UPTF-TRAM experiments for SBLOCA: Evaluation of condensation processes in TRAM tests A6 and A7

Sonneburg, H.G.; Tuunanen, Jari; Palazov, V. V.

doi:10.2172/107003

Cited by 1 publication

(1 citation statement)

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“…These temperatures are needed as input in the FM calculations. An alternative approximate approach to consider the local effect of cooling plumes is realized using the code GRS-MIX [2]. This code is based on an empirical model that allows the calculation of local heat transfer coefficients (HTC) and temperatures based on antecedent RELAP5 calculations to provide the boundary conditions for the computation of stresses.…”

Section: Introductionmentioning

confidence: 99%

Analysis of a reactor pressure vessel subjected to pressurized thermal shocks

Niffenegger¹,

Qian²,

González-Albuixech³

et al. 2016

Int. J. CMEM

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The integrity of reactor pressure vessels (RPVs) of nuclear power plants is one of the most important topics in the field of nuclear energy production. Therefore, the integrity of RPVs has to be assessed for normal operation as well as for emergency transients. A critical transient concerning the RPV integrity is the emergency cooling of a pressurized water reactor, initiated by a leak in the hot leg. Such shock-like cooling in combination with the pressure, the so-called pressurized thermal shock (PTS), causes high thermal stresses in the RPV wall and stress intensities of pre-existing cracks which could exceed the remaining fracture toughness of the material, which is additionally embrittled due to neutron irradiation. This may result in a cleavage fracture of the most safety relevant reactor component.We present a PTS study of a reference reactor, starting with the calculation of the thermal-hydraulic system behaviour, followed by the simulation of the cold water temperature injection and mixing by means of computational fluid dynamics (CFD) method and the subsequent structural and fracture mechanics calculation. In the safety assessment, we compare the evolution of the stress intensity factors (SIF) during an emergency cooling transient with the fracture toughness at the tip of postulated cracks. Results and open questions will be discussed in the light of a realistic estimation of safety margins.

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Section: Introductionmentioning

confidence: 99%