Fuel Element Failure:

In During operation of a nuclear reactor facility an equilibrium stage of fission products is created within the reactor coolant.  Those fission products are the output of trace impurities of fuel material holding within the cladding surfaces as either natural impurities or an output of the fuel fabrication procedure. The mechanism through that the fission products enter the coolant is generally through fission recoil.  The Weld porosity is another potential path for the fuel, other than commonly quality control avoids this from occurring.  In During common facility operation, those fission products are minor contributors to the overall radioactivity of the reactor coolant system.

Large amounts of fission products would potentially have a path to the coolant system if a defect was present or a failure of a fuel element occurred. Significant changes would occur within the reactor coolant chemistry parameters if this happened.  Since most facilities analyze for gross coolant radioactivity either periodically or continuously, an analysis would be likely to detect all other than the minutest failures.

While routine gaseous radioactive stages are monitored, raises within this parameter's value would be seen.  This is why several of the fission products are gaseous and those gases are more mobile than particles of exposed fuel (an exposed fuel commonly undergoes a procedures of erosion which washes the fuel within the coolant stream).  Another parameter which might modify is the ion exchange competence (where utilized), since several of the fission products released have a lower affinity for the exchange sites on the resin beads than the replace anion or cation. Accordingly, an ion exchanger would not efficiently erase these fission products and effluent radioactivity stages would increase considerably.  Fission gases would also pass on by the ion exchanger and contribute to effluent activity. Further, since a few of the fission gases have associatively short half-lives, the amount of time they are held up in the ion exchanger is enough for a few of these gases to decay to a radioactive solid.

These solid particles would contribute to effluent samples which might be concentrated prior to analysis. A few facilities monitor for specific fission product inventories within the reactor coolant to gives base level information.  These levels would obviously increase to denotes the failure if a defect or failure were to occur.