Predicted Water Chemistry in the Primary Coolant Circuit of a Supercritical Water Reactor

Generation of Ultrafast Transient Acid Spikes in High-Temperature Water Irradiated With Low Linear Energy Transfer Radiation

“…where the mean energy loss in a single energy deposition event (i.e., the mean energy deposited in a spur) in liquid water is taken to be ∼47 eV [63,[73][74][75] and 18) represents the change with time of r o due to the (3-D) diffusive expansion of the spur. Here, t is time and D is the diffusion coefficient of H 3 O + in water.…”

“…While the radiation-induced chemistry (radiolytic yields or G values and reaction rates) in water at elevated temperatures (say, up to 350°C) is relatively well documented [9][10][11], there are only very limited experimental data available on supercritical water radiolysis [12][13][14][15]. Direct measurements at elevated temperatures and pressures are difficult, especially beyond the thermodynamic critical point of water (t c = 373.95°C and P c = 22.06 MPa); thus, theoretical modeling and computer simulations are an important route of investigation [3,6,[16][17][18][19][20].…”

A Critical Review of Radiolysis Issues in Water-Cooled Fission and Fusion Reactors: Part I, Assessment of Radiolysis Models

“…The nuclear fission power reactor community only slowly accepted the ECP as the prime parameter in determining the accumulation of corrosion damage, possibly because electrochemistry is seldom, if ever, included in the Mechanical and Nuclear Engineering curricula at universities that form the basis of a nuclear engineering degree. The impact that ECP has on CGR is roughly exponential if the ECP is above a critical potential for IGSCC (E IGSCC ) [106,208,[218][219][220][221][222][223][224][225][226][227][228][229][230][231][232][233][234][235][236][237]250,257,[260][261][262][263][264][281][282][283][284][285][286][287][288][289], although the rate also depends upon the stress intensity factor, the extent of cold-working of the substrate, the conductivity of the environment, and the flow velocity of the coolant across the surface. Below this critical potential, the CGR is determined by mechanical creep that does not pose a threat to reactor integrity.…”

“…Accordingly, their participation in determining the ECP is readily incorporated by redefining the concentrations of H 2 , O 2 , and H 2 O 2 , as noted above. The most extensive work on modeling the coolant chemistry of fission reactors, at least in terms of the numbers of operating reactors modeled, appears to be that reported by Macdonald et al in the USA [216][217][218][219][220][221][222][223][224][225][226][227][228][229][230][231][232][233][234], Ibe and Ishigure in Japan [74,206,208,271], and by Yeh and co-workers in Taiwan [281][282][283][284][285][286][287][288][289], with the former dealing with fourteen operating BWRs and PWRs worldwide and the latter having modeled several BWRs, including Advanced BWRs, and a proposed Super Critical Water Reactor (SCWR) [288]. These models are now undergoing major refurbishment by inclusion of advanced submodels for calculating the ECP and damage due to stress corrosion cracking.…”

“…Emphasis was initially placed on BWRs because of the rash of cracking incidents that have occurred historically in those systems. The radiolysis model (Table 5) and the set of G-values (Table 9) employed in [216][217][218][219][220][221][222][223][224][225][226][227][228][229][230][231][232][233][234][281][282][283][284][285][286][287][288][289] are essentially those found in [44], with the latter being updated from the work of Elliot [60]. In applying these models and data to modeling operating BWRs, the decomposition of hydrogen peroxide [Table 5, Reaction (30)] was employed as the calibrating reaction.…”