Certified Mail - Return Receipt Requested

March 26, 2001
 

Dr. Inés Triay, Manager                             Mr. Hank Herrera, General Manager
Carlsbad Field Office                                 Westinghouse TRU Solutions, LLC
Department of Energy                                 P.O. Box 2078
P. O. Box 3090                                         Carlsbad, New Mexico 88221-5608
Carlsbad, New Mexico 88221-3090

RE: Final Determination, Class 2 Modification Requests
WIPP Hazardous Waste Facility Permit
EPA I.D. Number NM4890139088

Dear Dr. Triay and Mr. Herrera:

The New Mexico Environment Department (NMED) hereby denies the Class 2 permit modification request to the WIPP Hazardous Waste Facility Permit as submitted to the Hazardous Waste Bureau in the following document:

•    Request for Class 2 Permit Modifications, Dated 12/7/00, Rec'd 12/7/00

This modification, proposing changes to the Drum Age Criteria (DAC) in the Permit, was processed by NMED in accordance with the requirements specified in 20.4.1.900 NMAC (incorporating 40 CFR §270.42(b)). The basis for the denial of this modification is addressed below, while NMED's general comments on the proposed permit modification are in Attachment 1.

20.4.1.900 NMAC (incorporating 40 CFR §270.42(b)(7)) provides several reasons for denying a Class 2 permit modification request, such as the modification request is incomplete; it does not comply with applicable requirements; or it fails to protect human health and the environment. Although NMED issued an administrative completeness determination for this modification request on February 22, 2001, this determination did not consider the technical adequacy of the request. Numerous public commentors identified significant technical inadequacies in the modification request. One such inadequacy was the complete failure of the Permittees to address how sites would obtain the required information necessary to determine appropriate DACs, including but not limited to modifications to visual examination, radiography, and acceptable knowledge permit requirements.

NMED was unable to approve the modification "with changes" as allowed under 20.4.1.900 (incorporating 40 CFR §270.42(b)(6)(i)(A)) because none of the commentors proposed sufficiently detailed changes to rectify the technical inadequacies they identified. Such changes would have had to be fairly substantial to overcome the significant shortcomings of the proposed modification, and would also have to be subject to additional public comment. Furthermore, NMED was unable to reclassify this modification request to follow the procedures for Class 3 modifications specified in 20.4.1.900 (incorporating 40 CFR §270.42(b)(6)(i)(C)) because the request was not approvable as submitted.

Due to its complex technical nature and in consideration of NMED's and the public's comments, the Permittees may wish to resubmit this permit modification request as a Class 3 modification under 20.4.1.900 (incorporating 40 §270.42(c)) and 20.4.1.901.B(5) NMAC. The Class 3 modification process does allow an initially deficient request to undergo the notice of deficiency (NOD) and NOD response cycle prior to issuance of a draft permit, at which time it is subject to additional public comment. If the Permittees continue to submit technically complex changes as Class 2 modifications, they run the risk of having technically deficient requests denied on the same basis as this DAC modification request.

This Class 2 modification was subject to a sixty (60) day public comment period, which ran from December 11, 2000 through February 9, 2001. NMED received written comments from ten individuals and organizations during this time. The list of commentors and NMED's responses to these comments are incorporated in the following attachments:

•    Attachment 2 is a list of commentors, their affiliation, the date their comment was received, and the number of pages of comments.
•    Attachment 3 is a spreadsheet providing NMED's direct response to each comment submitted. This document will be mailed to each individual commentor.
•    Attachment 4 is a general summary of the permit modification request, the typical comments received, and NMED's general response to those comments. This document will be mailed to all other individuals and organizations on NMED's WIPP facility mailing list.

NMED expects that the Permittees will address all comments provided in Attachment 1, as well as evaluating the comments in Attachment 2, prior to submitting a revised permit modification request. If you have any questions regarding this matter, please contact Steve Zappe of my staff at (505) 827-1560, x1013.

Sincerely,
 

Gregory J. Lewis
Director
Water and Waste Management Division

GJL/soz

Attachments

cc: Paul Ritzma, NMED
James Bearzi, NMED HWB
John Kieling, NMED HWB
Steve Zappe, NMED HWB
Susan McMichael, NMED OGC
David Neleigh, EPA Region 6
Connie Walker, TechLaw
File: Red WIPP '01

Attachment 1

NMED General Comments on Permit Modification Request

NMED Comments on the BWTX Report

1.    The models proposed in the 1995 Lockheed Report (1995 Report) and the October 2000 BWTX Report entitled "Determination of Drum Age Criteria Prediction Factors Based on Packaging Configurations" (BWTX 2000) appear to assume that the method of sample collection will occur through an air tight needle entry and that no VOCs are lost to the atmosphere either through sampling or other handling (e.g., opening a vent in the rigid liner). However, it is unclear how this assumption would be achieved, particularly with respect to the potential loss of volatiles during Scenario 2 liner venting or Scenario 1 sampling through the rigid liner.

2.    The 1995 Report and BWTX 2000 reports were compared to assess differences in the assumptions or in the formulae used to generate the theoretical drum ages for the different scenarios and packaging configurations. The 1995 Report calculated DACs were compared to the Scenario 3 DACs in BWTX 2000, and there does appear to be a general sense of agreement between the approaches presented in each report with respect to comment elements addressed in each report. However, the presentation and terminology differed significantly between the two reports and it was not always clear if the approach between the 1995 and 2000 reports was the same. In general, the Permittees should provide additional clarification to demonstrate that the approach, assumptions, and inputs used in the 1995 Report were also used in BWTX 2000. Any changes in approach, assumptions, or inputs should be clearly identified. In addition to this general request for clarification, the following specific clarifications are among those that should be provided if the modification is revised and resubmitted (note that this is not a comprehensive listing of clarifications, which are presented only as examples):

• The 1995 Report included a term for calculating the VOC accumulation in the rigid liner (Equation A-4). This term does not appear to be addressed in BWTX 2000. The Permittees should provide clarification as to the use of this term and the impact of this term on the overall DAC calculations.
• The 1995 Report contains a series of equations (Equations A-7a through A-11b) that define the rate of change of the VOC concentration in each layer of confinement, but BWTX 2000 did not specifically discuss these equations. The Permittees should provide additional clarification to demonstrate how the rate of change in each layer of confinement is calculated and how the equations used in BWTX 2000 are equivalent.
• The equation for VOC diffusivity in air included in BWTX 2000 (Equation 7) is different than the equation used in the 1995 Report (Equation 3-2), as BWTX 2000 includes a temperature and pressure factor that is not in the 1995 equation. The Permittees should clarify the origin and purpose of this factor and how this factor was accounted for in the 1995 equation.
• Some model inputs are different between the 1995 Report and BWTX 2000. For example, the 1995 Report references the use of the NFT-20 filter that has a hydrogen diffusivity characteristic of 4.2E-06. The 2000 report calculates DACs based on three separate filter diffusivities, none of which are the NFT-20 filters.


3.    The BWTX 2000 software modeling report indicated that hydrogen generation was no longer included in the model. The Permittees should clarify if the hydrogen gas generation was considered in the 1995 Report and what impact not considering the gas generation has on the model.

4.    The VOC multiplier factors found in Section 5 of BWTX 2000 indicates that VOC multipliers could be used to extrapolate VOC headspace gas concentrations at the DAC by measuring the concentration at a different date and applying a multiplication factor. However, the Permit Modification did not indicate if this approach would be employed and how it would be implemented. If it is implemented, the Permittees should clarify the impact of these lower concentrations on TIC identification and reporting as well as target reporting for concentrations at or near the MDL in the samples taken at an earlier date. Furthermore, test data needs to be generated to support these calculations, as specified in Comment #5 below.

5.    It is unclear if any test data was generated to support the theoretical calculations provided in the BWTX 2000 report. The collection of test data to support DAC conclusions, particularly for those elements not considered in the 1995 Report (i.e., SWBs, pipe overpack, containers larger than 55 gallons, etc.), would appear to be crucial to both demonstrate practical applicability of calculated DAC values and to validate the extension of the methodology to other container types and sizes. Experiments would also lend serious credibility to the entire process. NMED notes that the methodology presented in the original permit application was supported by test data. If new test data were generated, the Permittees should discuss the results and the parameters of the test.

6.    Several clarifications should be provided with respect to BWTX 2000 to ensure complete understanding and implementation of the process. These clarifications should include but are not limited to the following:

• Sensitivity and uncertainty analysis should be discussed with respect to important parameters such as the presence/absence of liners, filter vent characteristics, opening size in the liner lid, etc. This is important to identify which parameters influence DAC calculations the most.
• Be sure that BWTX is very clearly written, particularly in the areas of Scenario descriptions. For example, it is not entirely clear from the Scenario 2 discussion on page 3 of the BWTX report that the drum is initially unvented until DAC1 is reached, after which the drum is vented and DAC2 must be reached before sampling.
• All assumptions and simplifications presented in BWTX should be justified (e.g., assumptions pertaining to waste drum configurations, selection of Scenario 3 packaging configurations for drums, Section 6.1 Modeling Assumptions, Appendices A and B, etc.).
• The information reviewed which supported the determination of various packaging configurations for SWBs and pipe overpacks should have been included
• Clarify how the Pipe Component DAC was calculated with respect to the relationship of this value and information presented in Section 6 of BWTX 2000.


7.    During the development of the draft permit in 1998, NMED examined the 1995 report and supporting mathematical calculations/assumptions, and accepted the methodology embodied in that report. It might be appropriate for NMED and the Permittees to discuss all code changes implemented since the 1995 report, particularly those used to implement changes in SWB and pipe overpack determinations. While the mathematics appear generally appropriate, NMED has a number of questions concerning assumptions, applicability, etc., which remain unanswered because NMED did not have access to the authors nor have an opportunity to interact with the Permittees after the modification was submitted. This is primarily due to the nature of the Class 2 permit modification process, which does not provide for supplementing the administrative record with information obtained from a request for supplemental information (RSI) or a notice of deficiency (NOD).

NMED Comments on the Permit Modification Request

8.    BWTX 2000 was used as justification for the proposed DAC modification. The authors of BWTX 2000 propose a very prescribed and ordered process to determine drum ages based on waste packaging configuration and other drum considerations. In this process, three distinct drum Scenarios are provided: Scenario 1 applies to unvented drums sampled immediately after venting; Scenario 2 applies to drums that were unvented for the Scenario 1 DAC time period, but were then vented; and Scenario 3 applies to drums vented at the time of packaging. In Drum Scenario 2, the sample may only be collected after the Scenario 1 Drum Age Criteria DAC (DAC₁) is met and the container is subsequently vented, followed by achievement of the Scenario 2 DAC (DAC₂). However, the Proposed Permit Modification provides only a single reference in Table B1-5 indicating that Scenario 2 drums are to meet both the Scenario 1 DAC and Scenario 2 DAC sequentially. That is, the Permit Modification does not clearly indicate that the Scenario 2 DAC must be considered in conjunction with the Scenario 1 DAC and that the Scenario 2 DAC begins once the Scenario 1 DAC is met and the drum is vented. This could be very confusing to generator/storage sites attempting to implement the Permit Modification.

9.    The proposed Permit Modification is unclear with respect to how samples will be collected under unvented rigid drum liners. The permit currently contains prescriptive criteria for collecting samples through a carbon filter or the drum lid of containers with vented rigid liners, but the Permit Modification is not equally prescriptive with respect to details for sampling through the rigid unvented liner. The Permittees should provide additional detail for collecting a sample through the rigid unvented liner.

10.    Section B-1c of the WAP specifies that all drums must have filters, which was a concern during WIPP permit hearings with respect to gas build-up and potential development of corrosive, ignitable, and reactive conditions. However, according to the proposed modification, it appears that unfiltered drums would be very acceptable and are currently present at sites. The Permittees should consider how this information impacts the Permit, particularly with respect to permit requirements and the mitigation of interior drum conditions with respect to D001, D002 and D003 waste. The Permittees should also clarify how they intend to have sites manage drums without filters.

11.    Table 4 (Table B1-8) presents the Scenario 3 Packaging Configurations and shows that for any Summary Waste Category Group, certain packaging is allowed under specific Packaging Configurations. However, BWTX 2000 indicates that different packaging considerations were assumed for S5000 and S3000/S4000 when calculating the DAC. For example, Packaging Scenario 3 assumed a bounding packaging condition of two liner bags for S3000/S4000 waste, and a bounding packaging condition of 4 inner bags/2 Liner bags for debris (S5000). As such, the BTWX 2000 report did not consider 4 inner bags/ and two liner bags for S3000/S4000 waste (the DAC for this condition would presumably be greater/more conservative than when two liners alone are considered), yet Table 4 allows this configuration for S3000/S4000 waste. Unless the Permittees can justify combining assessed configurations and making them applicable to all wastes, Table 4 should have differentiated between S5000 and S3000/S4000 waste allowable packaging configurations, as shown in the BWTX 2000 Report.

12.    The Permit Modification lists specific liner lid hole sizes, filter diffusivities, etc., that drums must have to use the included DAC tables. However, it is apparent that not all drums may fit the specified criteria. The Permittees state that additional DAC shall be calculated for new packaging configurations (and shall be submitted as permit modifications), but the Permittees should also have indicated how DAC must be calculated or selected when drum parameters don't exactly "match" those specified on Permit Modification Tables (e.g., interpolate between DAC values, choose the more conservative DAC, etc.).

13.    The Permit Modification was presumably submitted to allow sites the ability to select configuration and waste-specific DAC rather than using the single DAC(s) included in the Permit. Additionally, the modification allows sampling of unvented drums, which was not considered in the Permit. However, the Permittees do not appear to have considered the practical application of the modification with respect to implementation at generator sites. For example, packaging configuration determination specific enough to determine DAC would require modifications to VE, RTR, AK, and many other procedures. Additionally, drum filter and other criteria may not "match" those specified in the permit. As such, the modification could require sites to perform wholesale modification of their characterization programs and could even disallow some drums for shipment (if, for example, their packaging does not match those specified on the tables), or it could encourage significant repackaging of wastes (which is an ALARA concern). The Permittees should have considered the option of retaining some simplistic "default" DAC or set of DAC values that sites could rely on to simplify their characterization processes.

14.    The proposed Permit Modifications do not consider or include additional permit modifications that must also be made to support new DAC calculations. For example, RTR reporting requirements must be modified to specify all of the necessary information to determine specific packaging configurations, as must Visual Verification and Visual Examination requirements. AK requirements must be modified to require collection of DAC-related data (i.e. liner, bags, etc., on a drum-specific basis), and this would become mandatory, not supplemental, information. Reporting, data validation/verification, and other permit sections would also require modification. Without complete and comprehensive modification of all necessary permit sections, generator/storage sites would not have consistent direction with respect to implementation of the DAC and related processes, and the audit process could become unnecessarily complicated.