Regulatory Guide 3.11

Design Stability of Embankment Retention Systems for Uranium Mills

ML13350A256
Person / Time
Issue date:	06/30/1973
From:	US Atomic Energy Commission (AEC)
To:
References
RG-3.011
Download: ML13350A256 (2)

June 1973U.S. ATOMIC ENERGY COMMISSIONREGULATORYDIRECTORATE OF REGULATORY STANDARDSGUIDEREGULATORY GUIDE 3.11DESIGN STABILITY OF EMBANKMENT RETENTION SYSTEMS FOR URANIUM MILLS

A. INTRODUCTION

Each licensee who piocesses or refines ore in auranium mill is required to comply wiih the provisionsof 10 CFR Part 20. "Standards for Protection AgainstRadiation." Section 20.106. "Concentrations inEIffluents to Unrestricted Areas." generally provides thatlicensees shall not possess. use. or transfer licensedmaterial s) as to release to anl unrestricted arearadioactive material in concentrations which exceed thelimits. spccified in Appendix B. Tablc II of Part 20.The milling ol' uranium ore results in the productionof large volu nues of liquid and solid wastes. (tailings) bothof which usually contain concentrations of radioactivematerial in excess of those specified in Table .11,Appendix B of Part 20. It is therefore necessary toconfic such liquid and solid tailings and prevent theirrelease to the environment. Conflnement is usuallyacconmplished by the construction of an embankmentretention system. This regulator), guide specifiesacceptable methods of analyzing the stability ofembankments. minimum acceptable safety factors thatare applicable during construction and use ofembankment retention systems, and acceptablesurveillance procedures.

B. DISCUSSION

'The design, construction. and size of embankmentretention systems for uranium mill tailings will varysignificantly from one milling location to another. Thecharacteristics of these systems will depend on suchdiverse factors as the capacity of the mill. the type ofore processed. the amount of waste produced. theamount of solution impounded, the type of millingprocess, the topography of the area in which thle mill islocated, the amount of land thai is available for theretention systemn. the perifeability of the soil on whichtailings are deposited. and the materials with which theembanknments are constructed. It is imnportant that theseembankment retention systems be designed andconstructed in accordance with sound engineeringprinciples to assure that they will maintain dtcirstructural integrity. Several analytical methods areavailable that may be used to determine the stability ofemnbankments for various heights and slopes. seepageconditions, and soil strengtl" parameters. The results ofsuch stability analyses should demonstrate an acceptablefactor of safety against failure for all pertinent designconditions.

C. REGULATORY POSITION

I. Basic Design ConsiderationsEmbankment retention systems for uranium milltailings should be designed to assure structural integrityduring the intended lifetime of the system. The stability ofan embankment retention syslemn should be evaluatedfor construction and operating conditions utilizing theexpected in situ engineering properties of the foundationand embankment materials and pertinent geologicinformation.2. Methods of Stability AnalysisThe acceptable methods of analyzing tihe stability ofembanknients are the adaptations of lte circular arcmethod. Other proven methods of analyzing stability.such as the sliding wedge method. may be used if theyare more applicable to the particular situation beingconsidered.3. Design Conditions for AnalysisStability analyses of embankments should bel.performed for the following design conditions:a. End of Construction (upstream anddownstream slopes):USAEC REGULATORY GUIDES Copies of published guides may be obtained by request indicating the divisionsdesired to the US. Atomic Energy Commission. Washligton. DC. 20545.Guides are Issued to describe and make available to the public Attentson: Diretior of Regulatory Standards. Comments and suggetions lotmethods acceptable to the AEC Regulatory staff of implementing specific paris of imrtovements in thema guides ere encouraged and should be sent to the Secretarythe Commission's regulations, to delineate techniques used by the staff in of the Commlision. U.S. Atomic Energy Commission. Washington. D.C. 20545.ovaluating specific ptoblems or postulated accidents, or to provide guidance to Attention: ChlefPublic Proceedings Steff.applicents. Regulatory Guides are not substitutes for regulations and compliancewith them Is not required. Methods and solutions different from those Set Out in The guides Are itsued in the following ten broad divitions:the guides will be acceptable If they provide a basis for the findings requitite tothe issuance or continuance of a oermit or license by the Commistsion. 1. Power Reactors 8. Productspermt by2. Research and Trest Reactors 7. T'ransportation3. Fuels and Matefiets Facilities 8. Occupational HealthPublished guides will be revised periodically. as appropriate. to accommodate 4. Environmental and Siting 9. Antitrust Reviewcomments and to reflect new Information or eipetlence. 5. Materials and Plant Protection iO. General c. NI.Iir I ml tII So Poo (tSIICJ21II lIi)J1C llIi. I4. Minimum Factoi s of &&fe1ylO~ IlLIS SpC~h'Ii in IC, 0) klo\ pojlis Ilii C*.2.'Iiou'ld anII'i.IdC ~ t aCC pt aic l :C t)I it' -,.It -e.i1-1:iI1sl IjIilhCl t' fi ll ; III I IiincrI L10 11-111 0011dilliillS.NI u 110)1 :IC CI' abC ld oi~ ii sl C I le ar 2.i\tCll ill I IcS Surveillance~A rqgllnIar p !11 oarOf SiL-ilvulanICC Mind II1,0110na,1CCsh ould hl' es i abNi si d it) deleCci and repair dam ageresnIi~l1~tl Ioitim Cilviroimneiii al or othlier ciCCI whichnmnlniil lend to lessen life i lllgrilv ol' tlre cinhankinewnrelent ii))) msleiCII. (;enerallx. Visuial il)SpcCI1ions ()I1 ajeciular liasi ;liC acceplabIC mnless circumllstanIces indicateolherw~isC. R~epair oii damage rcit) loig froini anyl cause%klidlic icli.!l l eind it. ICsseI file iliuL!erit\' ol tIleemlaik)inewlL'l icIeiiI ) S\vsIcili shoiliid lie perl'Orned aisN0011 :ipssilIii.\h illiiC11iidtii. PC I(lijfurct It'm ii1(lllimuiullg tile'ol.dIS ii', ad s:1CI I it, :e C Cmbanlkluiiei, TheC bImicIiis-11liml)Clit l)ect~ictIli ['Mh ,llit)Illilm iljwiL ale pic/ol)1cle)I' in C1siilu 11clvalct ) p ;Siire n si~loNipe ilndicalll sCii'ik ilhIk Ile 11S. T Ife C \ ICellI to %\winch Stichil~ttul~entaiti ieed lit iitatlld w\ill lie evalumaed b1%tilt: 0 1m gsii 10)I.SI Il ill) 1 ;Iis basis.L. Cond , m L.0initrim F,1001; Ofl SaLeiIEnd ol" onsC Iti..n ...........................4..Pa:irtial I' l .............................. I..Mlaxiimuui Pool r... I... .i...................II;rd .tltliak ' ( Al l tl' l .ll) , v,.cbnditions wvill; s.ismi. loadings)I.. .......... I.I)SelIection) of tlie aipph))ia~le %eismilcc'CI¢jciein shuild bl baLsed (Ill t he ;Iiaxinllitcaiillkill-Ak LhCice.illit.i on he bisis ol liso;ic1.I 1-2