ML20237C539
| ML20237C539 | |
| Person / Time | |
|---|---|
| Issue date: | 04/08/1998 |
| From: | Federline M NRC |
| To: | Joseph Holonich NRC OFFICE OF NUCLEAR MATERIAL SAFETY & SAFEGUARDS (NMSS) |
| Shared Package | |
| ML20237C505 | List: |
| References | |
| FOIA-98-149, FOIA-98-A-9 NUDOCS 9808210258 | |
| Download: ML20237C539 (14) | |
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From: Margaret Federline To: JJH 1, MHF1, MCL, CEA2, TWP8.WFK, JTG I, TWP8. DAD 2 THm4 Date: 4/8/9810:37am NN l
Subject:
EIS Moab, Utah -Forwarded Joe, Charlotte, Layton, Fielgel, Debble--
Attached is the input from Pugh/ORNL as the basis for our discussion tomorrow. Let's plan to get together at 10am tomorrow to prepare for our 11am teleconference. I have a meeting with Thadani at 9:30 so i may be a few minutes late. Please proceed with the prediscussion until I get there.
I Betty l will not participate in the West Valley teleconference. Please put the 10am ORNL premeeting on my calendar. The teleconference at I lam should also be included on the calendar.
Bill / John-The management issue raised in ORNL's response is that they plan to handle the resolution of these inconsistencies under the existing NRC task and may not have enough money.
Our position has been that this is part of their internal QA and coordination process and they should foot the bill. Unless you direct me differently, I plan to take this position in the call tomorrow.
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TELCON AGENDA ORNL Work on Atlas Moab Mill April 8,1998 Discussion of NRC views on ORNL proposal for follow-up action to examine differences between ORNL/GJ and ORNL/TN work related to Atlas site Discussio , of next steps in process Proposed telcon between Bill Kane (Acting Deputy Office Director, NMSS) and Dr. R. G. Gilliisnd to discuss generic issue of preventing future occurrence of such inconsistencies A / i u,,[t t i r e4 qp b ** ' f+bb-1 i
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TELCON AGENDA ORNL Work on Atlas Moab Mill l ORNL management process for several groups working on the same issue for separate entities 1
ORNL work beyond agreements reached on SOW r
ORNL additional modeling for DOI QA/QC !
Coordination within ORNL l
Consequences l
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f NRC VIEWS ON IdSUES ATLAS MOAB MILL RECLAMATION Talking Points Tailinas extending into the groundwater
- ORNUGJ drilled two bore holes through the tailings at locations where Utah concluded the tailings extend into the groundwater.
- In both holes the results showed that the bottom of the tailings were well above the groundwater level.
This issue should be considered resolved.
Past seeoage from the tailinas that oroduced the current groundwater contamination NRC concluded that the seepage rate from the tailings, responsible for the present groundwater co .tamination plume, was greater than 50 gpm'and probably closer to 100 9Pm.
Analysis of measured water level drop in the tailings impoundment from 1990 to 1994, combined with an estimate of infiltration due to precipitation lead to an estimate of 50 gpm of seepage during that time period.
Atlas computed the seepage under the old alkaline leach operational mode of the mill as 78 gpm, based on the measured volume of water pumped to the pond during operation and the estim'ated evaporation / precipitation (NUREG-0453). It also gave a range of 48-166 p r seepage.
Iso estimated that infiltration into the tailings, resulting from precipitation and i evaporation, was about 16 gpm.
- ORNUGJ concluded that both past and present seepage from the tailings pile was approximately 6.7 gpm.
ORNUGJ attempted to determine past seepage by comparing concentrations of several l constituents in the groundwater and in the tailings water, in conjunction with a calculation of groundwater flux to the Colorado River.
! The three constituents used in the calculation, uranium, ammonia, and sulfate, yielded disparate results ranging from 6.7 gpm for uranium to 66.3 gpm for sulfate.
Concluded that the 6.7 gpm result represents the seepage rate that produced the present groundwater contamination.
I The reason given not to rely on a comparison with ammonia, i.e., that some ammonia i may have been converted to nitrate between the pile and the wells, does not explain the discrepancy. Accounting for the additional ammonia would lead to a higher, not lower ,
seepage rate.
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2 Uranium may not be a good indicator of seepage from the pile, since uranium contamination of the groundwater also came from past stockpiles of uranium ore on the site.
ORNUGJ also modeled past seepage from the tailings pile using a two-dimensional version of the PORFLOW model.
The initial condition assumed that the tailings pile is completely saturated, which is appropriate because during the period the mill was operating, the top of the pile was covered by a permanent pool of water. The model calculated the seepage at this initial time as about 0.0014 ft/d, which must be multiplied by the area of the pile to get a volume seepage rate.
Using the current area of the pile,130 acres, results in a seepage rate of about 41 gpm.
There were three assumptions used in the modeling that appear to be incorrect ar _'
which, if properly characterized, would result in model predictions similar to seepage rates discussed by NRC in previous reports.
First, the model assumed the pile was saturated only initially and desaturated under the
-influence of seepage and evaporation. In reality, the pile was active, with mill water continuously being added to a permanent pool of water that existed over almost the entire pile until the mill ceased operation in 1986. During that entire period the tailings pile was completely saturated. If that condition was properly input into the ORNL model analysis, it would presumably show seepage through the bottom at 41 gpm at least until 1986.
Second, the entire bottom of the pile has a saturated permeability of 10' cm/sec. Page 4 of the February 5 report, " Boring logs indicate that there are areas [on the bottom of the pile] where the slimes are absent but there is insufficient data to construct a reliable map of their extent and thickness." Only a small portion of the bottom needs to be covered with sandy tailings of permeability of about 105 cm/sec to considerably increase the seepage. In particular, it would only require a small percentage of the bottom to be covered with sandy tailings to raise the calculated seepage from 41 gpm to 100 gpm.
Third, ORNUGJ also assumed infiltration of precipitation as less than an inch per year, based on a fixed percentage of the average yearly rainfall of 8 inches per year. This may be a valid assumption for open ground in this part of Utah, where infiltration is controlled by precipitation, evaporation, transpiration, and runoff. However, the pile is a closed basin; the only precipitation that runs off is the small amount that falls on the outer slopes. Most precipitation drains to the center where it collects.
Subsequent to the ORNUGJ reports and the February 5,1998 meeting, ORNUGJ has informally acknowledged a seepage rate of 33 to 50 gpm. The NRC staff concludes that the best scientific evidence indicates that the present groundwater plume is the result of past seepage from the pile at a rate of 50 to 100 gpm.
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Location of maximum contamination in groundwater olume NRC concluded that the present groundwater plume represents past high seepage of j contaminants from the tailings pile.
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NRC also concluded that since the mill ceased operating (and especially since Atlas began dewatering the tailings) seepage of contaminants from the pile has diminished.
NRC further concluded that the peak of the contaminant plume in the groundwater has passed the toe of the pile and is now near the river. Historical data from well ATP-2S, near the toe of the pile, showed maximum concentrations of contaminants in the mid 1980s with concentrations declining since then.
l ORNUGJ's design for groundwater data collection, specifically the location of sampling wells, would have helped confirm this conceptual model. However, several planned wells along the toe of the pile were not installed.
At the only location near the toe (at well ATP-2S), concentrations were lower than at the well (TP-09) part way between the toe and the river. However, without other data from near the toe of the pile, this information is not definitive in determining whether the maximum of the plume has passed the toe and is close to the river.
I ORNL /GJ discounts data from well ATP-2S as showing a plume front passing, based on a statistical test.
NRC is not familiar with the statistical test used by ORNUGJ (the non-parametric Mann-l Kendall test for trend analysis). However, if the test were to determine if a linear trend l existed in the data, we are not surprised by the negative result. The well measurements
. does not show a linear trend. Rather it shows the concentration rapidly . rising to a peak and then slowly declining. A test for a linear trend is not valid for this type of data.
l Time to drain oile l
ORNUGJ used the PORFLOW model to try to estimate the time for the pile to reach l steady-state, defined as the point in time when the seepage from the bottom is the same as the infiltration at the top, and concluded it was 238 years l The ORNUGJ report (figure 2.2) shows that the seepage rate declines from an initial l value of about 0.0014 ft/d to the steady state value of 0.0002 ft/d in 238 years. However, l the decline from 0.0014 ft/d to 0.0003 ft/d occurs in less than 50 years. This value l represents near steady-state and is a better representation of the time to reach
( equilibrium. '
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l Steady-state seeoaae rate l -
' NRC calculated that infiltration into the pile would be about 8 gpm aftt tclamation, l based on Atlas' proposed cover permeability of 107 cm/sec.
l NRC concluded that 8 gpm would be the steady-state seepage rate with a 107 cm/sec cover, because the steady-state seepage from the bottom of the pile will be controlled by i the steady-state infiltration rate, j l
NRC recognized that its calculation was conservative because it assumed the cover l would always be saturated.
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- ORNL/GJ was tasked to use its model to more realistically estimate steady-state infiltration after completion of reclamation. ORNL calculated the steady-state infiltration for a 10~' cm/sec cuer as 3.7 gpm.
ORNL/GJ also calculated the steady-state infiltration for a cover with a 11 cm/sec permeability as 0.6 gpm. The NRC staff agrees with those results. ;
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Te!epnore CWere : Ca4 Samarj Date. Ma & 4 4 99 Time: 130 p m.
Participants:
Margaret Federline, Deputy Direc:cr, DWM, NMSS j Joseph Holonich. Chief URB, DWM. NMSS Michael Layton, URB, DWM, NMSS Deborah Demarco, PMDA, NMSS Myron Fliegel, URB, DWM, NMSS Claud Pugh, Director, ORNL NRC Programs Office Robert Reed, ORNL Project Leader for L2094 Lance McCold, ORNL NRC NEPA Program Manager Julie Simpson, Technical Assistant to Director, ORNL NRC Programs Office Steven Hildebrand, Director, ORNL Environmental Sciences Division The conference call was initiated by Nuclear Regulatory Commission staff to discuss reports ,
prepared by the Grand Junction office of Oak Ridge National Laboratory (ORNUGJ) related to !
the Atlas Corporation uranium mill site near Moab, Utah. Atlas holds NRC license SUA-917 I' and has proposed to reclaim the mill tailings at their present location. The Tennessee office of Oak Ridge National Laboratory (ORNL/TN) has been assisting NRC in the environmental reviews related to that action and has prepared a Draft Environmental Impact Statement, a '
Biological Opinion (BO) related to potential impacts to endangered species, a supplement to the BO, and other environmental documentation. Recently, ORNUGJ was tasked by NRC and the U.S. Department of Energy (acting on behalf of the U.S. Fish and Wildlife Service) to perform data collection and analysis at the Atlas site. ORNUGJ produced three reports: " Tailings Pile ,
Seepage Model" January 9,1998, " Limited Groundwater Investigation" Janue.ry 9,1998, and g, ,
" Supplement l' and Analysis Report
- Februa 5
NRC staff discussed the history of its interactions with ORNUTN on the Atlas site and the events that lead to ORNUGJ's involvement. )
The perticular technical concerns were documented in a February 13,1998, letter to -
e U. . Fish and Wildlife Service. A copy of that later was previously provided to ORN
.NRC would then use this information to help it make its regulatory decisions.
differences between ORNUGJ and ORNUTN reports and will get back to NRC for further 4
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1 TELCON ORNL Work on Atlas Moab Mill '
Talking Points l
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- I ORNL policy regarding working both sides of contested issue NRC spending close to $1 million for ORNL assistance evaluating environmental impacts of Atlas proposal !
ORNL produced Biological Assessment (BA), BA Supplement, and portion of NRC comment package on draft Biological Opinion specifically addressing endangered ies issues C q(.>
would like to hear RNL policy on is
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Remainin ORNL tasks, funded by DOE and directed by DOI, were to b ta collection ORNL additional modeling for dol l When DOI asked ORNL for additional modeling, NRC sought to becorne involved to l I
assure well planned and executed effort -
Arranged Feb. 5 meeting in Grand Junction to develop program At Feb 5 meeting, ORNL presented report of completed program ;
ORNL stated that additional work would not change its conclusions Parties agreed not to proceed with additional ORNL modeling ORNL REPORTS D
'E inforraa'.!:n ja th rEord was daie',ed h r.::rha;; w:ih tile fregora of information A:t, ex MicasI f0lA- 7 A D 0 T9f-/V7) .
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CONSEQUENCES Use of reports by media and environmental groups Use of reports by FWS Cost to NRC for ORNL to rebuke reports I
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< fontfamily > < param > Times < /param > < bigger Recommended Process to Assess -
Differences Between Variogs Estimate of Seepage R es from the Moab Uranium Mill Tallings Pilep
</ bigger > Oak Ridge National Laboratory Oak Ridge, Tennessee The Atlas Moab uranium mill tallings reclamation draft EIS (NUREG-1531) and the associated biological assessment (and supplement) are based on the data available at the time they were prepared. Since that time, additional data have been collected by Atlas, Oak RI National Laboratory Grand Junction (ORNL- and others.
M' or @D the Nuclear Regu atory Commission's (NRC) decision on decommissioning the tallings pile and the U.S. Fish and Wildlife Service's (FWS)
Biological Opinion, the most imponant issues include: ,
- how rnuch the seepage of ammonia from the pile would be reduced by capping the plie' and ;
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Ir.fct.T.fien b this r:cd whoWahdch time would pass before seepage from the pile would d ccccWnce w;lh the Fee:cm cf in:ctmation' act,De.W!masI - * .-
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Ca d Oak Ridge National Laboratory P. O. Box 2009 Oak Ridge, TN 37831-8063 -
Tel. (423) 574-d422, Fax (423) 241 -5005 E-Mail pug @ornl. gov -
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