This document provides a description of a model of the r_dionuclide behavior in the reactor coolant system (RCS) of a light water reacbor during a severe accident. This document serves _s the user's manual for the computer code called VICTORIA, based upon the model. The VICTORIA code predicts fission product release from the fuel, chemical reactions 5et.ween fission products and structural materials, vapor _nd aerosol behavior, and fission product decay heating. This document provides a detailed description of each part of the implementation of t5_ model into VICTORIA, the numerical algorithms used, and the correlations and thermochemical data necessary for determining a solution. A description of the code structure, input and output, and a sample problem are provided. The VICTORIA code was developed upon a CRAY-EMP at Sandia National Laboratories in tb_ U.S.A. and a CRAY-2 and various SUN workstations at the Winfrith Technology Centre in England.

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The primary and secondary photochemistry of NOBr and NOCl has been monitored by detecting infrared fluorescence from vibrationally excited NO following pulsed photolysis of the parent compound with a tunable laser. For wavelengths greater than 480 nm the primary photolysis of NOX to NO+X produces little if any vibrational excitation in the NO product. However, secondary photochemistry produces excited NO through the reaction X+NOX→X2+NO(v). From the dependence of the rise time of NO fluorescence on the pressure of NOBr or NOCl at a constant pressure of added argon, it is found that the rate constants for the Br+NOBr and Cl+NOCl reactions are (5.16±0.28) ×10−12 and (5.40±0.47) ×10−12 cm3 molecule−1 sec−1, respectively. The reaction of Br with NOBr produces more NO in v=3 and/or v=2 than in v=1. At 355 nm roughly half of the NO vibrational fluorescence is due to the primary dissociation NOX→X+NO(v).

Time-resolved infrared fluorescence from I* (*=2P1/2) and vibrationally excited water has been observed following pulsed laser dissociation of I2 at 500 nm. The time dependence of the fluorescence signals has been used to determine the rates for the total quenching of I* by H2O, HDO, and D2O as well as for the vibrational self-relaxation of two modes of H2O and D2O. H2O and HDO are roughly 50 times more efficient in quenching I* than D2O. Analysis of relative fluorescence amplitudes shows that the quenching of I* by H2O and HDO is due entirely to an electronic-to-vibrational mechanism which produces two quanta of stretching vibration in the water molecule. The E→V mechanism is also likely to be the dominant mechanism for quenching of I* by D2O.

Deactivation of I* (2P1/2) by HCl, HBr, and NO is directly observed to produce vibrationally excited states of the diatoms. The total deactivation rates are determined from either the decay of I* fluorescence or the rise of diatom fluorescence to be kEHCl= (4.46±0.77) ×102, kEHBr= (3.51±0.12) ×103, and kENO= (3.88±0.32) ×103 sec−1 torr−1. By comparing the intensity of I* fluorescence to that of the diatom it is found that the average number of vibrational quanta excited per deactivation of I* is 1.7±0.5, 2.3±0.5, and 3.4±0.7 for HCl, HBr, and NO, respectively. These findings are discussed in terms of recent models for E→V transfer.