ML20154M572
| ML20154M572 | |
| Person / Time | |
|---|---|
| Issue date: | 02/06/1986 |
| From: | Nataraja M NRC OFFICE OF NUCLEAR MATERIAL SAFETY & SAFEGUARDS (NMSS) |
| To: | Martin D NRC OFFICE OF NUCLEAR MATERIAL SAFETY & SAFEGUARDS (NMSS) |
| References | |
| REF-WM-39 NUDOCS 8603140337 | |
| Download: ML20154M572 (7) | |
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.gg/c2fnz/AA ut entwurc MEMORANDUM FOR:
Dan E. Martin, Section Leader Low-Level Waste and Uranium Recovery Projects Branch Division of Waste Management FROM:
Mysore S. Nataraja Section Leader Engineering Branch Division of Waste Management
SUBJECT:
WMEG REVIEW OF THE DOE UMTRAP TECHNICAL APPROACH DOCUMENT (TAD), REVIEW DRAFT, DECEMBER, 1985 As requested by TAR #WM-86003, WMEG has reviewed Sections 1.2.4, 2.3, 2.5-2.7, 3, 5.3, 5.4, and 5.7 of the subject document. Attached to this memorandum are WMEG's comments on these sections. These comments are based on the guidance we have provided in the Geotechnical Stability and Radon Attenuation Standard Review Plans.
Based on our review, we have the following major comments.
'1.
Section 2.5.2 presents a new seismic design criterion for evaluating stability at the end of construction condition using psuedo-static method of analysis.
It is recommended that this criterion be changed to that agreed by the DOE (TAC /RAC) and NRC task force committee which was set up in connection with this TAD.
2.
Section 3.1.3 lacks discussion on the methods that will be used for estimating values for several of the radiological parameters.
It is our recommendation that this information be contained in this document if DOE is not planning on including it in a subsequent document.
3.
Section 3.2 does not specifically identify how the long-term moisture content will be chosen. A definition for the long-term moisture content has not been provided. It is recommended that the TAD identify the procedure that will be used for estimating this value.
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Pages 118-122 and pages 136-138 include information on vicinity properties, land and building surveys, and the methodology for determining soil contamination levels. Since WMEG has not had the lead responsibility for reviewing these areas, we recommend that these sections be reviewed by the respective lead reviewers.
Sections 3 and 5.4 were reviewed by Steve Smykowski.
Banad Jagannath has reviewed Sections 2.3, 2.5-2.7, and 5.3.
Both reviewers provided a review of Sections 1.2.4 and 5.7.
Any questions regarding this review should be directed to the respective reviewers.
CRIGINAL SICMED BY Mysoro S. Nataraja Mysore S. Nataraja Section Leader Engineering Branch Division of Waste Management Distribution:
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WMEG REVIEW 0F TECHNICAL APPROACH DOCUMENT (TAD)
UMTRAP Prepared by; Banad Jagannath Steve Smykowski Section 1.2.4, Page 50, Paragraph 4 The TAD cites a reference by Sherard et al (1985). A complete listing of this reference should be provided in the bibliography.
Section 1.2.4 - Page 51, Table 1-3 The re ommended design criteria for Soil Group 4 needs to be clarified.
Section 1.2.4 - page 52, Paragraph 3:
The TAD states that when a rock blanket is used over filter, the maximum size of the rock should be equal to one-tenth of the blanket thickness.
It should be clarified whether it is the maximum or minimum size of the rock that should be equal to one-tenth of the blanket thickness.
Section 2.3.3 Page 79, Paragraph 1:
Guidelines should be added on the type and size of borings to be drilled at each of the alternate sites during this initial site selection phase.
Section 2.3.4, Page 60, Paragraph 1:
The first paragraph presents the scope of the first phase of the field study consisting of only piezoconc tests, and the second paragraph presents the scope of the second phase of the field study consisting of borings and sampling.
Statements should be added to indicate that the field investigations will be conducted in two phases, and the scope of the investigations may be expanded to suite data needs of the individual site.
Section 2.3.5, Page 84:
A section needs to be added on Laboratory Testing for this option of stabilizing the tailings.
SS/02/04/86 ATTACHMENT TAD,
Section 2.5.2, Page 98, Paragraph 2:
The proposed criterion for seismic stability evaluation for the end-of-construction condition is not in conformance with the decisions made in the meetings between DOE (TAC /RAC) and NRC. The consensus of the group was that the seismic coeffecient (k) to be used in the pseudo-static analysis for the end-of-construction condition should be higher of either 0.1 or 50 percent of the value of the peak acceleration at the site. This paragraph should be revised to reflect the agreement reached by the DOE (TAC /RAC) and NRC group.
Section 2.5.3, Page 100, Table 2.2:
For Situation 3 under Prefered Method column, it should read as "Either method:
C ' 'u from UU test or c, i plus estimated pore pressures,"
u Section 2.7.1 Page'107, Paragraph 1:
The paragraph should be revised to state that liquefaction potential of both foundation soil and tailings pile should be assessed.
Section 3.1.2, Page 115, Paragraph 2:
It is unclear what " anticipated characteristic size" is intended to mean.
Clarification of this term is recommended.
Section 3.1.2, Page 116, Sentence 1:
The TAD indicates that "an attempt would be made to define the extent and volume of off pile contaminated materials to be excavated to within roughly 20 percent." Does this imply that 20 percent of the total volume of off pile contaminated material will not be cleaned up; or does this refer to some other measure? Clarification of this statement is recommended.
Section 3.1.2, Page 116, Paragraph 1:
Better definition of the contamination will not only help to reduce overexca-vation, but will also help to avoid underexcavation.
Section 3.1.3, Page 127, Approach to Designing the Radon Barrier:
This section of the TAD does not fully discuss the methods that will be used for estimating values for several radiological parameters.
If DOE is not
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SS/02/04/86 ATTACHMENT TAD,
planning on identifying this information in a subsequent UMTRAP document, then it is recommended that this information be provided'in the TAD.
Section 3.1.3, Page 129, Radon Emanation:
The estimated long-term moisture content should be included in the range of moisture contents for which the radon emanating fractions are measured.
Additionally, as the staff has identified in the Standard Review Plan, the long-term moisture content should be factored into the determination of radon j
emanation.
l Section 3.1.3, Page 130, Radon Diffusion Coefficients:
Measurements of the radon diffusion coefficients should be made on samples with the moisture content and density at or near the predicted long-term values.
Section 3.1.3, Page 131, Cover Sampling:
The TAD should clarify the meaning of the "overall residual uncertainty" in the f
radon barrier thickness. What impact will this uncertainty have on assuring that the EPA standard on radon flux will be met?
Section 3.1.3, Page 133, Paragraph 1:
DOE is planning on taking undisturbed samples of the in place cover material l
for diffusion coefficient analysis.
Results from this testing may allow adjustments to be made in the required cover thickness during the construction phase. Considering the time that it takes to perform these tests, would testing at this time delay construction activities? What procedure will be used to adjust the in place moisture content of the sample to the predicted long-term moisture content such that uniform moisture will be assured throughout the sample? Test results may indicate minimum cover thickness varying around the pile due to heterogeneity of the radon barrier material.
From this information, how will the design cover thickness be determined? A discussion of these items should be included in the TAD.
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SS/02/04/86 ATTACHMENT TAD 9 Section 3.1.3, Page 134, Sentence 1:
The TAD states that "the mean value of the design parameter for each layer of pile or cover is of interest..."
It is unclear which design parameter (s) is being referenced. Does this statement solely refer to the radon flux or does it refer to the parameters that determine the radon flux? When mean values are used, the method for averaging the values should be defined (i.e. area-weighted, volume-weighted, arithmetic mean, etc.).
It is important to note that the long-term variability of several parameters, such as diffusion coef ficient and radon emanation, should be factored into their estimation.
Section 3.1.3, Page 135, Paragraph 4:
't Although there may be some attenuation of radon due to the rock and gravel cover, the resulting influence on the factor of safety is only temporary. The integrity of the erosion barrier cannot be assured for 1000 years. Thus, this factor of safety will diminish with time.
- Section 3.2, Page 139. Radon Barrier Moisture Content:
This section discusses methodology for determining moisture contents of soils at various bar suctions. However, no mention is made that would identify which bar suction will be used for estimating the long-term moisture content, nor does the TAD identify that the long-term moisture content will be determined on a site specific basis.
It is recommended that the TAD identify the procedure that will be used for estimating this value.
Section 3.2.2. Page 142*, Paragraph 2:
Before the staff is able to form a position on any of these conclusions, we would need to review the "real data" that has been mentioned and compare it with the results of the correlations.
Since this data is not presented in the TAD, it is recommended that this data be referenced.
Section 3.2.3, Page 144, Paragraph 4:
What is the definition of " stable moisture content?" Does this term refer to the same concept as the "long-term moisture content?" Are the in-situ results from tensiometers installed at the Gunnison, Tuba City, and Riverton tailings piles representative of the long-term moisture content? Clarification of these items should be included in the TAD.
SS/02/04/86 ATTACHMENT TAD '
Section 3.2.4, Page 145, Paragraph 1:
It is unclear how DOE will be investigating the " type of erosion prr.tection i
layers" when determining the long-term moisture content of the cover material.
It is difficult to justify giving credit to the erosion barrier layer when estimating the long-term moisture content.
Section 3.2.4, Page 145, Paragraph 2:
The TAD states that many factors will be considered when estimating the long-term moisture content.
In addition to these factors, the TAC will be running the computer program "DSUFW" to simulate the long-term moisture content of the cover and tailings. The staff is unfamiliar with this program and has not had the opportunity to review it.
If DOE is planning on using this program for designing the radon barrier, documentation of the program should be sent to the staff for review.
Section 5.7.2, Page 234, Bullet 3:
The sentence should read " Minimizing the Overall pile area to effectively reduce overall cover requirements (without adversly affecting pile stability)."
Section 5.7.2, Page 235, Bullet 3:
Stabilization on site may allow a reduction in the radiological characterization data needs of the ta111ngs. However, the ractological characterization data needs of the cover material will be the same regardless of SIP, SOS or relocation to an alternate site.
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