Simulation of the effect of x-rays on the cellular structure of the chamber walls of a nuclear power facility

Abstract

Computational and experimental methods are developed for simulating, by means of an explosion and shock, the wave processes occurring in the walls of the explosion chamber of pulsed nuclear power facilities under intense x-ray irradiation. The experimental measured and computed parameters of shock waves accompanying explosive and shock loading of different materials were in satisfactory agreement with one another. The methods developed are used to investigate the behavior of a liquid heat-protective film of Li 17 Pb 83 on the wall of the explosion chamber when the recoil pulse produced by evaporation is the main load factor. The possibilities of decreasing the explosive loads by changing the thickness of the lead shell of the charge and by including cellular structures and porous materials in the chamber walls are examined.Shock-wave processes in liquid metal coolants and rigid chamber walls of a reactor exposed to x-rays and other damaging factors are being studied in connection with suggestions for developing pulsed nuclear power facilities employing fusion and fission reactions [1][2][3][4]. Methods of experimental and mathematical simulation of these processes in application to facilities with TNT equivalent ranging from 0.2 to 2.5·10 4 tons, differing by a factor of 10 5 , have been developed to determine methods for decreasing dynamic loads, increasing service life, and refining the technical requirements for explosion chambers [2][3][4].The present article presents the results of a simulation, by means of explosion and mechanical shock, of the thermal action of x-rays on the coolant and materials of the walls of the explosion chambers being developed for pulsed nuclear power facilities, including structural heat shielding materials with cellular structure, and examines the possibility of decreasing the loads on the chamber walls and increasing heat removal by metal coolant forced through the cellular structure of the walls by x-rays as well as other reaction products.Nuclear explosions of a frozen D + T mixture with initial density 0.05 g/cm 3 and mass 1.57 mg inside a tube with inner radius 1 mm and consisting of 214 mg 238 U with 0.2 ton TNT equivalent and frequency 2 Hz have been studied in [3]. The mixture is compressed adiabatically by a factor of 30 along the radius of the outer lead shell with mass 5.5 g by a beam of the heavy platinum ions accelerated in an accelerator up to about 100 GeV/nucleus. The characteristic parameters of the x-ray pulse from the explosion are as follows: total energy 40 MJ, average power 40 TW, maximum power 240 TW, temperature 180 eV, duration of peak radiation 15 nsec, and total duration 1 µsec. The specific energy on the walls of an explosion chamber with radius 4 m is 20 J/cm 2 , and the radiation power is 20 MW/cm 2 .