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201.6/SN/83/10/12/0 OCT 1 4 ;gg3
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t Ms. Rose Marie Carr
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Economist Commonwealth of Kentucky Natural Resources and Environmental Protection Cabinet Department of Environmental Protection Fort Boone Plaza 18 Reilly Road Frankfort, Kentucky 40601
Dear Ms. Carr:
I As requested, we have reviewed the draft Decommissioning Plan for the Maxey Flats Disposal Site, Task 3:
Evaluation of Alternatives. We find that the document provides minimal technical information to permit in-depth assessments of the conceptual decommissioning design options and are concerned that the options presented have not been thoroughly evaluated.
1.
Untested or unsubstantiated design options, such as the trench drain system, may present potentially long-term maintenance and environmental problems.
2.
There is virtually no inention of potential health and safety hazards to site personnel and to the general public associated with specific design options.
Consideration has not been given, for example, to the pctential release of radioactive materials during the dynamic compaction procedure.
Nor has the document addressed the environmental impacts of potentially hazardous releases of toxic i
chemical and biological wastes.
3.
- areful consideration has not been given to the design of environmental monitoring and surveillance programs. There is no discussion, for example, of monitoring rationales tailored specifically to the Maxey Flats disposal site. Moreover, no plan has been proposed for a monitoring and surveillance program during the decommissioning operations. This plan should incorporate both radiological and non-radiological elements.
4.
The document does not address the ccqcept of a verification and certification survey associated with Decommissioning activities.
_ MINTONB7-235 PDR OFC :
NAME :
DATE :83/10/12
o e
201.6/SN/83/10/12/0
-g-This survey and the special monitoring programs are important elements of the Haxey Flats decommissioning operation.
5.
Finally, the document presentation raises certain reservations about the modeling methodologies and projected dose assessments. We urge that additional, more detailed analyses of the modeling and evaluation of design options be performed before final evaluations l
of alternatives are made.
I have attached specific comments on the Task 3 document.
Unless substantive evaluations are made, it remains unclear as to how the Commonwealth of Kentucky will be in a position to objectively select the appropriate design options for the Maxey Flats disposal site.
Sincerely, i
i Donald A. Nussbaumer l
Assistant Director for l
State Agreements Program Office of State Programs
Enclosure:
Specific Comments on Task 3 Document cc: Don Hughes, KY, w/ enc 1.
Distribution:
SA Reading Dir. Reading JKendig, w/enci.
KSchneider, w/ enc 1.
DNussbaumer, w/ enc 1.
LHigginbotham, w/ enc 1.
Kentucky File (fcl w/ enc 1.
OFC : WMLU WMLU WMLU
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Specific Comments On The Maxey Flats Decommissioning Plan, (Task,3),
1.
Page 8 Intruder Performance Standard:
" Ensure protection of any individual" to what degree?
2.
Page 17, 2.2.1.8 Monitoring system:
There are many other reasons for monitoring which were nct mentioned.
For example, to verify confinement, to detect changes, to indicate trends, to identify potentially problematic situations, to project doses, etc.
3.
Page 17-20, Environmental Surveillance Programs:
a.
These tables appear to be listings of generic surveillance j
programs rather than site-specific programs to Maxey Flats. Were j
these programs in place at Maxey Flats? Note that these programs were not recommended by the NRC for the Kentucky site and indeed may not be totally applicable. These monitoring programs first appeared in NUREG/CR-0570, Addendum, July 1981 for reference disposal sites.
b.
Much of this discussion is not applicable to decommission (e.g., establish baseline information, list of pre-operational monitoring activity, etc.).
c.
Conspicuously absent are (i) a non-radiological surveillance program and (ii) a surveillance program during the decommissioning activities.
4.
Page 20, Table 2-5, Post-0perational surveillance:
i a.
Define the post-operational period in terms of the active and
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passive institutional control periods.
b.
Here again, the post-operational surveillance program appears to be generic rather than site specific to Maxey Flats.
Components of an in-place monitoring program would ordinarily be continued
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into the active institutional control period.
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5.
Page 21, Deep dynamic compaction:
l The word "only" in the last sentence of the page, which reads
... densification of Maxey Flats trenches require only the i
development of methods to control potential releases of j
l radioactivity and personnel exposure," is grossly misleading.
l Densification procedures with pile removal may lead to major i
radiological and non-radiological hazards off site as well as on
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l site. The control of potential releases will not be readily i
achieved.
Indeed, pile removal may present insurmountable
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2 radiation control problems.(See Item 42).
6.
Page 25, Structural cap Clarify the extent of structural concrete caps. Are they to be above the trenches only? Explain " bridge over the trenches."
Is the cap to be below grade, on the soil surface or raised above the surface? Give examples and briefly explain what kind of cover will protect the cap in the long-term.
7.
Page 26, Clay cap:
The bentonite clay layer will only remain relatively impermeable as long as it is kept wet. This limitation condition should be included in the discussion to clarify why the bentonite layer must be protected.
It should also be noted that root systems can cause localized drying of the bentonite with attendent shrinking and infilling of the cracks by non-bentonite soil. This may effectively destroy the relative impermeability of the cap.
8.
Page 39-40, Trench inventories:
What are the units associated wfith the given quantities? What are the dates of these inventories? The curie contents listed in Tables 2-8 and 2-9 do not seem to be in agreement.
(e.g., it appears that Trench 001 has 306 Ci according to Table 2-9 but only a few mci according to Table 2-8).
9.
Page 42, Table 2-10, Radiological source term:
(a) units missing on all quantities.
(b) define " source term," and how used in the study.
(c) Where were the measurements made? (e.g., adjacent..o trench, site boundary, etc.).
j 10.
Page 45, Table 3-1, Potential accidents:
(a) what is the basis or source of information regarding " frequency" of various accident occurrences?
(b) define " performance scenario."
11.
Page 46, next to last paragraph, Careful control over quality:
l Give details or examples of quality control of the positive trench drains.
12.
Page 47, 3.1.3, Obse.'vation period:
(a) What specifically is to be observed and why?
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(b) What is the duration of the observation period?
(c) What criteria is to be used for determining the duration of the observation period?
(d) How will design performance be evaluated? What are the criteria?
13.
Page 47, 3.1.4, Active institutional control period:
What is the rationale for a 100-year active institutional control period?
14.
Page 48, 3.3, last few lines, models to evaluate adequacy:
Existing computer or other analytical models are frequently not appropriate for evaluating design adequacy for many reasons (e.g., gross uncertainties of input parameter values, oversimplification in the mathematical descriptions of phenomenological behavior, etc.). Modeling for comparative purposes would be more appropriate and meaningful.
15.
Page 51,. 4.1, Primary performance requirements:
Add a fouith component, namely " compliance with other standards" to the words " waste isolation, safety and long-term performance."
16.
Page 55, 4.1.13, ALARA:
Add the word "public" after " general" in that sentence.
17.
Page 56, 4.1.2.3, Operational safety-occupational:
" Occupational" should include radiological as well as non-radiological regulations. How does this differ with section 4.1.2.1, Operational Safety-Radiological?
18.
Page 56, 4.1.3.1, Active institutional control period:
(a) Here too, as before (item 13), give rationale for "a minimum of 100 years."
(b) 'iaat criteria will be used to terminate the active control period?
19.
Page 57, O 2, Secondary performance requirements:
Site characteristics determination is not a performance requirement.
20.
Page 59, Table 4-1, Site Characteristics to be determined for decommissioning:
Add to the list: wind speed and standard deviations, atmospheric pressure, relative humidity, meteorological and radiological background levels.
4 21.
_P_ age 66, Manage surface water:
The management of surface water is also closely related to, and influences, ground-water infiltration.
- 22. Page 70-72, 5.1.1, Trench consolidation model:
The model used (Sowers-1973) assumes that settlement due to decomposition of waste is negligible and that primary consolidation has been completed.
It has not been demonstrated that dynamic consolidation will collapse a significant number of t/ gallon drums or other structural containers.
Primary settlement may therefore continue to occur for long periods of time making this modeling formula inapplicable at Maxey Flats.
In addition, this formula is an empirical relationship developed on the basis of observations made at sanitary landfills. The applicability of this formula to Maxey Flats has not been demonstrated.
23.
Page 74, third paragraph, Structural covers:
Here again "structual covers would be able to span areas where formulation conditions in the trenches are poor" needs clarification. Connients made ind item 6, as to the extent of structural caps, apply here as well.
24.
Page 77, Figure 5-1, Trench design covers for Modeling:
Define symbols SC, 'CH, and GP which appear in the figure.
Explain " filters."
25.
Page 81-83, 5.1.4, Trench drain model:
Has this system of trench drains and laterals (channels) ever been tested anywhere? What about long-term maintenance problems? Will these De sources of radioactivity to the environment? What is the environmental impact of this system? What of the accumulation of radioactivity in the drain materials over time? This system raises many important questions which are not addressed in the document.
- 26. Page 82, Soil inputs:
Parameter values for trench covers (e.g., hydraulic conductivities) are different from those used in the infiltration modeling. This does not allow for reasonable comparative analysis.
27.
Page 83, third paragraph, Closed from solutions to the movement of ground water:
The ground-water modeling seems to be superficial in nature.
Not enough details are provided to allow for an adequate assessment of the methodology. The term " closed form" in the text leads one to
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believe hat a simplistic, one-dimensional flow model was used. The statem.. "These solutions assume that a phreatic surface forms within the laterals" needs elucidation. What are the real-world consequences of that assumption? Explain what is meant by
" behavior of the lateral drainage system." Behavior with respect to what?
- 28. Page 94, 5.1.6.2, Modeling methods:
(a) "... simplified analyses of contaminant transport in the ground water were made..."
What are the simplifying assumptions? What are the analyses? Describe the modeling.
(b) "... Ground water measurement through the site rocks was assumed to occur at a rate of 15 meters per year " This statement doesn't make sense. What is moving? Water? leachate? contaminants?
If so, which contaminants?
20 Fage 94, ast two paragraphs, Dose calculations:
What scenarios were assumed for the dose calculations? Was NUREG 1.109 used for all calculations?
(NUREG 1.109 is primarily applicable to nuclear power plan'ts). What were the radionuclides and source terms used for the cdaculations? What was assumed about exposure times and ingestion rates?
30.
Page 95, Table 5-2, Site configuration for dose evaluation:
Define " travel time." For what distance and what radionuclides? Are the values listed for trench infiltration ( 1/10 and 1/100 inch) assumed to apply to the decommissioning period? They do not appear to be conservative estimates.
Compare also page 96 of the text, which assumes an infiltration of one ine.h per year.
31.
Page 96, Discussion of dose calculations:
(a) Large volumes of surface water were apparently used, hence large dilution factors result.
A realistic scenario would be the nearby drinking water well used by an individual for daily intake. Little or no dilution may occur.
This scenario was not addressed.
(b) Which radionuclides and what concentrations were used for the drinking water scenario and for the consumption of milk?
What are the assumed pathways? Here again, an in-depth review is not possible because of insufficient information.
32.
Page 99-100, sources for costs:
Page 99 makes reference to the use of R. S. Means Construction Costs Data 1983 whereas Page 100 specifies the use of costs being provided by Law Engineering Company (without reference). This is ambiguous and does not permit analysis of cost data.
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6 33.
Page 101, Table 5-6, Cost Bases:
Cost comparisons between the Corps of Engineers, 1983 information (NUREG/CR-3144) and Law Engineering show wide descrepencies. (e.g.,
cost of clay cap, cost of flexible liners, etc.).
34.
Page 104, Modeling discussion:
The HELP model is questionable for use in determining exact values of infiltration (.01 inches per year). This probably exceeds the limits of this model. Very little input data used in the analysis hr.s been provided making an in-depth review impossible.
35.
Page 104, last line:
Describe " filters."
36.
P,.ce 105-106, Figure 6-1 and 6.2:
It may be difficult to obtain field permeabilities of 7 x 10-10 for the lower layer as indicated, unless nearby pure benetonites are t
used. 71n addition, it may not be possible to compact the local soils to 10- cm/see hydraulic conductivity.
37.
Page 109, 6.1.4, Trench drain model-(a) Explain how tne drains will be constructed to connect the interior trenches to the surround'ng collector trench.
(b) It is our understanding that several of the disposal trenches at the site were excavated into the sandstone layers. This will necessitate the excavation of the drains through the sandstone which could be quite expensive. What is the impact of excavating through the sandstone? The estimates for drain infiltration appear quite low unless an engineered cover is used over the drains. Has the cover been assumed?
(c) Provide rationale for seemingly wide drains (10-60 feet).
(d) Explain " drains are more effective in removing large slugs of water in the trench as apposed to handling continuing water.
volumes."
(e) How will these deep drains and trenches be maintained?
38.
Page 110, Table 6-1:
(a)Draininfiltrationvaluesseemtoolowunlessanengineered cover is in place.
(b) Travel time - for what radionuclides?
(c) What distances are assumed for travel time calculations? '
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39.
Page 111, second paragraph, These results demonstrate:
The second paragraph does not follow from the discussion in the previous paragraph.
40.
Page 111, third paragraph, A properly constructed drain system:
A " properly constructed drain system" has not been defined.
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-41.
Page 114-115, Migration pathway analysis; Table 6-2, Dose calculations:
(a) No details are provided for the dose calculations with regard to radionuclides, exposure periods, exposure scenarios, pathways considered, critical pathways, assumptions used (e.g.,
infiltration, leach rates) etc.
(b) " Dose calculated for all other cases are less than performance standards limits." What are the other cases?
(c) ".. these results are preliminary." Why? How will dose l
calculations be refined?
(d) Cases A through F in Table 6-2 have not been defined. What are they? Are they the same as " design concepts" A through F (pp 133) t or " design options" A through F-(pp.136)?
(e) Again, not enough information has been provided for any analyses.
Table 6-2 is one of the most important pieces of information in the entire study yet lacks the details necessary for analysis.
42.
Page 116, second paragraph, Dynamic compaction:
... dynamic compaction using driven pile.
Piles are driven to 7 meter depth at a spacing of 5 x diameter.
The pile are removed as i
l the work progresses." This is another untested, unproven method which may readily produce biological, chemical, and radiation hazards off site as well as on site. What levels of l
contamination would be expected on the piles themselves upon removal from the ground? What levels of gaseous activities will be released to the atmosphere? The document does not address hazards nor provide environmental impact assessments.
43 Page 116, 6.2.2, Positive trench drains:
(a) Here again, how will the drains be interfaced with existing trenches? See items No. 37 and 44.
(b) What, if anything, would prevent leakage into and out of drains? What would prevent a " bath-tub" effect in the drains, laterals and surrounding collector trench?
(c) The document does not address long-term maintenance problems of the trench drain system.
8 44.
Page 117, 6.2.3, Cutoff trench:
(a) How will the cutoff (collector) trench, at 21 meters down, interface with the drains at 13 meters down?
(b) Explain " stockpiles" (Pgs 116 and 117).
45.
Page 118, Table 6-3, Construction costs:
i The cost of a ground-water flow barrier was not estimated.
46.
Page 132, Design concept A:
Desfgn concept A with a lower barrier of hydraulic conductivity 10- cm/sec will not achieve the desired infiltration of.01 inches per year according to the graph on page 106.
47.
Page 133, Table 7-3, Recommended Monitoring:
(a) What is the rationale for monitoring off-site milk? Where are the nearest farms?
(b) This table is not in agreement with Table 2-5 (page 20) for the post-operation period. How do they interface? For example, monitoring of milk, fish and fann crops were not recommended in Table 2-5, but are recommended in Table 7-3.
48.
Page 134, Design concept D:
(a) Why is the plastic cover placed at the surface?
(b) Why not use plastic in conjunction with designs A or B?
49.
Page 134, Design concept F:
How was the 40 year service life for the asphalt membrane liner determined? A PNL document (PNL-4'752, 00E/UMT-0064) specifies a much longer service life.
50.
Page 152, top two lines, viability of option C:
Why is there a (premature) inclination to reject option C? Option C is very viable in that the waste is not disturbed.
51.
Page 156, last paragraph, Rockwell-Hanford demonstration:
l The demonstration of impact compaction at the Hanford site will not be completed before early to mid 1984. Also trench waste j
conditions at Hanford are quite different from those at Maxey Flats.
Results must be generalized with caution.
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