Comparative Study of the Park and Astral Post-Accident Decision Support Software

Abstract

The French radioecological assessment model ASTRAL and the German model PARK have been developed to evaluate the radiological situation in the case of an accidental release of radionuclides and a widespread contamination of the environment. For decision makers it is of importance that the results on foodstuff contamination and on dose to humans are in fairly good agreement, when areas of the common border are affected. Therefore a comparative study has been done for two scenarios, assuming accidental releases on 1 June and 1 October. The study indicates that the models' structures and the transfer parameters are in good agreement. Only model principles for root vegetables are different in both models. Significant differences in results on the contamination of foodstuff and on dose to humans by ingestion are caused by different assumptions on dates of harvest and feeding methods of animals. A corresponding harmonization is essential with respect to decision making.

Transfer of 131I from Fukushima to the Vegetation and Milk in France

“…The root transfer is insignificant here; therefore, we only take into account the foliar transfer. From the comparison of air and vegetation data (see previous section), it appears that dry deposition was significant for iodine, and thus the contamination of grass and leaves of vegetables was computed as dry deposition of iodine, following eqs and respectively, derived from ASTRAL model , C g r a s s ( d ) = R c Y × ∑ 0 d D false( d false) × exp nobreak.25em − [ false( normalλ w b + normalλ r false) × Δ t ] C v e g ( d ) = ∑ 0 d D false( d false) × F t × exp nobreak.25em − [ false( normalλ w b + normalλ r false) × Δ t ] where C grass ( d ) or C veg ( d ) is the grass or vegetable measured concentration due to the deposit of the considered day d (Bq kg –1 fresh weight); D ( d ) is the deposited iodine on day d (Bq m –2 ); Y and R c are the yield (kg fresh weight m –2 ) of grass and the retention ratio for deposit on grass, respectively. R c / Y ratio varies linearly between 1.4 (March) to 0.56 m 2 kg –1 fresh weight (May); the value Y used in ASTRAL (0.7 kg fresh weight m –2 ) is quite close to the yield given by field: 1.65, 0.48, and 1.18 kg fresh weight m –2 in Cadarache, Tricastin, and Agen, respectively; Ft is the dry foliar transfer factor of iodine for ...…”

“…The root transfer is insignificant here; therefore, we only take into account the foliar transfer. From the comparison of air and vegetation data (see previous section), it appears that dry deposition was significant for iodine, and thus the contamination of grass and leaves of vegetables was computed as dry deposition of iodine, following eqs 2 and 3 respectively, derived from ASTRAL model 12,13 C grass ðdÞ ¼ Rc Y Other parameters apart from deposition velocity were considered as default values in the equations. Indeed default parameters of ASTRAL fit well with values given by the IAEA EMRAS working group which aim to validate the 131 I ecological transfer models: the yield of grass ranging between 0.1 and 0.6 (kg fresh weight m À2 ) and the R c /Y ratio ranging between 0.5 to 1.65.…”

Towards a shared method to classify contaminated territories in the case of an accidental nuclear event: the PRIME project

“…Performance of the PRIME project steps has required federation of available radio-ecological data (field data, modelling, experimental results), as well as territory data and then the processing of these with the common approach defined by the project. The assessment method of the radiological sensitivity indicators invoked classic impact calculation models for radionuclides used at the IRSN: CASTEAUR code for river discharges (Duchesne et al [4]), ASTRAL code for forest ecosystem and food chain contamination following accidental radioactive pollution (Renaud et al [5], Calmon and Mourlon [6]), integrating the spatial variability of parameters.…”