The NBSR continued its leadership as one of the best utilized research reactors in the country with 25 simultaneously operable facilities surpassing that of any other major facility. Operated round-the-clock by the smallest staff of any comparable reactor, it again produced an outstanding operating record. It supports many extensive and diverse programs carried out by more than 150 scientists and engineers from within and outside NBS. These programs range from the development of standard reference materials, neutron standards and dosimetry, trace analysis of foods and artifacts, the development of energy resources, and the use of neutron radiography as an NDE tool for the determination of the structure and properties of technologically important materials. In all, 18 NBS Divisions and offices, 27 federal agencies, industrial and national laboratories, and more than 24 universities depend on the NBS reactor for vital programs.

The upgrade of the reactor power to 20 MW is progressing. The higher power will greatly enhance reactor utilization and versatility. Arrangements for the long-term supply of nuclear fuel have been completed through use of Department of Energy facilities and contractors, and delivery should commence by December, 1979.

All aspects of reactor operations continued to be excellent. Once again, outstanding on-line performance, reactor utilization and fuel efficiency were achieved until the forced shut down. A summary of overall statistics is presented in the following table for the period July 1, 1978June 30, 1979.

Again tens of thousands of samples were irradiated involving many important and diverse programs. These include trace analysis of foods, drugs, and environmental samples, forensic investigation, development of energy resources and minerals, and the analysis of archaeological treasures and moon rock samples. In addition, over half of the standard reference materials issued by the Bureau have been characterized using the reactor. The work in these areas at the NBSR surpasses that of any other research reactor in the U.S.

Many important new programs have been initiated. They include: the establishment of a national Environmental Sample Bank which will provide real-time monitoring data for pollutant trend evaluation as well as allow for more precise measurements in the future; the development of state-of-the-art measurement techniques and standards for nuclear material safeguards; image enhancement of underdeveloped photographic film; and finally the analysis of waste materials being fed to animals for their toxic effect on the food chain.

ACTIVATION ANALYSIS PROGRAM OF THE

FOOD AND DRUG ADMINISTRATION AT THE NBSR

J. T. Tanner and W. B. Stroube, Jr.
(Food and Drug Administration, Washington, DC)

The activation analysis unit of the Food and Drug Administration (FDA) is located at the National Bureau of Standards in the Reactor Building. Neutron activation analysis (NAA) has been used by the FDA for trace metal analysis of foods, drugs, hair, laundry aids, and cosmetics. The service of this group is available to anyone within the FDA both in the headquarters laboratory and in the field. The following projects are representative of the work of the NAA unit.

In support of FDA field operations, impurities from a boxcar load of oats were analyzed. Apparently the load of oats was introduced into the boxcar before it had been cleaned thereby resulting in contamination. The samples were analyzed by three different analytical methods; neutron activation analysis, electron excited x-ray fluorescent, and fluoride diffusion with detection by ion selective electrode. Results by neutron activation are given below.

The suspected contaminent was Na2SiF6.
Na2SiF6. Activation analysis was

used to determine the elemental composition of the samples and to determine the amount of each element present. Silicon was not detected by NAA.

Pure Na SiF should have an elemental composition of 24.5% Na, 60.6% F 2 6 and 14.9% Si. The percentage composition obtained by NAA for the Na2SiF6 standard sample is in excellent agreement with the calculated composition. Samples 79-193-304 and 79-193-451 appear to have the same major elemental composition as the Na2SiF6 (including a trace of aluminum). The results in the table are averages of several samples and the low value for 79-193-304 reflects one subsample which had an unusually low F content.

Sample 79-164-001 contained Ca and C1 (determined by XRF). It did not contain Na, F, or Si. Although the identity of this sample is not known, it is definitely not Na2SiF6.

The results were combined with the other analytical results and conveyed to the Field Laboratory. They in turn were able to contribute the cause of numerous cattle deaths and low milk production to the feeding of oats contaminated with Na2SiF6 to the cattle.

2.

Liver Copper Response of Swine Fed Graded Levels of Copper

The FDA proposed in 1973 to limit supplemental copper for swine diets to 15 ppm. Recognizing the problem in identifying dietary copper sources, it was desirable to establish a dietary tolerance above a level expected to result from feed ingredients plus supplemental copper. The literature suggested this would be approximately 40 to 60 ppm. A doseresponse study was undertaken to establish the dietary copper level which would elevate copper residues in swine liver.

In the first study conducted in this project, one hundred-twenty weanling, crossbred pigs were used in a dose response study to determine the effect of 7.5, 15, 30, 60, 120, and 240 ppm dietary copper on copper and iron stores in selected tissues. Dietary copper levels of 7.5, 15,

30, and 60 ppm had no significant effect on copper and iron content of liver and kidney. However, 120 and 240 ppm dietary copper increased liver copper 5 and 18 fold and decreased liver iron 2 and 3 fold respectively. A fit of liver copper and iron data to linear plateau models gave an inflection point of 60 ppm dietary copper. These data indicate that an elevation of dietary copper above 60 ppm will cause a change in the normal liver copper and iron concentrations. However, additional data points are needed to more accurately determine the inflection point. The objectives of the current study were to (a) determine the maximum level of dietary copper which will not result in markedly increased liver and kidney copper, (b) obtain tissue residue data in feeder pigs withdrawn from supplemental dietary copper at 75 pounds body weight, and (c) establish a data base for some mineral levels in swine tissue.

A total of 108 pigs were used in this study. Feed intakes were measured and diets analyzed periodically for copper content. At sacrifice the liver and left kidney were removed, weighed, homogenized, and sampled for mineral analysis. These tissue samples were analyzed by activation analysis for Cu, Fe, Zn, Mn, Mg, Al, Se, and Co. The results are currently being tabulated.

PHOTOGRAPHIC IMAGE INTENSIFICATION BY

NEUTRON ACTIVATION OF GOLD TONED NEGATIVES

C. D. Bond

(Naval Research Laboratory, Washington, DC)

A gold-toning neutron-activation process has been developed at NRL for the purpose of intensifying or amplifying the contrast in extremely weak images in photographic negatives where the exposure level may be as low as 1.5% of optimum. Such contrast enhancement of photoreconnaissance and intelligence films allows the recovery of image information which may be taken under adverse lighting or obscured in the shadows and which might