that one will find in any measurement of a fallout field. But for planning purposes we use that t-1.2 rule.

Mr. ROBACK. Does the Defense Atomic Support Agency have a formula which is different from that t-1.2 rule?

DEVELOPMENT OF t-1.2 RULE

Major STEBBINS. Before I answer let me attempt to summarize a little bit of the data that we have, and how one goes about attacking this particular problem.

Some years ago Way and Wigner developed a rule which attempted to define how the radiation levels from mixed fission products decays over a period of time. I believe it was in about 1942 or 1943, before a bomb had even been exploded. At that time they came up with this t-1.2 rule. The fact that it came out as a power relationship was based on a standard analytical procedure. They had some data which showed at early times there were very high rates, and at later times there were very low rates. An easy way to display their data was to put it on logarithmic paper. And as a first approximation, if you have two points on logarithmic paper and draw a line between those two points and measure the slope of the line this automatically gives a power rule; t-1.2 was their estimate at that time.

Later, when we had some actual bursts, sure enough, there were many cases where t-1.2 gave results which were compatible with the

rate at which the radiation levels fell off in those fields. However, there were other fields and samples for which it didn't work too well. If you put the high dose rates at early times and the low dose rates at later times from these fields on logarithmic paper and draw a straight line between the points, you would say, well, it decayed at t-0.9 or t-2.0

So we had this experimental data, and it wasn't too satisfactory in the sense that it provided an envelope much like the envelope that we heard mentioned today in discussing other matters. But we were trying to find a simple expression which would be good for planning purposes under many conditions of burst, including those we hadn't actually tested.

The Naval Radiological Defense Laboratory in San Francisco has for a long time studied the behavior of mixed fission products. In their studies they have developed rates of dosage one would expect to get from a certain kind of mixed fission products spread out on the ground in a uniform manner and over, say, a hard smooth plane, to a person 3 feet above this hard smooth plane, at certain times after the burst.

It was evident from this theoretical approach, using the known half life of various materials and the known gamma ray energies from these various materials, that the dose did not follow the t-1.2 rule, but it did diminish in time. Sometimes it was above this line, and sometimes below this line.

In the Defense Atomic Support Agency we refined this particular analytical approach by taking into account possible fractionation of the debris. By that I mean that as fallout comes down in different places it is not representative of the radioactive members of the debris

as they were originally distributed within the fireball. There are several physical phenomena which cause fractionation. As a rule in local fallout, it appears that we get a diminished amount of materials which have rare gas precursors, or which have low melting points and are consequently condensed on smaller particles that fall out farther away from the close-in fallout.

An attempt was made to subtract out these elements which might not appear in local fallout in as great a fraction as they do elsewhere in fallout, say in a worldwide fallout.

In addition, the original NRDL analysis was based on thermal fission of uranium 235. For the larger weapons the megaton weapons, it may be more appropriate to use fast fission of U238. And in addition, you will get induced activities in uranium 238 that captures the neutron without fission but rather becomes neptunium or plutonium, or uranium 237—one neutron goes in and two neutrons come out.

Major Dolan in our organization went through an analysis of this particular situation. We made available to the committee last year the results of Major Dolan's work in a paper prepared by Lieutenant Moreland which appears on page 561 of the previous hearing.

(The following additional information subsequently was received:) The analysis performed by Lieutenant Moreland was summarized by Dr. York and appears on page 521 of the previous (1960) hearings. In this summary Dr. York states: “* * * The t-2 rule is sufficiently accurate for almost all prediction problems from less than 1 hour to approximately 100 days after the shot * *. In any real situation one would measure the fallout field in order to establish the actual value at that time * * * after a few days or weeks, it is extremely conjectural to attempt prediction of dose rates because rain, snow, wind, and other weathering effects will in almost all conceivable cases alter the decay rate✶ ✶ ✶"

238

In order to improve on their previous work, NRDL prepared an additional theoretical study on the possible decay rate in a fallout field. This study used fission spectrum neutrons to produce additional fissions in Us and took into account fractionation factors. The results of this study, along with the induced activities calculated by Major Dolan, were used in the preparation of the final decay curve which is to be presented in the revision of the "Effects of Nuclear Weapons." This final curve is remarkably close to the t-12 rule throughout the period from the 1 minute to 200 days. The difference between the two is no more than 25 percent for short periods. After 200 days, which is longer by far than the period of major concern in which lethal acute doses can be delivered, the theoretical decay rate diminishes faster than the t-1,2 rule. This has the effect of altering the infinity dose but not the dose of greatest significance.

To answer the original question, DASA has used several different approaches in evaluating the problem of predicting the levels of activity in a fallout field as these levels diminish through radioactive decay. Each approach has produced slightly different curves but the more refined curves differ little from the original t-12 rule during the times of interest.

It should be emphasized that substantial departure from the above rule should be expected in a real situation and the actual decay rates and accumulated doses should be verified by actual instrument measurements as frequently as possible.

Mr. ROBACK. In the light of these several different possibilities and several estimates by formulas, is it wise, or does it make sense, on a practical basis for the Department of Defense or the Atomic Energy Commission, or whoever has the responsibility, to lay down what are

the recommended radiation decay assumptions for civil defense planning purposes?

Major STEBBINS. Well, we attempt to describe in some detail the phenomena that occur when the bomb bursts.

Mr. ROBACK. You are giving people many choices, you are telling them all the possibilities.

I am asking you whether it makes sense to say from a civil defense planning standpoint that this is what you should be guided by, this is the best one can say as a general proposition. The testimony has been that the t-1.2 rule is still basic for that.

Major STEBBINS. That is right. I think that is appropriate to say. As far as the effects of nuclear weapons are concerned, we do not make specific recommendations on it.

Mr. ROBACK. That is not your job, that is the policy of the civil defense planners?

Major STEBBINS. That is right.

Mr. ROBACK. Are you worried about that, Mr. Yarmolinsky?

Mr. YARMOLINSKY. I want to add, Mr. Roback, that while we use this formula where we need a formula, we also base our planning on the assumption, and indeed on the fact, that there are established large numbers of radiation monitoring stations, and larger numbers are being established. We have asked for funds in our budget to buy an additional 90,000 survey meters in order to provide specific information for planning at the time. Since local conditions vary so much, we are basing our planning on the assumption that the specific information has to be obtained on the spot.

BUDGET FOR NEW PROGRAM

Mr. ROBACK. Will you submit for the record a breakdown of the new budget request for civil defense into its components?

Mr. YARMOLINSKY. I will, indeed, sir.

Mr. ROBACK. And will you submit to the committee an analysis and costing of the provisioning of shelter?

Mr. YARMOLINSKY. Yes.

Mr. ROBACK. And also a breakdown analysis of the upgrading costs-improvement costs?

Mr. CANNELL. This third aspect won't be available until the survey is completed. That is part of the data we gathered.

Mr. ROBACK. Let me ask you this, Mr. Cannell. You probably had something to do with the input on the cost figures, have you not? Mr. CANNELL. Yes. And I am aware of the deficiency in this area of approximating the cost of the improvement phase.

Mr. ROBACK. There is a figure in the budget for improvement, isn't there?

Mr. YARMOLINSKY. There is a figure, yes, but it is not based-
Mr. ROBACK. As distinguished from the figure on marking?

(The following information subsequently was received:)

Department of Defense budget request for civil defense functions, fiscal year 1962

Insofar as analysis and cost breakdown of the provisions and plans for stocking shelters are concerned, we will not be able to supply information of a more definitive character than that indicated in the budget breakdown, above, until the program is further along and studies have been completed. Likewise, it will not be possible to supply information as to the cost of upgrading existing shelters until a later date since the accumulation of such information is one of the purposes of the planned survey program.

RADIATION MONITORING STATIONS

Mrs. GRIFFITHS. Are the monitoring stations going to be protected from blast?

Mr. YARMOLINSKY. I am afraid I just don't know to what extent fallout protection is available for them. I will supply that for the record.

(The following information subsequently was received:)

FALLOUT PROTECTION OF MONITORING STATIONS

The OCDM national plan, appendix I, annex 23, item II, section 2, indicates that radiation measuring devices should be located in areas protected from fallout. Many of the present radiation monitoring stations are located in basements or other areas where danger from fallout is reduced. The protection afforded these stations, however, is the responsibility of the State and local civil defense organizations.

We understand that the OCDM has had no plans to improve the fallout protection afforded radiation monitoring stations. We are developing plans to improve the fallout protection of monitoring stations.

Mrs. GRIFFITHS. Is it the theory of the monitoring station that it will be able to disseminate information as to the radioactivity of the air?

Mr. YARMOLINSKY. The theory of the monitoring station, as I understand it, is that monitoring stations which are still manned after the attack will be able to disseminate this information to control points, and from there to central headquarters.

73266-61- -10

Mrs. GRIFFITHS. And what does it depend upon for such dissemination? Does it depend upon the fact that you will still have intact some type of communications system other than word of mouth?

Mr. YARMOLINSKY. It depends on the radio communications backup, largely, on the assumption that most of the landlines will be out.

Mrs. GRIFFITHS. So that if an isolated group of people have survived, and they were not in contact with any monitoring station, they could then die because they didn't have the information?

Mr. YARMOLINSKY. The assumption is that the source of information for isolated groups will not be a hardened communication system, but rather communications from the emergency broadcasting system which is being hardened and which is being picked up on the regular conelrad frequency.

Mr. CANNELL. And instruments stored in the shelter.
Mrs. GRIFFITHS (presiding). Do you have other questions?

STATUS OF BATTLE CREEK OFFICE

Mr. ROBACK. Just one more.

I have a newspaper reporter in the audience who wants to know about Battle Creek. Can you tell us anything about Battle Creek?

Mr. YARMOLINSKY. I can tell you only that we visited Battle Creek yesterday, a number of us went out from the Department and met with the people in the installation out there and with a number of the members of the chamber of commerce and others. We went through the facility, met the heads of the various departments, and collected a good deal of information, which we will have to think about now that we are back home.

We are certainly not in a position now to reach any decisions about the organization and use of the Battle Creek facility.

Mr. ROBACK. As to whether it will be retained or not?

Mr. YARMOLINSKY. It is just too soon to say.

Mrs. GRIFFITHS. Any further questions?

Thank you very much for your testimony.

I believe that the reporter failed to get the answer to one of the questions I asked you.

Will you please supply it for the record?

Mr. YARMOLINSKY. Yes.

Mr. ROBACK. May I remind you that tomorrow the Atomic Energy Commisison will have representatives here to discuss in rather considerable detail the problems of radiation and effects.

Mrs. GRIFFITHS. Thank you very much.

(Additional information subsequently was requested from the Secretary of Defense by Congressman R. Walter Riehlman. This information appears as Appendix 18, p. 551.)

(Whereupon, at 12:05 p.m., the subcommittee recessed, to reconvene at 10 a.m., Friday, August 4, 1961.)