Thermal-hydraulic analyses
Mexico
The NPP Laguna Verde is the only nuclear power generation plant in Mexico. It consists of two BWR-5 (Boiling Water Reactor) units. The plant is owned by the Comisión Federal de Electricidad (CFE), which has requested IDOM to perform the thermo-hydraulic analysis of the Primary and Secondary Containment of the plant with the code GOTHIC 8.2(QA). The objective of this analysis is to respond to NRC Order EA-13-109, evaluating the habitability of the different rooms inside the reactor building after a series of severe accident scenarios proposed by the CFE.
In the first instance, the Primary Containment model has been developed and verified against customer-supplied results obtained from a MAAP model approved by the competent nuclear authority, i.e., the Comisión Nacional de Seguridad Nuclear y Salvaguardias. Secondly, a 3D model of the Secondary Containment has been developed taking as input general civil drawings of the building.
Finally, both models were coupled and simulations of the habitability of the building after severe accident scenarios were carried out. The scenarios studied consider as the initiating event an ELAP (Extended Loss of AC Power), accompanied by the loss of the diesel generators and a leak in the seals of the recirculation pumps.
The coupled GOTHIC model has allowed to evaluate the environmental conditions in different rooms of the reactor building where operators must take certain actions to mitigate the effects of the accident, for example, to make the relevant connections of the FLEX (Flexible Coping Strategies) system.
