Accelerated radiation damage test facility using a 5 MV tandem ion accelerator

We have developed a new irradiation facility that allows to perform accelerated damage tests of nuclear reactor materials at temperatures up to 400�C using the intense proton (<100 μA) and heavy ion (≈10 μA) beams produced by a 5 MV tandem ion accelerator. The dedicated beam line for radiation damage studies comprises: (1) beam diagnosis and focusing optical components, (2) a scanning and slit system that allows uniform irradiation of a sample area of 0.5-6 cm 2 , and (3) a sample stage designed to be able to monitor in-situ the sample temperature, current deposited on the sample, and the gamma spectrum of potential radio-active nuclides produced during the sample irradiation. The beam line capabilities have been tested by irradiating a 20Cr-25Ni-Nb stabilised stainless steel with a 3 MeV proton beam to a dose level of 3 dpa. The irradiation temperature was 356�C, with a maximum range in temperature values of �6�C within the first 24 h of continuous irradiation. The sample stage is connected to ground through an electrometer to measure accurately the charge deposited on the sample. The charge can be integrated in hardware during irradiation, and this methodology removes uncertainties due to fluctuations in beam current. The measured gamma spectrum allowed the identification of the main radioactive nuclides produced during the proton bombardment from the lifetimes and gamma emissions. This dedicated radiation damage beam line is hosted by the Dalton Cumbrian Facility of the University of Manchester

Effects of Water Radiolysis in Water Cooled Reactors, NERI Proposal No.99-0010

OAK B188 Effects of Water Radiolysis in Water Cooled Reactors, NERI Proposal No.99-0010. The aim of this project is to develop an experiment-and-theory based model for the radiolysis of nonstandard aqueous systems like those that will be encountered in the Advance Light Water reactor. Three aspects of the radiation chemistry of aqueous systems at elevated temperatures are considered in the project: the radiation-induced reaction within the primary track and with additives, the homogeneous production of H{sub 2}O{sub 2} at high radiation doses, and the heterogeneous reaction of the radiation-induced species escaping the track. The goals outlined for Phase 1 of the program were: the compilation of information on the radiation chemistry of water at elevated temperatures, the simulation of existing experimental data on the escape yields of e{sub aq}{sup -}, OH, H{sub 2} and H{sub 2}O{sub 2} in {gamma} radiolysis at elevated temperatures, the measurement of low LET and high LET production of H{sub 2}O{sub 2} at room temperature, the compilation of information on the radiation chemistry of water-(metal) oxide interfaces, and the synthesis and characterization the heterogeneous water-oxide systems of interest

A Novel Approach to Material Development for Advanced Reactor Systems

OAK B188 A Novel Approach to Material Development for Advanced Reactor System

Effects of Water Radiolysis in Water Cooled Reactors, NERI Proposal No.99-0010. Technical progress report

OAK B188 Effects of Water Radiolysis in Water Cooled Reactors, NERI Proposal No.99-0010. Technical progress repor

Effects of Water Radiolysis in Water Cooled Reactors. Technical progress report

OAK B188 Effects of Water Radiolysis in Water Cooled Reactors. Technical progress repor

High energy radiation femtochemistry of water molecules: early electron-radical pairs processes

International audienceThe damages triggered by ionizing radiation on chemical and biological targets depend on the survival probability of radicals produced in clusters of ionization-excitation events. In this paper, we report on femtolysis (FEMTOsecond radioLYSIS) of pure liquid water using an innovative laser produced high-energy, ultra-short electron bunches in the 2.5-15 MeV range and high energy radiation femtochemistry (HERF) measurements. The short-time monitoring of a primary reducing radical, hydrated electron e¯¯aq, has been performed in confined ionization spaces (nascent spurs). The calculated yield of hydrated electrons at early time,G(e⁻aq)ET , is estimated to be 6.5 ± 0.5 (number/100 eV) at t ~ 5 ps after the ultrafast energy deposition. This estimated value is high compare to (i) the available data of previous works that used scavenging techniques; (ii) the predictions of stochastic water radiolysis modelling for which the initial behaviour of hydrated electron is investigated in the framework of a classical diffusion regime of independent pairs. The HERF developments give new insights into the early ubiquitous radical escape probability in nascent aqueous spurs and emphasize the importance of short-lived solvent bridged electron-radical complexes [H3O+...e⁻aq..OH]nH2O (non-independent pairs). A complete understanding of the G(e⁻aq)ET value needs to account for quantum aspects of 1s-like trapped electron ground state and neoformed prototropic radicals that govern ultra-fast recombination processes within these non-independent pair configurations. Femtolysis data emphasize that within a time-dependent non-diffusion regime, spatio-temporal correlations between hydrated electron and nearest neighbours OH radical or hydrated proton (H3O+) would assist ultrafast anisotropic 1D recombination within solvent bridged electron-radical complexes. The emerging HERF domain would provide guidance for understanding of ultrashort-lived sub-structure of tracks and stimulate future semi-quantum simulations on prethermal radical reactions