ML20155B219
| ML20155B219 | |
| Person / Time | |
|---|---|
| Issue date: | 08/25/1988 |
| From: | Hawkins E NRC OFFICE OF INSPECTION & ENFORCEMENT (IE REGION IV) |
| To: | Arthur W ENERGY, DEPT. OF |
| References | |
| REF-WM-48, REF-WM-64, REF-WM-73 NUDOCS 8810060237 | |
| Download: ML20155B219 (3) | |
Text
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Y ., ,
e, ja sto UNITt3 STATES y 4 NUCLEAR REGULATORY COMMISSION RE0lON IV
,e URANeuM RECOYgMELO OFFICc DENVER COLORADO OSIN AJG 251988 URFO:ROG W. John Arthur III, Project Manager Uranium Hills Tailings Project Office Department of Energy Albuquerque Operations Office i P.O. Box 5400 Albuquerque, New Mexico 87115 i
Dear Mr. Arthur:
We have reviewed your submittal of July 12, 1988 in which you proposed revising the riprap specifications for Durango, Lakeview and Tuba City. The specifications in question require that, "individual pieces shall be dense, sound, resistant to abrasion. ..." Your interpretation of this requirement is that each individual piece of riprap has to be tested and inspected, thus you are concerned that the specifications are unduly restrictive. You propose to eliminate the words, "individual pieces," from the specifications and to establish an inspection and acceptance procedure for erosion protection materials. This procedure would reject and remove unsound individual pieces greater than eight inches in diameter. Also, pockets of unsound materials, I
' which are less than eight inches in diameter, would be removed. Occasional and ,
randomly located unsound individual pieces, less than eight inches in diameter could be left in place. The occasional unsound individual pieces would be less than five percent of the total riprap quantity. This approach would be patterned after the agreed corrective actions for Canonsburg, We do not interpret individually inspected.the specification as requiring that each piece of riprap be However, we don't have any cojections to deleting the words "individual pieces," as you suggest.
The second part of your proposal which cone. erns a procedure for inspecting and accepting erosion protection materials, is based on corrective actions proposed for Canonsburg. The procedure would remove unsound material from areas greater than eight inches in diameter, and individual riprap pieces that are larger than eight inches in diameter. These would be replaced with material meeting durability specifications. Although NRC agreed to this apt roach for Canonsburg, this decision was site specific based on field observations of the rock actually placed at Canonsburg and on the rock size us ed. The procedure may or may not be applicable to other sites and thus shoulJ not be used .
generically unless conditions are ident W to Canonsburg We suggest that instead of specifying an eight inch Ih e titable *ock to be replaced, that the rock selection and processine be sodtored more closely and that Bureau of Reclamation (80R) or C 4 *s (COE) procedures for rock placement be specified in your i . snd acceptance estoo60237 000025 PDR WM-40 W A31E INU hgd
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2 AUG 251988 procedures. For example, the COE in CE-1308, "Stone Protection," July 1958 recommends that:
...The larger stones shall be well distributed Jnd the entire mass of stones in their final position shall be roughly graded to conform to the gradation spectfled...The finished riprap shall be free from objectionable pockets of small stones and clusters of larger stones...The desired distribution of the various sizes of stones thro 9ghout the mass shall be obtained by selective loading of the material at the quarry or other source, by controlled dumping of successive loads during final placing, or by other methods of placement which will produce the specified results.
Rearranging of individual stones by mechanical equipment or by hand will be required to the extent necessary to obtain a reasonably well graded distribution of stones sizes....any material displaced by any cause shall be replaced..."
In summary, we concur with your proposal for eliminating the term "individual pieces" from the riprap specifications for Durango, Lakeview and Tuba City. We don't concur however, with your proposal for specifying an eight inch limit for removin0 and replacing unsuitable rock because this requirement may be unduly restrictive and may cause more problems than it solves. We therefore suggest that a greater effort be made to assure proper placement of rock in tially to i avoid having to remove and replace unsuitable rock.
If you have any questions, please feel free to call me at FTS 776-2805.
Sincerely, awkn',Yh Licensing Branch 1 Uranium Recovery Field Office Region IV
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