Real-time change detection monitoring using isotopic ratio signatures

A processing module configured to monitor a mass ratio of a first radioisotope relative to a second radioisotope, the first radioisotope and the second radioisotope being present in an irradiated salt mass within a decay enclosure having an input stream and an output stream, the input stream including an inflow of irradiated salts, the output stream including periodic batch removals characterized by a discard fraction and a discard interval, the discard fraction being a fraction of the irradiated salts removed from the decay enclosure at a conclusion of each decay interval, the processing module including instructions in a machine readable memory that, when executed, cause the processing module to perform the following method steps:

• determine a ratio signal corresponding to a mass ratio of the first radioisotope relative to the second radioisotope, the first radioisotope having a half-life that is greater than an effective half-life of the irradiated salt mass within the decay enclosure, the second radioisotope having a half-life that is less than the effective half-life of the irradiated salt mass within the decay enclosure, wherein the effective half-life is a function of the discard fraction and the discard interval;
• compare the ratio signal to a target range of signal values;
• and
• in response to the ratio signal failing to meet the target range of signal values, causing a transmission of a notification, the notification indicating an unaccounted removal of the irradiated salts from the decay enclosure.