Original scientific paper
Potential Impact of Reactor Core Damage on Severe Accident Management Actions in Vicinity of Spent Fuel Pool
Ivica Bašić,
; APOSS d.o.o. Repovec 23B, 49210 Zabok, Croatia
Ivan Vrbanić
; APOSS d.o.o. Repovec 23B, 49210 Zabok, Croatia
Davor Grgić
; Faculty of Electrical Engineering and Computing, University of Zagreb Unska 3, Zagreb, Hrvatska
Mario Mihalina,
; Nuclear Power Plant Krško Vrbina 2, 8670 Krško, Slovenia
Abstract
Fukushima Daiichi NPP accident showed that plant technical support center (TSC) in an
extreme and rare external event (design extended condition (DEC)) can have a problem in the case
of coincident loss of decay heat removal from the core (possibly resulting in significant core
damage) and loss of decay heat removal from spent fuel pool. From the point of view of prioritizing
severe accident management strategies it looks like the priority mitigation action should be to
reestablish the emergency core cooling in the reactor pressure vessel. The reason is the longer time
window available before the water inventory in the spent fuel pool would be evaporated and spent
fuel exposed to overheating. However, if such actions would not be successful and reactor core
would, consequently, be damaged, potential design basis leakage (or even greater leakage) from the
containment to the fuel handling building (FHB) can affect already established TSC measures or
operator accessibility to FHB, or it can jeopardize functioning of the systems, structures and
components due to radioactive releases and presence of hydrogen (independently of the fact that
containment atmosphere can be inerted by steam or that containment may be equipped with passive
autolytic recombiners (PARs)). Paper describes an engineering evaluation of possible hydrogen
presence in the containment annulus, its flammability and leakages through the penetrations toward
FHB in the case of long term station blackout (SBO) without successful restoration of the core
cooling in the reactor pressure vessel. SBO accident sequence progression and amount of produced
hydrogen is evaluated by MAAP code.
Keywords
core damage, SFP, SAMG, containment leakage, MAAP
Hrčak ID:
247103
URI
Publication date:
28.10.2019.
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