ML20210K824
| ML20210K824 | |
| Person / Time | |
|---|---|
| Issue date: | 04/23/1986 |
| From: | Clark A, Thomas Nicholson NRC OFFICE OF NUCLEAR MATERIAL SAFETY & SAFEGUARDS (NMSS), NRC OFFICE OF NUCLEAR REGULATORY RESEARCH (RES) |
| To: | Beratan L, Rouse L NRC OFFICE OF NUCLEAR MATERIAL SAFETY & SAFEGUARDS (NMSS), NRC OFFICE OF NUCLEAR REGULATORY RESEARCH (RES) |
| References | |
| REF-PROJ-M-32 NUDOCS 8604290080 | |
| Download: ML20210K824 (6) | |
Text
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APR 2 31996 Project M-32 MEMORANDUM FOR: Leland C. Rouse, Chief Advanced Fuel and Spent Fuel Licsensing Branch, FC Leon L. Beratan, Chief Earth Sciences Branch, RES FROM:
A. Thomas Clark, Jr.
Advanced Fuel and Spent Fuel Licensing Branch, FC Thomas J. Nicholson Earth Sciences Branch, RES
SUBJECT:
TRIP REPORT ON VISIT TO WEST VALLEY DEMONSTRATION PROJECT SITE TO MEET AND DISCUSS UFCOMING COMMENTS ON DOE ENVIRONMENTAL ASSESSMENT (EA) ON THE DISPOSAL 0F PROJECT LOW-LEVEL WASTE On February 26, 1986, the subject meeting was held following the attached agenda. Also attached is a list of personnel and their affiliations who participated in the discussions. A description of the discussion on each agenda topic follows.
Class B/C Tumulus Site Characteristics The DOE contractor, West Valley Nuclear Services, Inc. (WVNS) presented five subtopics related to site characteristics which were considered to have potential affects on the proposed tumulus design. They are: 1) seismicity, 2) foundation conditions, 3) hydrometeorology (precipation), 4) erosion, and 5) flooding. The last three characteristcs could all be considered under a heading of runoff, (i.e., all related to localized precipitation and its geomorphic effects).
An additional topic suggested and discussed at the meeting was that of the influence of site hydrology on the tumulus performance.
Engineering Design WVNS presented four.. subtopics under the general topic of durability as related to the tumulus. They are: 1) long-term behavior of the' concrete waste form or grouts used for. stability, 2) geotextile performance,-3) filters and drains, and 4) clay liners. Each of these topics were discussed in some detail. WVNS clarified the use of the geotextile as a structural material, (i.e, an open net of high density polyethylene which is used to provide tensile support.to clay 8604290080 860423 PDR PROJ M-32 PDR
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Multiple' Addressees 2
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L layers *which act as ground-water barriers, rather than a geomembrane which might be a barrier in and of itself). No_ geomembranes are planned for the tumulus. The effect of the disposed waste, in terms of its leachant, on the:
geotextile was discussed.
WVNS also discussed the tumulus stability as related tol design to prevent-subsidence. The likelihood of voids being created from concrete / drum disintegration and backfil1~ settling was discusssd. The efficacy of either_ pea gravel or grout as a backfill was discussed. The need for monitoring the tumalus for differential settling or other subsidence effects was discussed.
Surface effects which could affect tumulus performance were discussed. Among-these were frost penetration, dessication, moisture-content, gully erosion, slope, stability, heat effects, and drain design. WVNS suggested that localized flooding would be considered in'further design, if the tumulus were to be accepted.
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Location Relative to Previous Disposals f t,,
The effect of the tumulus on the existing water table in the disposal area was discussed. WVNS suggested that the erosional characteristics of the tumulus.as it might affect the facility disposal area would be considered in future design, if the tumulus were selected. Thersiwas some discussion of the need to relocate the existing monitoring well cluster USGS 82-3 and the relative value of emplacing new wells in light of the proposed gallery drain for the tumulus design.
Trenches for Class A Waste Collection and Analysis of Data The NRC emphasized the need to collect and analyze ground-water hydrology data in both the saturated and unsaturated zones. A-draft report referenced by the EA on this topic provides some useful information on this topic. There-is a data" gap"fortheUSGSmonitoringwellsofaboutninemonthssince1982,WVNS-stated that pata from the wells are now being continuously obtained and analyzed.
Status of Ground-Water Modeling The reliance ot ths EA analyses on computer codes FEMWATER and PRESTO was
' discussed Since PRESTO was developed and used by EPA as_a generic code its
- use for site specific purposes has been questioned. WVNS discussed its.use for-surface pathway analysis only and felt that'this_use was acceptable.
It was pointed out that input data to FEMWATER should be referenced and its validity understood. The 'related topic of mo' del verification and the use of information from a draft USGS report on modeling the FDA as related to model. development'
' was discussed. WVNS emphatically stated they did not intend to model the FDA nor its. associated ground-water pathway.
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Trench Design The factors leading to trench subsidence were discussed. There are: waste form, " piston effect"of the unit trench design settlement, use of grout or pea gravel., trench configuration, trench depth, ground-water infiltration, water table, and cap design. At present, trench depth is limited by backhoe capability. Perhaps the most important effect influencing trench design is the so-called " bathtub" effect, (i.e., the re-saturation or filling of the voids in the closed trench creating) water-levels to rise sufficiently near the surface to cause surface discharge. Preventive measures such as " bottom drains" to the Lacustrine layer, greater trench depths, and cap design were discussed as related to the "bathtubbing" effect. WVNS has considered an active maintenance period of 100 years for the disposal area and therefore the proposed class A trench.
Miscellaneous Basis for Selecting Reference Design The alternatives available to DOE were discussed, particularly storing low-level waste until a performance assessment is complete. WVNS feels that sufficient information is available at present to support the selection of the reference design.
There was some discussion of other options such as monoliths (such as those used at the Centre de la Manche, France), the Westinghouse SUREPAK, and deep augered holes. The state-of-the-art for these alternatives varies and there was no detailed discussion as to their overall performance.
Decontamination and Decommissioning Waste (D&D)
There was some discussion of the relation of D&D waste and site closure to the present decision to be made on the disposal of project waste. The NRC pointed out the the D&D wastes must eventually also be disposed and, perhaps, at this point their volumes and class may need to be estimated to determine the availability of space and location for their possible future disposal. The various complications for this assessment were not discussed in any depth.
Observations Seven observations based on the above discussions were reviewed as needing t
further resolution.
1.
Localized flooding and its affect on erosion, both gullying and mass wasting, of the tumulus and trench caps.
2.
Stability of class A waste as related to subsidence and trench re-saturation.
3.
Continuity of monitoring wells as related to tumulus location and design.
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APR 2 31996 Multiple Addressees 4
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Data collection and analysis to support modeling both calibration and validation aspects.
5.
Appropriateness of computer codes used for modeling.
6.
Description and use of geotextiles, especially as to long-term performance.
7.
Disposition consideration related to past solidification D&D waste.
NRC Comments The NRC indicated that its coments on the EA would be forwarded to DOE in two phases: the first, initial phase immediately upon return; the second following a 30-day review period.
ORIGINAL SIGNED BY:
Thomas J. Nicholson Earth Sciences Branch ORIGINAL SIGNED BY:
A. Thomas Clark, Jr.
Advanced Fuel and Spent Fuel Licensing Branch
Enclosures:
'As stated DISTRIBUTION:
Please return original concurrence sopy to FBrown SS 396 ipProjiict6N6.'432 NHSS r/f FCAF r/f FBrown Beveridge/ Cornell ATClark PDR & LPDR LCRouse TJNicholson LBeraton
- SEE PREVJOUS CONCURRENCE OFC: FCAF
- FCAF
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_'__ $ E -___ --
NAME:ATClark/jl:LCRouse :TJNicho sorf:LB aton:
4 86 :04/l//86:04/11/86:04/d/86:
DATE:04/
/
0FFICIAL RECORD COPY
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AGENDA.
NRC VISIT THURSDAY, FEBRUARY 20, 1986 o Review and discussion' of LLW EA 8:00 - * - 4:30 Blickwedehl
- Class B/C Tumulus
- Site characteristics
- Engineering design
. Location relative to previous disposals
- Class A Trenches
- Collection and analysio 'of' data
- Status of groundwater modeling
- Trench design j
- Miscellaneous
- Basis for selecting reference design
- D & D waste i
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- 12:00 break for lunch
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US NRC 1
Tom Clark Norman H. Davison NRC-RES-Tom Nicholson i
NRC-Waste Management-Stan Neuder US NRC Larry Saraka Lynn Deering i
Derek A. Widmayer i
DOE i
Eli Maestos William H. Hannum NYSERDA Ted'DeBoer Dick Spaunburgh i
4 WVNS j
Bob Lawrence f
Bob Blickwedehl j
Steve Reeves
\\
'Pete Newsom P. J. Valenti s
.i
.i Oak Ridge Nat'l Lab (ORNL).
William P.' Staub i,.
.