Regulatory Guide 3.9

Concrete Radiation Shields

ML12220A059
Person / Time
Issue date:	06/30/1973
From:	Office of Nuclear Regulatory Research, US Atomic Energy Commission (AEC)
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References
RG-3.009
Download: ML12220A059 (2)

U.S. ATOMIC ENERGY COMMISSION June 1973REGULATORY GUIDEDIRECOoAT OF REGULATORY SANDARDSREGULATORY GUIDE 3.9CONCRETE RADIATION SHIELDS

A. INTRODUCTION

Section 20.101 of 10 CFR Part 20, "Exposure ofIndividuals to Radiation in Restricted Areas," states thatno licensee shall possess, use, or transfer licensedmaterial in such a manner as to cause any individual in arestricted area to receive a dose in excess of the limitsspecified therein. Paragraph (c) of § 20.1 provides thatlicensees, in addition to complying with therequirements set forth in Part 20, make every reasonableeffort to maintain radiation exposures as far below thelimits specified in this part as practicable.Concrete radiation shields can be installed in nuclearfacilities such as hot laboratories, radiochemical plants,experimental facilities, and nuclear fuel fabricationplants to provide a barrier between personnel andradiation sources for the purpose cf reducing doses ofionizing radiation received by personnel to as low aspracticable levels. This guide describes practices for theconstruction of concrete radiation shielding structuresfor such nuclear facilities, which are acceptable to theRegulatory staff as methods of complying, in part, withCommission regulations with regard to reducingradiation exposures. Much of the information includedmay be applicable to shielding structures for reactorsand other nuclear and nonnuclear facilities which requireconcrete radiation shields.

B. DISCUSSION

Subcommittee ANS-li, Radioactive MaterialsHandling Facilities and Specialized Equipment. of theAmerican Nuclear Society has developed a standardpresenting requirements and recommended practices forthe construction of concrete radiation shieldingstructures and for certain elements of design that relateto problems unique to this type of structure. Thisstandard was approved by the American NationalStandards Committee NIOi. Atomic Industry FacilityDesign. Construction and Operation Criteria. and it wassubsequently approved by the American NationalStandards Institute- (ANSI) on December 22. IPQ2.and designated ANSI N101.6-1972. The standarddiscusses aggregateo. design of concrete mixtures andforms, placement of concrete, design and installation ofpenetrations. embedments. metal liners, and penetrationplugs and outlines testing and quality assuranceprovisions needed to verify that the desired quality ofdesign and construction has been achieved. The standarddoes not include detailed treatments of structural designor determination of shield thickness.

C. REGULATORY POSITION

The requirements and recommended practicescontained in ANSI N101.6.1972, "Concrete RadiationShields,"' are acceptable for the construction ofradiation shielding structures for hot laboratories.radiochemical plants, experimental facilities, and nuclearfuel fabrication plants subject to the following:I. Section 2 of ANSI NI01.6-1972 lists applicabledocuments which are intended to supplement thisstandard. The specific applicability or acceptability ofthese listed documents has been or will be coveredseparately in other regulatory guides or in Commissionregulations. where appropriate.2. Section 4.8 of ANSI N101.6-1972 delineates specialprecautions to be observed in the construction ofconcrete radiation shields. Where steel or other metalsare used as aggregate t,. increase the density of theconcrete, the metal should be of such type that it willnot cause hydrogen or other explosive gases to begenerated by reaction with the cement.'Copies may be obtained from the American NuclearSociety. 244 East Ogden Avenue. Hinsdale, Illinois 60521.USAEC REGULATORY GUIDES Coe Of pubished guide may be obtaned by requem indca.ing the divisionsdesrIsd to the US. Atomic Erurgv Commission. Washington, D.C. 2054S.Regulatory Guides or ISS*ed to describe ed mke lvwoiill4 to the public Atitenteio Director Of Regulatory Standards. Comnments and sol 1tions formenhods accepatmle to she AEC Regulatory staff of Imifes owtong specific parts of inovernwts in these guides oe encouraged and should be sent to the Secretarythe Comone.on5 -egat.:at1Os. CdP'isefe te-hrouee used by the seff in of the Commoonso. US. Atomic Energy Commssion. Washington. D.C. evaluating spec:fic ioblems 4; postulated eaecklnts. or to pro-ide guidance to Atlefstion: Chief. Public Staff.Ii**cnts. ReapulgO ry Guides not substitutes fw regulations end cooslaei swith them .not required. Methods and iolutions differenit from thoe at out in The guides ae issue in the following ten broad divisions:the ill b4 acceptable if they porovde b at for this findings tothe resuano or continuance of a permit or Oicene by the Commisson. 1. Power Reactors 6. Produacts2 Reseach end Test Reac ors 7. Transoortation3. Fuels an Mt erials Facilities a. HelthPubli'shad guides will be revised eiw.odimi. w appropriate, to acornmndsa 4. siting g. Antitrust Revieweninnent, and to reflect now informa~tion or eUperleis 5. Matarials end Plant Protection 1

0. General

3. Section 6.4 of ANSI NIOi.6-1972 does not explainhow some of" the variables which are used in theequations for bending moment and tensile stress are tobe determined. Therefore this section should not be usedas a substitute for detailed thermal stress analysis in thedesip of temperature reinforcement for control ofcracking in specific concrete radiation shields.4. Section 8.7.1 of ANSI Ni0i.6-1972 states, in part.that reinforcing steel or other means. be provided fortransferring shear forces through a construction joini.This requirement is not sufficient. Provision should bemade for adequate means of transferring shear and otherforces through the joint.N'3.9-2