Behaviour of fission products under severe PWR accident conditions VERCORS experimental programme—Part 1: General description of the programme

Research Program for the Evaluation of Fission Product and Actinide Release Behaviour, Focusing on their Chemical Forms

“…The single-effect tests for the evaluation of FP and actinide release behaviour are ORNL HI/VI [24], HEVA/VERCORS [25][26][27] and VEGA [28][29][30] tests. Those tests for the evaluation of FP and actinide transport behaviour were also reviewed; such as FALCON [31], STORM [32], and WIND [33] tests.…”

“…Te and Sb were first absorbed in zircaloy cladding, then they were released through cladding oxidation [24]. In another representative test series, the HEVA/VERCORS tests, the fuel specimens were re-irradiated in research reactors in order to investigate the release behaviour of short-lived FPs such as 131 I, 133 I, 132 Te, 99 Mo, 140 Ba and 140 La that were not accurately investigated in the ORNL HI/VI tests [25][26][27]. The HEVA/VERCORS tests gave the following results.…”

“…In the FP and actinide release tests including the VERDON program in SARNET, the release kinetics of FPs and actinides have usually been evaluated based on the results of on-line monitoring of released gamma-emitting isotopes such as 137 Cs by gamma-ray spectrometry [24][25][26][27][28]. The release amount was estimated from the total deposited FPs and actinides in thermal gradient tubes (TGTs) and filters in the experimental device that was determined by a combination of alpha-spectrometry, beta-spectrometry and chemical analysis.…”

Fission Product Release and Transport

“…Figure 5.5 (drawn from the VERCORS 5 test [9], [10]) illustrates these four categories: l volatile FPs (represented by 137 Cs); l semivolatile FPs (represented by 140 The first category includes uranium and neptunium whose releases can reach 10% before the fuel melts.…”

“…Six major analytical programs have been performed since the 1970s: SASCHA in Germany [12]; HI/VI in the United States [13]; CRL in Canada [14]; HEVA/ VERCORS in France [10], [15], [16], [17]; VEGA in Japan [18]; and QUENCH-VVER [19] in Russia.…”