In the PUREX process some zirconium, technetium, and other elements are extracted by the tributyl phosphate. Due to the radiation induced degradation of tributyl phosphate the first cycle organic phase is always contaminated with ruthenium (later extracted by dibutyl hydrogen phosphate). Because the very short-lived radioisotopes and the relatively long-lived caesium isotopes are either absent or in low concentrations the shape of the dose rate vs. time graph is different from Chernobyl both for short times and long times after the accident.
In the PUREX process, certain zirconium, technetium, and other elements are extracted using tributyl phosphate. Due to radiation-induced degradation of tributyl phosphate, the first cycle organic phase is consistently contaminated with ruthenium (later removed by dibutyl hydrogen phosphate). The absence or low concentrations of short-lived radioisotopes and long-lived caesium isotopes result in a distinct dose rate vs. time graph compared to Chernobyl for both short and long times after the accident.