ML20215N983
| ML20215N983 | |
| Person / Time | |
|---|---|
| Issue date: | 10/17/1986 |
| From: | Linehan J NRC OFFICE OF NUCLEAR MATERIAL SAFETY & SAFEGUARDS (NMSS) |
| To: | Greeves J NRC OFFICE OF NUCLEAR MATERIAL SAFETY & SAFEGUARDS (NMSS) |
| References | |
| REF-WM-1 NUDOCS 8611100162 | |
| Download: ML20215N983 (5) | |
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. MEMORANDUM FOR: John T. Greeves, Chief PHildenbrand Engineering Branch, DWM KStab1ein RCook FROM: John J. Linehan, Acting Chief Repository Projects Branch,:DWM
SUBJECT:
ENGINEERED BARRIER SYSTEM BOUNDARY DEFINITION As requested in your memorandum of September 18,'1986, the background draft position on the engineered boundary system definition has been reviewed, and '
considered as the basis for a formal Generic Technical Position (GTP). Staff comments are enclosed.
We agree that the draft position is consistent with the Nuclear Waste Policy Act, 10 CFR 60, and the NRC's response to public comments on the proposed rule.
Persistent concern by the DOE noted in your memorandum indicates a need for clarifying.various aspects of our position. Developing a GTP offers an opportunity to' reach technical consensus in a manner that allows broader public participation. Moreover..the existence of more complex technical issues such.
as where-to impose the boundary conditions in calculating the release rate from the EBS (see Comment No. 5 in the enclosure) assures that the GTP will be more
.than a restatement of our existing position.
Based on the foregoing considerations, I agree that the issue warrants development into a formal GTP.
Since an Engineered Barrier System Task Group has already been established (Memorandum, Greeves to Miller 6/17/85 and Miller to Greeves 7/24/85), the next steps are to prepare a formal scope and approach for briefing the branch chiefs and.to determine schedule and resources. In preparing the scope and approach, consideration should be given to the recommendation in.the enclosed WMRP staff comments to include the technical issues along with their alternative and recommended resolutions. An additional point to consider is whether the proposed title of the GTP accurately describes the content and intent of the document. A suggestion is to drop " Definition" from the title. What is being discussed is the locaticn of the boundary of the EBS and what analytic WM Record Ole WM Project /
8611100162 861017 N0k Docket N0- -
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109.2/PB/86/10/01 implications that location has.
Brian Theras, of my staff, is available to discuss development of a milestone schedule and resources with your staff.
$$!i3 Bf John J. Linehan, Acting Chief Repository Projects Branch, DhE
Enclosure:
As stated
Enclosure:
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WMRP Comments on ENGINEERED BARRIER SYSTEM b0UNDARY DEFIhlTION Recommendation:
This background draft position should be developed into a formal GTP. To assure that the guidance provided goes beyond a restatement of our existing position, the more substantive technical issues shculd be addressed in the GTP.
(Comment No. 5 addresses such an issue, namely, where to impose the boundary conditions in mathematical calculation of release rates from the EBS.)
Moreover, the more complex technical issues and their alternative and recommended resolutions shculd be identified in preparing the formal scope and approach to the GTP so that the process of obtaining staff technical consensus can be brought to closure as soon as possible.
General Comments:
The subject document appears to reflect a useful approach: (1) Identify the issue, (2) Prepare a point paper on the issue, (3) Obtain comments internally, (4) Address questions raised, indicating the proposed scope and approach, and (5) Review the result, and decide, in light of the HLW program as a whole, whether to go forward with a GTP. Should it be decided to proceed with development of a fornal GTP, the next steps would be to develop an agreed-upon scope and approach for presentation to the branch chiefs and a workplan/ schedule.
The first three pages provide a clear statement of the staff's position. The remaining questions and responses contain issues that are among those which might properly be addresscd in the discussion / rationale of a GTP. Such a rationale would require a logical structure that incorporates major aspects of the issue to be clarified.
Specific Comments:
- 1. It is suggested that ycu consider adding a paragraph to the Staff Position secticn which says:
If DOE wished to try to evaluate and take credit for some portion of the host rock in reducing the rate of release of radionuclides, DOE should propese an alternative release rate objective under the provisions ot Sto.113(b). The NRC will review the rationale for the proposed alternative and approve or disapprove it as appropriate.
- 2. In responding to Question 1 it shculd he noted that NUREG-0804 specifically stated that hcst rock is not part of the EBS.
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- 3. The response to Question 2 should include as the second sentence of the second paragraph the following:
For example, a backfill material consisting of mixed crushed salt and bentonite might reverse the argument presented in this question.
- 4. Jua alternative response to Question 3 is:
A more reasonable interpretation, and the one held by the NRC ctaff, is that the disturbed zone includes that portion of the host rock which.is disturbed by construction of the underground facility (or by heat), hence, that portion of the disturbed zone must extend outside of, and is separate from, the underground facility. We note that inclusion of grouted fissures in the EBS might unduly complicate analysis of the contribution of enhanced rock wall to limiting release rate.
- 5. In one sense Question 4 answers itself. Existence of a boundary condition requires the presence of a boundary. The location of this boundary is described in the staff position on page 3. However, a substantive technical issue is imbedded in the second sentence of the response, which states that it is possible to make the release from waste package alone indistinguishable from the release from the waste package plus several meters of host rock. The point here seem to be that a potential problem exists. Menely, it is important to develop criter1a for imposing boundary conditions for evaluating the release rates at the edge of the EDS in such a manner that not only is no credit taken for the host rock as a barrier, but also, environmental conditions established near the EBS/ rock-interface that are used to evaluate the boundary conditions are described with a conservatism concensurate with the uncertainties involved. An effort should be made to resolve this issue in developing any GTP on the EBS boundary.
- 6. The citation in Question 5 should read 10 CFR Part 60.ll3(a). In keeping with the suggested added paragraph to the Staff Position the following sentence might be added:
For alternative release rate criteria under lo0.113(b), see the Staff Position on page 3.
- 7. With regard to the response to Question 9, we note that:
NWPA does not define " underground facility." (It doesn't appear that NWPA uses the tern, either.) A better question would be "Is there censistency in use of the term, ' engineered barriers'?" NWPA and Part 60 are consistent with the staff position of page 3.
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- 8. The following sentences could be added to the response to Question 13.
Also, the~ purpose of $60.113 was to establish performance objectives for components of a repository which are identifiable and for which some hope exists for performing meaningful analyses. Including the disturbed zone in the EBS would do just the opposite. (
Reviewed by: Pauline Brooks, Dan Fehringer, John Libert Date: September 26, 1986