ML19343B759
| ML19343B759 | |
| Person / Time | |
|---|---|
| Issue date: | 12/03/1980 |
| From: | Scarano R NRC OFFICE OF NUCLEAR MATERIAL SAFETY & SAFEGUARDS (NMSS) |
| To: | Kirner N WASHINGTON, STATE OF |
| References | |
| REF-WM-33 NUDOCS 8012300288 | |
| Download: ML19343B759 (1) | |
Text
pmRfCp hk 8
' g[W r.c
'C, UNITED STATES hd.33 g
NUCLEAR REGULATORY COMMISSION C
WASHINGTON, D. C. 20555 e
a
~%J DEC 0 31980 '
R i
a Ms. Nancy P. Kirner m ?.-
S.
I Radioactive Materials Licensing
- 3f]
lmf.,
j i
Department of Social and Health Services Qij M
i' y
P.O. Box 1788 g
3 Ms j
". 5 Olympia, Washington 98504 5
=
o o
O m
=
Dear Ms. Kirner:
0 In response to an October 31, 1980 letter to you from Dawn Mining Company, we have reviewed Dawn's proposal for the use of an alterna-tive synthetic lining material for their planned below grade tailings disposal area. Attached is a copy of a letter from our consultant, Roy E. Williams, providing background supporting his conclusion that the proposed High Density Polyethelyne (HDPE) is an acceptable alter-native lining r..aterial.
In accordance with Dr. Williams' findings, the Uranium Recovery Licensing Branch recommends that your department approve the proposed lining material change. The affected sections of our DES input will be amended as part of our response to coments on the DES.
If you have any questions concerning this matter, please contact Mr. D. Gillen of my staff (301/427-4088).
Sincerely, W'/
W Ross A. Scarano, Chief Uranium Recovery Licensing Branch Division of Waste Management
Enclosure:
as stated 8012800928
- ENCLOSURE CX3C Kb / '
e Roy E. Williams and Associates, Inc.
P. O. Box 15 Viola, Idaho $3872 November 20, 1980 Mr. Dan Cwillen Uranium Resource Recovery Licensing Branch U. 5. Nuclear Regulatory Commission 7915 Ecstern Avenue Silver Spring, Maryland 20910
Dear Dan:
This letter constitutes my response to your request to provide a background on my decision to recommend the use of high density polyethylene as an alternative caterial for the liner at the Dawn Mining Company uranium mill tailings disposal facility.
I made the recommendation as a consequence of a conference with Dr. Henry Haxo of Metrocon Incorporated and as a consequence of reviewing the characteristics of HDPE.
I also received infomation from the Rossing uranium mine and mill in southwest Africa.
The Rossing mill was the first uranium company to use HDPE as a liner for uranium wastes. They uscthe material as a liner for en evaporation pond.
According to Rossing personnel, the pond has been in use for two years.
It has been lined through-cut its life.
The company has drained the pond (by pumping) every eighth month and inspected the liner for leaks.
In particular the seams have been tested sonically for air gaps.
No leaks or air gaps have been detected.
High density polyethylene is manufactured in such a way that it overcomes the primary objections to the other polyethylene liners.
These objections center primarily around the fact that polyethylene is unstable in the presence of ultraviolet radiation.
HDPE (marketed in the United States under the name Hydriline and also known as Gundle Sheeting) is saturated with carbon black in order to avoid this negative effect.
HDPE can now be produced in 20 or 40 mil thicknesses.
Until recently it was available only in E0 mii thicknesses.
These thinner membranes are reported to make seaming easier although a fairly narrow temperature window must still be maintained.
The HDPE liner has lower strength properties than hypalon.
It also expands more under normal temperature increases than does hypalon.
However, the Dawn pond is proposed at a three horizontal to one vertical slope and the membrane will be covered.
Therefore, I do not see that these two character-istics are particularly detrimental at the Dawn site.
HDPE is stable under exposure to almost all chemicals, including hydrocarbons.
It is not sensitive to any of the chemicals common to uranium mill wastes.
TOlhk0h
L
^
m s
Mr. Dan Guillen Page 2 November 20, 1980 Under these circumstances and because of the $100,000 saving in cost, I decided that it would not be detrimental at the Dawn to deviate from the normal use of hypalen and recommend the use of HDPE.
If you have additional questions, please call.
Sincerely, f6 J
'd Roy E. Williams Ph. D. Fydrogeolocy Registered in Idaho e
e