ML20023E108
| ML20023E108 | |
| Person / Time | |
|---|---|
| Issue date: | 05/20/1983 |
| From: | Martin D NRC OFFICE OF NUCLEAR MATERIAL SAFETY & SAFEGUARDS (NMSS) |
| To: | Morley J ENERGY, DEPT. OF |
| References | |
| REF-WM-73 NUDOCS 8306140336 | |
| Download: ML20023E108 (6) | |
Text
- a I s Distribution WY 2 0198 NMSS.r/f WM-73/ RAP /83/5/19 M sM@ WMLL r/f REBrowning WM-73 RAPennifill DEMartin LBHigginbotham Mr. James A. Morley, Project Manager EFHawkins Uranium Mill Tailings Project Officer PLohaus U.S. Department of Energy GGnugnoli Albuquerque Operations Office PDR P. O. Box 5400 Albuquerque, NM 87115
Dear Mr. Morley:
We have reviewed the working copy of " Environmental Assessment of Remedial Actions on the Uranium Mill Tailings at the Tuba City Site, Tuba City, Arizona" as you requested. The current section on ground water does not contain sufficient data to demonstrate that the EPA Regulations (40CFR192.2(a)(2)and(3))onprotectionofgroundwater have been met.
In order for NRC to concur on the final plan, a demonstration that these regulations have been met will be needed.
Enclosed are our initial comments on the Tuba City Environmental Assessment. We understand that since remedial action at this site is not planned for the near future, we will have another review opportunity at a later date.
If you have any questions regarding these comments please contact Roger Pennifill of ray staff at (301) or (FTS) 427-4546.
Sincerely, 0.Gt\\uQt{Oh5 hDan E. Martin, Section Leader Low-Level Waste Licensing Branch Division of Waste Management
Enclosure:
WM Record File WM Project 73 As stated Docket No.
PDR V
cc: w/ enclosure LPOR F. Bingham, SNL Distributica:
E. Caywood, FBD i
S. Woodbury, DOE j
(Return to WM,623 SS) c'
- W?1LL h
- WML
[
- WML 7:
FC :
g__:____.
e____:-___________:____
NAME : RAPennifill : GNG rfoli : DE p____:____________:____________:____________:____________:____________:____________.___________
DATE :83/05/20 db:5/20/83
- 5/f4/83
}
B306140336 830520 PDR WASTE WM-73 PDR
i NRC STAFF COMMENTS ON THE MARCH, 1983 DRAFT TUBA CITY ENVIRONMENTAL REVIEW 1.
Page 1-1 (Section 1.1? - It is stated in the EA that the tailings by themselves are unlike:y to cause death. However, the U.S. Congress has determined that the tailings "may pose a potential and significant radiation health hazard." The statements to the contrary should be modified to reflect the potential hazards associated with the no action alternative.
2.
Page 1-7 (Section 1.2) - A sandstone member of the Kayenta Formation is described as the most likely source of riprap for the project. Since the riprap is to provide long-term erosion i
protection, some data on the durability of the rock would be useful.
If no rock of suitable durability is locally available, much gentler slopes or below grade burial may have to be considered as l
the preferred option.
3.
Page 1-10 (Section 1.3.2) - Alternative 2 is for partial
- below-grade stabilization with a clay liner, but.it is evident that-the authors do not feel that a liner is necessary.
If this is the case, another alternative to be considered would be partial or total below-grade stabilization in place without a liner. This l
would also effect the cost estimates for'this option.
4.
Page 2-3 (Section 2.2) - The statement that-the site is above present-oay flood level would be clearer, if the present-day flood -
was better defined. This could be done by saying, above the 100-year flood, PMF or whatever is applicable.
The present sentence iraplies that past or historical floods have covered the site and that there is a potential for future floods covering the site.
5.
Page 2-8 (Section 2.6.182) - Radium and gross alpha-particle activity in the sewage lagoon have been shown to exceed EPA standards.
If leakage from these lagoons is occurring, it is probable that contamination of the underlying aquifer is occurring on a continuing basis.
In addition, the near saturated state of the tailings and the presence of standing water on the tailings would indicate that some infiltration through the tailings may still be occurring.
In spite of this, no data on ground water in the immediate vicinity of the site has been provided. In order to meet the requirements of 40 CFR 192.20(a)(2) and (3) any ground-water contamination associated with the tailings must be identified. This has not been done.
4
- - = ~ - -,-- -
w.-
(*--~~
--~~'**^"2;2''_TT_:2Q
e r
L 2
- 6.-
Page 2-9 (Section 2.6.2) - The analysis of travel time for contaminated ground water to Moenkopi Wash assumes that any
. ground-water contamination would still be contained inside the site boundaries and that no recharge from the sewage lagoon is occurring.. This has not been demonstrated.
7.
Page 2-12 (Section 2.8) - If one assumes that the ambient radon daughter equilibrium ratio on the pile is 3-13% and that a conservative wind speed of 5 mph prevails, then the travel time would imply an increase of the 3-13% range to perhaps one of 13-23%. Perhaps a generic 20 or 25% equilibrium ratio should be used at all of the UMTRAP sites.
8.
Page 2-12 (Section 2.8) - The only radiation exposures addressed here are inhalation of radon (and radon daughters) and galana (external)groundshine. The fact that 22 acres of tailings have contaminated an drea of approximately 270 acres indicates that' there may be a particulate inhalation / cloud submersion exposure of some significance.
9.
Page 2-12 (Section 2.8) - No mention of regional collective risk is made. The risk estimate reported concerns only the population of 100 people within 2 miles.
- 10. Page 3-1 (Section 3.1.1) - A basis should be given for the statement that other potential pathways of exposure are much less significant near the site. Given that the aquifer beneath the pile is a major source of water in the area and that it may be contaminated, this pathway in particular needs to be addressed.
- 11. Page 3-2--3-5 (Section 3.1.2) - The estimated impacts, especially health effects, are low but this doesn't indicate a control of the impacts as much as the small size of the affected population. A more meaningful indication of control of releases might be to compare the impacts to those of a standard operating uranium mill.
Comparisons to background levels generally indicate that even operating facilities contribute small increments to those impacts from natural background.
It is' evident that a more meaningful comparison strategy should be implemented; such as, comparing computed health impacts from each of the various alternatives.
12.
Page 3-2 (Section 3.1.2.2) - The health effects are small because the population is small, not necessarily because the exposure is low. There are over 5000 people living in Tuba City (less than 10 km away) and 44,000 people living in the northwest corner of the Navajo reservation. Have any estimates included these people and the rest of the regional population?
_-_-. = _ - -
~
3
- 13. Page 3-2 (section 3.1.2.1) - The figures of.025 and.0023 WLM, and therefore the.00014 lung-cancer death /yr are questionable.
Further comment will be made in comments to Appendix 1.
- 14. Page 3-3 (Section 3.1.2.1) - It appears that Dutton 1982 repor_ts mortality figures in the state, not.043 lung-cancer deaths /yr to the 100 persons in Tuba, City. This should be clarified.
- 15. Page 3-3 (Section 3.1.2.1) - The radiological consequences from the ditterent alternatives appear to be dismissed out of land.
- 16. Page 3-3 (Section 3.1.2.2) - The assumption of radon-daughter concentration doubling due to the disturbance of the tailings should be justified if possible.
It should be noted that estimates of the effects of tailings disturbance on concentrations were provided in the Vitro DES.
- 17. Page 3-5 (Section 3.1.2.2) - Has any analysis been done to quantify the increased exposure to workers due to transporting the tailings in the alternative actions? If the magnitude of the increase is not known, it should be so stated.
- 18. Page 3-5 (Section 3.1.2.2) - Doses to workers from inhalation of radioactive wind blown particulates may be underestimated, unless strict programs of dust emission control and of wearing respirators
~
are implemented.
Based on an average 0.33% ore grade and the controlled emission rates in Table C.8, emissions of close to one curie per year could be expected for radium, thorium or lead.
- 19. _Page 3-7 (Section 3.3) - The fact that 22 acres have contaminated 270 acres of surrounding soil should not be ignored as an impact on soils.
20.
Page 3-8 (Section 3.5) - Additional water may be needed to add to till material to achieve proper compaction. This has not been addressed here or in Appendix C, Section C.1.6.
l
- 21. Page 3-8 (Section 3.5) - This section assumes that there was no contamination of the ground water during operations. No evidence l
to demonstrate this has been presented. Given that the unconfined aquifer beneath the site is the major drinking water supply source in the area, this needs to be shown.
l 22.
Page C-17 (Section C.2.3) - It is estimated that 134,200 C.Y. of clean material will need to be excavated prior to placement of the liner. Could this material be used as part of the cover?
If so, the cost estimates should reflect the use of this material.
l m
1
4 I
t
- 23. Page C-19 (Table C-14) - The cost and hours for demolition of buildings is twice as much in Alternative 3 as in the other alternatives. This discrepancy should be explained.
- 24. Page C-19 (Table C-14) - The volumes of cover material for this option appear to be approximately 30% high based on the surface dimensions given for this option. The surface area is less than for stabilization in place, yet the material required is given as 50% higher.
-25.
Page C-18 (Section C.3.2) - It should be explained why it is necessary to use riprap in the below-grade disposal scenario.
If no riprap is needed, savings of over $1,000,000 would be realized.
Do you feel that the same type of erosion protection is needed for-an above grade pile with 5:1 slopes as in a below grade disposal facility?
- 26. Page E-2 (Section E.1.2) - Is the aquifer confined where the pumping will occur? If it were stated here, it would be helpful.
- 27. Page E-7 (Section E.2.1) - The analysis of per olation was based on tailings material being at the surface. The calculations should have been done for the proposed cover mat.erial instead.
In addition, rainfall and evaporation were averaged over monthly periods. Given that rainfall in the Tuba City area would probably occur as events of short duration this is a poor assumption.
Thirdly, it was assumed that all water in the top meter of soil was available for evaporation. This is also a questionable assumption. Although much of this water could be drawn to the surface by capillary forces or evaporated as air moves through the soil, these' processes are not addressed in the Thornthwaite method.
Lastly, the Thornthwaite method was designed for use in vegetated
- a reas. Its use for mill tailings covers in arid areas is somewhat j
suspect.
- 28. Appendix I - The use of the word "model" in Appendix I is misleading. The calculations yield very rough estimates, and should not be construed as a site-specific atmospheric l
transport / dosimetry model analysis. The estimates of risk appear small because the risk factors have been applied to a very small population (i.e.,100 persons). More meaningful results could be given by considering the collective dose to the region.
In i
addition, impacts from inhalation of windblown particulates and ingestion of contaminated food sources are not mentioned h' ire.
j
- 29. Page I-3 (Section I,2.1) - The last sentence states that the risk i
factor of 100 x 10 deaths per person - WLM is used to calculate j
an upper bound for lung-cancer deaths. However, BEIR III supports I
Jnv a:o
-n._y- % y L-
&% Mno & '-"A yfN&<AY
""E**'
5 avalueog380x10-6, NRC's GEIS uses a " central value" of 360 x 10 6, and NCRP estimates 150 x 10'6 NCRP also notes that 100 x 10, is the lowest or least conservative value that can be supported.6 The U.S. EPA is' using a. risk factor of almost 1000 x 10. Uncertainty in this factor shoufd be openly dCknowledged. We cannot agree that 100 x 10~ is an " upper _ bound."
- 30. Page I-4 (Section I.3.1) - The conclusion regarding the effect of-differing atmospheric stability conditions on the dilution of a contaminant between two points is vague and superfluous.
1
- 31. Page I-4 (Section I.3.1) - The use of health-risk estimators is best applied to collective dose (at least to a regional population). Application of such estimators to a population of 100 persons is not very meaningful.
- 32. Page I-5 (Section I.3.1) - The use of the 0.3 wind frequency correction coes not appear to be necessary. Having normalized from 1
ameasuredcopcentrationalreadyac5untsfrthisfr.ctor. Thus the 2.5 x 10- WLM/yr and 2.3 x 10- WLM/yr exposure estimates a;, pear to be underestimated by a factor of 3.
l 33.
Page I-6 (Section I.3.1) - It is stated that no meaningful calculation of health effects to the general population due to gamma radiation from the actual piles cari be made. - Is a calculation of gamma radiation effects due to dispersed tailings at the vicinity properties possible?
If not, it should be so stated.
- 34. Page I-8 (Section I-4) - What is the reference for the estimate of risk time for lung-cancer death of 50 years? This information would be helpful to a reviewer.
- 35. Page I-10 (Section I.5) - The diffusion coefficient values for gravel and sand appear to be somewhat optimistic. On the other hand, there appears to be some uncertainty in the terminology for clay, sand, sandy-silty soil. Some justification for the choice of I
diffusion coefficients would be very informative to the reader.
I k
i w unmkM&LanksG: