ML20151F602
| ML20151F602 | |
| Person / Time | |
|---|---|
| Issue date: | 07/25/1988 |
| From: | Linehan J NRC OFFICE OF NUCLEAR MATERIAL SAFETY & SAFEGUARDS (NMSS) |
| To: | Stein R ENERGY, DEPT. OF |
| References | |
| REF-WM-11 HLWR, NUDOCS 8807270167 | |
| Download: ML20151F602 (7) | |
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UNITED STATES 8
NUCLEAR REGULATORY COMMISSION o
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WASHING TON, D. C. 20665
. DOI 2 5 M Mr. Ralph Stein, Act.ing Associate Director Office of Systems Integration and P.egulations Office of Civilian Radioactive Waste Management U.S. Department of Fnergy RW-24 Washington, D.C. 20585
Dear Mr. Stein:
Subject:
Evaluation of NNWSI Project's Response To Information Requests From the April 14-15, 1987, Meeting Between the DOE and NRC
References:
(1) Letter, Gertz (WMPO) to Linehan (NRC), dated October 16, 1987 (2) letter, Gertz (WMPO) to Linehan (NRC), dated October 29, 1987 (3) Summary of DOE /NRC Meeting on Proposed Changes to the Nevada Nuclear Waste Storage Investigations Exploratory Shaft Facility, April 14-15, 1987 (4) Letter, Coplan (NRC) to Vieth (WMP0), dated April 14, 1983, "Information Considered Necessary Regarding Exploratory Shaft Construction and Sealing" (5) Summary of DOE /NRC Meeting on Exploratory Shaft Design and Construction, August 27-28, 1985 In References (1) and (2), the NNWSI Project 1.rovided responses to the following Information Requests (IR's) identified during the DOE /NRC meeting on the NNWSI Exploratory Shaft Facility (Ref. 3):
l IR Ib.
Because of the change in construction method for the proposed second shaft, DOE should provide reasonable assurance that the shafts are adequately separated so that construction in one shaft does not l
adversely affect ability to obtain required data in the second shaft and adjacent test areas.
IR IIIa.
Adopt adequate drift construction controls to meet 10 CFR 60 pre / post-closure performance requirements, i
IR IIIc.
Provide assurance that the planned drift lengths and directions are adequate for characterizing each of the target fault zones.
IR IV.
Describe measures to be taken to avoid interference of tests from drifting operations and with each other.
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Mr. Ralph Stein IR Vb.
Describe how the construction methods would include provisions to minimi.a shaft wall damage.
IR Vc.
Demonstrate that there will be minimal interference with testing from underground construction activities. In particular, address the potential for:
- movement of construction fluids through fractures from ES-2 to ES-1 test areas.
- damage to test instruments froa blasting vibrations.
-The NRC staff has reviewed the NNWSI Project's response and, based on this review, has concluded that the NNWSI Project has satisfactorily responded to Information Request Nos. IIIa and IIIc.
However, additional clarification needs to be provided by the NNWSI Project with respect to Information Request Nos. Ib, IV, Vb, and Vc. The NRC staff's detailed evaluation of the response to each of the Information Requests addressed by NNWSI is provided in Enclosure 1 to this letter.
Even with the closure of P o items by this letter, there remains a substant :'.
number of onan ' t :.7-fNm References 3, 4, and 5 as well as from the Consultation Draft Site Characterization Plan (CDSCP) NRC point papers related to exploratory shaft location, design, construction, and sealing.
At the July 18-19,1988 NRC/00E Exploratory Shaft Facility (ESF) meeting the NRC proposed that a meeting be scheduled in the near future to discuss how each open item can be resolved and a schedule for resolution. DOE suggested that such a meeting might most conveniently occur in anjunction with the CDSCP point paper meeting tentativelv scheduled for August 1988. The NRC agrees that August is acceptable for scheduling the meeting and my staff will contact Mr. Regnier of your staff in the near future to set a specific date. However, if the CDSCP point paper meeting is delayed, we feel that this meeting on ESF open items still needs to be held in August.
If you have any questions concerning this letter, please contact King Stablein (FTS 492-0446) of my staff.
S?ncerely, M/
J. J. Linehan, Acting Chief Operations Branch Division of High Level Waste Management Office of Nuclear Materials 3afety and Safeguards
Attachment:
As stated cc:
C. Gertz, 00E-NV/WMP0 R. Loux, State of Nevada DISTRIBUTION ANC CONCURRENCE:
SEE NEXT PAGE J
ENCLOSURE 1
~NRC STAFF EVALUATION OF THE NNWSI PROJECT RESPONSE TO INFORMATION REQUESTS Ib, IIIa, IIIc, IV, Vb AND Vc FROM THE APRIL 14-15, 1987, MEiTING BETWEEN THE DOE AND NRC IR Ib.
_Because of the change in construction method for the proposed second shaft, DOE should pro',1de reasonable assurance that the shafts are adequately separated so that construction in one shaft does not adversely affect s'aility to obtain required data in the second shaft -
and adjacent test areas.
In response to this infornation request, the NNWSI Project has responded that the zone of mechanical in'luence is small relative to the shaft separation; therefore, convergence and stress interaction between the two shafts are inconsequential.
We agree with the NNWSI Project's conclusion that the zone of mechanical influence is likely to be inconsequential compared with the distance between ES-1 and ES-2.
However, the information request, based upon the proposed change in construction methods (from boring to blasting), seeks information as well on the consequences of the proposed chanv s relative to shaft separation.
The response to our information request should include a discussion of the interaction effects resulting from drill and blast excavation (e.g.,
contamination of some of the test samples by drill water, blasting fumes and blast vibrations). The NNWSI Project's analysis of the adecuacy of the shaft separation should also consider realistic worst-case scenarios (e.g.,
consequences of a substantial shaft failure on data gathering from the other shaft).
Preventive actions against such an occurren e should also be considered.
The relevant details should include information on how construction activities are being scheduled so as to avoid interferences with testing.
IR IIIa. Adopt adequate drift construction controls to meet 10 CFR 60 pre /
post-closure performance requirements.
In response to this Information Request, the NNWSI Project has stated that "to control the amount of damage to the surrounding rock, smooth blasting, a type of controlled blasting, will be used." The NRC staff agrees with the NNWSI Project that, if adequate controls (including frequent test blasts, vibration monitoring, and evaluation of changes in permeability around drift walls) are used during excavation, smooth wall blasting would induce only minor damage to drift walls. We consider that since the planned approach is likely to lead to only limited damage around openings, the effect of drift construction on the ability of the repository to meet the 10 CFR 60 pre / post-closure performance requirements is likely to be small. However, as mentioned in Information L
Request IIIb, the NNWSI Project should recognize that penetrating the targeted geological / hydrological structures (Ghost Dance Fault, Drill Hole Wash, and the imbricate normal fault system) may require remedial measures to maintain the post closure isolation capability of the repository.
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In view of the NNWSI Project's position that smooth wall blasting procedure will be used for drif t construction, we consider the NNWSI Project's response to be satisfactory.
IR IIIc. Provide assurance that the planned drift length and directions are adequate for characterizing each of the target fault zones.
In response to this Information Request, the NNWSI Project has stated that projections of the target features to the drift intercept were predicted based on the surface expressions of the target features and knowledge of the geology.
Some uncertainty involved in predicting the target locations (i.e., drift-fault intersection) has been recognized.
It is stated that since the dips of the features are not well known, a wedge of uncertainty of +10 was assumed.
In view of the inherent uncertainties involved in extrapolating underground structural locations from surface features, we consider NNWSI's response to the Information Request regarding planned drift lengths and directions to be satisfactory.
IR IV.
Describe measures to be taken to avoid interference of tests from drifting operations and with each other.
In response to this information request, the NNWSI Project has pointed out that mining sequence plans are still under consideration; however, there should be little interference between the drifting operation ami testing because adequate separation, in space, in time, or both, between testing and drifting will ensure that there will be little interference.
The NRC staff recognizes that mining sequence plans have not been finalized.
However, to close out this information request the NNWSI Project will eventually have to provide additional information, including (i) layout of testing area with locations of various tests identified thereon; (ii)
Identification of tests that would be more sensitive to interference by vibrations, dust, water, fumes, other intrusions and drif ting operations; (iii) sequence and schedules of construction and testing, (iv) mining methods, including discussion of total quantity of water to be used for drilling (water flush or water mist), total charae and type of explosives and fumes it can generate, and (v) discussion of adequacy of separation of various tests from each other to avoid interference.
The NRC staff is concerned about the interference caused by locating the second shaft (ES-2) so close to the test area, and within the same traffic loop as the test area. This shaft is likely to be extensively used for hauling muck from the drift excavation. Traffic vibrations and dust caused by these operations could interfere with sensitive testing to be conducted in the test area over a period of time.
The NRC staff is also concerned about the potential interference caused by the proximity of sensitive tests to ES-1.
The NNWSI Project will need to address this issue in more detail in its eventual response.
Our Information Request also pointed out the need for the NNWSI Project to discuss the interference of tests with each other.
The NNWSI Project response
, o does not address this issue. The increase of approximately 2,500 ft of drifts in 'the test area should provide additional flexibility in better distributing the locations of site characterization tests. The NNWSI Project should describe provisions used to better distribute the locations of tests and to sufficiently separate tests from each other to avoid interference.
IR Vb. Describe how the construction methods would include provisions to minimize shaft wall damage.
In response to this Information Request, the NNWSI Project has stated that the recommended blasting procedure for the construction of both ES-1 and ES-2 is smooth blasting. Also, to assure best possible results with respect to limiting damage to the wall rock with smooth blasting, a comprehensive quality control procedure is planned to be developed and closely monitored.
The need for adjustments in blasting procedures along the shaft wall is also recognized.
The NRC staff agrees with the general approach and construction methods to be used by the NNWSI Project for minimizing shaft wall damage. The staff will review further details of the procedures when submitted by the NNWSI project.
In future submittals, the NNWSI Project should also consider and discuss the necessary reinforcement and support that may be required for the worst-case scenario where, for example, severe localized stability problems may be encountered. We consider that the response to our Information Request should be further amplified when details are available.
IR Vc. Demonstrate that there will be minimal interference with testing from underground construction activities.
In particular, address the potential for:
movement of construction fluid through fractures from ES-2 to ES-1 test areas.
damage to test instruments from blasting vibrations.
The first part of the DOE response discusses movement of fluids and states that only small amounts of water will be introduced, that they will remain in the immediate area where they are introduced, and that preliminary studies confirm that water will not travel to the adjacent shaft or test areas. Studies are in progress to quantify these fluid transport predictions.
The second part of the response postulates that blasting effects due to 30-1b charges will be inconsequential at 300 to 100 foot distances. Effects at shorter distances (less than 50 feet) will be determined in prototype tests planned prior to the ESF start.
We consider that the NNWSI Project will need to provide more information in response to the issue of potential interference with testing from underground construction activities. Specifically, the NNWSI Project needs to provide quantitative estimates of water injection pressures and volumes in detail and should provide analysis of the distance treveled. The results of this analysis should be analyzed with respect to planned locations of tests and sampling.
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- The NNWSI Project should also discus's the potential for blasting fumes to interfere with testing and sampling.
With respect to potential damage to test instruments from blasting vibrations, we agree that a limit of 30 lb/ delay should limit. vibrations at large distances and should be helpful in limiting the damage to test' instruments.
However, the NNWSI Project needs to provide preliminary details of the locations of these instruments with respect to the shaft bottom to demonstrate that damage will be controlled.
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DISTRIBUTION:
Central File B. J. Youngbicod R. E. Browning LPDR J. Bunting P. Prestnoit PDR R. Ballard NMSS R/F ChWRA J. Linehan HLOB R/F K. Stablein 0FC :HLOB LOB h___.in:
L han NAME
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DATE:(
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