Neutron and β/γ Radiolysis of Water up to Supercritical Conditions. 1. β/γ Yields for H₂, H^• Atom, and Hydrated Electron

Abstract

Yields for H2, H(.) atom, and hydrated electron production in beta/gamma radiolysis of water have been measured from room temperature up to 400 degrees C on a 250 bar isobar, and also as a function of pressure (density) at 380 and 400 degrees C. Radiolysis was carried out using a beam of 2-3 MeV electrons from a van de Graaff accelerator, and detection was by mass spectrometer analysis of gases sparged from the irradiated water. N2O was used as a specific scavenger for hydrated electrons giving N2 as product. Ethanol-d(6) was used to scavenge H(.) atoms, giving HD as a stable product. It is found that the hydrated electron yield decreases and the H(.) atom yield increases dramatically at lower densities in supercritical water, and the overall escape yield increases. The yield of molecular H2 increases with temperature and does not tend toward zero at low density, indicating that it is formed promptly rather than in spur recombination. A minimum in both the radical and H2 yields is observed around 0.4 kg/dm(3) density in supercritical water.

On the Temperature Dependence of the Rate Constant of the Bimolecular Reaction of Two Hydrated Electrons

“…Although H 2 is a molecular product, g(H 2 ) increases monotonically with temperature, particularly above 200°C [8][9][10][11][12][13]. H 2 , whose formation is favored by fast neutron (high-LET recoil-ion) radiolysis [4], is an important component associated with the corrosion environment of the coolant system in NPPs.…”

Environmental controls for higher temperature direct-cycle light water reactors

“…For the HTBWR, the G-values for radiolysis [7] are higher than for the ESBWR due to the higher HTBWR temperature. The higher G-values increase the oxidant concentration in the reactor coolant, which increases the requirement for hydrogen addition for the HTBWR.…”

Dose rate determination of gamma rays emitted by Thallium-201 and technetium-99m using a modified horseradish peroxidase based biosensing system

“…To observe the correlation between current response obtained by HRP-AQ on GC electrode toward standard H 2 (Fig. 4).…”

“…Since the water content of living cells is approximately 70%, the majority of ionization produced by gamma rays, take place through water molecules interactions. This process is called water radiolysis [2,3]. Radiolysis of cellular water will produce reactive oxygen derivatives such as the hydroxyl radical (OH • ) that may interact with cellular component and *Corresponding author.…”