Analysis of the Short Term-Station Blackout Accident at the Peach Bottom Unit-2 Reactor with Astec Including the Estimation of the Radiological Impact with Jrodos

24 Pages Posted: 17 Dec 2022

See all articles by Onur Murat

Onur Murat

affiliation not provided to SSRN

Victor Hugo Sanchez-Espinoza

Karlsruhe Institute of Technology

Fabrizio Gabrielli

Karlsruhe Institute of Technology

Robert Stieglitz

affiliation not provided to SSRN

Cesar Queral

Universidad Politécnica de madrid

Abstract

Driven by the Fukushima accident, the ASTEC code has been extended with new capabilities to describe the BWR-behavior, especially of the core, during severe accidents with core meltdown.  Hence, models for the BWR-typical core components like absorber cross, canister, water rods related to the chemical reactions, material relocation, and radiative heat transfer were added to ASTEC. To evaluate the prediction capability of ASTEC for BWR, a short-term Station Black-out (ST-SBO) severe sequence of the Peach Bottom Unit-2 was selected. The goal is to predict the radiological source term with ASTEC and the subsequent radiological impact using the JRODOS code. For this purpose, the fuel inventory isotope fractions are determined by the ORIGEN-code. It describes the change of the core isotopic composition during the operation. A comparison of selected parameters of the initial in-vessel phase predicted by ASTEC with the ones of MELCOR shows similar results. But the vessel failure times and mass of molten material ejected from the core calculated by ASTEC deviates from the one of MELCOR.  ASTEC predicts late oxidation of core structures leading to an accelerated progression of the accident and to an earlier lower head failure compared to the one calculated by MELCOR for the case of CORBH package. After the containment failure in the drywell head flange, the fraction of the elements released to the environment predicted by ASTEC are similar to the ones of MELCOR. Finally, JRODOS was used to predict the fission product dispersion and radiological impact around the Peach Bottom Unit-2 plant. The results showed that in the worst-case scenario, a total effective gamma dose rate of 7.2 mSv/h exist.

Keywords: BWR, ASTEC, JRODOS, ST-SBO, ORIGEN

Suggested Citation

Murat, Onur and Sanchez-Espinoza, Victor Hugo and Gabrielli, Fabrizio and Stieglitz, Robert and Queral, Cesar, Analysis of the Short Term-Station Blackout Accident at the Peach Bottom Unit-2 Reactor with Astec Including the Estimation of the Radiological Impact with Jrodos. Available at SSRN: https://ssrn.com/abstract=4305365 or http://dx.doi.org/10.2139/ssrn.4305365

Onur Murat (Contact Author)

affiliation not provided to SSRN ( email )

No Address Available

Victor Hugo Sanchez-Espinoza

Karlsruhe Institute of Technology ( email )

Kaiserstraße 12
Karlsruhe, 76131
Germany

Fabrizio Gabrielli

Karlsruhe Institute of Technology ( email )

Kaiserstraße 12
Karlsruhe, 76131
Germany

Robert Stieglitz

affiliation not provided to SSRN ( email )

No Address Available

Cesar Queral

Universidad Politécnica de madrid ( email )

28003 (Fax)

HOME PAGE: http://https://www.researchgate.net/profile/Cesar-Queral

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