Ratio between the radiation dose and the absorbed dose

The article indicates the difference between the concepts radiation dose and absorbed dose specific formulas are given for calculating an absorbed dose from the results of absolute measurements of a radiation dose, and the conditions of electron equilibrium during dosimetric measurements of x-rays and -radiations of various energies within the 200 kev — 32 Mev range are stated.     

Nuclear fusion from crack-generated particle acceleration

Summary In summary, the high-voltages necessary to accelerate deuterons to energies sufficient to produce modest numbers (10⁴–10⁵/sec) of d-d neutrons appears to be possible as a result of cracking or fracture of the metal lattice in the cold fusion experiments.This mechanism requires neither massive electrons nor exotic nuclear reactions to explain the apparent cold fusion d-d neutron production results. Instead, it is possible that high voltage electrostatic fields, known to be associated with cracking, can reside across a crack gap long enough for the deuterons to be accelerated to sufficiently high energy to produce the d-d reactions. Interestingly, the electrostatic acceleration is quite similar to that of laboratory accelerators except for its submicron scale. Clearly, much work is still required to determine whether such a crack-generated acceleration mechanism, a quasi-particle mechanism, some combination of these, or some other, as yet unidentified mechanism is responsible for the nuclear effects seen in cold fusion experiments.Presented at the Workshop on Cold Fusion Phenomena, Sante Fe, New Mexico, May 23–25, 1989.     

Plane-turns superconducting magnets: Option for fusion

A new concept for large size, complex geometry high field superconducting (SC) magnets has been proposed. According to the approach, a coil is comprised of plane helical turns with insulating layers between them. In this paper, the term superconducting plane-turns helical magnet or helicoid is often substituted by plane-turns magnet or plane-turns coil in order to avoid possible interpretation as the well-known fusion magnetic confinement scheme helical devices. The following advantages of these magnets over traditional ones are outlined for fusion applications: high bending stiffness, optimal current distribution, favorable high current design, and the possible utilization of brittle materials such as ceramics (HTc superconductors, insulators of high radiation tolerance). Some limitations resulting from hysteresis losses restrict the range of application by stationary mode magnetic systems. It is shown that these limitations aren't so severe for toroidal coils and that poloidal fields slightly affect operating characteristics, thus the design seems to be attractable for tokamaks. Brief theoretical and experimental foundation as well as some consideration on conceptual plane-turns SC coil for fusion are presented.     

The “18 Year” Alternative: A Business Proposal to Develop Commercial Fusion Energy by 2021—The Fusion Power Corporation

This policy essay asserts that the 35 year plan recently adopted by the U.S. Department of Energy's Fusion Energy Sciences Advisory Committee is too risk averse and too costly. An alternative 18 year schedule is proposed. All dollar amounts shown below are undiscounted, and are only intended to be indicative of approximate future costs.     

Thermodynamics of the extraction equilibria for uranyl nitrate

The fundamental thermodynamic principles of the extraction equilibria for uranyl nitrate are examined. The equilibrium characteristics are associated with considerable nonideality of the aqueous phase — a strong electrolyte, and the organic phase -a practically undissociated nonelectrolyte.It is shown that, at ionic strengths of up to 10, ion association in the aqueous phase does not significantly influence the distribution of uranyl nitrate. It is noted that in most instances the solutions of uranyl nitrate in the organic phase are close to regular solutions, and therefore there is no need to postulate solvation in the organic phase for interpretation of the equilibria. The effect of a salting out agent on the activity coefficient at constant concentrationx of the latter is examined. It is shown that the relationship between _{(x, m)} and the concentration of the salting out agentm is determined by the ratio of the Harned coefficient for the salting out agent to a quantity _e, characteristic for uranyl nitrate: log _{(x, m)}/_{(x, o)} = 2(_U— _s)J_s, where _(x,o) is the activity coefficient of uranyl nutrate in the absence of a salting out agent, and J_s is the ionic strength of the salting out agent. If _s < _U, then addition of salting out agent raises , and conversely; when _s = = _U (ammonium nitrate), is practically independent of the concentration of salting out agent. The value of _s decreases and the salting out agent becomes more effective with increasing number of molecules hydrating the cation. Equivalents of the salting out agents differ from chemical equivalents by activity coefficient corrections, and they can be only approximately constant.The variation of the distribution coefficient with the degree of dilution or saturation of tributyl phosphate in extraction by mixed solvents, and the conditions of mutual displacement of the substances being extracted from the organic phase are examined. The role of nonideality of tributyl phosphate — dilutent solutions in the extraction of uranyl nitrate is demonstrated.The parameters which determine the distribution of uranyl nitrate when different solvents and salting out agents are used are the distribution constantk, the nonideality constant of the solvent , and _s. The most important parameter is the distribution constantk, which varies several 1000-fold for different solvents. It is shown that the distribution curves have three characteristic regions, the extents of which depend on the value ofk and the nonideality constant of the solvent .     

Some comments on energy and particle confinement in advanced fuel EBT reactors

Results of a point model calculation for advanced fuel (cat. D and D³He) EBT reactors are used to determine some of the limitations on the ratio of ion particle to energy confinement time. The greater fraction of charged fusion products produced in the advanced fuel reactions and the greater fraction of their energy radiated cause the effect of on ash buildup to be a factor of 4 greater for the advanced fuels than that of DT fuel. Hence it is found that<5 for steady state ignited advanced fuel EBT reactors, whereas 22 is the restriction for DT fueled EBT reactors. A survey of for neoclassical bumpy torus ions reveals that in the plateau regime,<5 appears possible but is critically dependent on the nature of the electric field.     

The reversed-field-pinch (RFP) fusion neutron source: A conceptual design

The conceptual design of an ohmically heated, reversed-field pinch (RFP) operating at 5-MW/m² steady-state DT fusion neutron wall loading and 124-MW total fusion power is presented. These results are useful in projecting the development of a cost effective, low-input-power (206 MW) source of DT neutrons for large-volume (10 m³), high-fluence (3.4 MW yr/m²) fusion nuclear materials and technology testing.Work supported by U.S. DOE.     

Study of the zirconium apex op the Zr-Ta-Nb phase diagram

Metallographical examination thermal analysis and electrical resistance measurements have been applied to a study of the zirconium apex, up to 82% zirconium and a temperature of 1200C, of the ternary system Zr-Ta-Nb, with limited solubility of tantalum and niobium in -zirconium ( phase), limited solubility and complete solubility of niobium in -zirconium, with eutectoid decomposition of the \ solid solution and three-phase eutectoid equilibrium + between - and-zirconium. In the investigated portion of the Zr-Ta-Nb phase diagram, the following phase regions were found: a) two one-phase regions and ; b) three two-phase regions + , + and + : c) one three-phase region + + ; the region contracts as the temperature falls below 1200 C.The solubility of tantalum and niobium in -zirconium in the system Zr—Ta—Nb is about 0.5%. On passing from Zr—Ta to Zr—Nb, the + and + regions are displaced toward lower temperature and high niobium concentrations; the boundaries of the + and + + regions are lowered from 790 for Zr—Ta to 612 C for Zr-Nb. Passing between the + and + regions is a binary eutectoid line which, from Zr-Ta to Zr-Nb is displaced toward lower temperatures and higher niobium concentrations. The solubility of niobium in ot zirconium in the Zr-Nb system is about 0.5%by weight. Eutectoid decomposition in the Zr-Ta system shifts the maximum of the martensitic-like transformation to the left and results in an increase in the stability of the phase at room temperature in quenched alloys.     

Investigation of the Effect of Radiation and High-Temperature Treatment on the x-Ray Luminescence of Quartz Glasses

The x-ray luminescence of KI, KV, and KU-1 quartz glasses, irradiated with and n– radiation in the dose range 10²–10⁷ Gy and neutron fluence range 10¹⁵–10¹⁷ cm^–2 and subjected to high-temperature annealing in air at 450 and 900°C is investigated. It is shown that the spectra of the nonirradiated and the and n– irradiated glasses of the first two types are a superposition of bands with _max = 410 and 460 nm, which are due to an impurity center initially present in the glasses (_max = 410 nm) and the initial and radiation-generated with dose 10⁶ Gy and fluence 10¹⁶ cm^–2 E' centers (_max = 460 nm). X-Ray luminescence is not observed in nonirradiated KU-1 glasses; a band with _max = 460–470 nm, due to radiation-generated E' centers, appears in the spectra of and n– irradiated glasses. As the radiation dose and the neutron fluence increase, the number of impurity centers decreases and the number of E' centers increases. It is established that the 410 nm band is due to the component of the n– radiation. High-temperature annealing in air at 900°C induces in the spectra new bands with _max = 470 and 520–540 nm, which are believed to be due to interstitial defects of the type O^– and O₂ ^–, formed when oxygen from air diffuses into the glass and localizes in interstices. 6 figures, 7 references.     

Some characteristics ofγ-ray scattering at the boundary of two media

The characteristics of -ray scattering (0.33 E 1,25 MeV) at the boundary between two media were experimentally investigated. It was established that the scattered radiation was produced mainly by a narrow beam of primary radiation. The effective scattering area was contained within a region with a radius r 10h (for h z). The contribution to the total energy from radiation scattered by the medium increased for angles of incidence of the primary narrow beam up to 85–88 °, and then decreased monotonically.An estimate was made of the effective dimensions of the area from which scattered quanta were emitted into the backward half-space when an isotropie source was located at the surface of the scatterer.The energy flux of the scattered radiation was measured with a gas counter which had a practically constant sensitivity for -rays of different energies.The authors are deeply grateful to Prof. O. I. Leipunskii and to A. S. Strelkov for assistance and for discussions of the results.     

Fusion Power: Looking to the Future

Presentations that were made at a Fusion Power Associates symposium, Fusion Power: Looking to the Future, are summarized. The topics included overview and personal perspectives, status of ITER, stellarators, inertial confinement and innovative concepts. Also included is a summary of work on laser fusion at Osaka University.     

3D Wave Propagation and an Ultra–Low-Frequency Instability in Magnetopause

A model set of equations for the low-frequency electromagnetic perturbations in a magnetized nonuniform plasma is presented. A more convenient and systematic procedure is suggested to treat the fluid equations in order to deduce electrostatic and electromagnetic limits. A general dispersion relation is derived for the waves propagating in 3D under local approximation in nonuniform plasmas, which includes almost all the known modes of cold ion magnetized plasmas in the limit < _i (where _i is the ion cyclotron frequency). Both the limits 1 and O(1) have been discussed briefly. The shear Alfvén waves and electromagnetic ion acoustic waves near ultra low frequency (ULF) range are found unstable in the high plasma of magnetopause. The results are in complete agreement with the satellite observations.     

Paramagnetic effect under the influence of high-frequency pressure and electron paramagnetic resonance in plasma

The interaction of uhf fields ( = 2· 10¹⁰ sec^–1) in a space resonator containing dense plasma (n 10¹³ – 10¹⁴ cm^–3) in a steady magnetic field was studied experimentally. Under the influence ofhf pressure a paramagnetic current arises in the plasma; the associated effect of an increase in the static magnetic field inside the plasma agrees closely with the calculated relation.For _H/ = 0.5 paramagnetic resonance of the electrons takes place; this leads to a sharp rise in plasma pressure p₀, up to =8p₀/H₀ ²0.2.Translated from Atomnaya Énergiya, Vol. 20, No. 5, pp. 401–407, May, 1966.     

Resonance scattering of γ-rays in Mg24

Resonance scattering of -rays With energies E₁=1.38 Mev, corresponding to the transition to the ground state in Mg²⁴. have been observed in metallic magnesium. The energy given off by the -ray (E₁=1.38 Mev) in emission and collision with the nucleus, is compensated for by the energy obtained due to recoil associated with the emission of the preceding -ray with an energy E₂ = 2.76 Mev. Using a fast coincidence method and amplitude discrimination, coincidences were recorded between the -rays with energies E₁=1.38 Mev and E₂=2.76 Mev. Scattercrs of magnesium and aluminum were alternately placed in the path of the 1.38 Mev -rays. The source was radioactive Na²⁴ in a water solution of NaOH. At an angle of 120 ° between the -rays a strong attenuatlon of the 1.38 Mev -rays was observed; this is attributed to resonance scattering. When the angle between the -rays was varied by 5 °. the strong attenuation of the flux disappeared. The width of the level at 1.38 Mev in Mg²⁴ has been estimated at > 1.6· in^–4 Mev.     

The Oxygen to Carbon Ratio in the Solar Interior: Information from Nuclear Reaction Cross-Sections

Mass separation in the Sun may explain a serious difficulty that has plagued nuclear astrophysics for decades: Why the oxygen to carbon ratio in the Suns photosphere is only two, O/C 2. After correcting for mass fractionation, the ratio of these helium-burning products in the Sun is much larger, O/C 9–10. The lower value, O/C 9, is probably more reliable. It is based on measurements of mass separation of stable noble gas isotopes in the solar wind over the mass range of 3–136 amu. The higher value, O/C 10, is based on a comparison of neutron-capture cross-sections and the abundances of s-products in the photosphere over the mass range of 25–207 amu. Both methods indicate that Fe, Ni, O, Si, and S are the most abundant elements in the Sun. These elements are produced in the deep interior of supernovae.     

Safety and Environmental Activities for ITER

This paper will summarize highlights of the safety approach and discuss the ITER EDA safety activities. The ITER safety approach is driven by three major objectives: (1) Enhancement or improvement of fusion's intrinsic safety characteristics to the maximum extent feasible, which includes a minimization of the dependence on dedicated safety systems; (2) Selection of conservative design parameters and development of a robust design to accommodate uncertainties in plasma physics as well as the lack of operational experience and data; and (3) Integration of engineered mitigation systems to enhance the safety assurance against potentially hazardous inventories in the device by deploying well-established nuclear safety approaches and methodologies tailored as appropriate for ITER.     

Analysis of the composition of a mixture of249Bk+249Cf on the basis of x rays

Conclusion The results of the study enable us to conclude the following: the decay of²⁴⁹Bk is accompanied by an L series of x rays from the daughter product Cf. The yield of this radiation is low: (L+L+ L) 10^–4 ( disintegration)^–1, but because of the high specific activity of²⁴⁹Bk, 1 g of this isotope emits 3.7·10⁵ x-ray quanta per minute. This enables us to detect a fairly small amount of Bk (0.01 g) on the basis of x rays in a period of 5–10 min. The rapid accumulation of the daughter product²⁴⁹Cf does not interfere with the determination of the²⁴⁹Bk on the basis of x rays. Even when the mixture contains equal numbers of Bk and Cf nuclei, the ratio of the L lines corresponding to them is 0.46. Therefore the composition of a mixture of²⁴⁹Bk+²⁴⁹Cf can be determined on the basis of x rays over broad ranges of variation of the relative concentrations of Bk+Cf, roughly from 0.03 to 80. It is important to note that for relative measurements it is not necessary to prepare special specimens, since x rays with energies of 15–20 keV are not strongly absorbed in the solution and in the walls of the chemical vessel.Translated from Atomnaya Énergiya, Vol. 48, No. 2, pp. 106–108, February, 1980.     

Alternating-gradient focusing in linear accelerators

A linear theory for alternating-gradient (strong) focusing in linear ion accelerators is presented.Presented at the All-Union Conference on the Physics of High Energy Particles, May 18, 1956.     

Substantiation of the Choice of Threshold Parameters for the System Monitoring the Fuel-Containing Materials in the Object “Cover”

A substantiation is given for the choice of threshold values of the neutron flux density (threshold-1 – Attention and threshold-2 – Danger), and formulas are derived for calculating these values for systems which are being designed and are currently in operation for monitoring the state of fuel-containing materials in the object Cover at the Chernobyl nuclear power plant.     

Ion beam propagation and focusing

Inertial confinement fusion with ion beams requires the efficient delivery of high energy (1 MJ), high power (100 TW) ion beams to a small fusion target. The propagation and focusing of such beams is the subject of this paper. Fundamental constraints on ion beam propagation and focusing are discussed, and ion beam propagation modes are categorized. For light ion fusion (LIF), large currents (2–33 MA) of moderate energy (3–50 MeV) ions of low atomic number (1A12) must be directed to a target of radius 1 cm. The development of pulsed power ion diodes for LIF is discussed, and the necessity for virtually complete charge neutralization during transport and focusing is emphasized. Fornear-term LIF experiments, the goal is to produce pellet ignition without the standoff needed for the ultimate reactor application. Ion diodes for use on Sandia National Laboratories Particle Beam Fusion Accelerators PBFA-I (2–4 MV, 1 MJ, 30 TW, operational) and PBFA-II (2–16 MV, 3.5 MJ, 100 TW, scheduled for operation in 1985) are discussed. Ion beam transport from these diodes to the pellet is examined in reference to the power brightness . While values of =2–5 TW/cm²/sr have been achieved to date, a value of 100 TW/cm²/sr is needed for breakeven. Research is now directed toward increasing , and means already exist (e.g., scaling to higher voltages, enhanced ion diode current densities, and bunching), which indicate that the required goal should be attainable. Forfar-term LIF applications, the goal is to produce net energy gain with standoff suitable for a reactor. This may be achieved by ion beam transport in preformed, current-carrying plasma channels. Channel transport research is discussed, including experiments with wire-initiated, wall-initiated, and laser-initiated discharge channels, all of which have demonstrated transport with high efficiency (50–100%). Alternate approaches to LIF are also discussed, including comoving electron beam schemes and a neutralized beam scheme. For heavy ion fusion (HIF), moderate currents (10 kA) of high energy (10 GeV) ions of high atomic number (A200) must be directed to a target of radius 0.3 cm. Conventional accelerator drivers for HIF are noted. For a baseline HIF reactor system, the optimum transport mode for low charge state beams is ballistic transport in near vacuum (10^–4–10^–3 Torr lithium), although a host of other possibilities exists. Development of transport modes suitable for higher charge state HIF beams may ultimately result in more economical HIF accelerator schemes. Alternate approaches to HIF are also discussed which involve collective effects accelerators. The status of the various ion beam transport and focusing modes for LIF and HIF are summarized, and the directions of future research are indicated.