ML20029B226
| ML20029B226 | |
| Person / Time | |
|---|---|
| Issue date: | 02/27/1991 |
| From: | Jabannath B NRC OFFICE OF NUCLEAR MATERIAL SAFETY & SAFEGUARDS (NMSS) |
| To: | Surmeier J NRC OFFICE OF NUCLEAR MATERIAL SAFETY & SAFEGUARDS (NMSS) |
| References | |
| REF-WM-65 NUDOCS 9103060254 | |
| Download: ML20029B226 (6) | |
Text
1 8[oueg fo.g UNITED sT ATEs i
NUCLEAR REGULATORY COMMISSION
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I WASHINGTON, D. C. 20555 k.....
FEB 2 i a MEMORANDUM FOR:
John Surmeier, Chief Uranium Recovery Branch Division of Low-Levei Waste Management and Decommissioning, NMSS THRU:
Edward Hawkins, Acting Section Leader Special Issues Section Uranium Recovery Branch FROM:
Banad Jagannath, Project Manager Special Issues Section Uranium Recovery Branch
SUBJECT:
TRIP REPORT FOR VISIT TO FALLS CITY, TEXAS, UMTRA PROJECT SITE - FEBRUARY 13 THROUGH 14, 1991.
- 0n Fet,ruary 13, 1991, members of the NRC staff visited the r lls City Title I, a
and Conquista and Ray point Title 11 sites in Texas. On Ft ruary 14, 1991, the NRC staff met with the DOE and their consultants to discuss DOE's-approach for the proposed. remedial action at the -Title I site. in Falls City, Texas. presents a list of the attendees.
The primary purpose of this trip 'was for the technical staff to visit the Falls City Title I site as they are (.urrently -reviewing the preliminary final Remedial Action Plan (RAP) submitted by. the DOE for this sue.
In addition the staff also visited two nearby Title II sites to witne 5 tle conditien of their soil cover.
Observations by-the technical staff during the site visit and sunnary of
-discussions in a meeting with fne DOE are presented below.
Geotechnical En.1ir.cering Aspects
-(by Banad Jagannath)
The geotechnical enginur toured the Title I project site with-the technical counterpart from 00E. The tour covered all the six existing tailings piles and a > pond enntaining contaminated acid solution.
The weather _ was dry and r
comfortable.- The vegetation at the site included dry grass _ and small bushes.
-It had rained a few days _ earlier, and -there were small ponds or puddles of water.. Apparently it takes = a while for the rain: water to infiltrate through the. existing soil cover-on thesc tailings piles.
The soil cover was a local clayey soil spread over the tailings-piles, apparently not compacted,(as part of the closure. The side slopes of the tailings piles are close=to 1.5 H):1(V);
however, there were no signs-of any slope failures.
The - borrow ' material available' in this general area is a clayey material.
The northwest area adjoinirg _ the ~ site is the proposed sou"ce for the borrow material.
The vegetation in the borrow area is grass and small trees.
The site visit enhanced-the technical reviewer's understanding of the site and its surroundings
_from a geotechnical engineering perspective.
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- -John Surmeier 2
- The slope of the soil cover in the Title l' sites are 1 to 2 percent on top and 20 percent on the sides. There iere signs of minor erosion as result of a heavy rain activity in the area, e yerienced a few days before this visit.
Based on review completed to date, tht staff provided to the DOE a list of 1
geotechnical information missing in ihe RAP documents, and the DOE consented to provide the additional information.
The appropriateness of the value of the i
saturated hydraulic conductivity of the radon / infiltration barrier used in the i
design was discussed.
DOE stated that because of their strategy of classifying the groundwater at the site to be Class III, the contribution by the radon / infiltration 'ourrier in limiting infiltration is not critical, and therefore the value of the saturated hydraulic conductivity used in the design being correct is also not critical.
Besides the above, there were no major geotechnical concerns discussed at this meeting.
4 G'oundwater' Aspects-r (by Neil Coleman).
NRC hydrogeologists toured the Falls City site with representatives of the Department.of Energy.
This was a walking tour of the former Falls City mill site, including the tailings piles and locations of bai.kground monitoring wells.
Figure 3.11 from the RAP is attached to show the locations of these featr s.
The site visit familiarized our staff with present-day conditions at the sise. which has-been acandoned for many years. Only the-foundation' remains from the former mill, and is located just south of tailings pile #2. A former
- office building still exists, in an abandoned state, just northeast of the mill foundation. A dirt road leads north from the foundation to the crest of tailings pile #7.
The tour began at the southern end of-tailings pile #2. We proceeded to the foundation;of the former mill site, and then walked north to' pile #7, the
- inrgest of the-tailings piles. We traversed this pile toward the west, and
- then traveled southertt from pile #7 to piles #1, #5, and #4. The tops of the
- tailings piles were covered mainly with grasses, forming dense mats of
- vegetation l.
The sloping sides of:the piles were less densely vegetated than 1
the tops, and showed that som erosion has occurred.
Along oue traverse, there was.no obvious evidence of_ slope failures.' We then viewed waste area #6 which contains a large pond, and examinec an outcropping of the Deweesville Sandstone located-on a knoll southwest of waste area #6.- Later in the day we. toured the
- large ta'ilings pile #3 in Parcel-B, ano visited many of th'! background monitoring wells:for the site.
There was evidence of recent rain at the site because shallow, ponded water was
- obscrved at a number of locations. Stream beds in the site area were mostly dry,Lexcept-for an upper branch of Tordilla Creek that we crossed near waste area #6. That upper branch contained pools of shallow water but was not visibly: flowing. The western part of pile #7 contained a small boggy area of ponded water, and a pond was clso located near the access road east of the mill foundation. Another ponded area is located about 600 ft, northwest of the mill foundation.
This ponded area was reportedly used to dispose of leachate-that 1
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contained molybdenum as a contaminant.
The DOE tour leaders referred to this area colloquially as the " molybdenum pit."
Several perennial ponds were observed on and near the site. A pond exists in waste area #6 near the southern margin of Pe' el A.
A large pond with margins modified by mining operations.is located about 800 ft. southeast of waste area
- 6.
Another pond was observed east of pile #3, and reportedly is impounded by a small dam.
1 Throughout the tour we observed locations of piezometers and lysimeters, some of which were located on the tops of piles A series of piezometers with rectangular surface casings and locked caps were located on the piles.
These piezometers, which are identified on site maps with a B prefix, were reportedly coastructed by liorrison-Knudsen Engineers, Inc. The tour leaders indicated they did not presently have information about these piezometers.
Opec and abandoned surface casings were observed at many locations on and near the tailings piles. Those near the bases of tailings piles may have been used in solution mining activities. Two large well casings were found just southwest of the mill foundation. These casings appear to have been sealed with cement. These two wells. are tentatively identified as site wells A and B, which were to have been sealed by the State of Texas. Some abandonet' casings near the mill site may have been part of the water supply and slurry pumping system used during mill operations. These include casings in fourJations for pumping stations and abandoned fire hydrants.
According to the tour leaders, tailings piles #3 and #4 and waste area #6 were formerly strip-mining pits that were later used as tailings disposal areas.
The fact that these tailings sites were also mining pits suggests that they act as zones of enhanced infiltration to the uppermost aquifer.
Infiltration at the site is also enhanced by the presence of abandoned exploratory boreholes.
These boreholes were used to delineate uranium-bearing deposits prior to mMing. Based on discussions with the DOE tour leaders, thousands of these abandoned boreholes may have been drilled at the site. We have requested all available information about the locations and depths-of these boreholes.
During the af ternoon ne Mured many of the wells being used to assess background groundwt+er qua'ity. We were primarily interested in observing the condition of. the w face cacings and understanding typical land use patterns near the wells. A ;ypical bickground well consists of a steel outer casing with a locking cover. 'Inside the protective steel casing is a PVC casing (with cap) which serves as a piezometer.
For those background wells that we visited, surrounding land areas.are mainly agricultural in use, including crop land and pasture.
We had an op)ortunity to visit a drilling rig that was operating on site during our tour.. T1e drilling program was described as a joint operation between the
' exas Bureau of Economic Geology and DOE's. Technical Assistance Contractor. We oriefly exemined core sections taken from the Conquista Clay and the Manning Clay.
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' John Sart.ieler 4
On February 14tt we met with DOE representatives to discuss the site visit, to identify additional data needs, and to present preliminary concerns f rom our ongoing review. Our main concern relates to DOE's evaluation of background groundwater qualitj and the proposed Class 111 classification of the Deweesville/Conquista aquifer. The DOE maintains that the contamination of the background water quality at the Falls City site is not related to former milling activities at the site.
The DOE asserts that the contamination resulted from naturally occurring conditions and human activity, such as widespread uranium exploration.
However, it is not clear that water quality in the background wells is representative of pre. milling, ambient conditions.
Surface Water Hydrology and Erosion Protection Aspects (by Ted Johnson)
Tod Johnson was accompanied by several 002, TAC, and MKE rr1resentatives in touring several areas in the site ';icinity.
We visited se ";
areas where gullying and geomorphic phenomena had occurred and had been n eestigated by DOE. We also had several discussions regard ng oroblems with vegetation and with achieving a self-sustaining vegetet%, cover.
Site visits to the Conquista and Ray Point,ites indicou:c the presence of gullied slopes. These gullies were small and had occurred relatively recently.
Staff concerns regarding vegetative cover, erosion protection of slopes, and toe of the disposal cell were discussed with the DOE in a meeting on February 14, 1991.
The details will be documented in the draft TER for this project.
OEUGih!M gp & m,,
Banad Jagannath, Project Manager Special Issues Section Uranium Recovery Branch Division of Low-Level Waste Management and Decommissioning, NMSS :
List of Attendees :
Falls City Site Map Distribution: Central File #
NMSS r/f LLUR r/f J5urmeier JAustin PLohaus JGreeves RBangart i
MFliegel DGillen BJagannath TLJohnson NColeman(HLWM)
DBrooks(HLWM PDR YES NO Ca tegory:
Proprietary or CF Only ACNW YES NO y
SUBJECT ABSTRACT:
FALLS LIfY, TX UMTRA SITE TRIP REPORT DTC:LLUp
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- LLURV
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NAME:BJagannath
- EHawkins DATE:cl A) /91
- 2fy/91 Bf/5!TE VI5I 0FFICIAL RECORD COPT C
v ATTACHMENT 1 LIST OF ATTENDEES AT-FALLS' CITY SITE VISIT AND MEETING WITH DOE i
DEPARTMENT OF~ ENERGY Paul Mann - Site Managcr 505-845-5637 C11rton Smythe - Engineering and Construction Group Leader
. 505-845-5659 i
TECHNICAL ASSISTANCE CONTRACTOR (TAC)
Denise Bierley - Site Manager 505-845-4015 fled Larson-- Assistant Project Manager 505-845-4015 Jim Crain - Engineering 505-845-2277 William Downs
_ Geochemistry 505-845-5704 Erik Storms - Groundwater Hydrology (R.F. Weston) 505-845-5713 Charles Reith'- Ecologist 314-441-8086
. Gerald Lindsey -
505-845-5704
. MK-FERGUSON.-
q John Briggs:
Corstruction Engineer Manager-C05-766-1667 Robert Heneks - Engineering-Design
- 41E.442+7575 Wei Lint-Engineering Design 415-442-7634
' TEXAS DEPARTMENT OF~ HEALTH
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-William. Price 512-835-7000 Gary Gartzkef
. 512-835-7000 l
l Steve Ramsey-512-835-7000 j
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- NUCLEAR REGULA10RY COMMISSION
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<Neil Coleman
.Hydrogeologist
= 301-492-0530 Mark:Thaggard - Groundwater Hydrologist' 301-492-0568 Ted Johnson - Surfacewater: Hydrologist -
L8anad-Jagannath - Project Manager /Geoter.h.
. 301'-492-3440-301-492-0593 N
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FIGURE 3.11 LOCATIONS OF BACKGROUND WELLS FALLS CITY, TEXAS, SITE L
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