ML20215F843
| ML20215F843 | |
| Person / Time | |
|---|---|
| Issue date: | 06/05/1987 |
| From: | Rich Smith NRC OFFICE OF INSPECTION & ENFORCEMENT (IE REGION IV) |
| To: | Bailey E TEXAS, STATE OF |
| References | |
| REF-WM-43 NUDOCS 8706230029 | |
| Download: ML20215F843 (3) | |
Text
u
<.n. 4 DISTRIBUTION
.e
-Docket. File WM-43
-PDR/DCSL WM-43/GRK/87/04/30/0
'DBangart, RIV GKonwinski -
WDEQ (2)
JHaes, RCPD, WY JUN 0 51987 LLW Branch, WMLU i
URF0 r/f-URFO:GRK Docket No. WM-43 040WM043120E
.n cd
-a r? 1 Edgar D. Bailey, P.E., Director r;g:~
p g;
- Division of Licensing, Registration as a
'and Standards' G
2.
Bureau of Radiation Control s
5 Texas Department of Health C
22
'1100 West 49th Street P
~
Dear Ed:
1 As'requeste'd in your letter dated April 16, 1987, I have had my staff.
review the performance standards' proposed by Exxon for the Ray Point tailings basin.1 The review utilized our experience on other_ sites that are.in the process of preparing project surveillance and maintenance plans as.well as considerable engineering judgment.
Overall, our objective was to offer comments which would minimize the maintenance
. liability that'the title holder would receive during the perpetual care
- L.
' period.
. It is our conclusion that the reclamation plan appears to adequately address-long-term stability, radon exhalation rates and ground-water contamination as specified in 40 CFR 192, assuming that these design
,. -?'
. features meet regulatory standards, the approved design ~is constructed and post closure surveillance begins.
During the post closure period, various types of monitoring should be utilized to ensure the integrity of the cover and diversion ditches. -Furthermore, ground-water monitoring should indicate if the engineered cariditibhs have equilibrated with the environment.
Cover Settlement Monitoring i
Exxon has proposed to monitor the tailings cover for potential settlement for a period of.2 years.
Following this period, a decision will be made as to the necessity of any further monitoring requirements.
The staff 3
would recommend that the length of the tailings cover settlement 0FC :
8706230029 870605 R
WASTE PDR
~~"* " " " "~~":~"~~ " " "~:" " """~~
NAME :
DATE :87/05/27
I
. v.
y 1
WM-43/GRX/S7/04/30/0 M 05 N 2-i monitoring program' be based upon the amount of settlement that is taking place. Qurterly measurements should continue to be taken until the various settlement curves approach an asymptotic relationship.. The
' period of years that this will take is unpredictable and to the'best of our knowledge, no' data base exists.
We would, however, draw your attention to the Department.of Energy's Project Surveillance and.
Maintenance Plan (AL-350124.0000),- March 1985, which recommends a 10 year monitoring period.
Concurrent with settlement monitoring, it is reasonable to expect that-the entire cover as well as accompanying diversion ditches should be subject to inspection.
This inspection should include observation and measurements of cracking, erosion and sloughing of the cover.
Similar L,
observations should be made in all. diversion ditches.
Additionally,-
deposition within ditches should be noted as well as riprap durability
-and bedding performance.
Concurrent with these efforts, the-amount of vegetative cover should be noted.
For those piles which do not have'a rock' mulch cover, revegetation should occupy a percentage of the pile comparable to that of undisturbed adjacent land.
Ground-Water Monitoring Exxon has proposed to monitor the ground water in the vicinity of the reclaimed tailings pile for a period of 3 years, after which a decision will be made as to the necessity of further monitoring.
The staff would 3
note that in accordance with 40 CFR 192, it will be necessary to establish background data for indicator species at a well that can be considered typical of uncontaminated water moving under the impoundment.
Furthermore, similar data will need to be gathered for all specified point-of-compliance wells.
It is our opinion that monitoring of these g
wells should either show that no ground-water contamination has taken place or, if there were indications of p'reviously elevated levels of constituents, they have been appropriately mitigated.
We would expect that ali issues pertaining to ground-water monitoring would have been resolved prior to the post closure period.
Demonstration of this would be by way of conformance with 40 CFR 192.
Due to this, our office would recommend that all monitor wells, with the exception of a single well in the major axis of flow, be appropriately abandoned.
The remaining well may be monitored at the discretion of the title holder.
OFC :
NAME :
DATE :87/05/27
.n -
a WM-43/GRK/87/04/30/0 ' JUN 0 51987 Radon Exhalation Rates The tailings cover must be designed to limit radon exhalation rates below the 20 pCi standard.
Sufficient design tools exist, most notably the radon computer code, which ensure that exhalation rates will be at or below the standard.
Based upon our ability to accurately predict radon exhalation rates, we consider the design sufficiently conservative and, therefore, additional monitoring requirements can be deleted.
We appreciate this opportunity to comment on the performance standa'rds proposed by Exxon.
In summary, it should be noted that the. time at which a reclaimed tailings impoundment is in a position to undergo title transfer is not necessarily based upon years, but rather upon performance.
The critical considerations in this respect are measurements of the system's performance.
These measurements should be directed towards closure standards and consider the asymptotic relationships previously discussed.
Sincerely, Isl R. Dale Smith, Director Uranium Recovery Field Office Region IV 3
Case Closed:
040WM043120E p
0FC
- - - - -..U.
~
- URF0 URF0
.------ -.p..--------- -:------------:------------:------------:-----------
NAME : GK inski : EHawkins
- RDSmith
.--------- g,
DATE :87/05/27 h
-