1,721,004 research outputs found
Nuclear Technology Master: a New Tool for Supervising and Transfer Knowledge of Nuclear Technology
No full textScaling analysis in BEPU licensing of LWR
No full textScaling plays an important role for safety analyses in the licensing of water cooled nuclear power reactors. Accident analyses, a sub set of safety analyses, is mostly based on nuclear reactor system thermal hydraulics, and therefore based on an adequate experimental data base, and in recent licensing applications, on best estimate computer code calculations. In the field of nuclear reactor technology, only a small set of the needed experiments can be executed at a nuclear power plant; the major part of experiments, either because of economics or because of safety concerns, has to be executed at reduced scale facilities.
How to address the scaling issue has been the subject of numerous investigations in the past few decades (a lot of work has been performed in the 80thies and 90thies of the last century), and is still the focus of many scientific studies. The present paper proposes a “roadmap” to scaling. Key elements are the “scaling-pyramid”, related “scaling bridges” and a logical path across scaling achievements (which constitute the “scaling puzzle”). The objective is addressing the scaling issue when demonstrating the applicability of the system codes, the “key-to-scaling”, in the licensing process of a nuclear power plant. The proposed “road map to scaling” aims at solving the “scaling puzzle”, by introducing a unified approach to the proble
Relevance of Thermo-Fluid Dynamics for Establishing the Safety of Nuclear Power Plants
No full textAccident Management, and related terms ‘procedures’ and ‘strategies’ (instead of Management), constitutes
a branch of the nuclear reactor safety. The understanding of the meaning and of the objectives of the AM
branch requires the knowledge of the safety/licensing concepts like Design Basis Accident (DBA), Beyond
DBA (BDBA), and Severe Accident (SA), as well as Probabilistic Safety Assessment (PSA) and role of
Human Factors (HF) within nuclear reactor safety. Based on this terminology, the AM branch occupies a
virtual region before or upstream the SA area and aims at forming an additional boundary to the progression
of accidents that eventually escaped the DBA boundary. This is done consistently with findings and
requirements of the PSA branch, taking into account of the HF and of the available NPP components and
systems and of their actual status.
The purpose of this paper is to summarize the main findings from the execution of a wide range analysis
focused to AM in VVER-1000 (within a European Commission funded Project) with main regard to the
qualification of computational tools and the proposal for a optimal AM strategy for this kind of NPP
Investigation of a possible emergency procedure for the VVER 440/213 NPP in case of a Total Loss of Feedwater
No full textRelap5 analysis of an EOP based on mobile pumps, at a generic VVER-1000 NPP in case of a total loss of the primary heat sink (for DBDA conditions)
No full textThe loss of the primary heat sink is one of the most relevant BDBA scenarios. If the capability to
remove heat from the primary side cannot be restored, the primary side will be subjected to high pressure
for a long period of time. The actuation of the ECCS will be inhibited, primary side (PS) inventory
will be lost, finally the core will be in dryout conditions. The EOP which is investigated in this paper
proposes to utilise mobile pumps (e.g. using fire brigade trucks) to make additional sources of feedwater
available and thereby restore a heat sink for the primary side at least for a limited period of time. After
a certain time (which should be determined by calculations) of this measure, the PORV-valve and/or the
gas-removal system should be opened to lower the pressure in the primary side and actuate the ECCS
(primary side bleed and feed mode). The calculations indicate that this procedure is capable of saving
the plant, or at least extending the grace period. Three cases are presented: the effect of only primary
side feed and bleed, the benefitial effect of utilising mobile pumps first, and a scenario which assumes
no operator action
The BEPU (Best Estimate Plus Uncertainty) Challenge in Current Licensing of Nuclear Reactors
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