4 Early work at Columbia and Chicago was aimed at a low-temperature version of such a reactor for plutonium production only; however, present-day considerations are limited to high-temperature systems.

5 In more recent tests [43] with nonboiling solutions, in which oxygen concentrations were held at 2 to 3 ppm, no reduction and precipitation of uranium occurred.

6 By P. R. Kasten, Oak Ridge National Laboratory.

7 The thermal value for η23 was assumed to be equal to 2.30 instead of 2.25 used in more recent calculations (the 2.25 value is believed to be more accurate).

8 Conversations with utility people indicate there is no accident on record in which the high-pressure steam line failed instantly.

9 By H. F. McDuffie, Oak Ridge National Laboratory.

10 Taken from material prepared by C. H. Secoy for the revised AEC Reactor Handbook.

11 Taken from material prepared by C. J. Hochanadel for The Reactor Handbook.

12 Knallgas is the term describing the 2:1 mixture of hydrogen and oxygen obtained electrolytically and considered as a single gas.

13 By J. P. McBride and D. G. Thomas with contributions from N. A. Krohn, N. Lyon, and L. E. Morse, Oak Ridge National Laborator

14 By R. N. Lyon.

15 Information taken from reports by J. O. Blomeke (Ref. 10) and A. S. Kitzes and R. N. Lyon (Ref. 11).

16 By J. P. McBride.

17 A radioactivation method for sedimentation particle-size analysis of ThO2 was developed at ORNL [39]. The oxide was activated by neutron irradiation, dispersed at < 0.5 w/0 concentration in a 0.001 to 0.005 M Na4P2O7 solution and allowed to settle past a scintillation counter connected to a count-rate meter and a recorder. The scintillation activity, being proportional to thoria concentration, was analyzed in the usual manner, using Stokes' law, to give the size distribution data. Independently, an analogous method for use with U02 powders was developed at Argonne National Laboratory [40].

18 The x-ray crystallite (as opposed to the actual oxide particle, which may be composed of a great many crystallites in an ordered or disordered pattern) is defined as the smallest subdivision of the solid which scatters x-rays coherently. The crystallite size can, in principle, be determined from the width of the x-ray diffraction peak, the width being greater the smaller the average crystallite size [41].

19 It is common practice to present the particle-size distribution in the form of a plot of the logarithm of the particle size versus the cumulative weight percent undersize on a scale based on the probability integral. If the particle-size data follow a logarithmic probability distribution (as they usually do reasonably well for most ThO2 preparations), the resulting plot is a straight line and the steeper the slope of the line, the less uniform the material. The 50% size in such a plot is the geometric mean particle diameter (dg). The geometric standard deviation (σg) is equal to the ratio of the 84.13% size to the 50% size (also 50% size: 15.87% size) [44], For thorium oxide prepared from oxalate precipitated at 100C, σg was 1.2 to 1.4; σg increased with increasing precipitation temperature.

20 While most of the pumped slurries have been slow settling, composed of small particles (≤ 1 micron), and have yielded bulky sediments, on occasion the small particles resulting from the attrition of the original slurry particles reagglomerated to form large spheres 10 to 50 microns in size. This resulted in a slurry which settled rapidly to a dense but easily resuspended bed. Sphere formation appeared to be the property of specific oxide preparations and was observed most often with 800°C-fired material. Preparing the oxide in a particle size which does not degrade on pumping (~1 micron) and firing at 1600°C to improve particle stability appears in the initial pumping studies to have largely removed the problem.

21 This diameter should have no effect on slurry hindered-settling rate certainly up to 400 g Th/kg H2O concentration and possibly even higher.

22 By D. G. Thomas.

23 The resuspension velocity corresponds to the velocity at which a moving bed disappears as the mean stream velocity is increased

24 By D. G. Thomas.

25 By N. A. Krohn and J. P. McBride.

26 By L. E. Morse and J. P. McBride.

27 Molecules of water decomposed per 100 ev of energy dissipation in the slurry.

28 The homogeneous catalysis of the hydrogen and oxygen reaction in the case of solutions is first order with respect to the hydrogen partial pressure (see Article 3-3.4).

29 Estimated steady-state concentration of fission-product oxides to be produced in the thorium oxide by irradiation at a flux of 5 x 1013 neutrons/(cm2)(sec) and continuous blanket processing on a 250-<1ay cycle [155].

30 Written by N. A. Krohn.

31 By E. G. Bohlmann, with contributions from G. M. Adamson, E. L. Compere, J. C. Griess, G. H. Jenks, H. C. Savage, J. C. Wilson, Oak Ridge National Laboratory.

32 By H. C. Savage.

33 By J. C. Griess.

34 Experience indicates such occurrences are minimized by maintaining at least 600 ppm oxygen in solution. Careful attention to elimination of crevices in the system design is essential.

35 By G. H. Jenks.

36 Specimens exposed in the circulating lines before and after the core experienced similar attack rates.

37 By G. H. Jenks.

38 50% H2O, 45% concentrated HNO3, and 5% HF (48%).

39 By J. C. Griess and G. H. Jenks.

40 By E. L. Compere.

41 By G. M. Adamson.

42 (1) Double arc melting, (2) forging to a billet, starting at 850°C, (3) cross rolling 50% to plate, starting at 850°C, (4) straight rolling to finished plate, starting at 770°C, (5) press in one or more steps to the desired shape, at 40Q-650°C, (6) heat to 650°C, cool slowly in die, (7) weld subsections, and (8) repeat (6).

43 (1) Vacuum arc melt, (2) forge at 970-1050°C, (3) roll at 500-785°C, (4) heat to 1000°C and water quench or fast air cool, (5) roll 25% at 480-540°C, and (6) anneal at 760-790°C and water quench.

44 This article by J. C. Wilson.

45 By E. G. Bohlmann.

46 By R. A. McNees, with contributions from W. E. Browning, W. D. Burch, R. E. Leuze, W. T. McDuffee, and S. Peterson, Oak Ridge National Laboratory.

47 Contribution from T. D. Burch

48 Contribution from W. E. Browning.

49 Contribution from S. Peterson.

50 Contribution from R. E. Leuze.

51 Contribution from W. T. McDuffee.

52 Contribution from R. E. Leuze.

53 Prepared by J. A. Lane, with contributions from S. E. Beall, S. I. Kaplan, Oak Ridge National Laboratory, and D. B. Hall, Los Alamos Scientific Laboratory.

54 Prepared from reports published by Los Alamos Scientific Laboratory and other sources as noted.

55 Based on a paper by C. E. Winters and S. E. Beall [10].

56 One curie equals 3.7 x 1010 disintegrations per second.

57 Based on information supplied by S. E. Beall and S. 1. Kaplan and reports by members of the Oak Ridge National Laboratory as noted.

58 Article 7-4.7 is based on a paper by I. Spiewak and H. L. Falkenberry [22].

59 Article 7-4.8 is based on a paper by D. S. Toomb [23].

60 Other remotely operable tools are described in Sec. 19.5.6 of the Reactor Handbook, Vol. II, Section D, Chapter 19, ORNL-CF-57-12-49.

61 Based on material prepared by members of the Los Alamos Scientific Laboratories.

62 Detailed description of the nuclear data obtained during the test is set forth in "Control Rod Worths vs. Temperature in LAPRE-I" by B. M. Carmichael and M. E. Battat, TID-7532 (Pt. 1), p. 125, U.S.A.E.C., Technical Information Service Extension, Oak Ridge, Tenn

63 By I. Spiewak, with contributions from R. D. Cheverton, C. H. Gabbard, C. Hise, C. G. Lawson, R. C. Robertson and D. S. Toomb, Oak Ridge National Laboratory.

64 Prepared from material submitted by C. H. Gabbard.

65 Based on material submitted by R. D. Cheverton.

66 Based on material prepared by C. G. Lawson.

67 Based on material from R. C. Robertson, ORNL.

68 Based on material prepared by E. C. Hise.

69 Based on material furnished by D. S. Toomb.

70 U.S. Patent 2,610,300 (1952). [Assigned to the U.S. Atomic Energy Commis¬sion by W. W. Walton and R. C. Brewer.]

71 Based on material furnished by R. C. Robertson.

72 Material submitted by E. C. Rise.

73 Material submitted by D. S. Toomb.

74 By C. L. Segaser, with contributions by R. H. Chapman, W. R. Gall, J. A. Lane, and R. C. Robertson, Oak Ridge National Laboratory.

75 Aeronutronic Systems, Inc., a subsidiary of Ford Motor Company.

76 By R. C. Robertson.

77 By R. H. Chapman.

79 The fixed costs in a chemical processing plant are those due to plant investment; variable costs are due to materials, labor, etc.

80 Operating at 280°C; 480 thermal Mw, 125 elec. Mw; 80% load factor; optimum poisons, 5-7%.

81 By H. G. MacPherson.

82 By W. R. Grimes, D. R. Cuneo, F. F. Blankenship, G. W. Keilholtz, H. F. Poppendiek, and M. T. Robinson.

83 Low Intensity Test Reactor, a tank type research reactor located at Oak Ridge, Tennessee.

84 Materials Testing Reactor, a tank type research reactor located at Arco, Idaho.

85 By W. D. Manly, J. W. Allen, W. H. Cook, J. H. DeVan, D. A. Douglas, H. Inouye, D. H. Jansen, P. Patriarca, T. K. Roche, G. M. Slaughter, A. Taboada., and G. M. Tolson.

86 By L. G. Alexander.

87 Universal Automatic Computer at New York University, Institute of Mathematics.

88 Oak Ridge Automatic Computer and Logical Engine at Oak Ridge National Laboratory.

89 By H. W. Savage, W. F. Boudreau, E. J. Breeding, W. G. Cobb, W. B. Mc-Donald, H. J. Metz, and E. Storto.

90 By E. S. Bettis and W. K. Ergen.

91 R, C. Briant et al., Nuclear Science and Engineering, Vol. 2, No.6, 795-853 (1957).

92 By L. G. Alexander, B. W. Kinyon, M. E. Lackey, H. G. MacPherson, L. A. Mann, J. T. Roberts, F. C. VonderLage, G. D. Whitman, and J. Zasler.

93 Contributed by F. T. Miles, Brookhaven National Laboratory.

94 Contributed by J. Chernick, Brookhaven National Laboratory.

95 Based on contributions by D. H. Gurinsky, D. G. Schweitzer, J. R. Weeks, J. S. Bryner, M. B. Brodsky, C. J. Klamut, J. G. Y. Chow, R. A. Meyer, R. Bourdeau, and O. F. Kammerer, Brookhaven National Laboratory.

96 Based on contributions by D. H. Gurinsky, D. G. Schweitzer, J. R. Weeks, J. S. Bryner, M. B. Brodsky, C. J. Klamut, J. G. Y. Chow, R. A. Meyer, R. Bourdeau, O. F. Kammerer, all of Brookhaven National Laboratory; L. Green, United Engineers & Constructors, Inc., Philadelphia, Pa.; and W. P. Eatherly, M. Janes, and R. L. Mansfield, National Carbon Company, Cleveland, Ohio.

97 Kx=1000x units = 1.00202±0.00003A

98 Based on contributions by 0. E. Dwyer, A. M.Eshaya, F.B.Hill, R.H. Wiswall, W. S. Ginell, and J. J. Egan of the Brookhaven National Laboratory.

99 The stability of NaCl and KCl is so much greater than that of MgCl2 that their contribution to the oxidizing potential of the salt may be neglected. However, they do exert an influence upon the activity coefficient of MgCl2.

100 Molten salt which has been equilibrated for many days with molten Bi containing high concentrations of Mg and U. When each phase has reached constant composition and there is no U in the salt, it is ready for use.

101 Based on material by T. V. Sheehan, Brookhaven National Laboratory, Upton, L. I., New York.

102 Based on material by 0. E. Dwyer, Brookhaven National Laboratory.

103 Based on a contribution by C. Raseman, H. Susskind, and C. Waide, Brookhaven National Laboratory.

104 The vendor is Berkeley Pump Co., Berkeley, Cal. The 7½-in.-diameter impeller and the pump casing are made of AISI type-410 steel. The pump is V-belt driven by a 30-hp motor.

105 This chapter is based on studies made by Babcock & Wilcox Company for the USAEC, BAW-1046, March 1958, and on a 17 company report BAW-2, June 30, 1955, for which Brookhaven National Laboratory contributed information and supplementary design studies.

106 American Nuclear Power Associates: Raytheon Manufacturing Co., Waltham, Mass.; Burns and Roe, Inc., New York City; The Griscom-Russell Co., Massillon, Ohio; Clark Bros. Co., Olean, New York; Orange and Rockland Utilities, Inc., Nyack, New York. Reference design by Raytheon Manufacturing Co. This section is based largely on contributions from W. A. Robba, Raytheon Manufacturing Co.

107 This section is based largely on material from Los Alamos Scientific Laboratory, LA2112, R. M. Kiehn