Departmentof Energy Carlsbad Field Office P. 0. Box 3090 Carlsbad, New Mexico 88221 October 7, 2002

Mr. Frank Marcinowski Office of Radiation and Indoor Air U.S. Environmental Protection Agency 401 M. Street, S.W. Washington D.C., 20460

Dear Mr. Marcinowski:

The Carlsbad Field Office (CBFO) of the Departmentof Energy (DOE) requests your approval of a proposed change to the EPA 40 CFR Part 194 Certification of the Waste Isolation Pilot Plant (WIPP) with regard to the design of the Panel Closures. Specifically, CBFO requests that the Environmental ProtectionAgency (EPA) modify Condition 1 of the WIPP Certification decision by agreeing that the New Mexico Environment Department (NMED) is responsible for final review and approval of the design and constructionof the panel closure system at WIPP. At the same time, the CBFO recognizesthat EPA's review and approval of the impact analyses relatingto the 194Certification Final Rule on Panel Closures is still required, and that EPA must be satisfied that any design change will not adversely affectthe long-term performance of the repository.

As you know, the purpose of the panel closure system inthe WIPP facility isto control volatile organic compound (VOC) emissions duringthe operating life of the facility. The panel closure must also protectthe health and safety ofworkers as required bythe Mine Safety and Health Administration and by the DOE. There are no long-term design requirementsor performance specificationsfor these closures, beyond the necessity to demonstrate that any design change does not have an adverse affect on long-term performance. The analyses that accompanythis letter demonstrate that the long-term performance of the repository is not sensitive to the closure design, within a broad range of likely closure permeability values.

The CBFO believes it istherefore reasonable that the NMED be responsiblefor final review and approval of panel closure design and construction. The CBFO requeststhat the EPA modify Condition 1 of the Final Rule to recognizethis responsibility. We suggest that such a change might include the following:

That the Department will implement a panel closure system as approved bythe NMED

That the Department will demonstrate, by an appropriate impact assessment, that the panel closure system proposed to NMED does not adversely affect the longterm performance of the repository



### OCT 

### Q 8ZW2Mr. Frank Marcinowski -2- October 7, 2002

The currently approved panel closure design ("Option

### D") specified in Condition 

### 1 involves installation of a concrete block "explosion wall", removal of the DRZ along a section of the panel access drifl, and emplacement of a concrete monolith composed of Salado Mass Concrete (SMC) inthat section of access drift. After three years of experience with WlPP as an operationalfacility, we have re-evaluateda number of its engineering and construction aspects. This effort included detailed planning to install Option 

### D closures in Panel 1and a parallel analysis of alternative closure designs. As
a result of this re-evaluation, we believe a redesign of the panel closure system is warranted. The redesigned panel closure (called the WlPP panel closure (WPC))will be much simpler and significantly less expensive to build, will reducethe risk of accidents and industrial injury to constructionworkers, will providefor re-use of mined salt, and will reducethe potential for disruption of wasfe emplacement activities. All of these benefits will accrue without influencingthe short- or long-term performanceof the repository.

The proposed change in Condition 

### 1 requires that the EPA befully cognizant of the CBFO's Permit modification request to the NMEDfor panel closures. To this end, the details of the redesign and its performanceare included in the attachments to the enclosed Notification of Proposed Change. Attachment A of the Notification, Design Reportfor a RevisedPanelClosure Systemat the Waste Isolation Pilot Plant, provides
a description of the proposed design and demonstrates its adequacy to meet and exceed requirements of the Resource Conservationand Recovery Act (RCRA) during the operational period. This design report has been certified by a Professional Engineer registered in New Mexico. Attachment A is being transmittedto the NMED as part of a Permit Modification Request to change the Closure Plancontained inthe HazardousWaste Facility Permit (HWFP).

Attachment B, Effective Permeabilityof the Redesigned PanelClosure System, provides estimates of the permeability of the WPC as a function of time. Specifically, it demonstrates that the new closures will have a permeability between m2 and 

### IO-'~ m2throughout the regulatory period. This range is significant because it isconsistent with the range of panel closure permeabilityevaluated inAttachment C.

Attachment 

### C, PanelClosure Impact Assessment Documentation, evaluatesthe impacts of panel closures on the long-term performance of the repository. This analysis report is prepared pursuant to 

### 40 CFR Part 

### 191,Subparts B and C, and 

### 40 CFR Part 

### 194. The report demonstrates that impactsto the predicted long-term performance of the repository associated with the installationof the 

### WPC are negligible compared to the currently prescribed Option D design.

The HWFP issued by the NMED specifies panel closure requirements that comply with the reauirements of the New Mexico hazardouswaste reaulations durina the operational period of the repository. The analyses in ~ttichments B an: C demonstrate that the long-term performance of the repository is not sensitive to the closure design, within a broad range of closure permeability. Becausethe panelMr. Frank Marcinowski 

### -3- October 7, 2002 closure specifications cover only the operational period and because long-term performance is insensitive to this design, CBFO believes that the NMED, which regulates hazardouswaste disposal in New Mexico, should have responsibilityfor final approvalof the panel closure system design. CBFO therefore requests that EPA modify Condition 1of the WIPP Certification decision to acknowledge that the NMED is responsible for regulatingthe design and construction of the panel closure system at WIPP, provided that the Department demonstrates that there are no long-term impacts
on performance.

The EPA will continue to be involved as regardsthe long-term performance of panel closures even if Condition 

### 1 is modified. The CBFO must demonstrate to the EPA that any future panel closure redesign will have a long-term permeability within a range that is acceptable to the EPA, e.g., the range evaluated inAttachments B and C to this Notification. If this is not the case, a full performance assessment would be requiredfor
a new range of closure permeabilities.

We appreciateyour timely considerationof this request. Shouldyou require further information, please contact Mr. Daryl Mercer at (505) 234-7452. Sincerely,

Dr. Ines 

### R.Triay Manager

Enclosure

cc: w/enclosure L. Smith, EM-23 B. Forinash, EPA-ORIA 

### C. Byrurn, EPA-ORIA 

### S. Ghose, EPA-ORIA N. Stone, EPA-RegionVI S.Zappe, NMED M. Silva, EEG

CC: W/O enclosure 

### J. Bearzi, NMED 

### C. Zvonar, CBFO B. Lilly, CBFO 

### J. Pigg, CBFO 

### J. Lee, WTS P. Shoemaker, SNL

### Mr. Frank Marcinowski

bcc: W/O 

### enclosure 

### J. 

### Plum, CBFO D. 

### Mercer, 

### CBFO S. Casey, WTS R. 

### Chavez, WTS October 7, 2002Department of Energy Carlsbad Field Office P. 0. Box 3090 Carlsbad, New Mexico 88221 

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Mr. Frank Marcinowski Office of Radiation and IndoorAir U.S. Environmental ProtectionAgency 401 

### M. Street, S.W. Washington D.C., 20460

Dear Mr. Marcinowski:

The Carlsbad Field Office (CBFO) of the Department of Energy (DOE) requests yc approval of a proposed change to the EPA 40 CFR Part 194 Certification of the W Isolation Pilot Plant (WIPP) with regard to the design of the Panel Closures. Specifically, CBFO requests that the Environmental Protection Agency (EPA) modif Condition 

### 1of the WIPP Certification decision by agreeing that the New Mexico Environment Department (NMED) is responsiblefor final review and approval oft design and construction of the panel closure system at WIPP. At the same time, CBFO recognizes that EPA's review and approval of the impact analyses relatingt 194 Certification Final Rule on Panel Closures is still required, and that EPA must satisfied that any design change will not adversely affect the long-term performanc the repository.

As you know, the purpose of the panel closure system inthe WIPP facility is to cori volatile organic compound (VOC) emissions during the operating life ofthe facility. panel closure must also protect the health and safety of workers as required by the Mine Safety and Health Administration and by the DOE. There are no long-term de requirements or performance specifications for these closures, beyond the necessit demonstrate that any design change does not have an adverse affect on long-term performance. The analyses that accompany this letter demonstrate that the long-te performance of the repository is not sensitive to the closure design, within a broad range of likely closure permeability values.

The CBFO believes it is therefore reasonable that the NMED be responsible for fina review and approval of panel closure design and construction. The CBFO requests the EPA modify Condition 

### 1of the Final Rule to recognize this responsibility. We suggest that such a change might includethe following:

0 That the Department will implement a panel closure system as approved by the NMED

That the Department will demonstrate, by an appropriate impact assessment, th the panel closure system proposed to NMED does not adversely affect the longterm performance of the repository