ML20235V815
| ML20235V815 | |
| Person / Time | |
|---|---|
| Issue date: | 12/09/1983 |
| From: | Nussbaumer D NRC OFFICE OF STATE PROGRAMS (OSP) |
| To: | Carr R KENTUCKY, COMMONWEALTH OF |
| Shared Package | |
| ML20235U845 | List:
|
| References | |
| FOIA-87-235 NUDOCS 8707230317 | |
| Download: ML20235V815 (20) | |
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WM 00CSET CC:tTROL .
Ref: SA/JFK DEC SIN i, I POR LPDR ---- _ - .
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Ms. Rose Marie Carr, Economist -
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Commonwealth of Kentucky b. * ' " " 935
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Natural Resources and Environmental Protection Cabinet i Department of Environmental Protection 1
Fort Doone Plaza 18 Reilly Road Frankfort, Kentucky 40601
Dear Ms. Carr:
As requested, we have reviewed the " Revised Task 3" report. A copy of l our comments are attached as well as a general sumary. l It is our understanding that thts review completes our comitment to the Department in this very important project. We hope you find our i coments useful in your development of a decommissioning plan for the Maxey Flats disposal site.
Sincerely, P- '
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.:n Donald A. Nussbaumer Assistant Director for State Agreements Program Office of State Programs
Enclosure:
As stated cc: Don Hughes, KY, w/ encl.
Distribution:
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. s General Commants on Task 3 Decommissioning of Ma,xey Flat,s,,
In general, the revised draft.for Task. 3 - Evaluation of Decommissioning Alternatives provided specific information that responded to many previoL31y expressed concerns of the reviewers. Technical information.in this draft was clearly presented and included sufficient detail needed to assess the proposed decommissioning alternatives and the modeling meti.odologies.
Ai; hough most of the questions raised in our previous reviews of Task 3 have been addressed, several areas of major concern remain.
(1) The Propos'ed Cut-Off Trench and Barrier Wall.
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The performance of I the cut-off trench is uncertain. The potential is there for. i i creating a large " bathtub" if infiltration is not reduced'and l carefully controlled (See Specific Comments pp. 11, 30-32, 82, 89, 97).
(2) The Propcsed Deep Compaction of Existing' Waste. Potentially adverse ,
consequences of this option include releases of hazardous chemicals .}
and radioactivity into the environment, worker exposure, destruction ;
of trench walls, and negative public perception (see Specific 4 Comments pp. 40,50,103)< -
(3) Comoarison of Decommissioning Concepts. Methodology for:
intercomparisons are not described despite well-developed listings of associated advantages and disadvantages. ~The list of.
eight proposed Decommissioning Concepts is by no means exhaustive.
Variations on some of the Concepts, which may improve the design, are not addressed (see Specific Comments pp. vii, 5, 27, 50, 55, 68, 69, 71-2, 86).
(4) Conceptualized Lngistics. Performance is based on implied site conditions (i. e. , relatively dry trenches,1/100 inch annual infiltration rate, and that the leach rate will be the same as the infiltration rate). These conditions may not be realized with existing trench water and some trench bottoms below the water table (see Specific Comments pp. 11, 30, 33, 51, 82, 97).
(5) Source Term Assumptions. The assumption that radioactive concentrations in the 16achate will remain constaat at the present levels found in trenches is questionable. C Ptainer degradation and especially deep compaction will substantially increase the source term (see Specific Comments pp. 11, 40, 50, 71-2, 89-90, 94).
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3201.6/SMN/83/11/25/0 (6) Modeling Methodologies. Little input and output data has been- j provided for oiost of the modeling. Sensitivity analyses were not J quantified. Heavy reliance was placed on limited data. Validation.
of some of the models used was not addressed. Values.of several important parameters were based ~on speculative assumptions (ses i Specift: Comments pp. 82-84, 87-89, 106-110, 114-117, 120-122).
(7)J Dose Projections. The projected dose is based on currently existing.
site conditions.. Dilution factors were estimated.from limited data, based on currently existing flow patterns. Leachate concentrations were assumed to remain at present levels. Stringent contruls on very low infiltration rates were assumed to be achievable. All infiltration were presumed to exit downward into the groundwater.
Since. multilayered trench cap and cuV off trench will drastically alter the groundwater flow patterns, most of the assumed modeling parameter values will change. Dose projections will therefore be different than those specified (see Specific Comments pp. 92, 94, 121, 122, 127).
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3201,6/SMN/83/11/25/0 Specific Comments on Task 3 Decommissioning of Maxey Flats Page vii, Last 4 Lines Quantify the basis for the statement that Concepts A and E are most responsive.
Page xi, Top Line Define life cycle and why Concepts A, D, and E have the lowest life cycle.
Page xi, Conclusions and Recommendations These conclusions do not fully reflect the broad content and significant findin'gs of the document.
Page 5, 2nd Item ; )
The proposed evaluation criteria were'never identified as such. Are they the same as the various " categories" addressed in Chapter 5?
Page 11, 2nd Criteria What is the rationale for the 100 year functional life?
Page 11, Item (1)
Eliminating lateral flow through the fractures in the sandstone marker beds may generate one large bathtub, even for an infiltration rate of 0.01 in/yr. What are the assumptions regarding exit pathways for the leachate under the conditions of no lateral flow? What evidence, if any, is there for no accumulation of leachate under the conditions of no lateral-flow?
Page 14-16. Decommissioning Concept A Rationale for the indicated thicknesses of the various trench cap layers should be provided.
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Page 14, 2nd Paragraph Does the dynamic compaction option in Concepts A, B, and C imply pile driving and surface compaction?
Page 15, Figure 3-1 (a) It would be difficult to implement as well as maintain the integrity of 6-inch layers in the multilayered trench cap. Bioturbation of the thin upper layers may be a problem in the long-term. Recommendations based on experience are that layers be a minimum of 9 to 12 inches thick.
(b) The compacted fill material should be identified.
(c) Limestone cobble may not be the best choice. The chemistry of the cobble should be. con.sidered. If water percolates through the cobble.
layer it will pick up HCO3 - fr m the cobble. The effect on trench water chemistry is complex.
(d) The lower sand / gravel layers should be designed as a granular filter. Consider standard soil mechanic design procedures for gradation of filter materials.
(e) The trench cap represents about 10 feet of relatively heavy overburden load across the entire site. What about possible future settlement of the natural subsoil mate' rials?
Page 18, Figure 3-2.
(a) Cracking may.be a major problem with the soil / cement layer.
(b) A sand layer mcy need to be added above the geotextile in order to prevent gravel punctures in the filter fabric.
Page 19, 1st Paragraph A geotextile will not minimize root intrusion.
I Page 25, Decommissioning Concept E Greater detail should be provided on the physical description and extent of the concrete cap. A 3-dimensional sketch would help.
Page 26, Fioure 3-5 Will localized consolidation and subsidence beneath the concrete cap cause bowing?
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3201.6/SMN/83/11/25/0 Page 27, Decommissioning Concept F (a) The impression here is that an objective and constructive approach to Concept F has not been presented. Appropriate variations on Concept F will present a more. viable option.
l (b) The evaporator should be permitted to remain in the event of l premature failure of the selected decommissioning concept.
Page 30, Cut-Off Trench (a) It would be informative to model the entire cut-off trench rather than just the flow barrier north of the site.
(b) What are the assumptions regarding leachate movement with the cut-off trench-in place?
(c) What is the required and expected permeability of the cut-off.
trench?
(d) Why the need for an additional north wall flow-barrier if the cut-off trench is relatively impermeable?
(e) There is some question about the amount of off-site groundwater flowing in from the north sector. Recharge in that sector and influx to the site should be quantified in order; to justify the proposed wall barrier.
Page 31, Cut-Off Trench (a) It would be extremely difficult and expensive to implement a 35-ft I deep cut-off trench of width 12 to 15 ft. Backfill compaction, for example, may need to be implemented by hand in six-inch lifts. A standard slurry wall should be considered. Stability and soil compaction j in a 35-ft' deep trench without support (slurry) will be a major problem. '
(b) The backfill compacted site soil represents a " disturbed" soil. l Whatassuranceisthergthatthepermeabilitywillbelessthanthe surrounding soils (10 cm/sec)? The concern is that the cut-off trench i
. may act as a collector of leachate resulting in a large " bathtub."
(c) Consider using a filter fabric or soil filter gradation at all interfaces.
(d) How does the cut-off trench interface with the trench cap or concrete cap?
(e) A 3-dimensional sketch of trench configuration would be helpful.
Page 32. Last Two Lines Define " effectiveness" of the cut-off trench and how effectiveness may be monitored.
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Page 33, Missing Paragraph Paragraph number 3.2.4.2 is missing.
Page 33, Relocate Sandstone Rubble Some of the sandstone rubble may be used for the cobble layer.
Page 33, Borrow Area l
1 Soil borrowing may change hydraulic gradients and alter site groundwater flow. This may ultimately alter the dilution factors and projected dose.
Page 33, Add Paragraph An additional paragraph should be added to discuss current and future water removal operations from the existing trenches and the prevention of further infiltration prior to and during the implementation phase of decommissioning.
Page 35, Demonstration Trench -
i Define and describe the purpose of a demonstration trench and how it l I relates to existing conditions and the near-term decommissioning? )
Page 40, Deeo Compaction f 1
l (a) In addition to the numerous disadvantages associated with deep compaction (e.g., potential releases of toxic chemicals, gases, and radioactivity, increase in trench leachate concentrations, potential destruction of trench walls, additional fracturing, generation of additiona.1 pathways to the environment, hazardous exposure of site workers, etc.) potentially adverse public reaction must be considered.
(b) Composition and compressive strength of landfills are different than those of the low-level waste site. j 1
l Page 41, 3rd Paragraph References are incomplete.
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l Page 43, 4th Piragraph The disadvantages of the two pile-driving procedures are very different.
The installation of foundation piles for the concrete trench cap (Concept 1 E) provides a much smaller disadvantage than that associated with pi h driving for deep compaction (Concept A). The major difference is that trench cap foundation piles are not removed whereas the compacting piles ;
are removed. (See Page 40 comments on deep compaction.)
Page 45, 1st Paragraph 1
With only 10 percent bentonite, shrinkage and dessication cracking should l not be significant. Another clay which is locally available may be l useful. The Estill Shale Member of the Noland Formation is one. This is a local clay that is quite plastic.
Page 45, 3rd Paragraph Here too, use local material such as the Estill Shale.
Page 49, Cut-Off Trench ~~
Excavate the cut-off trench under a sfDrry head.
Page 50, Table 4-1, Concept A
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(a) The degree of the uncertainties associatec with the listed items in I the " Unknown" column are very significant. In evaluating the decommissioning concepts, the quality of the unknowns must be weigned accordingly. Agreed that this requires a certain amount of subjective judgement, nevertheless sound judgment needs to be exercised.
(b) Add to the list of Disadvantages: Extremely high potential for trench wall rupture and increased radioactivity concentrations in the leachate.
(c) Maintenance, although of a different character, may not be any less vigorous than that of, say, Concept F. An objective evaluation should be made.
(d) The degree of tolerable subsidence needs to be quantified in order to make objective Concept comparisons.
(e) Under " Disadvantages" add continued long-term custodial care because of vegetation control. Add the same remark to Concepts B through F.
(f) Under " Disadvantages" add potential adverse public reaction to likely release of contaminants.
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Page 51, Table 4-1, Concept B Under " Disadvantages": )
(a) Deep compaction technology is already known. Perhaps the technology {
j development refers to methodology necessary to control potentially l
adverse effects (see Page 40 comments).
(b) Having to replace the cap periodically may cause major problems. {
Removal of infiltration controls during periods of precipitation may ,
result in sufficient infiltration to require months of continuous evaporator use.
Page 55, Table 4-1, Concept F (a) Again, the term " intensive care maintenance" should be quantified for comparison / purposes.
(b) Similarly, need to quantify " intensive" monitoring.
(c) Several variations or subsets of Concept F should be evaluated with the same detail. Variations of Concept F will result in a more viable .
decommissioning option than the one presented. For example, subsidence and high infiltration rate may be reduced by appropriate engineering and agronomy methods. Similarly, environmental release via evcporator use may be reduced by improving plant m-ana'gement methods.
Page 60, Table 4-2 (a) The last number in the table should Le 110,943.
(b) Are the given cost estimates for 100 years?
(c) Cost estimates for Concept F appear excessively 'nigh. A cost breakdown would be in order.
Paae 66, Demonstration Testing j 1
Concept F is being tested, in part, with the lysimeters at Maxey Flats. l These tests may be continued in cooperation with other state and/or federal agencies.
Page 68, Table 5-1, Cost Comoarison I
The cost for 90 year institutional control for Concept F is listed as being about four times at high as that for Concept A. This cost-estimate a snould be broken down. Reasons for the large difference in cost is not ;
obvious.
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i Page 69, 2nd Paragraph q (a) Should read " Concept E is considered to provice the best technical solution" rather than "least technical solution."
(b) Concept F should rank bigher in terms of technical maturity in view of many years of agronomy research.
(c) Details of Concepts comparison methoelegies are not provided.
These are key considerations in the evaluation process and should be spelled out. How are "judgements" exercised?
Pages 71-72, Conclusions and Recommendations (a) Conclusion 1 - It is not obvious that the eight Decommissioning Concepts exhaust the range of technologies applicable to Maxey Flats.
(b) The statement that only decommissioning Concepts A through F meet ,
off-site dose criteria has not been justified. For example, Concept H- i may provide sufficient reduction in infiltration rates to reduce the projected dose to acceptable levels. What is the projected off-site dose uider Concept F?
(c) Recommendation a - Before considering the selection of Concept A, B, or C it would be essential to "refi:ne the source term" by considering the increased leachate concentrations'.and consequent effects on projected off-site dose. The analysis should be:. quantified.
Page 81, 2nd Paragraph ,
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-(a) The environmental consequence of airborne emissions, although
" judged to be of little consequence," should be quantified. Moreover, airborne. emissions may be a potential hazard to the inadvertent intruder.
This pathway should be evaluated. l (b) The discussion seems to imply that there is an additional warning i barrier other than the cobble layer. If'so, what would that be? It is not at all obvious that the system will function properly in the event of animal intrusions into the trench cap layers above the cobble.
Page 82, Last Paragraoh The assumption that "the volume of leachate movement from the trenches is equal to the amount of infiltration into the trenches" appears to be invalid because of the existing " bathtub" effect in many trenches and' '
because the groundwater table in some areas might be above the bottom of some trenches. Alternatives to this assumption should be considered ;
carefully since leachate movement directly affects off-site dose.
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. i 3201.6/SMN/83/11/25/0 Page 83. 2nd and 3rd paragraph (a) The 50 ft/yr groundwater velocity has been deduced from observations at only one trench location. Assuming that 50 ft/yr is the water velocity applicable to the entire site results in a tenuous description of groundwater flow. Calculated concentrations in the alluvial water and projected dose to the individual are all based on this assumed velocity.
The error bars on the projected dose due to variations in assumed water ;
velocities should be addressed.
l (b) Conceptually, there is no meaning to an " instantaneous release" velocity. This needs to be defined. The velocity range " instantaneous to 20 ft/yr" does not seem to include the 50 ft/yr value as it should have been. Similar question applies to the 15 ft/yr velocity reported in Table A-5, Page 93.
(c) The results of the sensitivity analysis were never given.
(d) The value assumed for the groundwater velocity is rather critical since the radiological exposure is mainly due to tritium (half-life 12.3 years).
Page 85, Last Paragraph 1981 reference is incomplete.
Pace 86, Table A-2 Several other radionuclides are present in the inventcry (e.g., Ni-63, C-14,etc.). Have these been included in dose projections? Add their K d values to the table.
Page 86. Last Paraaraoh Should quantify " insensitivity to reascoable variations in porosity and density." Here, again, the results or sensitivity analyses were not given.
Page 87, 2nd Paragraph The purpose for considering dilution 1 actors and inout parametcrs to LADTAP should be provided.
3201.6/SMN/83/11/25/0 Page 87-89, Dilution Factors l
Dilution analyses is based in part on work by Zehner,'1983. How confident can one be about Zehner's data? What would the error-bars on the dilution factors be? Has a sensitivity analysis been performed? If so what are the findings?
Page 89-90, Source Term Discussion (a) The assumption that future concentrations of radionuclides in trench leachate will not exceed concentrations which currently exist in the trench leachate is questionable. While no consistent trend of increasing radionuclides concentration ir the trench leachate has been identified to date may be due to the relatively short observation period. Increase in concentrations would be expected over the next few decades as drums and other containers eventually degrade. .
(b) More importantly, the assumption of constancy of radionuclides concentration in trench leacnate is totally invalid if any one of the Concepts A, B, or C will be used (dynamic compaction options). Dynamic compaction would relenne radionuclides in the trenches which may initially increase tha concentrations 20-fold or more with secompanying increases in projected doses. The concentrations will then steadily aecay in time. ,
(c) The results of (a) andL(b) implies a non-conservative assumption in the assumed source term. Consequently a more stringent limit on infiltration rate criteria would be necessary.
Page 91, Table A-4 )
8 (a) The number, 1.6 v 10 picocuries per liter, next to Cs-137 should be 1.6 x 104.
(b) Other radionuclides such as C-14 have not been listed.
(c) How might these concentrations change witn dynamic com'paction?
Page 92, 1st Paragraph (a) Define the " general population" used for dose projections.
(b) Describe the water pathway scenario for population dose. Is it the surf ace drinking water pathway only or does it include forage irrigation.
(c) What is the actual and assumed farm and animal population in the J' vicinity?
3201.6/SMN/83/11/25/0 Page 92, 4th Paragraph (a) The statement that the " meat and milk pathways were excluded from the groundwater pathway calculations" is not clear, as these pathways are I
mutually exclusive.
(b) Elaborate on the statement that " exclusion of these pathways results in doses which are approximately one-half the value calculated with all pathways included." This does not seem to agree with the reported calculational results given in Table A-6, Page 94, where, for example, the groundwater pathway yields 254 mrem / year while the surface water pathways yields 19 mrem / year, a factor of.13 difference. !
l (c) The discussion on pathways. in general needs further clarification !
j and the assumed parameter values need to be spelled cut.
1 Page 94, Table A-6 (a) It is important to keep in mind that the calculated doses presented in this table are based on the currently existing radionuclides concentrations in the waste trenches. Exercising Options A, B, or C will significantly increase the dose estimates.
(b) An additional concern is that higher radionuclides concentrations may exist at other site locations.and there .is some uneasiness with the fact that dose projections are based on site data at only one or two locations. The question of higher radionuclides concentrations at other-locations should be addressed if sufficient data exists.
Page 95, Middle Paragraph Since dose results almost exclusively from exposure to tritium (half-life 12.3 years) and dose projections are based on current leachate concentrations, it would be appropriate to the overall decommissioning plan to project doses over a 200 to 300 year period under various f scenarios (i) constant source term, (ii) slowly. increasing source term {
due to container decomposition, (iii) possible change in source term due l to selection of Option E, and (iv) sudden, large increase in source term' j due to selection of Options A, B, or C. Of concern here is that dynamic j compaction (part of Options A, B, and C), will significantly increase the source term and projected doses.
Page 95, Last Paragraoh (a) The statement that " monitoring data... indicates that base case dose 1 estimates are high" should be quantified. l (b) The statement that " calculated doses are larger than will occur" is j not necessarily true because (i) major portions of the radionuclides have l not as yet leached / arrived at those locations, (ii) monitoring may not !
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3201.6/SRl/83/11/25/0 have detected possible higher concentrations at other nearby locations, and (iii) modeling is based on existing (uncompacted waste) source terms.
(c) How does one explain the existing discrepancies between estimated and measured concentration data?
(d) It would be appropriate at this point to address the appreciable levels of tritiue concentrations found in local tree samples. The levels translate to dose rates equaling or exceeding 25 mrem / year due to a hypothetical drinking-water well.
Page 97, 1st Paragraph (a) How effective is tne cut-off trench or low permeability wall expected to be in preventing potential lateral movement?
(b) Will any trenches be deeper than the flow barrier? If so, how will this affect the dose projection?
(c) Most important is the fact that the groundwater table in some areas night be above some trench bottoms, rendering a cut-off trench ineffective.
I Page 97, 2nd Paragraoh :
Elucidate on " hydrological isolation" snd ' precipitating agents."
Page 97, 3rd Paragraph l Is an infiltration rate of 0.01 inches per year impracticable? What 'l infiltration rates does the modeling predict for Concepts A through H? I Does one conce;,t provide more effective ir. filtration control than I another? This is a key question which is not answered in the '
infiltration control model results (Page 109-110). The choice of trench cap options will certainly depend on the ability to meet the 0.01 inches ,
per year. 1 I
Page 100, 3rd Paragraph j Should read " secondary compression occurs."
Page 103. Consolidation Model Results After impact compaction, the model predicts ft. to 1 ft., long-term settlement. In view of the potential radiological nazards, chemical
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3201.6/SMN/83/11/25/0 hazards, additional costs associated with' impact compaction and resioual long-term settlement, is compaction a viable design element?
Page 106, Modeling Methods
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How valid is the HELP model for the present application?' The HELP model.
has several levels of approximation which should be discussed. The EPA.
uses this model to evaluate surface runoff and drain flow but does not use it to evaluate liner performance. Of special concern is how HELP handles flow when the layers are only partially saturated. The model may assume no flow conditions'when the soil is not saturated. This assumption may significantly affect accuracy of prediction when l simulating systems with low flux. HELP also ignores vapor flux and might I therefore not be appropriate to investigate potential drying of liner..
layers. These issues should be addressed in the discussion.
Page 106, Last Line It is unclear how the 3 percent slope will be implemented. Will it be across' individual trenches, across sev.eral trenches or across the-entire site? How readily can.3 percent slope's be implemented in-two-dimensions across- an extended area with drains arip .long-term maintenance requirements? Greater detail is necessary.
Page 109, 2nd Paragraph
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Synthetic membranes were considered but model output was not presented. 'l Page 109, 3rd Paranraoh ,
l Modeling results which indicate that the chosen design is the most effective are not presented to support the conclusion.
Page 110, 2nd Paragraph Data is not presented to support the conclusions.
1 Page 110. 3rd Paragraoh Increasing soil layer thickness is straightforward and much more reliable .)
than decreasing its hydraulic conductivity. j i
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3201.6/SMN/83/11/25/0 Page 110, 4th Paragraph The use of the HELP code in this generic analysis is very valuable for comparing alternative designs. The analysis, however, may not be sufficient to predict percolation performance of 0.01 inches / year.
Page 110, 4th and 5th Paragraphs l (a) What are the results of the infiltration modeling? Details are not provided to support conclusions. )
(b) Since one is at the limits of the model used, what uncertainties would be expected in the calculated percolation rate of 0.01 in/yr?
(c) Most. importantly, the multi-layered trench cap will effect the piezometric contours. How will the projected off-site doses be changed l from those predicted on the basis of presently existing site ennditions?
Pages 114-117, General Discussion (a) More consideration should be given to the fact that drainageways will require additional protection aga, inst erosion and that the calculations were done for single trench slopes. The designs shown in Figure B-3 and B-7 indicate slope leng,th's much longer than' 9.75 meters and erosion may increase significantly as a result.
(b) In discussing the HELP model, short drainage pathways were also used. Since the cover will be placed across the entire site, drainage path lengths will be longer and infiltration higher than calculated.
l Page 120, 3rd Paragraoh (a) The trench excavation option is mentioned but not modeled.
(b) A three-dimensional diagram and additional descriptions would help.
Does the cut-off trench surround the entire site?
Pace 120, 5th Paragraph Model input values should be presented. Wss this model " calibrated"?
What is the significance of the geometric mesn? A discussion of Zehner's analyses would be helpful.
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Page 121, 2nd Paragraph (a) Again, model input and rationales are not provided.
(b) Line 5 should read " constant head boundary." l (c) Results of sensitivity analysis were not presented. j Page 121, Last Paragraph l
Radionuclides travel time, dilution factors, and resulting dose 4 projections were modeled on the basis of currently existing surface and j groundwater flow patterns (Pages 83-97). A low permeability, multilayered trench cap will not only decrease infiltration of precipitation but will also alter flow patterns because of changes in the direction of the hydraulic gradients. Different flow patterns will affect dilution factors. The concern here is that other dilution factors '
should have been used for establishing infiltration criteria.
Page 122, Groundwater Flow Barrier-Modeling Results Here again, the estimated radionuclides, travel time will be altered because the combination of low permeability trench cap and flow barrier will produce a significant change in hydraulic gradient across the I disposal area. It would be more meaningful to estimate dilution factors ]
and off-site doses with the decommission options in place. I Pages 124 and 126, Figures A-11 and A-13 (a) It would be extremely helpful to indicate the location of the
" equivalent flow barrier" on the figures. l Page 127, 2nd Paragraph (a) The flow barrier and up gradient drain will divert the flow away from the waste disposal site. The crop in piezometric head will ultimately affect dilution. Consequent changes in the dilution factors and dose projections should be addressed and quantified if possible.
(b) The quoted values for changes in the piezometric heads are not apparent from the figures. ;
Page 127, Assumptions Elaborate on the rationale for, and the consequences of, the two stated as s ump tions.
3201.6/5MN/83/11/25/0 Page 127, Las:. Paragraph The easing of the requirement on infiltration rate will alter the projected dose. Dose estimates over the following 200 to 300 years should be quantified.
Page 141, Figure B-B It appears that some waste disposal trenches are located outside the l
perimeter of the cut-off trench which defeats the purpose of the cut-off trench.
Page 181, Glossary It would be helpful to add (or to refer to the appropriate description page) the following: alluvium, consolidation, void ratio, dilution factor, cut-off trenen, barrier wall, upper and lower marker beds, flume, positive trench draia, evaporator, and sump.
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CONVERSATION RECORD l TiMc3:oo pm 12/21/8.3
- WPL motmNs TELEPHONE
{! -
O VISfT Q CONFERENCE O INCoMtNG ~
Location of WM/ Conference: @ outgo!NG
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MAME OF PERSONtSP CONTACTED OR IN CONTACT ORGANIZATION (Omca. shCt bureau. TELEPHONE WO:
WITH YOU - ser.4 DSyle Mills Kentucky L.pt of Natura i Resources ~*
susJEcf amd Environmental Protection '
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Maxev Flat- _ _ . _
SUMMARY
(The following is being typed and composed at the same time. Gross errors in l syntax chould be ionered) , i I
- 1. Nee Sacratarv: The new Secretary of the Dent. of Natural Rescuices is Challotte Baldwin. Reba Page is r waining in charge of the Environmental Protection Cabinet for the time being.
9 , c rit t o P nnnces- The e ta_to ayunts a deficit ne (44n millinn fnr FY'3. This means that it is unlikely that there would be massive funding for closing .Maxey Flats (Comment: Some of the " concepts" favored by Hittman would run $30-50 million).
miiis seio tnat tncy couio expect a few miiiion 6 wnica couiu ue useu ivr smaii Y_ _ e- c . a . a ,,,
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- 3. Site Evaporator: It is still off and they have a request in to k W it off until t ney are going to try to Keep a t oTT__ even >onger Marcn 44, im. >T Uney can. inis l l
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h 4..' Condition of the clastic: The PVC installed over the 40 series trenches '31 months I ago is very brittle. ine tire span is turnig out to oe snorter tnan Rentucky nac.
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MAME OF PERSON DOCUMENTING CONVERSATION 34GMTUttg DATE t
Edward O'Donnell ACTnoN TAKEN I
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- 5. Installation of new sumos: Hittman has been installing new sumos at the site There have been a few surprises. For example Trench 27 is 15 foot deeper that they'd previously thought. (Comment: It is adjacent to the l NRC experimental trenc.S. The additional depth wculd explain why the experimental !
I trench appeared to fill with water that rapidly bubbled up from below). Kentucky I is also discovering that many of the trenches have effective dams in them.
For example in one instance when a new sump was installed 20 foot from the old. one it was fcund that water depth in the old sump was 2 feet but 15 feet in the new sump. This means that there's more water in the trenches than had been anticipated. Mills said that they didn't know how they'daccomodate that.
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- 6. Removal of plastic and water sntry into trenches _: In October Hittman removed !
plastic from about 10 acres of the site to install the new sumps. They got caught by 3 bad period of excessive rain. They have not been abie to recomr
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that area. The ground is still muddy and the trenches have taken in a lot of water.
- 7. USGS wells: Last summer the USGS installed 2 large dia (1 ft.) wells and 7 small wells on the west side of the site and 3 on the east. A small amount of liquid has been found in a few of the wells which could be analvzed as to radionuclides content.
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- 8. Radionuclides movement in around water: The Department of Human Resources has been monitoring the hillsides adjacent to Maxey Flats. They've used a USGS device to get soil samples down to a depth of 12 feet. At one place as they approachec the lower sandstone layer the H-3 level went up from 100 pi Ci/l to about 100,000 This happened over a few feet. Analyses for radionuclides shows a little Co (typically less than i pi Ci/gm). (Coment: Late in the sumer PNL found i l tree on the west side of the site within 50 meters of the fence where the tree sap contained 12 million pi Ci/1 of H-3. W. Rickard said that they'd expected to find small seeps like that. Other trees nearby were close to bavground, levels and analyses for other. radionuclides in the tree containing the high H-3 shawed almost nothing else. Considering the localized nature and that it was within State own6d property and that there'd be terrific dilution of the H-3 by the time it seeped down the hill Rickard said that it was not a hazard to anyone).
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