Total Fission Power Plus 120% Decay Heat Transient for 29 MK Scram

摘要

The N Reactor is a graphite-moderated pressurized water thermal reactor. There are 1003 53-foot long by 2.713-inch ID Zircaloy-2 pressure tubes. The fuel consists of 34.8-foot long columns of Zircaloy clad enriched uranium metal fuel segments. Each segment is approximately 2-feet long and is made up of two concentric cylindrical elements. The fuel is cooled by water forced through the pressure tube contacting the fuel element on both the outer and inner cylindrical surfaces. Reactivity within the reactor is controlled by retracting or inserting boron-carbide control rods which pass through the reactor from both sides and are perpendicular to the pressure tubes. To increase reactivity (power) the control rods are extracted from the reactor and to decrease power they are inserted. Predetermined trip points have been programmed into the reactor control system such that when any of the limiting parameters exceed operating limits the control rod safety system is tripped and the rods are automatically inserted fully into the reactor resulting in a reactor scram. The purpose of the report is to describe the decay heat scram transient for N Reactor that was used in NUSAR accident analyses. (ERA citation 04:036499)