (1)
Mill Tailings Sites," February (2) supplemental standards, (3) demonstration that applicability demonstration, the remedial action complies with the supplemental standards, and (4) demonstration that the remedial action comes as close to meeting the otherwise applicable standard under the circumstances. The Regulatory Alternatives document should be revised to be censistent with the guidance in Section 5.5 of the Standard Format and Content Guide.
9.
Section 3.2.3, Page 56 The text states that groundwater restoration at the Mexican Hat, Utah, site is technically impracticable because the shallow bydrogeologic unit is not transmissive enough to allow pumping. Given the general purpose of the Regulatory Alternatives document and the lack of a successful demonstration that restoration at Mexican Hat is technically impracticable, the document should be revised either to delete the specific reference to Mexican Hat or to provide or reference a demonstration of the impracticability of restoration.
- 10. Section 3.3, Page 57 The text uses the phrase "as low as reasonable" as an abbreviated version of EPA's requirement that remedial actions should come "as close to meeting the
4 otherwise applicable standard as is reasonable under the circumstances" in 40 CFRPart192.22(a).
NRC staff considers that while similar, the two phrases have different implications for remedial actions, For example, NRC staff considers that EPA's requirement may be less stringent than DOE's paraphrase of the requirement.
In addition, EPA's requirement links the supplemental standard demonstration with the primary standards for groundwater protection that would otherwise be applicable.
In contrast, bOE's paraphrased requirement is not similarly tied to the primary standards and, thus, could impose an additional requirement that remedial actions achieve concentrations that are as low as reasonably achievable. Therefore, the R6gJ1atory Alternatives document should be revised to paraphrase EPA's requirement in 40 CFR Part 192.22(a) correctly to preserve the flexibility intended in the standards.
- 11. Section 3.3, Page 58 The text states that the reasonableness of designs needs to be determined on a site-specific hasis. However, the text also states that specific design alternatives, such as elaborate multiple cover systems, geochemical amendments, R
thermal alteration, and Claymax, are not appropriate. NRC staff agrees with the former statement that the reasonableness of designs should only be determined on a site-specific basis. Statements that NRC does not consider certain design alternatives reasonable have no place in this generic document.
Therefore, the Regulatory Alternatives document shN'd be revised to delete
- generic conclusions about the reasonableness of de n alternatives or provide the generic analyses that demonstrate that certain Jesign alternatives are not appropriate in any combination at UMTRAP sites.
- 12. Appendix A 1
In general, Appendix A pravides the types of land and water use information l
that are necessary to support ACL demonstrations and may be necessary to
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support supplemental standard proposals.
In comparison with the evaluation presented in the Appendix, DOE may wish to decrease the level of detail on land use and increase the level of detail on water uses for land and water use evaluations at actual sites. Additional information would be necessary for water use evaluations because several conclusions in the water use portion of the Appendix are based on unsupported assertions and information that is not referenced or provided in the document.
For example, assessments of potential water uses in Section A.6.2 do not provide sufficient information to support conclusions that groundwater is not considered potable, groundwater development would require' substantial investments, and that the groundwater is too deep to reasonably develop.
- 13. Appendix C Although the staff realizes that the risk assessment in this appendix was never completed by DOE, the NRC staff has several suggestions for future risk assessments based on its review of this preliminary assessment.
First, the text needs to be completed; Section 3 of the attachment (referenced on page 19
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l and in the table of contents) and much of the bibliography are missing.
Second, the assessment should recognize that the concentration limits listed in Table C.2.2 are not ACLs, but rather Maximum Contaminant Levels (MCLs) or background limits. The risk assessment presented in the appendix is unusual in that such an assessment would not be performed for MCLs or background limits.
Third, the assessment omits several hazardous constituents known to exist at the Green River site. Fourth, the assessment incorrectly implies that the carcinogenic potency factors for radium-226 and uranium are not based on conventional radiotoxicity considerations. The potency factors used in the assessment are based on the ICRP 30 model and, thus, are consistent with conventional evaluations of radiotoxicity. Fifth, the risk assessment presented in the appendix is actually a consequence analysis because it assesses potentici hazards associated with exposure to hazardous constituents without considering the probability of exposure. Risk assessments should consider the probability of hua n and environmental exposure in addition to the consequences of such exposure.
Sixth, the assessment does not justify important assumptions or fully document the approaches used in estimating the consequences of exposure. For example, the text is unclear about how the total human dose via vegetable ingestion was calculated and does not justify assumptions used in estimating root uptake factors. Finally, Section 2 of the attachment has significant arithmetic errors that should not be present in an actual risk assessment.
- 14. Appendix 0 In general, the design analysis approach presented in Appendix D appears reasonable for a hypothetical site. Analyses of actual sites would be expected to provide or reference the analyses used to assess performance of the alternative design configurations, to justify assumptions used in assessing performance, to consider a broader range of alternatives, to provide stronger justifications for alternatives that were considered but rejected, and to consider appropriate combinations of design alternatives.
In addition, such analyses should use reasonable baseline conditions for comparisons of performance. For example, the analysis compares infiltration for the different cover designs with a steady-state baseline flux, which is at least an order of magnitude greater than the maximum potential infiltration for a properly designed disposal unit. Thus, the baseline condition selected in the analysis is not representative of baseline performance and may bias consideration of alternatives. Further, the analysis should identify real advantages and disadvantages of the alternative design options.
In contrast, the appendix identifies several disadvantages that are not acuta 11y disadvantages (i.e.,
other cover designs may reduce infiltration further). Actual advantages and disadvantages are needed to select an optimal design configuration based on an objective evaluation of the alternatives.
- 15. Appendix E Appendix E of the Regulatory Alternatives document provides the Water Resource Protection Strategy for the Spook site as an example of an acceptable
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l supplemental standards demonstration. NRC staff has set al concerns about the use of the Spook site as an example of a typical ap..ication of supplemental standards.
First, the Spook appU.co... is considered atypical of supplemental standards applications because DOE was not required to propose specific concentration limits for hazardous constituents in groundwater. Such concentration limits were not appropriate at the Spook site because of the nature of the disposal action and the low probability of human and environmental exposure to contaminated groundwater. The Regulatory Alternatives document should be resised to acknowledge the atypical nature of the Spook supplemental standards or discuss why DDE considers it representative of other potential supplemental standards applications.
Second, the NRC staff identified several deficiencies of the Spook application during its review of'the Water Resources Protection Strategy for Spook. These deficiencies should be rectified in future supplemental standards applications.
They are discussed in the NRC's Technical Evaluation Report for the Spook disposal action. NRC staff prepared Section 5.5 of the Standard Format and j
Content Guide based, in part, on lessons learned from the Spook review.
Consequently, future supplemental standards applications should be prepared i
i consistently with the staff's guidance in the staff technical position on
" Standard Format and Content For Documentation of Remedial Action Selection at Title I Uranium Mill Tailings Sites," February 1989.
Finally, future risk assessments in support of supplemental standards applications can be improved beyond the qualitative assessment presented in Addendum El by ensuring that the assessment consi h rs (1) the probability of humanandenvironmentalexposuretohazardousconstituentsand(2) envircamental toxicology of the hazardous constituents. The Addendum does not i
consider the probability of human and environmental exposure to hazardous constituents. As stated previously, risk assessments need to evaluate both the probability and consequence of exposure to hazardous constituents to estimate risks. The NRC staff's approval of supplemental standards for groundwater protection at the Spook site was' based primarily on the finding that there is a j
i very low probability of human and environmental exposure to hazardous constituents in groundwater. Without such a finding, the supplemental standards for groundwater protection at the Spook disposal site may have been 3
more stringent.
In addition, the Addendum does not evaluate toxic effects of environmental exposure to hazardous constituents for populations e her than humans and livestock. Risk assessments need to evaluate the conurnences and probabilities of exposure of other environmental populations such rs aquatic biota and terrestrial wildlife, as appropriate based on site characteristics.
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