[en] A novel system for energy production is presented. This system has a modular composition of homogeneous reactors with H₂O and ^242mAm as a fuel. These reactors are spheres of 0.11-m radius and 1-MW(thermal) power and with a critical mass of 0.0201 kg of ^242mAm. The advantages of homogeneous reactors are constant fuel reprocessing and constant refueling. As a result, there is a reduction of fission products, which improves the ratio of natural cooling to heat production with respect to a loss-of-control accident (LOCA) and other safety aspects. Homogeneous reactors also have a large negative temperature coefficient and small inherent excess reactivity during operation. The reactor concept the authors have presented for a very small, homogeneous reactor, further enhances the safety aspects in the case of a LOCA, because of a large surface-to-volume ratio. The improved safety, the simplicity, and the small volume should compensate for the use of an unconventional nuclear fuel

[en] The SWAN optimization code was recently developed to identify the maximum value of k_eff for a given mass of fissile material when in combination with other specified materials. The optimization process is iterative; in each iteration SWAN varies the zone-dependent concentration of the system constituents. This change is guided by the equal volume replacement effectiveness functions (EVREF) that SWAN generates using first-order perturbation theory. Previously, SWAN did not have provisions to account for the effect of the composition changes on neutron cross-section resonance self-shielding; it used the cross sections corresponding to the initial system composition. In support of the US Department of Energy Nuclear Criticality Safety Program, the authors recently removed the limitation on resonance self-shielding by coupling SWAN with the SCALE code package. The purpose of this paper is to briefly describe the resulting SWAN-SCALE code and to illustrate the effect that neutron cross-section self-shielding could have on the maximum k_eff and on the corresponding system composition

[en] The goal of radiation therapy is to deliver a lethal dose to the tumor, while minimizing the dose to normal tissues and vital organs. To carry out this task, it is critical to calculate correctly the 3-D dose delivered. Monte Carlo transport methods (especially the Adjoint Monte Carlo have the potential to provide more accurate predictions of the 3-D dose the currently used methods. IG0 is a Monte Carlo code derived from the general Monte Carlo Program - MCNP, tailored specifically for calculating the effects of radiation therapy. This paper describes the IG0 transport code, the PIG0 interface and some preliminary results

No abstract available

[en] A preliminary design for a nuclear engine is presented. The engine is based on the nuclear heating of a gas composed of H₂ and ^242mAm as a nuclear fuel. This engine has an initial volume of 0.135 m³ and at 64 MPa the critical mass is 0.228 kg. The simplicity ^242mAm of the engine design might compensate for the use of rare nuclear fuel, such as ^242mAm

No abstract available

[en] Short communication

[en] The upper bound estimation method is applied for estimating perturbations in reactor theory calculations. The results of this method are numerically compared with the regular first-order perturbation theory. It is concluded from the comparison that first-order perturbation in the integral formalism gives the best estimate for the changes in eigenvalues. For those cases in which first-order perturbation yields low estimates, it is possible to obtain lower and upper bounds by applying both methods. A discussion of the possibility of obtaining a rough estimation to a perturbation without knowing the unperturbed regular and adjoint fluxes is presented and demonstrated with a numerical example

No abstract available

[en] The best sources of neutrons for neutron capture therapy (NCT) are nuclear reactors. To consider installing nuclear reactors in hospitals, such reactors must be cheap and inherently safe. To meet these requirements, the power of the reactor should be low. To obtain low reactor power and high flux, the critical mass should be small.A preliminary design for a 10-kW homogeneous reactor with a critical mass of 19.22 g ^242mAm is presented. The obtained results of this reactor are compared with the NCT requirements. Although the presented design could potentially be a cheap reactor, there is uncertainty regarding the cost of the ^242mAm fuel