Presented before the Division 01 Chemical Educrtlon at the 113th Meeting of the American Chemical Society
Introductory Remarks J. A . S WARTOUT Oak Ridge National Laboratory, Oak Ridge, Ten’,,.
prior to the advent of the uranium pile nearly all radiochemical researoh was conducted in standard chemical laboratories. The small amounts of radioisotopes from natural s o m or high energy accelerators constituted minor radiation hazards. In wntraet, the uranium pile made possible the production of the relatively large amounts of radioisotopes which are now being distributed to -h institutions. Because of the urgency of the s r c h p-m for the production of 6ssionahle materipl it was necessary during the war to utilize existing Inboratories or temporary structures. Modification of these facilities was r-rted to as high intensity sources
became available for research. The research centers of the Atomic Energy Commission are now undertaking pmgrams for replacing the temporary chemieal laboratories with permanent laboratories designed specifically for radiochemical work. In addition, other institutions engaged in researoh with radioisotopes distributed from Oak Ridge are b m i n g concerned with the design of such laboratories. Because few radiochemical lahoratoriea h a v e yet heen constructed, current designs and concepts are, in many cases, preliminary and untested. In general. they are based upon extensive and varied radioehemical research with a wide range of levels of radioaetivitg.
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ITHtheadvent of theuraniumreactorand the subsequent distnbutlon ” from Oak Ridge of radioisatopes produced in this reactor,the extent of radiochemical researoh and the number of institutions engaged in it have greatly increased. A logical consequence of this growing emphasis is a more general coucern about optimum methods for handling radioactive materials and the types of lahorntorim in which such chemical work may be satisfactorily conducted. An eqnal, if not greater, reason for this intereat in the design pf laboratories specifically suited for radiochemical researoh is the pronounced increase in the amount of radioisotopes which have thus been made available. In contrast with the microcurie quantities obtainable from the cyclotron, which was the primary source of artificial radioisotopes prior to the war, as much as several hundred millicuries are contained in individual shipments now leaving Oak Ridge. Within the laboratories of the Atomic Energy Commission the differential is amplified further in that chemical research is frequently performed with many curies of radioiaotopes. Nearly all radiochemical research, with the exception of that with relatively high levels of radiation in a few special laboratories of the Atomic Energy Cornmiasion, has been performed up to the present time in standard chemical laboratories. The chemical laboratories of the various installations under the Atomic Energy Commission are, in general, of temporary, wartime construction patterned after prewar university and industrial laboratories. During the war a few laboratories with provisions far accommodating moderate and high levels of radiation were constructed at the Metallurgical Laboratory of the University of Chicago (now Argonne National Laboratory), Clinton Laboratories (now OaL Ridge National Laboratory), and Los Alamos Scientific Laboratory. In general, thee early versions of “hot” laboratories whom design w88 neoesSarily based on relatively little experience have become inadequate and outmoded.
The laboratories of the Atomic Energy Commission are nou in various stages of replacing the unsatisfactory and temporary StNCtureS with permanent laboratories designed specifically for chemical research with various lev& of radioactivity. Included among these are Argonne National Laboratory, which has commenced construction on a new site west of Chicago; Brookhaveil National Laboratory, for which permanent replacements for thp temporary laboratories modified from the army buildings of former Camp Upton are being designed; Hanford Works operated by the General Electric Company where new research laboratories me planned; the Institute of Atomic Research at Iowa State College, also constructing a metallurgical and chemical laboratory; the Knolls Atomic Power Laboratory of the General Electric Company now under construction; .Lo8 Alamos Scientific Laboratory; the Marion and Miamisburg, Ohio, lahoratorim operated by the Monsanto khemical Company; Oak Ridge National Laboratory, which will replace its extensive temporary buildings with permanent structures on the same Site; and the Radhtion Laboratory, University ol California, which has completed new laboratories for moderately hot research. In addition, similar building program are under way at the Naval Radiation Laboratory in Ssn Francisco and the Institute lor Nuclear Studies of the University of Chicago. Because many of these in themelves are major construction projects, the composite of this program for the construction of facilities for nuclear research represents a tremendous expenditure. Coordination of the design work of the various Atomic Energy Commission sites has been achieved to a considerable extent by regularly scheduled information meetiugs held at Argonne, Brookhaven, and Oak Ridge National Labaratoriea over the past year. Despite this, differencesexist between concepts of what constitutes ideal radiochemical laboratories. In part these variations arise from diEerencea between the general types
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INDUSTRIAL AND ENGINEERING CHEMISTRY
of research emphasized at the individual locations, in part from the lack of opportunity to date to prove the validity of some design details, and finally from the inherent differences in the manner in which any two individuals might accomplish the same task. UNIVERSITY AND INDUSTRIAL LABORATORIES
Although the scale of construction planncd by the Atomic Energy Commission is necessarily large because of its primary emphasis on nuclear research, the greater interest, numerically a t least, probably is in the const,ruction or remodeling of laboratories on a more modest scale. University and industrial laboratories in which the emphasis is more diversified or which use radiochemical techniques merely as a research tool are concerned with, at most, a few laboratory units usually for tracer research. The problems of designing such units and of remodeling existing laboratories are considered in separate papers in thi5 symposium.
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Vol. 41,
NO. 2
GENERAL FACTORS
Because of the wide range between the levels of radiation from the microcurie to the multicurie scale involved in current research problems, the variety of radioisotopes which are being used in chemical research, and the differences between the types and intensities of the radiation emitted by these isotopes, the problem of designing working spaces in which research may bp carried out efficiently and safely necessarily has no single solution. These factors may be subdivided on the basis of the hazards attendant on chemical operations with each. This analysis, in turn, permits consideration of the design features and manipulative methods requisite or desirable for the corresponding subdivision. RECEIVSD3Iay 10, 1948. Based on work performed undev Contract W-35-058-eng-71 for the Atomic Energy Proieot a t Oak Ridge National Laboratory.
Impact of Radioactivity on Chemical laboratory Techniques and Design PAUL C. TO3IPKINS AND HENRI A. LEVY Oak Ridge iVutional Laboratory, Oak Ridge, Tenn.
T h e radiative properties of radioactive substances are independent of their chemical properties and impose additional requirements on chemical laboratory design and practice. A general philosophy is developed through which problems associated with the handling of radioactive materials may be successfully attacked. A n attempt is made to establish a basis on which to build satisfactory standards of practice, and to evaluate the resulting impact on the facilities for implementing them. In particular, the segregation of areas of work, and types of facility appropriate to each, are discussed. Problems of ventilation, accumulation of activity, and material control are examined in the light of these considerations. The selection of laboratory furniture, surface materials, floors, and shielding is discussed.
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111s paper discusses features of chemical laboratories and laboratory practice peculiarly ielated to the full and safe use of radioaktive materials. Present design and technique are tailored to the chemical properties of materials of investigation. Design and technique for radiochemical laboratories should be compatible as Fell with radiative properties; these, being essentially nuclear, are independent of chemical properties and impose additional variable requirements in laboratory practice. The requirements imposed by radioactivity are discussed relative to two major parameters: radioactive contamination and pcnetrating radiation. The objective of technique and design is the execution of operations, which are chiefly prescribed by chemical considerations, n7ithout jeopardy to personnel, experiments, or products from undesired effects of radioactivity. In choosing a manipulation for carrying out a chemical operationfor example, the separation of a solid from a liquid phase-filtration by gravity or suction, or centrifugation, is no longer a matter of convenience or purely chemical effectiveness; the choice is one in which the radioactive parameters, contamination and radiation, often play a determining part. In the absence of radioactivity, the wide variety of manipulative problems encompassing the practice of chemistry is reflected in different kinds
of laboratories-for example, those for microchemistry, control analysis, physical chemistry, or general experimental chemistry. The impact of radioactivity on each will be different, but in all cases it will depend on the magnitude of the contamination and radiative levels. COhTbR.I~NA'ITONPARAMETER
By radioactive contamination is meant the unwanted migration of radioactivity into places where it may harm persons (on skin or in lungs), experiments (into reagents or analytical samples), or products. The prevention of serious contamination is really a problem of matcrial control, as radioactivity is always associated with matter. It differs from more usual problems of material control in that the amounts of material involved may range down to small fractions of a microgram. I n discussing the problem of contamination it is uaeful to define several concepts. The critical quantity, q, is defined as that mass or volume of material containing an amount of radioactivity, a, which may bo objectionable in a given situation. For example, for hard betscontamination on an open table top, a is taken from health considerations as 0.001 microcurie per square foot. Thus, for a solution containing 0.01 pc. in 10 ml., q is 1 ml., with which there is no difficulty of control; in contrast, for a solution containing 1 mc. in 10 ml., q is 10-6 ml., a volume which can easily bc lost during chemical operations and whose control may be difficult. For solid materials, uranium is analogous to the first example, radium to the second. The complement of the percentage of the total activity which constitutes a is defined to be the re uired degree of control: Thus in the second example a is 1 0 - 4 of the total (1 me.) and the required control is thereforc 99.9999~&
%
Chemical operations can rarely be expected to meet such stringent control requirements. If this is the case, there pxisls a contamination potential: This term the authors define as the ratio of the quantity of material which may be lost in a given operation performed by a given technique to the critical quantity, q. Thus in the second example quoted above, if a pipetting is made by ordinary methods, for which loss of 0.01 ml. is easily possible, the contamination potential of the operation is 0.01/10--6 = 1000. A value of the con-
