Return can be increased on the order of $1000 to $2000 per calendar day at each K Reactor if the goal exposure for natural I & E slugs is reduced from 800 to 700 MWD/T. This gain is predicated on primarily a decrease in rupture losses. The recommended goal is a straight line on a linear graph of exposure in MWD/T versus maximum tube power in kw per tube, passing through the following two points: (850 kw/tube, 900 MWD/T); (1400 kw/tube; 490 MWD/T). In addition, I & E natural uranium charges running below 850 kw, if any, should be discharged not higher than 900 MWD/T. At a maximum tube power of 1300 kw, the recommended goal will give a weighted average exposure of about 700 MWD/T. Power at which a tube operates should be determined as recommended in HW-57937, ``Goal Exposure for Enriched I & E Material at the C and K Reactors.`` These are interim recommendations. We expect to recommend some changes in the goal, for reasons explained below. The recommended goal was calculated on the IBM-650, using an equation for return. The equation included, we believe, proper allowance for all but two factors. Principle affecting factors were included.

A method of predicting the oxidation rates by HNO/sub 3/ in aqueous solutions is indicated by the results of experiments on the ferrous nitroso clock reaction. (auth)

A new method of introducing predetermined quantities of hydrogen into zirconium was developed and evaluated. The procedure is simple, effective, and inherently good in preverting oxygen and nitrogen contamination. Zirconium samples containing four levels of dissolved hydrogenated to 100, 300, 3500, and 7700 ppm hydrogen. Dissolved oxygen was found to decrease hydrogen absorption in both the alpha and beta modifications of zirconium. The effect of hydrogen on density, hardness, and microstructure was determined. X-ray-diffraction measurements were also obtained. (auth)

Two simplified models are discussed in order to gain insight into the problems of a flux-trap reactor. The first model consists of source of fission neutrons, embedded into D/sub 2/O, Be, BeO, or C moderator, or a moderator of zero absorption cross section. The source is assumed not to absorb amy neutrons. This model gives five to eight times the thermal flux obtainable at the center of the fluxtrap reactor. The other model is a flux-trap reactor idealized by neglectimg all absorption in the moderator. This model does not differ markedly from the D/sub 2/Omoderator case. (auth)

None

The rate of annealing due to primary neutron-carbon atom collisions transferring 3 to 25 ev to the recoil atoms is much too slow to accouat for irradiation annealing rates observed in pile annealing experiments. It is necessary to assume that much of the annealing is accomplished by the slowing down of carbon atoms produced by high energy neutrons. The fraction of primary recoil energy going into arealing reactions is estimated to be about four per cent. Irradiation annealing occurs before vibrational equilibrium is established with the lattice and should not be considered as equivalent to additional thermal arealing. Irradiation damage to the properties of graphite should saturate when the irradiation damage rate equals the irradiation and thermal annealing rates. The effects of irradiation annealing on the damage distribution function are discussed. (auth)

The criteria established for thermal design of APPR pressurized water reactors are given. These include heat transfer coefficient, power distribution utillzation, hot channel factors, lattice requirements, and instrumentation tolerances. Calculations are shown for hot channel factors, lattice requirement determination, and heat release distribution. (T.R.H.)

The theory of neutron scattering by magnetic crystals as given by Halpern and Johnson predicts changes in the polarization state of the neutron beam upon scattering which depend upon the relative orientation of the neutron polarization vector and the crystal magnetic axis. This was investigated experimentally with a polarized beam spectrometer using single crystals of Cr{sub 2}O{sub 3} and alpha - Fe{sub 2}O{sub 3} in which reside netic axes. Studies were made on several different reflections in both crystals for a number of different temperatures both below and above the Neel point. Results support the theoretical predictions and indicate directions for the moments in these crystals consistent with previous work. A more detailed study of the polarization changes in the (111) reflection in alpha - Fe{sub 2}O{sub 3} at room temperature on application of a magnetic field was carried out, The results indicate that the principal source of the parasitic ferromagnetism in hematite is essentially independent of the orientation of the antiferromagnetic domains within the crystal.

Somewhere in the future lies the possibility that the existing HAPO reactors will no longer be required for the production of weapons grade plutonium. This could come about either through advances in technology or through changes in the requirements for this particular fissionable isotope as a weapons material. In any event, should these reactors no longer be utilized for plutonium production, it would be appropriate to consider the possibility of their conversion to other uses, notably that of electrical power production. Accordingly, this study has been made with the objective of investigating the economic and technological feasibility of such conversion. However, it must be recognized that the results presented herein are based on present day technology and economic philosophy and that within the next five years we may experience considerable renovation of these criteria which could alter the conclusions of the study appreciably. The primary benefit to be gained from this preliminary study is to narrow the area of future and more detailed investigation as much as possible so that if and when such a conversion appears likely, a significant fraction of the almost infinite number of combinations of reactor and power plant parameters may be rejected at the outset.

Experience in replacement of highly radioactive components of Homogeneous Reactor Experiment No. 2 is discussed, with particular emphasis on containment of air-bonne contamination and control of personnel exposure. The design and operation of tools and viewing devices developed to observe the hole in the HRE-2 core tank are described. (auth)

Theoretical formulas are presented for prediction of the flow velocity at which collapse occurs in long parallelplate assemblies Beyond the critical velocity the pressure-unbalance forces developed as a consequence of a small deflection exceed the corresponding elastic restraining forces, and the plates collapse. Both flat- and curvedplate assemblies are considered, and the applicability of the formulas to design of reactor fuel-plate assemblies is discussed. (auth)

A program is given for the establishment of flow requirements of a tailored flow core. It is capable of handling either one- or two-pass cores, with flow direction optional in each pass, and a reflector coolant flow in parallel with elther pass. The various configurations which may be investigated are illustrated. Although the program is specifically intended for APPRtype elements, flows may be established for any set of dimensions snd pressure and temperature conditions and corresponding to any desired maximum allowable surface temperature. It hes expected that, due to pressure drop considerations, for two- pass flow all control rods will be in the same pass. Calculated results include flow requirements of each indivldual type of element, as well as total internal flow, lattice flow, and finally the total required flow for each pass. Calculation of the maximum ratio of operating to burnout heat flux and maximum internal temperature is optional. (auth)

The study of interactions and decay of K mesons continued, using the 10- inch liquid hydrogen bubble chamber and emulsions. Four emulsion stacks were exposed for two internal groups and twenty-three stacks were exposed for seventeen groups from outside the Laboratory. Interactions of pi /sup -/ mesons were observed with a 30-inch propane bubble chamber and with emulsions. Ten emulsion stacks were exposed to neutral-particle beams and one stack to the internal 6.2-Bev proton beam. The 30-inch propane bubble chamber and emulsions were used to study the interactions of antiprotons. Eighteen target bombardments in the internal proton beam were made for the chemistry group. Successful tests were completed of two static-electromagnetic velocity spectrometers for the separation of highenergy particles. One was of coaxial construction, the other of parallel-plate construction. (For preceding period see UCRL-6114.) (auth)