method for controlling radiation levels from no 16 in the steam of boiling water reactors.

摘要

PURPOSE: To reduce the amount of radioactive16 N that is discharged to a part with a low shielding degree of a reactor system by suppressing the migration of a gas-shaped nitrogen compound from a liquid phase to a steam phase. CONSTITUTION: Volatile16 N compound mainly migrates to a steam phase at two regions in a reactor container. One of them is a reactor core region including an inchannel region where nearly all boiling occurs and the other is a region at the upper part of the reactor core where water and steam from a bypass region are mixed and the lower part of a gas separation region. For reducing the16 N in the steam phase, the ratio of volatile16 N compound to be generated is decreased or the migration of the volatile16 N compound into the steam phase is suppressed or the arrival of the volatile16 N compound in the steam phase at a turbine is delayed. For example, for reducing the ratio of the volatile16 N to be generated, a reaction path reaching the generation of the volatile16 N compound is changed by adding a chemical substance (especially a liberation group capturing agent), thus reducing the amount of radioactive16 N to be discharged to a part with a low degree of shielding.