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Kauioiogitai t'roLecLion ot tne Public in a Nuclear Mass Disaster FIRST RESULTS FROM THE PROGRAMME OF ACTION FOLLOWING THE PALOMARES ACCIDENT 106758 Junta de Energia Nuclear - Madrid - SPAIN. In reply to the kind invitation of the Fachverband fur Strahlenschutz, we would like to give an idea of the work which is being carried out in con nection with the wellknovm Palomares accident, and give indications of some of the general results obtained, with the idea that in the Symposium on Agricultural and Health Aspects of Radioactive Contamination in Normal and Emergency Conditions which is going to be held in Cordoba (Spain), organized jointly by the I.A.E.A., F.A.O., and W.H.O., we shall present more detailed studies on each of the sections we shall briefly refer to here. As a consequence of the air crash which caused, on the 17th January 1966, the explosion of part of the conventional explosive, which was a constituent, of two thermonuclear bombs, an aerosol of plutonium and uranium was created which caused the contamination of a total area of approximately 226 hectares, of which 2.2 hectares had an alfa contamination of more than 700,900 d.p.n/ 100 cm^, being the areas closest to the points of impact of the two bombs, which were 2,600 m. apart in a line drawn through the air. An area of approximately 17 hectares showed contamination between 700,000 and 70,000 d.p.m/100 cm2, the rest, seme 207 hectares, showed contaminations of less than 70,000 d.p.m/100 cm^, rather more than half of these being less A great proportion of the houses of the town were either v:eli out of the contaminated area, or in the parts where contamination levels were lowest The number of persons who were in the tov.-n at the time of the accident was In another communication presented to this Symposium, it has been explainsi how the limits of the said zones were fixed, the decontamination operation carried cut, and steps taken with people and vegetation at a time soon aft the accident. Here v;a are going to deal with, although in a somewhat summa form, the work plan devised for the vigilance of the people and the area, and the deduction of the consequences which might, in the future, result from such an accident and the measures which were taken. Our greatest worry, as is logical, was to determine whether or not there w‘ s ^ ^ internal contamination by plutonium-239 of the persons present in the area during the moments following the accident, what possibilities there were o contamination during the period of time when the operations of limit-fixinj and decontamination were being carried out, and whether there was any risk from the measures which it had been decided would be taken in the areas where contamination levels were lower than 700,000 d.p,m./100 cra^. This risk might be derived from: BEST COPY AVAILABLE a) inhalation of plutonium if, as a consequence of the tilling of the land, and the winds which are present, an aerosol, contaminated with the said clement, is created, which reach a definite diffusion.
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b) contamination‘as a consequence of tilling operations on ground where a certain quantity of plutonium-239 was left. c) contamination by contact with or ingestion of vegetable products which are cultivated in the area, in the case of these showing external contami d ) contamination of vegetable products used as foodstuffs in the case of their producing, during their growth, an absorption of plutonium-239 or We make the reservation that there is no risk of contamination through drinking water, since the water existing in the said area has such a high concentration of salts that it is completely undrinkable, and the drinking water which the public consumes is brought from a distance of 50 kilometres. As a consequence of these considerations, we summarise below the deductions obtained during the first year of work in connection with the contamination of persons, ground, air and vegetation. The study of the determination of possible internal contamination of the people of Palomares, both in the case of those who went there afterwards, and especially those who walked through contaminated areas during the first moments, was planned under the following two aspects: 1) Determination of the Plutonium-239 excreted in urine, in order to de termine the fraction which could have passed the pulmonary and lymphatic 2 ) Determination of the quantity of plutonium-239 present in the lungs. To obtain this information, after the analysis of plutoniun-239 and total alfa activity in urine had been carried out soon after the accident, on the persons who at that time were considered those most likely to have been internally contaminated, a selection was made from the people of Palomares, with respect to the following considerations: 1) Situation nearest to the points of impact of the fractional bombs, and the areas of greatest contamination at the moment when the accident occurred, therefore with the greatest possibilities of inhaling the aerosol created in the conventional explosions. 2) Stay in zones of highest contamination during the day of the accident and the following day. BEST COPY AVAILABLE 3) Residence, at the time of the accident and the days following it, in houses and areas of the town where a higher contamination had been found, within the lower limits where contamination was produced in the town, as may be seen from the plan of the contaminated area. DOE ARCHIVES 4) Situation during the accident and following it, in houses and areas of the town where contamination was nil, so that they could serve as controls, and at the same time we could find out with certainty whether a mistake had been made in not considering evacuation of the people of that area as necessary in the operations of contamination limit fixing and decontamination. Taking the above factors into account, a total number of 100 persons were selected, of which 49 were males over 14 years of age, 32 were females over £
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ley were taken to Madrid for the said tests to be carried out in the la vatories of the Division de Medicina y Proteccion de la Junta de Energia iclear. They first underwent a cor.plete nedical examination, in order to Ind out their state of health and take it into account in the study and subi order to determine the concentration of plutonium-239 excreted in urine, tree complete 2h-hour samples of urine were taken from each one of the said srsons, on three consecutive days. These samples were submitted to a lemical treatment in order to determine the content of the said element, by .fa spectrometry, on the final electrodeposit following a separation by ion le result of this analysis showed th*at in 71 per cent of cases there was no idication of the existence of plutonium-239, IS per cent showed, in some lalyses, contents of less than 0.1 disintegrations per minute in the urine : 24 hours, 9 per cent showed contents of between 0.2 and 0.1 disintegrations :r minute over 24 hours, and finally, 2 per cent showed a content of between .2 and 1 d.p.m. in the urine of 24 hours. taring in mind what these values represent on the alfa spectrum corresponding j the 1000-minute measurements taken, we have taken a deliberately pessimistic .ew, although in almost all cases they could be considered negative. i order to determine the pulmonary content of plutonium-239, measurements tre taken on all the previously-mentioned persons, with proportional ilmonary counters, considering the region between 10 KeV-23 KeV, where the . rays of uranium are found of 13.6, 17.4 and 20.2 KeV in an abundance of .> per disintegration. These counters consist of two gas flow proportional lanbers, with a capacity of 14 litres and a sensitive detection surface of '.4 x 30.1 cm each, 'which work with a mixture of argon (9C%) and methane .0ps) and which have been designed in the "Los Alamos National Laboratory" • Mr. P. Dean. The calibration of the said chambers was effected with a »int source of plutonium-239, and two sheets of metyl metacry late 2.54 cm lick to simulate the tissues of the thorax. iking into account the background of the chambers, the counting time and ieir efficiency, it was found that the minimum detectable value of .utonium-239 was 40 x 10“^ Ci. In the test made under these conditions, all (e values obtained were on the order of background, which indicates that the lount of plutonium-239 which might be found in the lungs, if any, would be ss them 40 nanocuries, a value which is quite encoui'aging, as the maximum missible pulmonary burden is 16 nanocuries. 'certain modification was made in the chambers which permitted the lowest .lue detectable to be reduced to 16 x 10”^ Ci. The measurements taken under ese conditions with some of that people showed that in no case did the JLues obtained exceed this figure. 'KTAMIIIATION OF THE GROUND BEST COPY AVAILABLE POE ARCHIVES has already been mentioned, the contamination of the ground surface was t homogeneous. In order to determine the degree of distribution, and what is distribution was on the surface, as well as its depth, after the operaons of decontamination, and those planned to eliminate surface contamination areas required, a study has been planned in order to find out -which these •e. We hope that it will permit us, as years go by, to discover the dynamics plutoniun-239 in cultivated land, both as regards its dynamics parameters,
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and those ii oduced by tillinc and cultivat i methods. for this purpose, six areas have been chosen of 50 each, two from each of the 3 zones into which the total contaminated area was divided, corres ponding to the two areas where the bombs fell and broke into fragments, and the intermediate zone where the town is situated. These areas were chosen in places which had remained most contaminated after the removal of a layer of earth on the areas which had contaminations higher than 700,000 d.p.m./ 100 cm^. Those in zones 2 and 3 comprise areas where total alfa contaminations were found to be between 700,000 d.p.m./100 cm^; area 2-1 belongs to a part where the upper layer of earth was also removed during decontamination operations. The areas in zone 5 showed contaminations of the order of In order to find the average background of total alfa activity on the ground of the zone, tv:o similar areas have been chosen, with similar geological characteristics end situated at 1,000 m. and 7,000 respectively from the zero line of the contaminated zone. In each of the areas, and in accordance with its diagonals, during the first year, 1966, nine samples were taken which were divided into fragments, corresponding to depths of 0-5, 5-15, 15-25, 25-35 and 35-45 cm. Of the homogenised samples corresponding to each fragment, two fractions of 0.50 gn. were taken, which were submitted to chemical treatment and alfa counting, in order to determine the total alfa activity. At present we are continuing to do this, and in successive years samples will continue to be taken at points in the same areas and following a preplanned distribution order in order to obtain complete knovrledge of the dynamics of the contamination, as well as to deduce the contamination factors of the vegetable products which are cultivated in them. In 1967 the number of samples taken was higher, with a factor of two, than that of the previous year. With these last samples, the tests have been not only to measure the total alfa activity, and consecuently, through its relationship with the values obtained in the background sampling places, and the high specific activity of plutonium-239, deduce what amount is due to the said plutonium-239. Besides radiochemical separations are being carried out for each of the The alfa activity of the soil in the region of Palomares (Almeria) is one of the highest in Spain, as has been shown in the comparison of results obtained from the background areas, situated fax' enough away to be certain that they were not contaminated, and those from othei-> provinces and types of soil, as may be seen from Table I. In order to give you an idea of the results we are obtaining, in Table II may be seen the average values of alfa activity from the samples taken in 1956 from each one of the zones, and in relation to depth. From these values it may easily be deduced that: 1) In zone 2-1, where a 5 cm layer of soil was removed, the remaining contamination is nil. 2) As a result of ploughing and breaking up of the ground, a distribution of contaminating elements have been obtained to a depth of 30 cm. Generally highest contamination levels are found in layers between 15 and 25 cm down.
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3) The maxiriun average, value of alfa activity found iiv-^the areas studied is approximately 50 tin; higher than the minimum value natural alfa activity found in the background soil of the zone, which in turn is two times higher than the minimums found in the areas studied. The unhomogeneous distribution of the contaminating particles, even after the ploughing operations carried out in order to dilute the radioactive ele ments, plutonium and uranium, on a layer 30-35 cm deep, is perfectly clear from the values obtained, as might logically have been expected. Even results from different samples from the same point and fragment, after the greatest homogenisation possible in the laboratory, show quite a considerable dis persion, as may be seen from Table III. On this table may be seen the values from all the analyses corresponding to each one of the fractions of ground which gave the highest alfa activity values, in area 2-2, one of those of greatest contamination. CONTAMINATION OF THE AIR A network of aerosoles sampling has been set up in order to discover what possibilities there might be of internal contamination of the people who live in the zone and cultivate the fields, as an isolated or related con sequence of the ploughing operations on the ground and the climatological characteristics of the zone* especially those related to the low rainfall and prevailing winds. This network consists of four sampling stations, and two for the study of the speed and direction of the winds. The samples stations are situated in the places marked on the figure S-l, S-2, P and 3-1, which respectively correspond to the zones where the two fragmented bombs fell, and one point at the urban centre of Palomares. Those for measuring the characteristics of the winds are situated at S-l and P. In each one of these stations, at a height of 1.70 m, continuous 24-hour samples are taken, -with a volume of approximately 95 n^, every day of the year, on membrane filter paper. The samples are prepared for sending to the laboratories of the Medicine and Protection Division of JEN, where in principle, a minimum of one week after they are taken, a count is made of the total alfa activity due to …
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