Panel Closure Redesign:

Update

August 2011

Thomas Klein-URS, Regulatory and Environmental Services, 

Carlsbad, NM 88220

1
Introduction

This presentation will cover operational and longterm design aspects:

•Major Design Criteria

•Research Activities

•Interim Closure

•Gas Monitoring

•Current Research Activities

•Planned Change Request

•Regulatory Schedule

2
EPA Certification (long-term)

• Option D design represented in Performance Assessment

• Salado Mass Concrete

NMED Hazardous Waste Facility Permit (operational period) 

• Limit migration of volatile organics at the point of compliance for 35 years.

• Maintain functionality under loads generated by salt creep.

• Maintain functionality under loads generated by internal pressures.

• Maintain functionality under loads generated by a postulated methane-based explosion.

• Limit migration of Volatile Organic Compounds (VOCs).

3

Major Design Criteria
• 2001- DOE identified several changes needed to the panel closure design after 

initial investigations. These changes were:

1. Replace Salado Mass Concrete with generic salt-based concrete. 

(EPA/NMED)

2. Replace isolation wall with construction wall. (NMED)

3. Replace freshwater grouting with salt-based grouting. (EPA/NMED)

4. Allow option of implementation of panel closure completion within a year 

instead of 180 days. (NMED)

4

Research Activities
Interim Closure

• 2003- To comply with the requirements of the Hazardous Waste Facility 

Permit, the DOE constructed the block wall portion of the Panel Closure 

Option D design for Panels 1 and 2. This allowed DOE to study the effects of 

salt creep on the block wall and verify previously identified changes.

5
Gas Monitoring

•2007- DOE -Hydrogen and Methane monitoring is being performed in waste filled 

panels and the results have shown that methane and hydrogen levels are below 

regulatory limits (NMED).

6
7

•Continue to collect Hydrogen, Methane and VOC data. 

(NMED)

•Review and evaluate Hydrogen, Methane and VOC data. 

(NMED)

•Run Performance Assessment with the new panel closure 

design represented in the models. (EPA)

•Integrate with new Hazardous Waste Facility Permit 

requirements. (NMED)

Combining Research Activities 

and the Planned Change Request
• Evaluates monitoring data from panels with 

emplaced waste and evaluates potential for 

explosive gas (NMED).

• Performance assessment that incorporates updated 

design (PC3R) (EPA).

• Ensure long-term porosities and permeability of the 

new design are comparable to the Option D design 

(EPA).

8

Planned Change Request 
9

Planned Change Request Cont.
EPA-Planned submittal September 2011.

-18 to 24 month review (Rulemaking)

-Projected approval 2013

NMED-Planned submittal January 2012.

-12 to 18 month review and comment period.

-Projected approval 2013.

10

Regulatory Schedule
Conclusion

19

• As a result of increased understanding of the repository and the stored 

waste obtained over 12 years of operation, the DOE has determined that 

a revision of the approved Option D panel closure design should be made. 

• The revised design described in this PCR will reduce the risk of injury to 

construction workers, enhance constructability, reduce construction cost, 

and reduce the impacts on on-going repository operations. 

• A change to the design specified in Condition 1 of the Certification 

Decision is required because of the problems in manufacturing SMC to 

the specifications in the CCA. 

* An analysis of the results of earlier PAs suggests that this revised design 

will have a long-term performance essentially the same as with Option D.