The matter I wish to raise tonight is one of transcendent importance to every man, woman and child in this country, and, indeed, to the human race, namely, the hazards which are created by nuclear fission. Let me say, at the outset, that I am not raising this matter in an alarmist spirit. My whole intention is to give the Government, through the Minister, an opportunity of placing the whole matter in proper perspective. There is an abundance of data on this question, but it is remarkable how inconclusive it is and how contradictory the expert interpretations of this data can be, and it is to the Government that we must turn for final authority. In this matter, above all others, they have the duty of clarity.
The matter is of particular interest and concern to us in North-West Wales for two reasons: first, the projected building of two nuclear power generating stations in the area; and, secondly, there have been recent reports that the incidence of strontium 90 in the area is far higher than the average for the country and that it is increasing.
Let me take the question of the nuclear power stations first. Clearly, the hazard which they notionally present is quite different in origin and in controllability from the other kind of danger. In common with the great majority of the people of the area, I have very strongly welcomed the intention to build these two stations, as my hon. Friend the Member for Merioneth (Mr. T. W. Jones) has done. One of them is now being built in Trawsfynydd, in Merioneth, and we very much hope to see the second go up in Edern, in Caernarvonshire, in my constituency. We regard them as examples of a new, beneficial industry of the future which will provide constructive employment in an area at the head of the queue which is waiting for work.
My own view, not one reached hastily but after considerable inquiry and study, is that such installations are at least as safe for the workers and local population as most other industries. That is my view. There are, however, fears expressed in some quarters that such establishments constitute a fearful hazard. To clarify the position, I should like to put a number of questions to the Minister. The Windscale mishap is widely quoted by critics of these stations. Is it correct to say that that kind of accident is not technically possible in the type of reactor which is projected in the Trawsfynydd installation and the other new stations?
Secondly, there are suggestions that those stations are subject to seepage or leakage of radioactive matter which could adversely affect the health and safety of human beings, animals in the locality and also of vegetation. What truth is there in that? Is it correct to say that what leakage there may be is so small as practically to be harmless?
Thirdly, can the Minister reassure us about the disposal of radioactive waste? What method of disposal will be adopted with regard to an inland station like Trawsfynydd and to a coastal station like the one projected at Edern, and will the results be harmless to the population, agriculture and fisheries in the area?
I turn to the second part of the inquiry I made. The reason we want the maximum assurance about the safety of the stations is that, after all, they are to be built in an area where the intake of strontium 90 is as a result of nuclear explosions throughout the world is already higher than in the country generally. It is quite well known that parts of Wales, like parts of Cumberland, Scotland and other districts in the United Kingdom, show a greater intake of this substance as a result of the fall-out from nuclear explosions.
This factor, naturally, has attracted the anxious attention of some of the foremost scientists. I call to mind two outstanding Welsh scientists who, very properly, have made a special study of these peculiar conditions in Wales, Dr. Glyn Phillips, of Cardiff University College, and Dr. Eirwen Gwynn, of Criccieth, both of whom have written ably and responsibly about these hazards.
Recently, the Medical Officer of Health for the Borough of Caernarvon and the rural district of Gwyrfai—also a Dr. Phillips, Dr. E. A. Phillips—presented a report to those two local authorities in which he explained how in areas of high rainfall like North-West Wales the rate of deposition of strontium 90 on the ground and on foliage is very much higher than in other areas. He says that it may be passed to humans through their intake of water, milk, vegetables and meat. He further points out that both the soil and the drinking water of this area are deficient in calcium for which strontium 90 is a hideous and intrusive substitute.
The medical officer of health gives figures to show what the position is. I will quote only a selection tonight, contenting myself with sending to the Minister the officer's full report. Recent tests of drinking water in North-West Wales have shown that the radioactivity in terms of strontium 90 micro-curies per litre was 5·6 and 5·2. These figures are equivalent to 7 per cent. of the international maximum permitted limits for radioactivity in drinking water, and, expressed as the maximum permitted limit for Thames water, this would be 28. The report also quotes figures showing that the extent of strontium 90 detected in humans, animals and vegetation in these areas is considerably higher than in others, and there are suggestive facts about the indication in such areas of peculiarly dreaded diseases.
The question is what conclusions should we draw from these figures. I sometimes think that ten times practically nothing is still practically nothing, but there is need for greater clarity and precision as between the Government and the general public, and perhaps officers in various departments of the public service. These figures certainly provide grounds for concern. My question is: do they provide grounds for alarm? Are the Government alarmed? We think that the official interpretation of these figures should be made absolutely clear, and I join with my hon. Friend the Member for Brecon and Radnor (Mr. Watkins), who has most advisedly been pressing the Prime Minister to make the position clear in terms which the average layman can understand.
What the medical officer of health in question has done is simply to draw attention to the facts. Very wisely and responsibly he and the authorities whom he serves have refrained from interpreting them. We feel that the burden of interpretation is on the Government, and I hope tonight that the Minister can put the whole matter in clear perspective so that we may avoid both complacency and alarmism in this vital matter.
There are one or two specific questions on this matter of area susceptibility to strontium 90 which I will put as briefly as I can. First, what is the hazard that faces these areas of high rainfall and low calcium? Can it be defined and measured? Secondly, is there now an authoritative assessment of the true safety level of absorption of these substances? Thirdly, we know that tests for radioactivity in humans, animals and vegetation are now carried on in three places in Wales—in Talgarth, Cwm Ystwyth and Lake Vyrnwy. Should not these tests be conducted in other parts of Wales and, indeed, in the United Kingdom, and proper records kept?
In sum, what we seek tonight is: first. a reassurance—which I think the Minister can give—about the safety of these new nuclear stations; and, secondly, an expression of a sense of perspective and clarity in regard to the position in what are now known as the susceptible areas in the United Kingdom.
I am grateful to the hon. Member for Caernarvon (Mr. G. Roberts) for raising this matter. He will agree that at this late hour and in the small amount of time available I cannot go into great detail. Fortunately, there will be an opportunity very shortly, when the Government present the Nuclear Installations (Licensing and Insurance) Bill, to go into these matters more thoroughly.
I will, if I may, cover in reverse order the two heads of the hon. Gentlemen's questions. I will take the one he puts second first because it is a little more complicated than the one about the nuclear stations themselves. This is, of course, a highly technical matter, and I do not pretend to be a medical expert upon it. Fortunately, there is more or less general agreement between the Medical Research Council, the body which is the principal adviser of the Government on this matter and which is of the highest standing, and the United Nations Scientific Committee which has issued a Report, which the hon. Gentleman may have seen.
I think that it is fair to say that a good many of those who have been in the opposition, if I may put it that way— I will not say alarmist—have been people who, while they are, in many cases, scientists of very great eminence in other fields, are not, by and large, working in this particular field.
Speaking as a layman, as the hon. Gentleman asked me to do, I would say that the first point we should be clear about in understanding the situation is that these radioactive isotopes— strontium 90, caæium, iodine, and one or two others—all have physical half-lives. Some die away faster than others, strontium in a matter of years, some of the others in minutes. What is more important, and, perhaps, not so widely realised, is that there is a biological half-life, too. The whole body is perpetually renewing itself. Even the bone structure is changing, and, therefore, the rate of elimination of these things from the human body is faster, and the equilibrium level to which they build up is very much lower than would otherwise be the case. Not only is that so, but— and this is very important—there is, as it were, a series of filters through which these things go.
To take radioactive strontium in particular, what happens is that it is washed down from the stratosphere and goes on to the ground. Only a small proportion of what goes on the ground comes up in the grass, and only a small proportion of what comes up in the grass goes through the cow and comes out in milk. Speaking in very general terms, it is only about one-sixth. Only a small proportion of what goes into the human body with the milk goes into the bone, and that is what matters.
I will take a case which, at least at the beginning, is very well known to the hon. Gentleman. In Cwm Ystwyth, strontium units of radiation—I will come to that unit of measurement in a moment —of between 120 and 180 have been stated to occur. But the maximum coming out in the milk of the cow is about 30. The equilibrium level for the build-up of that in the bone would be between five and six. It is, therefore, very important that the public should have clearly in mind that measurements of what is, so to speak, lying about, though I do not say they are irrelevant, do grossly exaggerate the risk.
Next, we should be clear that measurements of strontium units can lead to a great deal of confusion. Even the Medical Officer of Health for the Borough of Caernarvon is reported to have stated that he was under the impression, although he may have been wrongly reported, that the radioactive danger in drinking water, for instance, could be measured in terms of these so-called strontium units. Of course, they are quite inappropriate for that purpose.
I can illustrate the absurdity of using them, which might cause alarm, in this way. They are related to measuring the relation of radioactive strontium to calcium which the body takes in, because that is how they start building up in our bones. If we were to put all the drinking water in this part of Wales through a perfect softener, so that there was no calcium whatever in the water, measured in strontium units it would be infinite, but we would not have increased the radioactive strontium that the body was taking in. There would be no difference whatever in the danger to health in drinking it. I assure the hon. Member that, in fact, the best evidence we have is that he could go on drinking this water for ever without its having the slightest effect on his health.
The next thing which I should like to make quite clear is the truth about the increase in the amount of radioactive strontium which is coming down on us from the stratosphere. It is true that it is increasing. It is not true that the rate of fall is, by and large, increasing. The best advice we can get is that if it went on falling at its present rate for several generations the equilibrium level at which it would build up in the bones of the population would still be well within what I might call the "amber" band. That is not when it becomes definitely dangerous, but the period when, as the Medical Research Council said, definite action would be called for. The best analogy would be the amber light and not the red light.
If the present rate of increase went on for two or three generations, it would still correspond to an equilibrium level in the bones of the general population which, while not necessarily being desirable, would be well within only the warning limit and not rise to a level of serious danger. Of course, without going into the politics of tests, and so on, it would be a very depressing prospect if we were to go on doing tests of this kind for the next sixty or one hundred years.
I ought to say a word, in passing, on the question of leukaemia. I am advised that this rare disease is a cancer of the blood; it sounds peculiarly unpleasant, but it is a very rare disease. It is true that it is increasing, but, to show the difficulty of the problem, the increase began a generation before the first tests. It had been increasing for about thirty years before strontium 90 began descending upon us. Not only that, but the rate of increase did not show any particular jump when this outfall of strontium from the stratosphere began. That is a curious thing, but there are many curious things in biology.
The second thing that we should bear in mind and which can give us some reassurance is that in a rare thing of this sort, one must be very careful with statistics. It is possible to get absurd figures of percentage increases when dealing with ratios of about one in 1 million. I am, however, advised that there are at present no statistically significant differences, either by area or in time, in the incidence of this disease.
So much for the general picture of the hazards from fall-out. Admittedly, it is increasing, but it is far below any danger level, and all the indications are that it is likely to remain so. There is no need for alarm.
There is no statistical difference between North Wales and other parts of the United Kingdom. It is like trying to find out the number of people who die through being kicked by a horse; there is no statistical significance. I am advised that it is within the margin of error. There is an increase of leukaemia, but that has been going on for a long time and it is no indication of any need for alarm.
Against this background, we have to think of the area where, because of extra rainfall, for example, more of this radio-strontium descends on to the ground and two, or certainly one, nuclear power station is to be built. In normal operation —and I am speaking with extreme brevity —I am able to assure the hon. Gentleman that there are certain radioactive substances which may go up the stack, but they are of such short life that they can be ignored. Seepage has been referred to, and I think that that, too, can be ignored.
There may be circumstances in which portions of coolants might be released, but the monitoring is done with such extreme care and there are definite arrangements which in due course will, no doubt, be turned into legislative arrangements to ensure that radioactive effluent is most carefuly controlled. The short answer is that in normal operation there are few branches of British industry that take such intense care to see what is going on; few branches where there is such care to see that what is going on is properly controlled.
The second matter with which we are concerned is the possibility of accidents, and here there is a different position from that concerned with the ordinary fallout of strontium. Nobody suggests that there will be a series of accidents in any one of these plants, so we have to think of what the maximum temporary emission of radioactive substances is. It is here that it is important to remember why the Windscale accident is irrelevant to this matter. It must be pointed out that no damage to health was done to anybody by the Windscale mishap. It was unnecessary, we believe, to have dumped all that milk, but we were being extra careful.
The Windscale accident took place as a result of the release of Wigner energy, but that type of release will not be necessary in the new stations. The second reason is that the coolant was air. Uranium burns in air, although it does not burn at anything like the same temperature in carbon-dioxide, which is the coolant in power stations. The coolant at Windscale was also an open system and the air went up the stack. Anything radioactive went up with it, but at Trawsfynydd and other stations, there is to be a closed system, and the carbon-dioxide does not go outside the system. It is in a very carefully tested circuit, so that there would have to be extraordinary circumstances for large quantities to leave the system.
I can reassure the hon. Member. I hope to have the opportunity of saying more on this subject at a later stage, but he will be doing a good service to his constituents if he assures them that Britain is in the forefront not only in constructional ingenuity, but in safety devices in this field.