The Minnesota Pollution Control Agency (mpca) permit in the case of the Monticello nuclear generating station issued to Northern States Power Company was prepared by the mpca’s consultant, Dr. E. C. Tsivoglou, pur­suant to a long report on Monticello previously submitted by him to the mpca.

Dr. Tsivoglou sent a copy of his report to the International Commission on Radiological Protection (see p. 148 above for a description of icrp), the publications of which were referred to extensively in the report. Dr. F. D. Sowby, secretary of the icrp, sent Tsivoglou’s report to Mr. H. J. Dunster for review. Mr. Dunster is Deputy Division Head of the Radiological Protection Division, Health and Safety Branch, United Kingdom Atomic Energy Au­thority at Harwell, England. He is a member of the icrp’s Committee 4, on ap­plication of icrp recommendations, and chaired the icrp task group that pre­pared icrp Publication 7, Principles of Environmental Monitoring Related to the Handling of Radioactive Materials.

Mr. Dunster commented on the report in a letter to Dr. Tsivoglou. In a separate letter to Dr. Lester R. Rogers, Deputy Director of the AEC’s Division of Radiation Protection Standards, dated August 20, 1969, Mr. Dunster indi­cated that he expressed his views to Dr. Tsivoglou in his capacity as chairman of the task group for icrp Publication 7 and added with respect to his letter to Tsivoglou: “Lest you should think that some of this criticism might equally be aimed at the aec, particularly in respect of concentration limits, I should add that I recognise the legislative difficulties of establishing discharge rate limits in individual cases in a country as large as the United States, and par­ticularly having a federal organisation. . . The problem of Minnesota on the other hand, seems to me of a different character and I cannot see why, if they are to depart from common standards with the aec, they should not adopt a more logical approach. On a state scale, there seems no problem in setting dis­charge rate limits, which are at least reasonably closely related, if one takes the trouble, to human exposure.”

Mr. Dunster’s comments are to the effect that the environmental moni­toring requirements recommended by Dr. Tsivoglou are extreme and not in ac­cord with icrp Publication 7. In fact, it is indicated that Dr. Tsivoglou was working, partly at least, from “seriously out of date” icrp publications which have been replaced. He also expresses the view that the radiation standards recommended in Dr. Tsivoglou’s report misinterpret icrp recommendations. Mr. Dunster came to the conclusion that there are “some special political dif­ficulties” in Minnesota with respect to radiation control “which would make a logical programme limited to genuine needs unlikely to be acceptable.”

The Dunster letter, to which italics have been added, follows:

20th August 1969

Dr. E. C. Tsivoglou,

1974 Starfire Drive, N. E.,

Atlanta, Georgia 30329, U. S.A.

Dear Dr. Tsivoglou,

Dr. Sowby has sent me a copy of your final report on “Radioactive Pollu­tion Control in Minnesota” because I was chairman of the icrp Task Group that prepared icrp Publication 7.1 regret the delay in writing to you, but I had some difficulty in finding time to study the report in adequate detail.

Prompted by Science, 7th March 1969, and reading between the lines of your report, I came to the conclusion that there are some special political dif­ficulties associated with pollution control or the introduction of nuclear power into Minnesota, which would make a logical programme limited to genuine needs unlikely to be acceptable to the legislators. I thus read your report in the context of an attempt to get as close to a logical solution in the face of difficul­ties of this character. Even so, your proposals seem somewhat extreme and could certainly not be related to the recommendations of icrp.

The following comments are of a more detailed nature and the references are to your page numbers.

16. The central paragraph on this page struck me as being an excellent statement of policy, as did the remark about question and answer on page 20. It did not seem to me, however, that the recommendations of the report were based on these excellent principles.

27.1 do not think I agree with the last three lines of this page, in particu­lar with the reference to effluent concentration. I do not think standards for human radiation protection can in principle be related to effluent concentra­tion in any but the most unusual circumstances, when members of the public are directly exposed to undiluted effluent. In all other situations, it seems to me it is the rate of discharge in units of activity per unit time that is related to hu­man protection. A concentration in waste can be halved by doubling the flow of diluent but the dose to people in the environment will usually not be signifi­cantly affected by this change.

31 & 34. Both of these pages contain references to the complexity of con­

trolling environmental situations, but I am satisfied that a programme of en­vironmental measurements based on the recommendations of icrp Publication 7 would require less routine effort and expense than the programme you have suggested and would give a genuine assurance of safety. It would, however, re­quire more effort at the design stage. Nevertheless, I do not necessarily dis­agree with your argument that the primary standards should be those of efflu­ent discharge. If these are properly assessed and based on discharge rate rather than concentration, they can, and in your circumstances would, give complete control of safety. The monitoring could then be confined to the effluent dis­charges, apart from some confirmatory checks on possible critical pathways during the first year or so.

42. The icrp quotations on this and subsequent pages are seriously out of date. In my view, they were never particularly sound and the replacement ma­terial in icrp Publication 9 (paragraphs 44 and 74) and icrp Publication 7 (paragraphs 14-17) express the policy much more clearly. The earlier ap­proach and your material fail to take into account the effect of critical path­ways other than those through air and water. Further, the individual limit of 1/10 was always, in practice, the limiting case. If individuals, including chil­dren, are limited to 1/10, then the average population dose is always much less than 1/30 of the relevant dose limits. I think from your text that you are suggesting applying the 1/30 figure to the concentration in the air and water, expressed as an average over a local population, and not over a national popu­lation. You are then apparently hoping that this will protect the individual within the distribution of exposures in the local population. This has never been the way icrp intended these numbers to be used. They were intended as separate limits, both of which had to be considered, and, at the time, the Com­mission believed that there might be circumstances in which the average popu­lation dose was the limiting one rather than the dose to individuals. The situa­tion has been further confused by the use of the same factor of 1/ 3 for provid­ing protection to individuals when monitoring was done by sampling over broad averages, e. g. over whole milk sheds. It is now clear that the figures of 1/10 and 1/30 used for individual and population limits are not both neces­sary. In any event they can only be applied to genuinely critical pathways, and if applied to air when inhalation is not the critical pathway, as with iodine, they are demonstrably dangerous.

57.1 like the second and third lines of this page and can only regret that you have not achieved your intentions. I can say categorically that the radio­activity standards you have recommended are not based on icrp recommenda­tions.

59.1 must take exception on behalf of icrp to the first sentence of your item (5). ICRP limits for continuous occupational exposure are expressed in terms of concentrations in air which is breathed or water which is to be con­sumed or, more fundamentally, in dose to individual organs of the body. It is a travesty to use these as a basis for limiting the concentration in an effluent, unless the effluent is directly consumed or directly breathed and these are gen­uinely the critical pathways concerned.

This is not to say that discharge limits cannot be derived from icrp rec­ommendations. They can and should, but the methods involve assessing a re­lationship between the discharge or discharges and the doses to critical and other groups. The dose level selected as a basis for control can then be the icrp dose limit or a lower figure chosen as a compromise based on keeping doses “as low as is readily achievable, economic and social conditions being taken into account” (icrp Publication 9, paragraph 52). The needs of the operator and his economic pressures can be considered also at this stage. The final doses to people and the concentrations in air, water, foods, etc., in the environment will not then be directly related to any numerical recommenda­tions of icrp, but the control structure will be in accord with the general pol­icy expressed in the Commission’s recommendations. These methods have the additional advantage of flexibility, in that the numerical limits applied to one operator can logically be made different from those applying to another whose discharges behave differently in the environment. The basic standards are the same, the practical standards can take into account the different environ­mental situations, and the different compositions of the wastes. Indeed, this flexibility can even be carried to the lengths of expressing the discharge limits in terms of concentration in circumstances where the total volumes discharged are known to be limited and where the quantity to be discharged is very small. A typical example might be a concentration limit applying to hospitals other than those using radioisotopes for therapy. The appropriate limit would be de­rived on the principles outlined above and would not necessarily bear any re­lationship to the mpc’j for drinking water recommended by the Commission.

61. In your item (c) there seems no justification for discussing concentra­tions. If an individual assessment is being made in a claim for a variance, there is surely no reason why the basis of the claim should not be expressed in terms of dose to individual members of the public rather than in terms of concen­tration. In any event, you should surely specify concentration in what.

89.1 find it difficult to agree with the last few lines of this page because it seems extremely unlikely that an offsite monitoring programme of the type you recommend will contribute anything to elucidating the remaining areas of uncertainty.

112. The first sentence of the paragraph starting in the middle of this page is not convincing to me in regard to the proposed reactor and is demonstrably false in respect of the final few words. There are gaseous wastes from hospitals and other licensed users of small amounts of radioactivity but it is certainly unnecessary to conduct environmental monitoring programmes in relation to these wastes. They are too small for this to be required. Even for the liquid wastes from these users environmental monitoring is usually unnecessary though may be adopted in areas of high concentrations of licencees. icrp Pub­lication 7, paragraph 1 makes it clear that the Commission does not expect environmental monitoring programmes round the majority of installations.

135. The recommended programme in this summary table is not con­sistent with icrp recommendations. If it is adopted, it will involve the citizens of Minnesota in higher taxes and higher charges for nuclear electricity than necessary. They may wish to incur this additional expense and this is of course their inalienable right. However, I am not convinced that they will be getting value for money and am certain that the expense cannot be laid at the door of ICRP.

I am sorry to have expressed these criticisms at such length, but a con­siderable amount of effort and discussion went into the formulating of Pub­
lication 7. It has subsequently been criticised as doing little more than state the obvious, but I am now convinced even more of its importance. I am sorry to see that it has not had the expected impact in Minnesota.

cc. Dr. F. D. Sowby, icrp