Towards an enhanced accident management of the hydrogen/co combustion risk
Combustible gases are one of the few elements that can really challenge the containment integrity. An appropriate management of the associated risk is paramount to avoid the potential release of large amounts of radioactive material to the environment. Surprisingly, the Severe Accident Management Guidelines (SAMGs) have not been updated according to the knowledge gained in the last decade and the database extension resulting from recent and ongoing projects. The AMHYCO project intends to respond to practical questions, such as the right timing and mode for actuation of containment safety systems (i.e., FCVS, sprays, fan coolers) to reduce as much as feasible the threat posed to containment integrity. To do so, all the available tools to enhance the present status (i.e., LP, 3D and CFD codes, together with experimentation and the best use of engineering judgement) are to be applied. Three specific objectives are set:
•            To improve the Severe Accident Management Guidelines (SAMGs) for both in-vessel and ex-vessel phases with respect to combustible gases risk management, using both numerical and experimental results.
•       To investigate experimentally phenomena that are difficult to predict numerically: H2/CO/H2O distribution and combustion and PARs behavior under realistic accidental conditions, taking into account the safety systems interaction.
•        To improve the predictability of the numerical tools - Lumped Parameter (LP), 3D containment and Computational Fluid Dynamic (CFD) codes - used for explosion hazard evaluation inside the reactor containment to gain relevance in supporting SAMGs design and development.
The scope of this project is outlined by the most common reactor technology in the EU: PWRs. The whole project is structured in 7 WPs (coordination included) in which an entire WP is to be devoted to the enhancement of SAMGs. Finally, AMHYCO has received the NUGENIA label and 9 organizations have shown their interest with support letters .