First Results from the Programme of Action Following the Palomares Accident

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FIRST RESULTS FROM THE PROGRAVME OF ACTION FOLLOWING THK PALOMARES ACCIDENT. Junta de Energfa Nuclear - Madrid - Spain. US DOE ARCHIVES 826 UJS. ATOMIC ENERGY SYMPOSIUM ON RADIOLOGICAL PROTECTION OF THE PUBLIC IN A NUCLEAR MASS DISASTER Mitgliedsgeaellschaft der International Radiation Protection Interlaken 26 May - 1 June 1968 BEST COPY AVAILABLE

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FIRST RESULTS FROM THE PROGRAMME OF ACTION FOLLOWING THE PALOMARES ACCIDENT Junta de Energla Nuclear - Madrid - SPAIN. In reply to ihe kind invitation of the Fachverband filr Strahlensohutz, we would like to give an idea of the work which is being carried out in connection with the wellknown Palomares accident, and give indica tions of seme of the general results obtained, with the idea that in the Symposium on Agricultural and Health Aspects of Radioactive Contami nation in Normal and Emergency Conditions which is going to be held 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 Janua ry 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 iolal area of approximately 226 hectares, of which 2.2 hectares had en alia conlaminition of more than 700,000 d.p.ta/lOO cm , being the areas closest to the points of impact of the two bombs, which were 2,PCC 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 cm , and the rest, some 207 hectares, showed contaminations of less than 70,000 d.p.m/100 cm , rather more than half of theee being less than 7,000 d.p.m/100 cpn . . A great proportion of the houees of the town w re either well nul oj the contaminated area, or in the parts where contamination levels were lowest. The number of persons who were ir the town al the of the accident was approximately 1,000 - 1.2D0.

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In another communication presented to this Symposium, it has been ex plained how the limits of the said zones were fixed, the decontamination operations carried out, and steps taken with people and vegetation at a time soon after the accident. Here we are going to deal with, although in a somewhat summarised form, the work plan devised for the vigilan ce of the people and the area, and the deduction of the consequences which might, in the future, result from such an accident and the measu res which were taken. Our greatest worry, as is logical, was to determine whether or not there was internal contamination by plutonium-239 of the persons present in the area during the moments following the accident, what possibilities there were of contamination during the period of time when the operations of limit-fixing 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 This risk might be derived from: 5a) inhalation of plutonium if, as a consequence of the tilling of the land, and the winds which eve present, an aerosol, contaminated with the said element, i$ c< cated, which reach a definite diffusion. b) contamination as a consequence of tilling operations on ground where a certain quantity of plutouium-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

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We make the reservation that there ie 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 drin king water which the public consumes is brought from a distance of 50 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. CONTAMINATION IN PERSONS 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 orden to de termine the fraction which could have passed the pulmonary and lympha 2) Determination of the quantity of plutonium-239 present in the lungs. To obtain this information, after the analysis of plutonium-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 Paloma res, 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 occu rred, therefore with the greatest possibilities of inhaling the aerosol crea ted in the conventional explosions. DOE ARCHIVES 2) Stay in zones of highest contamination during the day of the accident and the following day.

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3.) Residence, ai the lime of the accident and the days following it, in houses and areas of the town vifjere 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, 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. Talcing 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 14 years of age, 10 were males under 14 years, and 9 were fema les under 14 years. They were taken to Madrid for the said tests to be carried out in the la boratories of the Divisidn de Medicina y Proteccidn de la Junta de Energfa Nuclear. They first underwent a complete medical examination, in order to find out their state of health and take it into account in the study and subsequent epidemiological control. In order to determine the concentration of pluloniuxn-239 excreted in urine, three complete 24-hour samples of urine were taken from each one of the said persons, on three consecutive days. These samples were submitted to a chemical treatment in order to determine the content of the said ele ment, by alfa spectrometry, on the final elecirodeposit following a separa tion by ion exchange resins. ______ The result of this analysis showed that in 71 per cent of cases there was no indication of the existence of plutonium-239, 18 per cent showed, in so me analyses, contents of less than 0.1 disintegrations per minute in the urine of 24 hours, 9 per cent showed contents of between 0.2 and 0.1

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disintegrations per minute over 24 hours, and finally. 2 per cent showed s content of between 0.2 and 1 d.p.m. In the urine of 24 hours. Bearing in mind what these values represent on the alfa spectrum corres ponding to the 1000-nunute measurements taken, we have taken a delibe rately pessimistic view, although in almost all cases they could be consi In order to determine the pulmonary content of plutonium-239, measure ments were taken on all Ihe previounly-mentioncd persons, with propor tional pulmonary counters, considering the region between 10 KeV-28 KeV, where the XL, rays of uranium are found of 13.tj, 17.4 and 20.2 KeV in an abundance of 4% per disintegration. These counters consist of two gas flow proportional chambers, with a capacity of 14 litres and a sensitive'tli-etection surface of 17.4 x 30.1 cm each, whch work with a mixture of argon (90%) and methane (10%) and which have been designed in the "Los Alamos National Laboralory""by Mr.P. Dean. The calibra tion of the said chambers was effected with a point source of plutonium- '239, and two sheets of mety! metacrylate 2.54 cm thick to simulate the tissues of the thorax. r“ & Taking into account the background of the chambers, the counting time and their efficiency, iy was found that the minimum detectable value of pfbtonium-239 was-^O x 10 Ci. In the test made under these conditions, all the values obtained were on the order of background, which indicates that the amount of plutonium-239 which might be found in the lungs, if any, would be less than 40 nanocuries, a value which is quite encouraging, as the maximum permissible pulmonary burden is 16 nanocuries, ^_ A certain modification was made in the chambers which permitted the loCi. The measurements

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case did the values obtained exceed this figure. CONTAMINATION OF THE GROUND As has already been mentioned, ihe contamination of the ground surface was not homogeneous. In order to determine the degree of distribution, and what this distribution was on ihe surface, as well as its depth, after the operations of decontamination, and those planned to eliminate surface contamination in areas required, a study has been planned in order to find out which these are. We hope that it will permit us, as years go by, to discover the dynamics of plutonium-239 in cultivated land, both as re gards its dinamics parameters, and those introduced by tilling and culti For this purpose, six areas have been chosen of 50 m each, two from each of the 3 zones into which the total contaminated area was divided, corresponding to the two areas where the bombs fell and broke into frag ments, 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 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 shoIn order to find the average background of total alfa activity on the ground of the zone, two 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. DOE ARCHIVES In each of the areas, and in accordance with its diagonals, during the first year, .1966, nine samples were taken which were divided into frag ments, corresponding to depths of 0-5, 5-15, 15-25,25-35 and 35-45 cm.

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Of the homogenised samples corresponding to each fragment, two fractions of 0.50 gm. 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 pre planned distribution order in order to obtain complete knowledge of the dy namics of the contamination, os 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 pre With these Iasi samples, ihe tests have been not only to measure the total alfa activity, and consecuently, through its relationship with the values ob tained 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 far enough away to be cer tain that they were not contaminated, and those from other provinces and types of soil, as may be seen from Table I. In order to give you an idea of the results we ere obtaining, in Table II may be seen the average values of alfa activity from the samples taken in 1966 from each one of the zones, and in relation to depth. Prom these values it may easily be deduced 1) In zone 2-1, where a 5 cm layer of soil contamination is nil. . 2) As a result of ploughing and breaking up of contaminating elements have been obtained was removed, the remaining of Ihe ground, a distribution to a depth of 30 cm. Genera-

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lly highest conlam'mai.ion levels are found in layers between 15 and 25 cm 3) The maximum average value of alfa aoUvily found in the arees studied is approximately 50 times higher than (he minimum value of natuial alfa ac tivity found in the background soil of Ihe zone, which in turn is i.wo times higher than the minimums found in the areas studied. The unhomogeneous disliibution 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 frcm different samples from the same point and fragment, after the greatest homogenisation possible in the laboratory, show quite a considera ble dispersion, 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 frac tions of ground which gave the highest alfa activity values, in area 2-2, one of those of greatest contamination. CCNTAMI TAT ION OF THE AIR A network of aerosoles sampling has been set up in order to discover ' /hat possibilities there might be of internal contamination of the people who live in the zone and cultivate the fields, as an isolated or related consequen ce of the ploughing operations on the ground and the climatological characte-

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of i.he speed a.tl diiection ol the -winds.. The samples stations are situa ted in the places marked on Ihe figuie S-l, S-2. P and 3-1, which res pectively correspond to the zones where the two fia^menled bombs fell, and one point at the mi nan i t-nire of Pajoma t es. Those lor rncasniing the n.iaractt risliv-s ot tlie winds ate situated at S-l and P. In each one ol ien, with a volume of appi oxnnnlely 95 m , every day of the year, on m-rmbrane filler paper. The samples are prepared for sending to the labo ple, a minimum of one week after Ihey are taken, a count is made of ihe …