ML20196E287
| ML20196E287 | |
| Person / Time | |
|---|---|
| Issue date: | 04/30/1988 |
| From: | NRC OFFICE OF NUCLEAR MATERIAL SAFETY & SAFEGUARDS (NMSS) |
| To: | |
| Shared Package | |
| ML20150E008 | List:
|
| References | |
| FOIA-88-514 NUDOCS 8812090308 | |
| Download: ML20196E287 (48) | |
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TECHNICAL P051T!0N ON I
ALTERNATE CONCENTPATION LIMITS FOR URAN!LM MILLS 5TANDARD FORMAT AND CONTENT GUIDE AND STANDARD REVIEW PLAN FOR ALTERNATE CONCENTRATION LIMIT APPLICATIONS l t
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TECHNICAL BRANCH 0: .. ON ' 'F LOW-LEVEL WASTE MANAGEMENT AND DECOMMIS$10NING ;
AFFl(E OF NUCLEAR MATERIAL SAFETY AND SAFEGUARD $
U.S. NUCLEAR REGULATORY Com15510M i
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I ORAFT TECHNICAL Pos! TION On ALTEptlATE CONCENTAA1.0h t,lHITS FOR URAN!UN MILLS STANDARD FORMAT AND CONTENT GU!Of IND STAhDARD REVIEW FLAN i TOR ALTERNATE CChCENTRATION tlMIT APPLICATIONS l Section Page Nu.ser ,
1 REGULATORY POSITION i
1.1 Introduction . . . . . . . . . . . . . . . . . . . . . . . 2 j
1.2 Purpose of the Guidance. . . . . . . . . . . . . . . . . . 3 r 1.3 ACL lepleir.entation . . . . . . . . . . . . . . . . . . . . 4 l
2 APPLICATION CONTENT AND FORMAT l f
2.1 Application Content. . . . . . . . . . . . . . . . . . . . 8 l
2.2 Application Format . . . . . . . . . . . . . . . . . . . . 9 f
3 APPLICATION REVIEW PROCEDURES l 1 i l
3.1 Areas of Review. . . . . . . . . . . . . . . . . . . . . . 13 i 3.2 Acceptance Criteria. . . . . . . . . . . . . . . . . . . . 14 l 3.3 Review Procedures. . . . . . . . . . . . . . . . . . . . . .*6 j 3.4 l<ev iew ' T ind i ng s . . . . . . . . . . . . . . . . . . . . . . 4 5 l l
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- 1. REGULATORY P051T!0N 1.1 16troduction Pursuant to the Uranium Mill Tallings Radiation Control Act of 1978 (UNTRCA),
the U. 5. Environmental Protection Agency (EPA) promulgated Enytronmental Standards for Uranium and Thorium Mill Tallings at Licensed Coronercial Processing Sites (40 CFR Part 192, Subparts D and () on Septerter 30,1983(48 FR 45926). These standards incorcorated groundwater protection regulations previously developed by EFA under authority of the Solid Waste Disposal Act.
The incorporated regulations include provisions for establishing alternate concen* limits (ACLs) as a part of sitt specific groundwater prot "fon prograu. ,hese provisions have been subsequently incorporated into the U. $.
Nuclear Regulatory Consnission (hRC's) regulatiens governing the disposal of uranium mill tailings (10 CFR Part 40. Appendix A) on Noveeber 13,1987(52FR 43553).
The site specific groundwater protection programs are corprised of four elementn (1) a list of hazardous constituents; (2) groundwater concentration limits for these constituents; (3) a location where coepliance with the concentrationlimitsisverified;and(4)atimeperiodduringwhichcompliance is required. Concentration limits N y bt established as Concentrations representative of background grcundwater quality (background limits),
concentrations listed in Table 5C of Criterion 5 of Appendia A to 10 CFR Part 40 (drinking water limits), or ACLs. Under40CFRPart192.32(a)(2)(ty),NRC l Ny approve ACl.s for contaminants in groundwater provided that these l concentration limits are as low as is reasonably ishievable considering practicable corrective actions, and that the contaminants will not pose a substantial present or potentis hazard to human health or the environment, as long a' the ACL5 are not exceeces at the ccepliance point.
Soon af ter EPA promulgated it6 regulations for active uranfue mills in 1983, hKC and EPA staffs agreed to develop a rutually acceptable /,CL methodology for l
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This Technical Position provides the establishing ACLs at uranium mills.
I ritually acceptable Nthodology to review and approve ACLs at uranium m '
a site specific basis.
This Technical Position has been tailored for general characteristics of l uranium and thorium mill tailings sites that entstThe or are likely Position to exist applies l during the next several decades in the United States. [
only to review of ACL applications for ur'nium and thorium mill tailings It does not apply to reviews of ACL applications at regulated under UMTRCA. :
hazardous waste canagenent sites regulated by EPA or authorized States Resource Conservation and Recovery Act (RCRA) or Comprehensive fE This Position is based on Response, Cortpensation, and Liatility Act (CERCLA). [
and is generally consistent with EPA's "Alternde Concentration Limit Guidj ACL Policy and Information Requirements," which EPA published in hl Part 1: l 1987 for establishing ACLs at hazardous waste ranagerent sites underl This Pcsitioe, provides a uniforra framework for consideration of the 19j listed in 40 CFR Part 264.94(b) as referenced in 40 CF and incorporated into NRC's regulations in Criterion 5B(6) of Appendi L CFR Part 40.
l 1.2 Furpose of Guidance !
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(1) NRC staff's j is to est311sh:
The purpose of this Technical Position l interpretation of requirements for establishing ACLs in Criterion $
(2) standard foru t and content of applications i Appendis A to 10 CFR Part 40:
I and (3) NRC staff review procedures for ACL for ACLs at uranium mills; This Position is intended to help licensees assemble, assess, applications. application to the NRC for and prepare infors;ation in the form of a r. In addition, the Position [
establishing site specific ACLs at uranium allis. j describes the characteristics of an ACL application that the NRC sta .
find generally acceptable under criterion SB(6) of 10 CFR Part 40 Af t
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4 This Technical Position also provides guidance to the NRC staff about the conduct of and criteria for reviews of licensee applications for ACLs. The principal purpose of Chapter 3 is to ensure quality and uniformity of staff reviews and to present a well defined basis from whir.h to evaluate changes in the scope and requirements of reviews. This Technical Positicn documents the regulatory process that the NRC staff will use to develop findings about the acceptability of licensee applications for ACLs, thus improving public understanding about the staff review process. Although Chapter 3 of this !
Technical Position is intended to be used by NRC staff, it can also be used by ,
Agreement States and other interested parties responsible for conducting :
reviews of ACL applications.
1.3 EL_leplementation ACLs may be established as part of site specific groundwater protection i standards. In accordance with NCC's requirer 4nts for uranium m) Is in Appendix A of 10 CFR part 40, licensees implement detection r.onitoring programs to detect early release of hazardous constituents from mill tailings impoundrents.
These programs progress into ccepliance ronitoring if they indicate that l constituent concentrations and paraineter values exceed background concentration (
limits. Site-specific groundwater protection standards provide the frainework l for the conduct of compliance monitoring programs. These standards consist of I a Itst of hazardous constituents, concentration limits for the hazardoe,s constituents, a point of compliance (POC) in the uppersest aquifer, anc a period of coepliance. The corcentration limits are generally specified as either background concentrations Jr as the concentration limits selected from the table ir Criterion SC of Appendix A to 10 CFR Part 40. As an alternative to backgrcund concentrations or the limits listed in Criterion SC, licensees r.ay propose ACLs for specific hazardous constituents, provided that they demonstrate that: (1) the constituents will not pose a substantial present or potential hazard to human health or the environrent as lorg as the ACLs are not exceeded; and (2) the ACLs are as low as renonaD1y achievable considering practicable corrective actions.
205/MFW/88/01/27/ACL 5-tipun approval by the Corrnission, ACLs will be established as the concentra If concentrations of hazardous limits for hazardous constituents at the PCC.limits, coepliance monitoring in groundwater exceed these ccnstituents progresses into corrective action, the third phase of the graduated groundw Licensees r.ay not propose monitoring and response progran.5 at vianium mills.
However, licensees ray ACLs to delay irplementation of correctivt action.
propose revised ACLs if new information indicates tl.st the ACLs should be incrtated or decreased to protect hunns or the environrant or to maintain concentrations that are as low as reasocably achievable.
The NRC staff censiders two locations in reviewing applications for ACLs at the POC and points of exposure (POEs). The Intrcduction to uranium till sites:
Appendix A to 10 CFR Part 40 defines the POC as the site-specific locatio the upperrest aquifer where the groundwater protection standard rest be met.
In contrast, POEs are defined for the purposes of this Technical Fosition as or other environrantal species could the locations where humans, mildlif e, reasonably be exposed to harardous constituents from the groundwater in the For exarple, hunns could construct a domestic well at the upperrest aquifer.
cuntaminated groundwater for consurption as drinking water.
POE and withdraw As another example, the POE could be the locations wnere aquatic biota my be of contaminated groundwater esposed to hazardous constituents as a result discharge to a river. Thus, groundwater cuality at the POEs must ce protective of potential huran and environmental receptors.
The hRC staff expects shat there my be rultiple plures of groundwater contaminated with hazardous constituents and svltiple F0Es at uranium tailings sites. These two aspects of actual groundwater contamination contribute ACL applications need to additional coeplexity in the establishinent of ACLs.
consider the site-specific characteristics that significantly affect the hazards posed by hazardous constituents and the practicability of corrective actions. In all cases, ACLs apelications must deronstrate that hazardous constituent concentrations will not pose substantial present or potential hazard; to humans or the environr.ent at the POEs, and that the ACLs are as lo
I 205/MPW/88/01/27/ACL i
as reasonably achievable considertag practicable corrective actions for existing and projected groundwater contamination. ,
i Understanding the spatial relationship betwrien the POC and POEs is critical tc !
implementation of ACLs at uranium mills. Natural processes such as dilution. l dispersion, decty, and sorption may attentuate hazardou s constituent [
concentrations between the POC and PCEs. Thus, hazardous constituent concentrations my be established at the IOC that are greater than appropriate I health and environmntal concentration limits for hazardous constituents !
established at the POEs. ;
For exarple, the two cases depicted in Figure 1 illustrate the importance of considering the POC and POE in establishing ACLs at uranium mill tailings l sites. Both of these cases could exist at the same site, where the migration of c.4 nerardous constituent has been retarded relative to another constituent. !
In the Nst case, groundwater monitoring my indicate limited contamination of
- groundwatar by a hazardous constituent associated with seepage from the f tallings inpoundment. ACLs may be established at the FOC by considering :
attenuation of the transport of the hazardous constituent between the POC and i POE. If hazardous constituent concentrations do not exceed the ACL at the POC l presently or in the future, then the licensee would not be required to l irplement a corrective action program to regain and Nintain ccepitance with l the groundwater protection standard. Cos911ance with the ACL at the POC would l prevent substantial present or potential hazards to humns or the environsent atthePOE(s). However, the Itcenset would be required to implemnt corrective -
action if groundwater monitoring at the P0C indicates that the ACLs have been j exceeded. Such correctivt action would be expected to limit the downgradient migration of the hazardous constituent above t.ppropriste health and environ- I mentallevelstothePOE(s). {
r In contrast, the groundwater contsminant plume for another hazardous constituent eay extend considerably downgradient from the FOC as a result of l seepage from a uranium mill tailings irpoundment, in this case, the NRC staff l i
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! Figure 1. Comparison of groundwater plumes for a relatively immobile hazardous constituent (Constituent 1) and i a relatively mobile constituent (Constituent Y).
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would place special emphasis on the contaminated groundwater between the POC and POE(s) in its review of an ACL application, to assure that the ACL prevents substantial present and potential hazards to humans and the environwnt at the F0E(s). In this case, the ACL would be applied at the POC and downgradient from the POC, in conjunction with the corrective action program, to ensure that the ACL prevents substantial present and potential eazards to humans or the environment, and that the ACLs are as low as reasonably achievable.
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- 2. APPLICATION CONTENT AND FORMAT l
2.1 Application Content ,
Table 1 provides on outline of a generic ACL application. ACL applications should contain or reference sufficient information to demonstrate th:tt (1) hazardous constituent concentrations will not pose a substantial tresent or ,
potential hazard to hunan health or the environment as long as the ACLs are not exceeded; and (2) ACLs are as low as reasonably achievable considering practicable corrective actions. The demonstration should consist of an l assessment of the hazards associated with present and potertial exposure to ;
hazardous constituents, and an assessment of the reasonableness of concentration limits, considering corrective actions. The demonstration shculd consider the 19 factors listed in Criterion SB(6) and in Table 2 of thio Position. in general, hazard assessments should evaluate the: (1) existing distribution and extent of hazardous constituents as we)) as the potential source (s)forfuturereleasesoftheseconstituents;(2)transportofhazardous constituents in groundwater and hydraulically. connected surface water; and (3) .
risks associated with esposure of humans and the environnent to hazardous t constituents. Corrective action assessments should include: (1) identification of alternative corrective actions; (2) assessment of the technical feasibility of alternative corrective actions; (3) assessment of the costs and benefits l associated with performance of practicable corrective actions; and (4) .
l selection of practicable corrective actions to achieve hazardous constituent l concentrations in groundwater that are as low as is reasonably achievable. l Section 3.2.2 of this Fosition provides a more detailed description of the content of ACL applications that the NRC staff would fir.d acceptable. >
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ACL applications prepared by licensees should be sufficiently detailed to I
permit the NRC staff to verify indererdently that the ACLs will not pose a '
substantial present or potential barard to tur.ans or the environrent and that they are as low as reasonably achievable cor.sidering practicable corrective i actions. It is expected that ruch of the information, required to support a l l
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,9 successful ACL application is already available in other documnts submitted in support of the license reviews. For example, inforntion about hydrogeologic :
l characteristics should already be included in aavironmental reports, license (
applications, previous detection monitoring submittals, or documents prepared (
l by the liccnsees to resolve licensing issues identified by the staff. ;
j Additional inforation needed to suppurt the ACL application may include (
assessments of transport rates and directions of hazardous constituents, and effects of tuun and environmental esposure to hazardous constituents.
The content of site specific applications is expected to vary from site to site I i
because of differences in site characteristics, ellling processes, disposal (
l operations, and ore composition. Licensees are encouraged to reflect these [
differences in the content of site specific ACL applications. Detailed i inforntion related to each of the '3 factors listed in Criterien 5B(6) of Appendix A to 10 CFR part 40 is not necessarily required. For example, a L
! licensee my not need to consider irpacts of contaminated groundwater discharge l to surface water if contaminated grcundwater does not and is not projected to l discharge to any surf ace water bodies near the facility. In this example, a ;
l licensee ray not need to provide detailed informtion such as stream flow l
characteristics and transport assessr.ents withth surf ace water. However, the f burden of prcof resides with the licensee to derenstrate that selected factors [
do not need to be considered in the derenstration. i I I 2.2 Application Format f i
This section provides guidance about the Standard Formt of ACL applicatichs j for uraniue ell) ta11 togs sites. Use of a Standard formt for ACL applications }
willt (1) help assure that applicaticns contain the inforntion required in 10 CFR part 40, Appendix A; (2) aid the licensee and the NRC staff in ensuring ,
that the inferration is corplete; (P help persons reading the application to f locate informtt" and (4) contribute to reducing the tire needed for the ACL app 1(cation review process. Conforunce with this formt is not required. The ;
NRC staff will accept applications with different form ts if these applications I i
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205/MFW/88/01/?7/ACL adequately demonstrate the suitability of the proposed ACLs. However, staff reviews of ACL applications with different formats may require more tire, because the staff is familiar with the Standard format described in this section, and the staff's review procedures are based on receipt of applications in this Standard format.
The licensee should present the information contained in the ACL application as clearly as possible. Technical bases should support the licensee's demonstration of the adequacy of the ACLs relevant to the requirements in Criterion 5B(6) of Appendis A to 10 CFR Part 40. Licensees should follow the numbering system and headings of the Standard Format. Licensees are encouraged to use appendices to the application to provide supplerentary information not specifically identified in this secticn. Conventional abbreviations should be used consistently throughout the ACL application. Any abbreviations, symbols, or special terms should be defined where they first appear in the text. Where appropriate, calculated error bands or estimated uncertainties should be included along with numerical values. Graphic presentations such as maps, graphs, drawings, and tables should be used to present information more clearly or more convenient'y than text descriptions. Licensees should ensure that graphic materials are legible and that the physical scales are sufficiently large so that details and notations can be easily read. Syd ols should be clearly defined.
ACL applications should conform to the following physical specificatiuns: (1) paper size should be 8 1/2 x 11 inches with larger charts and maps folded into '
the application so that the bound size does not exceed 81/2 x 11 inches; (2) ink must be stefficiently dense to record the application on microfilm or image-copying equipment; (3) text should be single spar,ed and printed on both sides; (4) pages should be punched for a standard three-hole looseleaf binder; (5) revisions tn v.he application should be provided on pages that will replace the criginal pages, with the changes indicated by a "change line," which is a vertical line placed in the outside margin next tu the portion of the text that was changed; (6) the date of changes and change nuders should be indicated in
205/MfW/88/01/27/ACL
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the bottom outside margin of each change page, and each change submittal should include a listing of all pages changed in that submittal.
As noted, Table 1 provides an outline of a generic ACL application. This outline is based un the general types of information that the NRC staff considers necessary to address the two criteria and nineteen factors listed in Section 3.1. As previously discussed, however, licensees should adjust the content of ACL demonstrations to accomodate facility-specific characteristics.
Therefore, the format and content of ACL applications may vary somewhat because of site-specific differences in compliance demonstrations.
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'- Table 1 Standard Format of an Alternate Concentration Limit Application at a Uranium Mill Tailings Site .
EXECUTIVE
SUMMARY
.. 1. GENERAL INFORMATION 1.1 Introduction 1.2 General Faci)ity Description 1.3 Extent of Groundwater Contaminat..
1.4 Proposed Alternate Concentration Limits
- 2. HAZARD ASSESSMENT 2.1 Source and Contamination Characterization 2.2 Transport Assessment 2.3 Exposure Assessment
- 3. CORRECTIVE ACTION ASSESSMENT 3.1 Alternate Corrective Actions 3.2 Feacibility of Corrective Actions 3.3 Corrective Action Costs 3.4 Corrective Action Benefits 3.5 Selection of Corrective Actions
- 4. PROPOSED ALTERNATE CONCENTRATION LIMITS 4.1 Proposed Alternate Concentration Limits 4.2 Proposed Implementation Measures
- 5. REFERENCES t
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- 3. PROCEDURES FOR NRC REVIEW 0F APPLICATIONS 3.1 Areas of Review Based on NRC's regulations in Criterion SB(6) of Appendix A to 10 CFR Part 40, NRC staff has developed a systematic approach to review ACL applications. As components of this approach, the NRC staff has identified two major and eight ninor elements of its review of ACL applications to approve or deny proposed ACLs for hazardous constituents in groundwater at uranium mill tailings sites.
The two major elements include:
- 1. i :ard Assessment Review The NRC staff reviews the licensee's assessment of the: (1) existing distribution and extent of hazardous constituents, as well as potential source (s) for future releases of constituents; (2) transport af hazardous constituents in groundwater and hydraulically-connected surface water; and (3) risks associated with exposure of humans and tha environment to hazardous constituents.
- 2. Corrective Action Review The NRC staff reviews the licensee's: (1) identification of alternative corrective actions for groundwater contamination; (2) assessment of the technical feasibility of the corrective actions; (3) estimated costs of practicable corrective actions; (4) estimated benefits of practicable corrective actions; and (5) selection of practicable corrective actions for controlling, reducing, mitigating, or eliminating groundwater contamination. Based on the hazard assessment and corrective action reviews, the staff evaluates the licensee's proposed ACLs and accompanying selection of measures necessary to ensure compliance with proposed ACLs.
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205/MFW/88/01/27/ACL 3.2 Acceptance Criteria Upon receipt of an ACL application, the NRC staff performs an acceptance review to determine whether the types and amounts of information submitted in the application prcvide a sufficient basis for reviewing the proposed ACLs relativa to the requirements in Criterion 5B(6) of Appendix A to 10 CFR Part 40. If the staff concludes that the information submitted in the application is insufficient, the NRC staff will return the application to the applicant and identify what additional information is necessary before the staff can begin its review. If the application contains sufficient information, the NRC staff will accept the application and begin its review in accordance with the procedurcs described in this Technical Position. Acceptance of the ACL application af ter the completion of the acceptance review does not preclude subsequent requests for additional information by the NRC staff during the course of the review.
3.2.1 Regulatory Basis and General Criteria EPA issued standards for control of uranium and thorium mill tailings at comercial, licensed mill sites (40 CFR Part 192, Subparts 0 and E) pursuant to Section 275 of the Atomic Energy Act (42 U.S.C 20?2) as amended by UMTRCA, et seq. EPA standards in 40 CFR Part 192.32(a)(2)(iv) provide for the establishment of site-specific ACLs. NRC has incorporated this provision in its requirements in Criterion SB(6) of Appendix A to 10 CFR Part 40. Criterion 5B(6)providesforestablishmentofACLsasfollows:
Conceptually, background concentrations pose no incremental ht:ards and the drinking water limits in paragraph SC state acceptable '.arards but these two options may not be practically achievable at a specific site.
Alternate concentration limits that present no significant hazard may be proposed by licensees for Comission consideration. Licensees must provide the basis for any proposed limits including the demonstration that limits are as low as reasonably achievable considering practicable
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205/MfW/88/01/27/ACL t
corrective actions and information on the factors the Comission must consider. The Comission will establish a site specific alternate concentration limit for a hazardous constituent as provided in SB(5) of this criterion if it finds that the proposed limit is as icw as reasonably achievable considering practicable corrective actions, and that the constituent will r.ct pose a substantial present or potential hazard to human health or the environment as long as the alternate concentration limit is not exceeded. In making the present and potential hazard finding, the Comission will censider the factors listed in Table 2.
To approve licensee-proposed ACLs, the NRC must find with reasonable assurance that (1) the ACLs will not pose a substantial present or potential hazard to human health or the environment as long as the ACLs are not exceeded and (2) the ACLs are as low as is reasonably achievable, considering practicable corrective actions. Successful ACL demonstrations, therefore, synthesize site-specific, regional, and generic information to derar, strate that hazardous constituents in groundwater will meet these two criteria. The ACL application should provide or reference sufficient information to allow the NRC, as an independent reviewer, to verify the demonstration used to support the proposed ACLs and to reach comparable, but not necessarily identical, conclusions.
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205/MFW/88/01/27/ACL Table 2 Factors for Consideration in Establishing Alternate ConcentrationLimits[10CFR40,AppendixA, Criterion 5B(6))
A. Potential Adverse Effects on Groundwater Quality
- 1. Physical and chemical characteristics of the waste in the licensed site including its potential for migration
- 2. Hydrogeological characteristics of the facility and surrounding land
- 3. Quantity of groundwater and the direction and rate of groundwater flow 4 Proximity and withdrawal rates of groundwater users
- 5. Current and potential future uses of groundwater in the area
- 6. Existing quality of groundwater, including other sources of contamination and their cumulative impact on groundwater quality
- 7. Potential for health risks caused by human exposure to waste constituents
- 8. Potential damage to wildlife, livestock, crops, vegetation, and physical structures caused by exposure to waste constituents
- 9. Persistenct and permanence of potential adverse effects B. Potential Adverse Effects on Surface Water Quality
- 1. Volume and physical and chemical characteristics of waste in the licensed site
- 2. Hydrogeological characteristics of the facility and surrounding land
- 3. Quantity and quality of groundwater, and the direction and rate of groundwater flow
- 4. Patterns of rainfall in the region
205/MFW/88/01/27/ACL Table 2 Fsctors for Consideration in Establishing Alternate ConcentrationLimits[10CFR40,AppendixA, Criterion 5B(6)](continued)
- 5. Proximity of the licensed site to surface waters
- 6. Current and potential future uses of surface waters in the area and water quality criteria established for those surface waters
- 7. Existing quality of surface water, including other sources of contamination and their cumulative impact en surface water quality S. Potential for health risks caused by human exposure to waste constituents
- 9. Potential damage to wildlife, livesteck, crops, vegetation, and physical structures caused by exposure to waste constituents
- 10. Persistence and permanence of potential adverse effects
205/MFW/88/01/27/ACL 3.2.2 Specific Criteria 3.2.2.1 Review Element 1: Hazard Assessment Review l The hazard assessment review includes three minor elements that are based on i the 19 criteria provided in Criterion SB(6) of Appendix A to 10 CFR Part 40. l These elements are: (1) characterization of the source (s) and extent of i groundwatercontan,ination;(2)assesseentofhazardousconstituenttransportin I groundwater and hydraulically-connected surface water; and (3) assessment of risks associated with exposure of humans and the environment to hazardous constituents. Infotmation from these three elements should be synthesized into ^
a demonstration that the proposed ACLs will not pose a substantial present or potential hazard to human health or the environment as long as the ACLs are not exceeded, t
Source and Contamination Characterization i 3.2.2.1.1 Characterization of the contaminant source (s) and extent of contamination provides the source term for contaminant transport assessments, which are needed to estinate the hazards associated with potential human and environmental exposure to hazardous constituents. Soure.e characterization is acceptable if it provides reliable estir,ates of or conservatively limits existing and potential release rates of hazarduus constituents and ;
characterizes existing distributions of these constituents. Source characterization includes characterization cf the uranium milling facility, ;
on-site wastes, and groundwater and soil contaminated with hazardous constituents, i
Facility characterization is acceptable if it includes such information as [
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detailed descriptions of: (1) the uranium recovery process (es) used at the facility; (2) types and relative quantities of the reagents used in the milling process; (3) ore compositions milled at the facility; and (4) waste managemen' practices (e.g., lucation of waste dhcharges, retaining structures for wastes,
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205/MfW/88/01/27/ACL relative amounts of wastes, and history of waste discharges). This information should be considered in conjunction with the physical and chemical composition of the waste and properties of the waste constituents, to estimate the source tere for contaminant transport.
Waste characterization is acceptable if it includes such information as (1) identification of hazardous constituents in the waste, including any degradation products of the constituents; (2) a ssessirent of the leaching potential of the hazardous constituents from the waste, described as a relationship between estimated aqueous concentrations of constituents and the corrposition of the waste; and (3) spatial distribution of hazardous constituents in the waste. Additional information may be necessary to support acceptable waste characterization depending upon the hazardous constituents present in the waste, such as: (1) physical and chemical characteristics of the hazardous constituents such as density, solubility, valence state, vapor pressure, visecsity, and cctanol-water partitioning coefficient; (2) presence and effect of cortplexing ligands and ctelating agents, to the extent that they may enhance constituent mobility; (3) potential for constituents to degrade as a result of chemical, biological, and physical processes; and (4) attentuation properties of constituents and affected hydrogeologic radia to characterize processes as ton exchange, adsorption, absorption, precipitation, dissolution, and ultrafiltration. Waste characterization includes those characteristics that significantly influence or control the release or transport of hazardous constituents.
At sites where release of hazardous constituents has contaninated extensive volumes of groundwater, soils, sediments, or rocks, characterization of the
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extent of contamination should include assessrent of the distribution of hazardous constituents in groundwater and contaminated soils at the facility.
) This information is needeo' to calibrate contaminant transport models and to I evaluate whether humans ano' environmental populations are currently being exposed to elevated concentrations of hazardous constituents. Characterization of the extent of contamination is acceptable if it provides such infortnation
g e 205/MFW/88/01/27/ACL as: (1) the distribution of hazardous constituents in groundwater; (2) the distribution of hazardous constituents in contaminated raterials other than the uranium tailings; (3) concentrations and values of indicatory water and soil quality constituents and parameters determined in the detection monitoring program, including pH, Specific Conductrice, major ions, minor ions, trace constituents, uranium (natural), radium-226/228, and thorium-230; and (4) docurnentation of sampling, analysis, and quality assurance programs used to sample groundwater and soll, analyze the samples, and assess the distribution of hazardous constituent concentrations.
3.2.2.1.2 Transport Assessrnent The transport asses *. ment provides the basis for assessing the site-specific, projected distribution of and exposure to hazardous constituents.
Characteristics of the transport assessment should be tailored to be consistent with site-specific characteristics that affect the significance and extent of hazardous constituent transport. For sor.e aspects of the transport assessrent, applicants may develop estimates that conservatively bound the magnitude of processes or phenomena that affect hazardous constituent transport. The transport assessrent generally consists of the following subelements: (1) hydrogeologic characteristics: (2) groundwater flow direction and quantity; (3) rainfall patterns; (4) background water quality; and (5) estiinated rates of transport and concentrations of hazardous constituents in groundwater and hydraulically-connected surface water. The inforration in subelerents 1-4 should be used to estirate the rates and directions of hazardous constituent transport and constituent concentrations in groundwater and hydraulically-connected surf ace water.
Acceptable characterizations of site hydrogeology, groundwater flow rates and directions, and rainfall patterns should consider advection of groundwater and surface water, as well as advection and dispersion of contaminants from the tources of contamination. The scope of hydrogeologic characterization should be corronensurate with the anticipated ragnitude of potential hazards associated
205/MFW/88/01/27/ACL with groundwater contamination, as well as the relative distance of human and environmental populations from existing and projected contamination.
Acceptability of hydrogeologic characterization is determined based on its ;
completeness and adequacy to support assessment of hazardous constituent transport. Such assessments may either provide conservative limits or reasonably likely estin.ates of hazardous constituent concentratiuns. (
Acceptable characterizations of site hydrogeology should generally include: ,
(1) identification of hydrogeologic units that have been or may be affected by transport of hazardous constituents; (2) representative characteristics cf ;
hydrogeologic units (including unsaturated units that may significantly influence contaminant transport) such as geometry, stratigraphy, structural ,
geolcgy, lithology / mineralogy, hydraulic conductivity, effective porosity, hydraulic head distribution and gradients, recharge / discharge locations and ;
rates, and dispersivity; (3) representative conceptual s,odels of the ground- -
water flow system that is or may be affected by contaminant transport; (4) reliable surface water characteristics to be used in assessing the significance of surface water transport of hazardous constituents, such as location, volume, ,
flow rate, bed and suspended load fractions, channel morphology, current !
patterns, and hydrographic modifications; (5) representative climatic [
characteristics such as distributions and amounts of precipitation, potential {
evapotranspiration, temperature distributions, and estimated infiltration rates into contaninated materials, and the effects of variable recharge on giound-water and surface water flow characteristics; (6) representative lateral and vertical groundwater flow rates and directions, including information such as groundwater flow nets, estimated discharge and recharge rates, temporal i variations in flow rates and directions, and the calculations and assumptions used to estimate flow rates and directions; and (7) descriptions of generally accepted characterization and monitoring practices, procedures, and quality assurance programs used to characterize te hydrogeology. f Background water quality is defined as the quality of water that would be expected if contamination had not occurred from the designated facility. l
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205/MfW/88/01/27/ACL Background groundwater quality should be establided baced on monitoring data collected <' the site. Beckground water quality characterization is acceptable if it "cludee the following types of information, as appropriate: (1) maps of sufficient detaf! showing the locations of background mnr.iterirg locations; (2) characteristics of background monitorirg devices, including wells, springc, comunity water supplies, surface wat~ samplers, suction lycincters, and other devices; (3) descriptions of the distrihcti n of vastes at and near the site; (4) descriptions of historical changet, Cn hydraulic heads, flow directions, and flow rates relevant to the location of background locotions; (5) analytical background water nuality data; (6) descriptions and analysis of potent-fi sources of of f-site contamination; and (7) descriptions of generally accepted and reliable protocols for sampling, analysis, preservation, transportation, and quality assurance used to characterize backgrcund water quality.
Estimates of contaminant trarsport are based on the licensee's assessment of hydrogoologic charact er htics , background water quality, extent of contamination, and sources of contamination discussed previously. The objective of the hazardous constituent transport assessment is to develop conservative, but realist.ic, exposure estimates based on reasonable projections of contaminant concentratioas in groundwater and surface water. This assessment should consider anticipated future events that may significant?s perturb exposure or transport pathways and consider transfer of hazardous constituents from aqueous media to other environrental media as necessary on a site-specific basis. Transport assessments are acceptable if they include:
(1) reasonably conservative or best estirnates of the rate of transport of hazardous constituents in groundwater and hydraulically-connected surface water; (2) reliable estimates of the duration of constituent migration and deterministic or statistical representation of constituent concentrations relative to duration of exposure ano constituent characteristics (i.e., average daily concentrations over an exposed individual's lifetirne for carcinogenic constituents, mean daily concentrations for acutely toxic constituents, and mean annual concentrations for chronically toxic constituents); (3) projected temporal variability of constituent concentrations; (4) projected spatial l
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205/HW/88/01/27/ACL oistribution of hazarcous constituents; (5) solid composition and water quality monitoring data used to validate projections of constituent transport; (6) assessments of the long-term notential for re7 ease of contaminants from the solid phase into groundwaf r or hydraulically-connected surface water (e.g.,
desorption); (7) characterization of the source term for hazardous constituents for groundwater and surface water transport (see Section 3.2.2.1.1); and (3) coroplete assessment of uncertainties associated with the pro,1ected concentrations and distributions of hazardous c.onstituents.
3.2.2.1.3 Exposure Assessment The objective of the exposure assessment is to assess the rh ks associated with human and environmental exposure to hazardous constituents, to determine whether projected concentrations of hazardous constituents pose substantial !
present or potential hazards to human health or th: environment, and to identify maximum levels belcw which such hazards do no: occur. The maximum allowable concentrations provide the b: sis for the proposed ACLs. The exposure messment eierent is composed of three component assessments: (1) resource ;
, classification and water uses, (2) evaluation of human health hazards, and (3) !
evaluation of environmental hazards, i
Assessment of groundwater and surface water uses supports the analysis of human exposure to hazardous constituents. The rigor of the humar exposure analysis, ;
in part, depends on the extent to which people are likely to use water resources that may be affected by contamination from the site. Acceptabl6 analysis of current and future uses of groundwater and surface water includes assessment of such factors as existing and anticipated water uses, classification of water resources, institutional controls on water uses, relevant water quality standards, and the availability and characteristics of alternative water supplies. The following types of information shculd be includ6d in assessments of existing and future water uses: (1) characteristics of existing water uses in the vicinity of the site (e.g., locations, types, intended uses, rates of withdrawal / injection, statutory and legal constraint!
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on water use); g) relevant water quality criterit, standards, and guidelines, 3 (3) classifications of groundwater resources hsed on EPA's Groundwater Protection Strategy cr comparable State wat'. p otection strategies; and (4)- r availability and chracteristics of 41ternative watzr supplies and comparison !
of these resources with present water supplies. Types of water uses to be considered include agricultura*,, industrial, doinestic/ municipal, environmatal, [
and recreational uses.
Health and environmental hazard assessments are composed of four components:
exposure pathway identification, hazard identification, dose-response assessment, and risk characterization. Acceptable hazard assestments project t the resper,se of human and environmental populations to exposure to hazardous ,
constituents based on projected constituent concentrations, anticipated exposure pathways, and available toxicological and epidemiological information.
Hazard assessments consider two potential human exposure pathways: ingestion [
of contaminated water and ingestion of contaminated foods (e.g. , aquatic f organisms or irrigated produce). Hazard assessments also evaluate inhalation f and dermal exposure pathways, if these pathw3ys could result in substantial i hazards to people or the environment based on the properties of the hazardous !
constituents and projected levels of exposure. The assessments distinguish !
between health impacts associated with threshold and non-threshold l
! constituents. Mutagenic, teratogenic, and synergistic effects are considered l in the analysis, if available information indicates their occurrence based on j toxicological testing, structure-activity relationships, or epidemiological l
- studies. Information supporting the hazard assessmcht justifies significant !
l assumptions invoked in preparing the a*.sessment and identifies uncertainties !
I associated with projected health and environmental impacts.
l Hazard assessants also assess potential responses of environmental (non-human) [
populations to exposure to hazardous constituents, if such populations my !
{ reasonably be exposed to contaminated groundwater or hydraulically-connected I
surface water. Acceptable environmental exposure assessments consist of analyses of projected responses of terrestrial and aquatic wildlife, plants,
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livesto:k, and crops fm estimated exposures to hazardous constituents. The assessments should provide: (1) inventories of potentially expcsed enviroprental populations; (2) reconnended tolerance or exposure limits; (3) :
! interacticns of contaminants and their cumulative o f"': s:u on exposed populations; (4) projected responses of environmental popuhtions from exposure t to hazardous constituents; and (5) anticipated changes in populations independent of exposure to hazardous constituents. Alternatively, an appl: cant ray demonstrate that environmental hazards are not anticipated because exposure to wildlife, livestock, plar.ts, crops, and aquatic biets does not and will not occur.
Acceptable hazard assessments avJ1uato potential darnage to physical structures caused by exposure to hazardcus constituents in groundwater and hydraulically :.onnected surface water. Such assessments examine potential exposure pathways, waste characteristics (e.g., corrosivity), environmental variables that may influence damage (e.g., temperoture), and structural materials that may be exposed to hazardous constituents. Alternatively, an applicant ray demonstrate that damage to physical structures is not anticipated because exposure does not and will not occur.
Acceptable hazard assessments conclude with a brief statement of the concentration limits below which hazardous constituents do not pose substantial present or potential hazards to human health or the envi oninent. The concluding section also provides sunnary descriptions of the basis for each proposed concentration limit.
P 3.2.2.2 Review Element 2: Corrective Action Review Acceptable assessments of corrective actions are composed of six elements, including: (1) identificatier, of alternative corrective actions; (2) assessment of the technical feasibility of the corrective actions; (3) evaluation of the costs associated with implementation of practicable corrective actions; (4) evaluation of the benefits associated with
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, implenentation of practicable corrective actions; (5) selection of practicable corrective actions for implementation based on appropriate optimization of the costs and benefits associated with the corrective actions; and (6)
. demonstration that the proposed concentratio1 limits are as low as reasonably acMevable, considering practicable corrective actions. Acceptable assessments provide supporting calculations and identify important asst,mptions used in estimatfr.g the costs and 'b'nefits of alternative corrective actions.
The asseanients are linked with the proposed concentration limits identified in the concluding portion of the hazards assessment section. Acceptable assessments demonstrate that ACLs will be no higher than the maximum allowable concentration limits identified in the hazards assessment. If -these concentration limits are higher than the lowest concentrations that can be achieved by practicable corrective actions, the corrective action assessment considers at least three different target concentration li.mits that represent a reasonable range of limits that may be attained by practicable corrective actions. The assessment identifies and evaluates costs and benefits associated with each set of target concentrations. Evaluation of the costs and benefits associated with corrective action to attain the target concentrations assures that the proposed ACLs are as low as reasonably achievable, considering practicable corrective actions.
3.3 R_eview Procedures 3.3.1 General In conducting reviews of ACL applications, the NRC staff may conduct literature surveys, data assessments, and performance evaluations as needed to audit the basis' for the proposed ACLs and to verify that the proposed ACLs satisfy the two general criteria listed in Section 3.2.1. NRC staff identifies open issues !
that preclude approval of the proposed ACLs if reviews indicate that supporting (
information is ambiguous, incomplete, inadequate, or incorrect. These issues l will be connunicated to the licensee in the form of written coments. The
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connents docurrent the issue, provide the basis for the staff's content, discuss the relative significance of the coment in terms of the proposed ACLs, and suggest, if appropriate, at least one approach that the NRC staff would find acceptable to resolve the issue. In general, the sta,ff focuses its r' view. on inforination that significantly affects the selection and justification of the proposed ACLs.
3.3.2 Review Element 1: Hazard Assessrr.ent Review :
NRC staff reviews the hazard assessment used to support ACL demonstrations to ensure that the following criteria are satisfied: !
- 1. Has the source term of hazardous constituents been adequately characterized with respect to transport assessments?
- 2. Have the rates and directions of hazardous constituent migration been adequately determined with respect to exposure assessments?
- 3. Have the routes, amounts, and effects of human and environmental exposure to hazardous constituents been adequately assessed?
- 4. Do the proposed concentration limits for hazardous constituents ensure prevention of substantial present or potential hazards to humans and the environment?
3.3.2.) Source Term Characterization The reviewer evaluates information relevant to the characterization of the source term of hazardous constituents as necessary to support the transport essesstnent. Source term includes existing contaminated groundwater, contaminated soils, and tailings tnd other wastes that may cause future releases of hazardous c nstituents. Based on the adequacy of this information, the reviewer deterr.ines whether source term characterization is sufficient to ,
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205/PJW/88/01/27/ACL provide a conservative or realistic estimate of the types, characteristics, and release rates of hazardous constituents that have been or are anticipated to be releated from contaminated groundwater, soils, and tailings at a given facility.
The reviewer will ensure that the demonstration: (1) identifies hazardous constituents present in the tailings or in leachate derived from the tailings; (2) identifies hazardous constituents potentially derived from the degradation or reaction of waste constituents; (3) identifies the extent and characteristics of contaminated groundwater and soils; (4) characterizes the properties of the hazardous constituents that affect their transport and fate in the environment surrounding a facility; and (5) estimates release rates of hazardeus constituents as a function of time and space, as appropriate.
Adequacy of the dernonstration is reviewed with respect to the source term required in the assessment of contaminant transport rates and directions.
The reviewer assesses: information on the enraction process used at the facility to recover uranium; the relative amounts and types of reagents used in the extraction process; composition of ores; li kely chemical and biologically-mediated reactions within the tailings; transport characteristics of the hazardous constituents (e.g., solubility, sorption / desorption, complexation, degradation information); leachability of dissolved and solid species present within the tailings; total volume of waste materials at the facility; physical characteristics of the waste materials as they would affect leaching potential, corposition ard distribution of uranium tailings and contaminated soils; composition and distribution of contaminated groundwater; and the leaching characteristics of the waste materials, considering both the duration of leaching and magnitude of leached concentrations. The reviewer may also assess information about characteristics such as volatility, octanol-water partitinning coefficient, viscosity, degradation rate constants, and density, if the:e properties twy significantly affect transport or toxicity of hazardous constituents. Based on this assessaant, the reviewer either confirms the licensee's characterization of the source term or determines that the source
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205/MFW/88/01/27/ACL term has not been conservatively or realistically characterized with respect to hazardous constituent transport assessment.
3.3.2.2 Rate anu Direction of Transport in reviewing the adequacy of the licensee's determination of the rate and direction of hazardous constituent transport in groundwater, the reviewer verifies the licensee's characterization of: (1) site hydrogeology; (2) rate and direction of hazardous constituent transport in groundwater and surface water; and (3) rainfall patterns near the facility as they may affect traasport of hazardous constituents. The reviewer also "erifies the licensee's characterization of background water quality to suppo t assessment of existing and potential future uses of water resources.
In reviewing the licensee's characterizatic; of the rate (s) and direction (s) of hazaroous coristituent transport, the reviewer determines whether the hydrogeologic characterization of the site is adequate to support assessments and conclusions about the projected extent and distribution of hazardous constituents. The scope of the staff review includes consideration of site-specific and regional (i.e., beyond the incdiate zone of influence of the fccility) information on the physical and hydrogeologic characteristics of groundwater and surface water systems, as appropriate. The reviewer determines whether the licensee's hydrogeologic characterization employed accepted and defensible practices, techniques, methods, and approaches supporting the determination of transport rates and directions. The reviewer also evaluates:
(1) anticipated and potential changes in transport rates and directions caused by reasonably foreseeable events; and (2) historic changes in transport rates and directions that may have been caused by the construction or operation of the facility. The revtewer elso confirms assessments of the effects of existing and likely distributions of rainfall at and around the f acility to the extent that such patterns may significantly affect transport rates and directions. This assessment includes consideration of: temporary increases in recharge into waste materials; effects on releases of hazardous constituents;
205/MFW/88/01/27/ACL changes in the location of recharge and discharge of groundwater systems; and modifications to surface water-groundwater relationships.
The reviewer verifies assessments of the transport of hazardous constituents in groundwater. This review includes evaluation of hazardous constituent transport in surface water, if contaminated groundwater discharges or is projected to discharge to surf ace water. The reviewer determines whether estimated hazardous constituent concentrations and projected distribution of hazardous constituents are best estimate or reasonably conservative re. presentations of the rate, extent, and direction of constituent transport I based, in part, on the existing distribution of constituents in contaminated grouadwater. The reviewer confirms that all likely and significant pathways of constituent transport in groundwater and surface wa'.er have been identified and adequately assessed with respect to estimating conservative or realistic effects caused by human or environmental exposure to hazardous constituents.
In addition, the reviewer verifies that the assessments used to estimate constituent transport are appropriate for use in support of regulatory decisions. For best estimate projections, the reviewer confirms that the ,
projections have been sufficiently validated and calibrated based on available site-specific information. The reviewer confirms that temporal and spatial '
estimates of hazardous ccnstituent concentrations are adequate to support assessments of the risks of human and environmental exposure to the constituents.
The reviewer evaluates information relevant to the establishment of background water quality at facilities, including, but not limited to, water quality data, facility characteristics, protocols used to establish background concentrations, vicinity characteristics, and conceptual and analytical hydrogeologic models. Based on the adequacy of this in armation, the reviewer determines whether the assessment reasonably characterizes the background quality of groundwater and surface water that has been or may be impacted by ,
the facility. Establishment of background water quality may be corplicated at sites where existing or potential water contamination may affect water quality
205/MFW/88/01/27/ACL in several aquifers or water bodies. The reviewer determines whether the assessment establishes background water quality for each aquifer potentially affected by water contamination, and for surface water bodies that are hydraulically connected with hydrogeologic units that are downgradient from the facility.
At sites where water samples representative of background quality cannot be '
collecte , (e.g., where entire aquifers are contaminated by seepage of tailings leachatt), the reviewer evaluates (1) the licensee's justification for not charactarizing background quality and (2) the licensee's assessment that f proposes reasonably conservative concentration and value estimates for appropriate water quality constituents and parameters. The reviewer evaluates site and facility information and either confirms the determination of background water qu611ty or determines that the estimates are not reasonably conservative. The reviewer ensures that estimates of background water quality are sufficient to support analyses of potential use of water resources and adverse effects associated with human ano environtrental exposure to hazardous constituents that may be transported in the groundwater and surface water.
3.3.2.3 Exposure Assessment Based on the confirmed characterizations of the source term and rates and directions of hazardous constituent transport, the reviewer evaluates the assessment of the ri:,ks associated with huran and environmental exposure to hazardous constituents. The scope of the assessment includes characterization ,
of existing and potential uses of water resources that may be affected by the l facility, evaluation of human and environmental exposure to hazardous
! constituents, and assessment of the permanence and persistence of any adverse effects associated with exposure.
i
! The reviewer determines whether the characterization of exposure pathways is adequate with respect to relevancy, completeness, reliability, and accuracy of l input to the assessa,ents of human and environmental exposure to hazardous l l
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1 e l 205/MFW/88/01/27/ACL constituents. The scope of this characterization includes quantitative and/or qualitative description of physical and biological pathways of constituent transport via groundwater and surface water to exposed pcpulations. The reviewer confirms the licensee's identification and characterization of l sensitive human and environmental populations. The reviewer also confirms that l sensitive populations have been adequately considered in the exposure assessrent. The reviewer determines whether the assessment adequately characterizes physical and biological exposure pathways. The reviewer verifies )
that the licensee has at least assessed the following two pathways in assessing
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human exposure: drinking water ingestion and ingestion of contaminated food ;
products.
Based on the confirmed characterization of exposure pathways, the reviewer verifies the licensee's assessn.ent of adverse effects associated with present and potential hur.an exposure to hazardous constituents. The scope of the humai, exposere assessment includes: (1) classification of affected water resources; (2) assessment of existing and potential uses of water resources; (3) evaluation of the likelihood that people will be exposed to hazardous constituents; and (4) evaluation of adverse effects associated with exposure to j hazardous constituents, including assessment of the permanence and persistence ;
of adverse effects. l L
3.3.2.3.1 Resource Classification and Water Use l The reviewer assesses the classification of water resources at the facility and the existing and potential uses of these water resources. The reviewer I confirms that the licensee considers the following uses of surface water and {
groundwater in the area surrounding the facility: domestic and renicipal d'rinking water, fish and wildlife propagation, industrial, agricultural l (livestock watering and irrigation), recreation, and special ecological !
cormonities. The reviewer verifies the licensee's: (1)assessmtntofexisting and potential uses of water resources; (2) assessrent of potential and safe yields of water resources in relation to requisite supply rates; (3) evaluation l
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205/MFW/8E.'01/27/ACL of the relative costs for development of water resources for beneficial uses; and (4) assessment of legal, statutory, or other administrative constraints on use and developunt of the water resources. The reviewer assesses the licensee's evaluation of existing and potential water uses for both surface water and groundwater. The reviewer verifies that the licensee's assessment of existing and potential uses of water at the facility is generally consistent with evaluations prepared by Federal, State, and local governmental organizations (e.g., State water well inventories, U.S. Geological Survey (USGS) sumary appraisals of groundwater resources, state water use sumary reports). The reviewer confirms that the evaluation of water uses provides an adequate basis on which to assess existing and potential human and environmental exposure to hazardous constituents.
The reviewer ensures that the assessment conservatively estimates the probability of human exposure to contaminated water. Such estimates are often difficult to establish quantitatively, so defensible qualitative estimates may suffice in lieu of quantitative determinations. Examples of such qualitative determinations include the following:
(1) Reasonably likely - expusure has or could have occurred in the past, or available information indicates that exposure r.ay reasonably occur during the duration of the contamination; and (2) Reasonably unlikely - exposure could have occurred in the past, but will probably not occur in the future, because initial incentives for water use have been removed, cr available information indicates that no incentives for water use are currently identifiable, based on foreseeable technological developments.
Review of qualitative determinations of exposure probability considers existing and potential water uses and comparisun of background water quality with appropriate water quality criteria. In general, the reviewer considers existing and potential uses of water resources that may Se affected by the
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f a cility. Existing use may include past use, even though water resources are not presently being used. Potential uses include anticipated and possible uses. Anticipated water use includes only those uses that are reasonably sure to occur. Possible uses are those that are corpatible with background water quality without water treatment before use. The reviewer places greater er.phasis on protecting anticipated uses than on possible uses. At sites where water treatment is necessary before use of water, the rey H:r confirnis that such treatment would be at least partially effective in protecting populations from exposure to hazardous constituents, to support assessment of the risks associated with human exposure.
In reviewing long-term water use, the reviewer also considers aquifer classifications consistent with EPA's Groundwater Protection Strategy (August 1984) and the "Guidelints for Groundwater Classification under the EPA Groundwater protection Strategy" (December 1986). The reviewer assures that exposure is likely to occur for Class I groundwaters, unless the licensee demonstrates that exposure to people using the Class I groundwater is impossible. The reviewer considers potential uses of Class !! groundwaters, but such uses are not considered for Class III groundwaters, unless they currently supply water for beneficial purposes.
The rev! ewer confirms the assessment of existing and anticipated uses of water by comparing background water quality with relevant Federal, State, and local water quality standards. Appropriate water quality standards are selected for comparison based on background water quality, existing and potential water uses, and legal considerations. When standards are inconsistent, the most stringent criteria prevail, unless the licensee demonstrates that less stringent standards preempt the more stringent U iteria, based on legal or technical arguments. In addition to information provided in the assessment, the reviewer may assemble and consider infornation on water use from such organizations as local water supply co :panies or agencies, regional water cosaissions, State and Federal agencies, and local water users. In addition, the reviewer considers water use based on dmography of the facility vicinity,
205/MFW/88/01/27/ACL decographic projections, zoning patterns, and average and maximum projected estimates of population growth.
The reviewer generally assumes that the most significant pathway for human exposure to waterborne contaminants is through consumption of contamir,ated drinking water, unless scoping assessments indicate that other exposure pathways (e.g., dermal contact, inhalation, food ingestion) ray be of equal or greater significance. Consistent with th's assumption, the reviewer classifies the water resources as either Class A or B resources in support of the exposure assessment. As an initial approach, the staff considers that Class A resources have a mean annual total dissolved solids (TDS) concentration less than 3,000 mg/l in water representative of background quality. Class B resources are defined as aquifers or surface water bodies in which the mean annual TDS concentration equals or exceeds 3,000 mg/l in water representative of background quality. However, the reviewer ray determine whether the water is Class A or B, on a site-specific basis, by considering concentrations of other constituents that affect hunan exposure to hazardous constituents.
For class A resources, the reviewer assumes that humans withdraw water from affected aquifers and/or surface water bodies at any point beyond the site boundary in the direction that is hydraulically downgradient from the facility.
This assumption applies for Class A resources regardless of whether water resources are currently being used. For class B resources, the reviewer evaluates adverse effects on human hea'th due to exposure to hazardous constituents considering the location (s) and purpose (s) of the nearest, downgradient, existing or potential water use. In general, the staff i9 viewer does not consider evaluation of human health effects due to exposure fra the use of water resources with background s.ean annual TOS concentrations in excess of 10,000 mg/1, unless such an evaluation is warranted because of existing )r anticipated uses.
3.3.2.3.2 Evaluation of Health Hazards
205/MFW/68/01/27/ACL The reviewer determines whether the licensee's assessment provides reasonably conservative or best estimates of potential health effects caused by human exposure to hazardous conrtituents associated with existing or potential uses of water resources. This determination is based on comparisons of existing and projected constituent concentrations with appropriate exposure limits and dose-response relationships from available literature. The reviewer confirms that the licensee considers Maximum Contaminant levels (MCLs) for drinking water, reference doses (RfDs), or risk specific doses (RSDs) in assessing potential hesith hazards for each hazerdous constituent for which an ACL is proposed. In the absence of applicable MCLs, RfDs, or RSDs, the reviewer confirms that the licensee has assessed dose-response relationships for the constituents, based on comprehensive literature searches or toxicological research. The reviewer verifies that the exposure analysis distinguishes j between threshold (toxic) and non-threshold (carcinogenic) effects associated 4
with human exposure. The reviewer also verifies that the licensee considers i other adverse effects such as teratogenic, fetotoxic, mutagenic, and 1 synergistic effects, based on available information.
The RfDs discussed above are arounts of toxic constituents to which humans can be exposed on a daily basis without suffering any adverse effect. RSDs
- characterize the potency of carcinogenic cogstituents or suspected / potential
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carcinogens. RSDs are amounts of constituents to which humans can be exposed on a daily basis without increasing their risk of contracting cancer above a i specified risk level. RSDs and RfDs for most hazardous constituents in uranium
- mill tailings can be obtaired from epa. Both of these types of values are
- calculated based on laboratory testing and/or epidemiological research. In j reviewing the AfDs and RSDs selected by the licensee, the reviewer verifies that the licensee assumes a human mass of 70 ( and consurption of 2 liters of
]
drinking water per day, unless sensitive populations are likely to be exposed to the hazardous constituents. The reviewer also confirms that the licensee's assessrent assumes reasonable exposure to hazardous constituents via pathways other than ingestion of drinking water (e.g., consurption of food containing thehazardousconstituer.t). The reviewer confirais that the licensee adequately
Oe 205/MFW/88/01/27/ACL i
characterizes for sensitive populations the exposure variables that significantly influence the adverse effects due to hazardous constituent exposure, In calculating the RSDs, the reviewer confirms that the licensee has used an appropriate risk level. In general, risk levels of the order of IE-6 lifetime risk associateo with exposure should be assuu d. The reviewer confirms the licensee's selection and justification of an alternate risk level in the range of 1E-4 to 1E-7 considering: (1) facility-specificconsiderations that influence the likelihood of human adverse effects associated with exposure; (2) other environmental health factors borne by the affected population;and(3)uncertaintiesassociatedwiththedataandassessmentsused to evaluate potential adverse effects.
The reviewer will ensure that the licensee considers the cumulative effects of human exposure to hazardous constituents. The reviewer verifies that the licensee's assessment evaluates effects associated with exposure to hazardous 4 constituents for which ACLs are proposed and other constituents present in contaminated groundwater. As a minir.um, the reviewer confirms that the licensee uses an additive approach in assessing adverse effects associated with exposure to constituents that produce the same adverse effects by similar toxicological mechanisms.
The reviewer confirms that the licensee identifies and adequately justifies a raximm allowable human exposure level for each ACL constituent. The reviewer verifies that the justifications for the maximum expcaure levels f.entify uncertainties inherent in estinating the risk of adverse exposure to constituents. The reviewer verifies that the licensee considers the persistence and permanence of adverse effects on people. The reviewer determines whether the proposed human exposure levels are reasonably conservative, defensible, and sufficiently protective of human health to avoid a substantial present or potential hazard to peuple for the estimated duration of the contamination.
3.3.2.3.3 Evaluation of Environmental Hazards
205/MFW/88/01/27/ACL Similar to the review of human health affects, che reviewer verifies the licensee's assessment of risks associated with hazardous constituent exposure to environmental populations. The scope of the review includes consideration of adverse effects to aquat'c and , terrestrial wilolife, plants, agricultural crops and animals, and physh.a1 structures. The reviewer verifies that the assessrent especially considers potential adverse effe;ts on mangered species and critical habitats. The reviewer confirms that the ev6 vo: ion edequately identifies endangered species and critical habitats by consult .ig with apprcpriate organizations within the U.S. Fish and Wt ' .' life Service. The reviewer confirms that the assessment adequately identifies and evaluates adverse effects such s contamination-induced biotic changes, loss or reduction of unique or critical habitats, and jeopart :ation of endangered species. The reviewer also confirms that the assessment is adequate with respect to relevancy, completeness, ritbility, and accuracy to justify maximum allowable environmenta. exposure lewis. .
For each potential exposure pathway, the reviewer corpares existing and predicted constituent concentrations with chronic toxicity levels for plants and animals. The reviewer may consider acuta anu subchronic effects, when ;
- warranted, based on estimated constituent concesrations and limits for acute and subchronic trvirow *.a1 exposure. For physical structures, such as foundations, enderground pipes, ard roads, the review 3r ensures that estimated constituent concentrations will not result in any substantial degradation or loss of function as 6 result of exposure to the contamination. The reviewer verifies that the licensee's aesessment adequately identifies all environcental species or representative gro ps of species and physical structures that may reasonably be exposed to contaminated groundwat0r and hydraulically-conne.cted gurface water, er appropriate. The reviewer confirms that the assessrent adequately identifies and assesses potential adverse effects associated with
) environmental exposure to hazardous constituents and other constituents that may be present ir contaminated water.
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205/MFW/88/01/27/ACL r In reviewing adverse effects, the reviewer ensures that bioaccumulation and food web interactions are adequately considered, based on available literature.
For effects on aquatic wildlife, the reviewer confirms that estimates of water dilution potential are reasonably conservative with respect to maximizing potential constituent concentrations and environmental exposures. The reviewer generally evaluates aquatic wildlife effects by comparing estimated constituent concentrations with appropriate Federal and State water quality criteria. The reviewer ensures that the licensee considers terrestrial wildlife exposure to constituents via direct exposure and food web interactions. At sites where terrestrial wildlife may be exposed to hazardous constituents, the reviewer confirms that the assessrent adequately identifies and assesses dominant terrestrial habitats in the vicinity of the facility, and that comunity diversity assessrents of these habitats include consideration nf species richness and community structure. The ru iewer confirms the licensee's characterization of terrestrial habitats based on comparisons with ,
representative background data.
Review of agricultural effects considers both direct and indirect exposure pathways, including crop ir. pacts, reduced productivity, and bicaccumulation of constituents. Similar to the review of aquatic wildlife effects, the reviewer compares reasonably conservative estimates of constituent concentrations with re'avant Federal and State water quality criteria and literature values to estimate agricultural effects associateo witn constituent exposure. The reviewer verifies that the assessment considers crop exposure via contaminated soil, shallow groundwater uptake, and irrigation. The reviewer also verifies that the assessrent considers livestock exposure via direct ingestion of contaminated water and indirect exposure via foraging and grazing. The reviewer ensures that the agricultural as essrent is consistent with any assessF4nt of human exposure to hazardous Constituents via ingestion of contaminated food products.
For both human and environmental hazard auessments, the reviewer confirms that the assessment provides an reasonably conservative or best-estimate basis for l
205/MFW/88/01/27/ACL establishing ACLs to prevent substantial present and potential hazards associated with exposure of people a r.d the environment to hazardous constituents.
3.3.3 Review Element 2: Corrective Action Review In conjur.ction with the NRC staff hazard assessment review, the staff reviews the licensee's astessment of the need fcr and selection of corrective actions.
The scope of the eval".ition includes previous, ongoing, and future corrective actions. The reviewer determines whether the licensee adequately demonstrates that the proposed ACLs are as low as reasonably achievable, considering practicable corrective actions. The scope of the demonstration includes identification of alternhtive corrective actions, asse:: ment of the technical feasibility of these actions, evaluation of the costs and benefits associated with implementation of feasible corrective actions, and selection of practicable corrective actions, based on a comparison of the costs and benefits of feasible corrective actions for contaminated groundwater.
The NRC staff reviews the corrective action assesspent used to support ACL demonstrations to ensure that the following criteria are satisfied:
- 1. Have a relatively complete set and range of alternative corrective actions been identified?
- 2. Does the assessment adequately identify feasible corrective actions that are appropriate to reduce hazardous constituent concentrations in contaminated groundwater at tt.e :ite?
- 3. Have the corrective ections been designed adequately to optimize their
. effectiver.ess in reducing hazardous constituer.t concentrations and to mitigate potential hazards that may be associated with their implerentation?
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- 4. Does the assessment provide en objective comparison of the costs and benefits associated with the performance of feasible corrective actions?
- 5. Does the assessment demonstrate that the proposed ACLs are as low as reasonably achievable, considering practicable corrective actions?
The reviewer verifies that the assessment identifies and assesses a reasonable range of corrective actions and that these actions have been designed to optimize their effectiveness in protecting people and the environment. The representative reviewer confirms that optimization calculations provide The approximations of the performance of the affected hydrogeologic system.
review.r also ensures that the set of corrective actions represents a reascoable range of actions that are appropriate to reduce, control, mitigate,
- or eliminate water contamination.
Af ter reviewing the identification of a range of corrective actions, the reviewer verifies the licensee's assessment of the technical feasibility of implementing these actions. Reviews of the technical feasibility vary, based ;
on site-specific considerations, such as hydrogeologic characteristics, extent f l
l of contamination, and potential for human and environmental exposure. The l reviever verifies the feasibility assessment based on the hydrogeologic (
characterization and hazard assessrrent reviewed under Review Element 1 and the
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optimization calculations dis;:ussed above. The reviewer confirms that the licensee's feasibility assessment is also based on proven applications of corrective action techniques and methods at other contaminated sites with similar characteristics. The reviewer ensures that the assessment considers combinations of corrective action sv:asures, including natural restoration, where appropriate. The reviewer confirms that the licensee identifies a range of feasible corrective actions, based on the assessment.
The reviewer determines whether corrective actions have been designed to optimize their effectiveness in reducing hazardous constituent concentrations and to mitigate hazards associated with their implementation. The reviewer
l 205/ttFW/88/01/27/ACL confirais that conceptual desigr,s of the corrective ac', tons are sufficiently detailed to implement the corrective actions upon celeet on. The scope of the review varies based on the: selection of feasible corrective actions; characteristics of the affected hydrogeologic system; probability of human and environmental exposure; and potential hazards associated with exposure. For example, the review of a corrective action that includes a slurry wall would include confirmation of: (1) the ccrp:.tibility of the wall with anticipated geochemical conditions; (2) barrier wall compo:ition and mixture ratios; (3) design specifications; (4) methods of determining the effectiveness of the slurry wall; (5) method of trench excavation and wall construction; (6) contact with rdjacent confinir.g beds; (7) hydraulic prcperties and geochemical characteristics; (8) projected changes in the hydrogeolog.c system caused by wall construction; and (9) contingency treasures. For an aquifer restoration program, the reviewer would confirm such design aspects as: (1) the characteristics of ccntaminated water treatment techniques (2) installation and construction of withdrawal and injection wells or trenches; (3) projected performance of the restoration system; (4) pumping rates and locations; (5) disposal of treatment wastes (both liquid and solid); (6) characteristics of the treatment westes; (7) methods of determining restoration effectiveness; (8) restoration target levels; (9) estimated duration of restoration, (10) the monitoring program during restoration; and (11) contingency measures.
The reviewer confirms that corrective action programs can effectively enhance protection of the public and environnent from hazardous constituents in water, which includes confirmation that: (1) the actions are reasonable (i.e.,
actions are appropriate and achievable at the facility); and (2) the actions are specific, clearly documented, and designed such that their implementation and the results of their implementation can be verified through subsequent field observations.
The reviewer cor. firms that performance of the feasible corrective actions complies with relevant Federal, State, and local regulations and statutes. A comitment by the licensee to comply with these provisions satisfies the
, s 205/MFW/88/01/27/ACL reviewer's responsibilities, unless the reviewer is aware of other regulations or provisions that have not been specifically identified. In this case, the omitted regulations will be identified through the comenting process. .
Authority for determining compliance with all such regulations and statutes ;
resides with the agency or administrative body charged with implementing these regulatory programs (e.g., the or authorized State for the National Pollutant DischargeEliminationSystem(NPDES) program).
The reviewer confirms that the direct and indirect benefits of performing the r corrective actions have been objectively cortpared with the cost s of such actions. Adequacy of the cost estimates is based on completeness and accuracy of cost assessment, including consideration of such corrponents as: capital cops for implementation; operation and maintenance costs for continued !
operation; and depreciation and discount modifications to projected costs. ,
I Adequacy of the benefits assessment is evaluated on a similar basis, considering such benefits as: avoidance of adverse health effects; protect an j and recovery of the value of contaminated groundwater resources; prevention of lano value depreciation; benefits accrued directly from performance of the corrective action; and other benefits realized by avoiding adverse i environmental effects identified in the hazard assessment under Peview Element
- 1. [
The reviewer verifies estimates of the current and projected value of [
contaminated water resources by first confinning that the resources have been j identified and appropriately valued in the licensee's assessment. The reviewer confirms that the estinates ore relikble, based on information such as:
appropriated water rights; costs of bottled water; availability of alternative water supplies; and projected water u;c cenands. The reviewer generally ;
considers the value of potentially contaminated water resources to be equal to i either: (1) the product of the safe yield of the water resources and the unit
- cost of supplied water for its intended purpose (e.g., cost of potable water for domestic or municipal drinking water supplies); or (2) the cost of supplied l water to replace the contaminated resources. The reviewer determines whether
I i
205/MTW/88/01/27/ACL proposed alternate water supplies would be adequate to replace contaminated ,
supplies considering the availability and characteristics (e.g., capital and operationalcosts,suppliablerates,andquality)ofalternativesupplies. The absence of alternative supplies on a local or regional scale increases the relative value of potentially contaminated water resources.
The reviewer assesses the adequacy of the licensee's consideration of practicable corrective actions and derenstration that proposed ACLs are as low as reasonably achievable. The reviewer confirms that the assessrent provides a reasonable balance between the cost of the corrective actions and the societal, environmental, and econcniic benefits to be accrued in the imediate future and over the long-term through performance of the corrective actions. The reviewer considers relevant guidance such as the as low as reasonably achievable philosophy in Apptndix ! to 10 CFR Part 50, hational Council on Radiation Protection and Peasurements Report Number 39, and International Connission on Radiological Protection Publication 22. The reviewer verifies that the licensee's assessment demonstrates that the proposed ACLs are as low as reasonably achievable, considering practicable corrective action.
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205/MFW/88/01/27/ACL 3.4 Review Findings If the licensee's ACL application satisfies the acceptance criteria and the NRC staff's review confires the basis for the proposed ACLs, the reviewer concludes that the derrenstration provides reasonable assurance of corpliance with NRC's requirement in Criterion SB(6) of Appendix A to 10 CFR Part 40. Based on this conclusion, the reviewer recomends approval of the site-specific alternate concentration limits fur the constituents requested by the licensee. The reviewer decurents the recomendation, provides the technical basis for the i recomendation, and concludes the recomendation as follows:
Eased on NRC staff review of the alternate concentration limits (ACLs) ,
proposed by [specify name of licensee) on [specify date) in accordance with Criterion 5B(6) of Appendix A to 10 CFR Part 40 for (specify naine and !
location of facility), the staff recomends that ACLs be established for 1
[specify hazardous constituent (s)) in groundwater at this facility because !
(1) the proposed ACLs will not pose a substantial present or potential l hazard to human health or the environrent as long as constituent ;
concentrations do not exceed the ACLs, and (2) the proposed ACLs are as low as reasonably achievable considering practicable corrective actions. ,
The reviewer may also recomend establishing ACLs for only those constituents for which the licensee's demonstration is sufficient to satisfy NRC's requirenent in Criterion 5B(6) of Appendix A to 10 CFR Part 40. In this case, the reviewer would document the recomendation as above and include a description of the ACLs proposed by the licensce that were not recommended for establishment. Such descriptions should list the unapproved ACLs, cite specific inadequacies that caused the licensee's descnstration to fail for selected constituents, describe the technical basis for the review conclusions, and identify alternative technical approaches that the NRC staff finds acceptable to resolve the inadequacies, if appropriate.
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205/MFW/88/01/27/ACL , ,
If the reviewer concludes that the licensee's demonstration fails to demonstrate compliance with Criterion SB(6) of Appendix A to 10 CFR Part 40, then the reviewer documents the basis for f ailure, cites specific inadequacies j that caused the demonstration to fail, describes the technical basis for the f review conclusions, and identifies alternative approaches for the licensee to resolve the inadequacies, if appropriate.
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In addition, documentation of recomendations for or against establishment of ACLs identify: (1) aspects of the ACL review that were particularly [
errphasized; (2) deviations of the review from the review criteria and procedures detailed in this technical p'sition; (3) justifications for these i deviations; and (4) any conclusions that require confirmatory monitoring or surveillance to ensure consistency with assumptions invoked in support of the ,
ACL demonstration.
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