Minutes of Advisory Committee for Biology and Medicine, Chalk River, Canada May 8-9, 1953

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Chalk Uver, Canada The Advisory Cormnittee f o r Biology and Medicine of the Atomic Energy Commission and t h e Project Coordinating Committee (Medical Committee of the Atomic Energy of Canada Limited) held a joint conference a t ChaLk River, Ontario, I Canada on Friday and Saturday, Piay 8 and 9, 1953. Advisory Cormnittee f o r Biology Division of Biology and Piedicine Division of Technical Information Department of the i m y Department of National Health

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Yr. J. Lorne Gray Dr. ii. Pi. Noore Dr. Laris, Vice President i n charge of Research and Development, welcomed the iidvisory Cod tte e and stated that he and his colleagues were very pleased I that it had been possible t o arrange a joint meeting of representatives of the Canadian ktomic Energy Project and the United States Atomic Energy Conmission. It was his belief that such collaboration will bring understanding and mutual benefits to all ooncerned. The meeting opened with D r r Cipriani presiding. Agenda bgenda provided to the committee by the conference was The first subject on the agenda was presented byPermissible Doses of Rah ation fo r~ hil it ary and Defense Uorkers Dr. Bugher with Dr. Claus reporting i n detail on npermissible emergency doses" f o r (I) operational,

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they are somewhat out of the ordinary, and are contained i n t h e lowOperational emergency levels are emergency only in the sense that limitation of 0.3r i n any one week, has permitted twice this level, or 0.6r i n any one week, provided the total exposure averages out t o Oc3r over a period of one-quarter, or, 13 weeks. permitting a s much as O.9r i n any one week, provided some penalty is attached, such as limiting the quarter's exposure It is often impossible t o operate efficiently under the For sever& years, LEC dose of 3.9r per quarter f o r atomic test personnel, without regard for the rate at which the dose i s accumulated. authorization has been made f o r workers such a s welders who must work on reactors i n fairly intense fields on isolated occasions. Workers from the U.S. who came t o assist i n rehabilitating the Chalk River reactor have operated under this permissible dose rate, Nedicine i s considering expressing its maximum permissible dose rate as 3.9r per 13-week period for -all operations, without regard t o the rate at which the exposure i s accumulated, on the grounds that this rule would give the necessary flexibility to all operations under nearly all circumstances; tut that its leniency i s self-limiting inthe sense that operators cannot use up thsir available ewosure - pot cnt i als in laxgo chunks and skill be able t o operate on a continuous basisr For several years, the iLEG has authorized the permissible The Division of Biology and recently proposed by E(. 2. Ibiorgan, though not officially recognized by IIJCRP o r AEC. This deals with an emergency exposure t0 internal emitters, such that the total annual exposure to the critical organ amounts t o 15.7 rem. For isotopes havlng makes little difference whether one averages the dose over one W e , very sizeable exposures might be permitted on this basis8 50 times a one-week dose of tritium, 6.8 times a one-week dose of carbonma, 15.3 times a one-week dose of k third semi-emergency exposure rate in this group is one.: But for isotopes of short effective halfThis is an interesting concept in its d. For emergency monitoring teams composed of liM: and contractor perso s e t up limits of 10r

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for persons regularly working with radiation, and 25 rfor persons not ordinarily exposed. these levels are probably archaic. Although not rescinded, e. An omsrgency operating exposure i s one proposed by Dr.Fail lats Subcommittee on Permissible External Exposure, 25r i n the lifetime of a person, without limiting his availability for exposure to O.3r per week. measures would be desirable b u t not obligatory. This proposal would permit one exposure of 2 5 - per week for a total of 8 weeks. readily permissible under dire emergency, and particularly for people of the class who would compose civil defense teams: in good physical. condition and who are n o t ordinarily exposed t o radiation inthe course of their work. Civil Defense permissible emergency exposure has been setat This dose i s believed t o be Acceptable levels of contamination of drinking water and food by fission products have been suggested by the Division of Biology and Medicine, and have been accepted by both Civil Defense and the Safe levels of contamination were calculated on the assumptions-t hat : 1. All activity may be calculated a s due t o Sr89. 2. 0.7 repiday isa safe exposure t o the bone, with a maximum accumulated exposure of 50 rep. 3 . That all the Sr89 isin 1/10 of the skeleton. Acceptable levels were then calculated as 25 times the above safe levels, on thesis of an estimate that the safety factor is Beta-Gamma activity, 10 days use; Alpha activity, 10 days use, O.OO~,*-~c~cc l’3, For military usage, the Division of Biology and Medicine has suggested the following; \ a, Q1At what acute exposures of troops t o gamma rays will they become ineffective as troops? A , SOr will not appreciably affect their efficiency as individuals nausea- vomiting, but not t o an extent lO Or will produce in occasional

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that will render the force ineffcctive as a fighting unit. Such troops should be given, as soon as possible, a pcriod forrest and individual evaluation. 1SOr o r more can be cxpected within a fcw hours t o mcra group ineffective a s troops, through a substantial incidence of nausea, vomiting, weakness, and prostration. Mortality w i l l bc low, and recovery of physical fitness may be expected. Field officers may expect that if substantial numbers of their men receive substantially more than 100r, there i s grave risk that their commands will rapidly become ineffective as fighting units. What dosage will rend6r an aircraft crew inefficient - that is, unable t o complete a mission? To crews previously unexposed t o such levels, doses up t o 75r will not be detrimental, Doses in excess of 75r, combined with the human stresses associated with military aviation missions in war tim, are considered t o increase seriously the odds against successful completion of a mission. How often may an aircraft or submarins crew accept an exposure of 25r p a - mission and still be a reasonable risk for subsequent missions? 25r pt;r mission, atleast8 missions a t weekly o r personnel should be carefully checkedi substantially reduce the life expectancy of the Mor6 missions may be feasible, but . crews of sampling a i r craft during tests, wc- have suggestcd that exposures be limited t o 20r during any one test series, and that these aame individuals should not be s o exposed again, although this exposure i s not t o prevent their participating in radiation work a t the usual level of 0,3r per weeki This suggestion is inline with #l(e) above, c I Permissible doses of mixed gamma rays and neutrons f o r aircraft crews i s under experimental study, using monkeys and chimpanzees, Data are not presently available.+' A general discussion followed with the suggestion made that som6 uniformity i n bio-assay measurements must bc developed and t h a t bio-assay procedures will haw t o be standardized i f permissible internal doses are t o be sufficiently meaningful. SECURI INFORMATION

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Industrial health measures i n 9r. Claus reported on permissible exposure i n uranium mines with the discussion primarily focused on the Colorado Plateau area. He stated that t h e uranium mining industry i n the Colorado Plateau consists of nurxrous small mines, probably over a 1,000, most of which a r e under lease t o small operators and are worked by two, three or four miners. Health Service and the Colorado Public Health Service i n conjunction with the Atomic Energy Commission has for several years been conducting a survey of the mines and nills t o evaluate the health hazards i n the industry. Preliminary studies showed that in mining uranium ores the primary health hazard i s probably that created by the presence of radon and its immediate daughters condensed on dusts inthe mine atmosphere. it was the AEC policy that radiation exposure of individuals employed asa result of kEC operations shall be kept below levels of substantial hazard. k careful re-evaluation of t h e dangers associated with radon therefore He stated further that In connection with the discussion on ventilation in mines, the Canadians brought out that their principal concern was how the AEC i s tackling the problem of high radon concentration. Dr, Cipriani said that there is a desperate need for an instrument that can be taken into the nines so thata measurement can be teken simply - - without t h e operator being an electronic Dr. Bugher replied that "our problem is different because we have no concentration of uranium of any magnitude". which isn ' t actually comparable to that in Canada o r the Belgian Congo. have small mines with a few men, o r maybe with only one nand This has lead t o a type of mining ventilation is a question of cos

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Dr. Ci;:riani stated that th me had been three o r four cases of cancer ir? employees of a mine. However, it has bem determined that there was only one case that could be attributed to working i n the mine. D r . Dauphinee propounded the question of whet'?er radon is a hazard. Dr, Claus advised that it vas proposed thata study would be made of several known stable populations in areas surrounding mjhes to find out if high levels of radon i n the mines i s a contributory cause of cancer. Dr. Warren referred tothe sputum test for cancer and said thatI indications were t h n t if you have a negative test, you have a 95% chance of not having a bronchial cancer. It has been found that this testis more for the pur?ose of making atour of the laboratories and facilitiss. The meeting was adjourned a t 11:30 A.M. Tour of ChalJk- Mver Laboratories. The Committee was conducted on a tour of the laboratories which included an inspection of t h e reactor and tho new Many favorable comments were expressed on t h e far-reaching investigations that are under way and of the profoun'd accomplishments that were In connection with the inspection of the reactor, tho Committee was impressed with the apparent dispatch and efficiency with which the engineering problems involved in the repair of the reactor are being met. The tour was

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The Chairman asked Mr. Butenhoff t o oilen the afternoon discussions with a report or Fermissible Doses for Radiation for Militar.yand Civiliah Defense mentation programs of Federal Civil Defense Administration and the U. S . Department of Defense is that of serving ina consultatory or advisory capacity without direct responsibility for these programs. He explained the differences inthe programs of the two agencies and str ted that attention in both t h e Department of Defense and Federal Civil Defense Administration hes been focused on two general closses of instruments - the dosimeter which registers the total accumulated exposure t o ionizing radiation and the survey instrument which measures the intensity of the radiation or the rate a t which the rndiation dose i s being received. c - 1' Mr. Butenhoff pointed out that both the military and civil defehse have restricted their dosimeter rcquirements t o instruments which measure only gms rz di ation and x-rays. It is felt that although it may be desirable in some cases t o measure beta and other radiations, a gamma dose measurement isall that is generclly rcquire?, The civil defense org mim tion divides its dosimeter requirements into three categories, - (1; pcrsoral dosimeters, (2) organi mt ional dosimeters -..-c'osiaeters are those that mi According t o FCLA definitions, the personal ceivably be worn by cvery man, woman and

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child. 2nd could bc purchascd by rnyonc desiring such en instrument. dosimetcrs would correspond. to what the Czncrdians and English czll a "Flash the initial burst of radiation from En atomic explosion. fore be high rmge instruments. Their Frimary purpose 1.1oul2be to measure the exposure due to Or.eanizationn1 dosimgsgs would be worn by members of en organized civil defense unit and would be purchased by the government. would be used to measurc residual radiation exposure and would have ranges suff icicnt to cover the esteblished permissible emergency dosages. The civil defcnsc traininedogimeters are high sensitivity dosimeters with 200 mr f u l l scale and, as the name explains, they are used for civil Zefonse training where unnecesscry cxposurc to radiation is to be avoided. The military dosimeter requirements roughly parallel thosc of civil diefonse, but nomenclature is different. T5e three general classes corresponding to the civil defcnse cle.sscs ere (1) administrative, (2) tactical and soldier to measurc lrrge dosages. military pcrsonncl prforming missions in contcminated ereas. -2osimetcrs-..-.. - m e used in military laboratories an6 for training. The military administrative dosimeters might be worn by each The tacticd dosimeters would bc worn by chart (Attachmcnt#l) vi11 summarize the desircd operational characteristics of thosc dosimeters. (Various typos of dosimoters were shown and described) Both the FCDA and the DCD arc going toward smaller sim, lighter weight instruments for use as survey meters. Yany developmental contrects have been Ict to develop instruments which will read, from about 0.02 up to 5CO r/hr. (Many of these instruments were shown and described. )

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The latest deaantamination agents D r . Taylor of the Chalk River Project opened the discussion and remarked that the tlhistory of decontamination had water, conplexing agents and detergents mixed with bacteriacidal substances. It has also been recommended that soep and wLter should be omitted. Recommendations have been made for the use of soap 2nd Dr. Bugher brought out thet the Canadians had had unusually broad experience in studies on decontamination and that they had really enlarged the knowledge of the general approech and also the general accomplishments ., After a full discussion the conference agreed that the most practical treatment for human decontamination was soap and water and that diluted hydrochloric a c i d should be used on contaminated wounds. problem, it was suggested t h a t the Handbook on Decontamination which has been A s an aid to this published by t h e National Bureau of Stmdards should be referred to. t h e acute radiation syndrome The conference considered t h e problems relating to the two subjects, Specific treatment for ra diet ion Dr. Bugher summarized two reports, i.e., …